Dog Neurological Conditions: How To Recognize And Treat Them?
Neurological diseases in a dog
Neurological diseases in dogs, they are a difficult topic, and their diagnosis and treatment are often a challenge for the veterinarian.
This difficulty in diagnostic and therapeutic management is due to several reasons.
First of all: many different types of neurological diseases can manifest themselves in a very similar way, which at the beginning of an arduous diagnostic journey causes the doctor to face the first obstacles.
Another factor is the difficult contact with the patient: the dog will not say that he is dizzy, that he has problems with his eyesight or hearing.
Any irregularities "caught " are noticed by the doctor during a conversation with the guardian, careful observation of the dog in the office and on the basis of a properly conducted examination.
Often, the animal's guardian delays the visit to the doctor, believing that the sleepiness, dementia or problems with movement of the animal result from the age of the animal.
The inability to accurately describe and define the observed changes by the animal's guardian is also quite a serious barrier.
It is understandable, after all terms such as plegia, paralysis or anisocoria are foreign-sounding terms for most people that they do not know at all.
Neurology has its own rules and uses specific terminology, the knowledge of which is difficult to require even from the most caring and health-conscious keepers of their animals.
Unfortunately, there are diagnostic problems and no answer to the question “What can cause these symptoms?? ”May also result from insufficient information possessed by the doctor.
In fact, it is often not possible to make an appropriate diagnosis (and thus introduce effective treatment) because caregivers often deviate from additional diagnostic tests and further therapy of the animal.
This is due to several factors, e.g. the lack of availability of more advanced diagnostic techniques (e.g. computed tomography or magnetic resonance imaging), high costs of treatment, lack of improvement in the current treatment, careful or poor prognosis, as well as the usual fatigue of the patient and his caregivers.
This article addresses the issues related to neurological disorders in dogs.
As I have already mentioned - this is a very difficult topic in which it is necessary to use some specific terms, and you can find their explanation in the text.
In this study, I will describe the most common symptoms in dogs with neurological diseases, which require a visit to the veterinarian as soon as possible to observe.
I will present how a veterinarian conducts neurological examinations, and I will also explain to more inquisitive readers why each observed symptom, even the slightest twitch of a dog is important not only for recognizing a given lesion, but also for locating the disease process at a specific point in the nervous system.
I will also mention the prognosis for various disorders and the most common neurological diseases in dogs.
I invite you to read.
- Structure and functioning of the dog's nervous system
- Central nervous system
- Peripheral nervous system
- Functional organization of the central nervous system
- Movement system
- Autonomous nervous system
- Causes of dog neurological disorders
- Symptoms of neurological diseases in a dog
- Diagnosis of neurological diseases in dogs
- Description of the animal
- Recognition of the most common symptoms of neurological disorders
- AND. Physical examination
- B. A neurological examination
- C. Traffic evaluation
- D.Study of reflexes
- E. Assessment of cranial nerves
- F. Assessment of feeling
- G. Localization of changes
- H. Differential diagnosis
- Additional research
- Diagnosis - the cause of neurological diseases in the dog
- Classification of neurological diseases
- The most common neurological diseases / conditions in dogs
- Prognosis of neurological diseases
Structure and functioning of the dog's nervous systemStructure and functioning of the dog's nervous system
The nervous system is made up of billions of neurons, or nerve cells.
Each neuron is made up of the cell body and projections through which information is transmitted (dendrites transmitting a stimulus to the cell body, and axon transmitting information from the cell body to other neurons or muscles).
The nervous system as a whole can be divided into:
- central nervous system (CNS or central - CNS)
- peripheral nervous system.
Central nervous system
The central (or central) nervous system consists of the brain and the spinal cord.
These delicate structures are covered by the so-called. meninges:
- a hard tire,
- spider web
- a soft tire.
The space between the arachnoid and the dura mater is called the subarachnoid cavity.
This cavity is filled with cerebrospinal fluid, which is also present in four chambers of the brain and in the middle canal in the spinal cord.
The brain (encephalon) is located in the cavity of the skull. The five main areas of the brain are:
- Cresomrain (telencephalon, brain - cerebrum).
- Interbrain (diencephalon).
- Midbrain (mesencephalon).
- Secondary backbrain (metencephalon).
- Medullary or medulla elongated (myelencephalon s. medulla oblongata).
It is the first and best developed part of the brain.
- lobes of the cerebral hemispheres,
- subcortical basal ganglia,
- olfactory bulbs (cranial nerve I),
- cerebral pedicels,
- the hippocampus.
From a clinical point of view, the changes observed during the clinical trial cannot be reliably located in a specific lobe in the brain.
Lobes of the cerebral cortex:
- Frontal lobe - This lobe includes neurons responsible for voluntary motor functions, especially learned and trained responses.
- Pear-shaped bark - this is the junction of the roads that transmit information about the smell.
- Parietal lobe - it mainly works to consciously feel touch, pressure, temperature and harmful stimuli.
- Temporal lobe - participates in conscious sound perception (hearing) and shares some functions with the parietal lobe.
- Occipital lobe - This lobe contains the vision centers.
The interbrain includes:
The thalamus contains testes that receive sensory information from various areas.
It serves as the main messenger for afferent (sensory) fibers entering the cerebral cortex.
The hypothalamus lies ventrally to the thalamus and has neuroendocrine and autonomic functions.
It connects to the pituitary gland through a funnel.
The midbrain contains neurons for the III (oculomotor) and IV (block) cranial nerves that innervate the extraocular muscles of the eye.
The nasal and caudal thalluses, located in the midbrain cover, are associated with visual and auditory reflexes and the transmission of information to the cerebellum.
The centers for the pupillary light reflexes (parasympathetic-pupillary constriction - parasympathetic motor nucleus of the III nerve) are also located in the dorsal part of the midbrain.
Underneath the cover lies the cap - the beginning of the cephalospinal tract, which is the upper motor neurons for sympathetic innervation.
There are also centers for motor gait control.
The hindbrain consists of:
The bridge contains neurons for the V (trigeminal) nerve, whose axons innervate the masticatory muscles.
It also provides sensory innervation of the face (maxillary and eye areas) and the mandible and is the location of the micturition center.
The reticular formation of the bridge, formed by scattered nerve nuclei interspersed with white matter fibers, affects wakefulness, sleep and consciousness.
The bridge contains motor pathways that run from the brain, the synapses of which are in the cerebellum.
The cerebellum is a place where, among others, regulating centers are located:
- muscle tension,
- coordination of movements,
- maintaining the correct body posture,
- both at rest and in motion and are decisive for the proper cooperation between the muscles.
The extended core has the shape of a truncated cone or club-shaped bead.
This is where most of the cranial nerves begin or end (V to XII).
There are also functional centers important for life, such as the center:
- heart rate,
The spinal cord consists of peripheral white matter composed of nerve pathways and lies within the spinal canal.
These pathways are organized into specific motor (drainage) and sensory (supply) paths.
Gray matter is centrally located and consists of interneurons and motor neurons that innervate the muscles.
Spinal nerves go in and out of the spinal cord between the vertebrae of the spine.
They form the peripheral nervous system that supplies the trunk and limbs.
The following parts are distinguished in the spinal cord:
- jugular (pars cervicalis - C),
- thoracic (pars thoracica - T),
- lumbar (pars lumbalis - L),
- cruciferous (pars sacralis -S)
- caudal (pars caudalis - Cd).
The core and the corresponding nerve roots (i.e. the bundles of nerve fibers leading directly from the spine to the spinal nerve) are divided into the following segments:
- 8 cervical segments, numbered 1-8 (C1-8),
- 13 thoracic segments (T1-13),
- 7 lumbar segments (L1-7),
- 3 cross segments (S1-3),
- 5 or more tail segments (Cd1-5 or>).
Peripheral nervous system
The peripheral nervous system connects the central nervous system with the rest of the body.
It contains the axons of the spinal and cranial nerves as well as their receptors and effector organs (e.g. muscles, glands).
The peripheral fibers can include motor fibers, sensory fibers, or both.
Functional organization of the central nervous system
Functionally, the central nervous system can be classified in many ways.
One of them is the division into:
- movement system (drainage),
- sensory (affecting),
- autonomous systems (both afferent and efferent).
Afferent (i.e., afferent or sensory) nerve fibers transmit impulses from receptors to the central nervous system.
With the help of these nerves, special sensations such as smell, vision, balance, hearing and taste are conducted, as well as somatic sensations of touch, pain, temperature and proprioceptive (body positions).
The sensory nerves of the peripheral nervous system are stimulated either directly or through special receptors.
The stimulus is then transmitted to the body of the neuron (in the ganglia of the peripheral system).
Then, axons coming out of the sensory neuron enter the CNS and join the nuclei in the brainstem or spinal cord (nuclei are groups of nerve cell bodies in the CNS).
Central nervous system sensory neurons leave the testes and enter the brain via organized sensory pathways (these pathways are often named where they begin and end, e.g. spinal-thalamic road).
Efferent nerve fibers (centrifugal or executive) - transmit impulses from the central nervous system to effectors, which are usually muscles and glands.
They are responsible for the movement of all skeletal and smooth muscles.
Motor nerves originate from the nuclei in the brain and the brainstem and pass through structured pathways that are also usually named after where they begin and end (e.g. vestibulospinal route).
Central motor neurons make up the motor paths.
Peripheral motor neurons build peripheral nerves that innervate skeletal and visceral muscles.
The cell body of the motor neuron is usually located in the central nervous system. The body of the nerve cell, its axon, the axon-muscle junction (neuromuscular junction), and the muscle are known as the lower motor neuron unit.
Both afferent and efferent fibers serve the somatic and autonomic nervous system.
The motor system consists of two parts: the upper and lower motor neurons.
Damage to the locomotor system produces clinical symptoms called paresis or paralysis (depending on the severity of the changes).
The upper motor neurons are responsible for initiating any motor functions and modulating the activity of the lower motor neuron units.
They are located in the cerebral cortex and the brainstem and affect both the somatic and the autonomic nervous systems.
Their axons are organized into specific pathways and synapsize on the interneurons (connecting central and peripheral motor neurons) in the gray matter of the spinal cord or directly on the lower motor neurons.
The upper motor neuron system is divided into a pyramidal and an extrapyramidal system.
The pyramidal system allows the animals to make precise movements, but is not essential for the animals to start walking.
Neurons are located in the frontal / parietal lobe of the cerebral cortex, and axons are contained in the cortico-spinal tract.
Axons intersect in the pyramids located in the medulla and descend on the contralateral (opposite) side.
Axons synapse on the lower motor neuron in the spinal cord and the lower motor neurons of the cranial nerves in the brainstem.
The lower motor neurons connect the central nervous system with muscles and glands.
All motor activity of the nervous system is ultimately expressed through the help of lower motor neurons.
DNRs are found in all segments of the spinal cord in the middle and ventral horns of the gray matter and in the nuclei of the cranial nerves (III to VII, IX and XII) in the brainstem.
The axons that emerge from these cells form the spinal and cranial nerves.
The nervous system is segmented. The segment of the spinal cord is defined by a pair of spinal nerves.
A muscle or group of muscles innervated by one spinal nerve is called a myotome.
Myotomas are segmented in the paraspinal muscles but are more irregular in the limbs.
Autonomous nervous system
The autonomic (otherwise vegetative) nervous system, unlike the somatic system, functions beyond the control and consciousness of the animal.
It affects the work of internal organs that are responsible for the processes of metabolism, blood circulation and reproduction.
It primarily affects the system:
The autonomic nervous system is divided into sympathetic and parasympathetic.
It is a multi-neuron system.
Central neurons are found in the hypothalamus, midbrain, pons, and medulla.
The hypothalamus is the primary center that integrates autonomic functions.
Axons traverse the brainstem to influence autonomic lower motor neurons (DNRs) located in the brainstem and spinal cord.
Autonomous DNR innervate the smooth muscles of the blood vessels and visceral structures, glands and the heart muscle.
The sensory fibers of the viscera are contained in the peripheral component.
The inferior motor neurons of the sympathetic nervous system are distributed over segments of the thoracolumbar spinal cord and essentially use spinal nerves to travel to the muscles and skin.
Specific nerves control visceral functions.
The lower motor neurons of the parasympathetic nervous system are located in the brainstem (III, VII, IX, and X cranial nerve) and in the sacrum of the spinal cord.
The vagus nerve is the main motor nerve innervating the muscles of the larynx, esophagus, and the internal organs of the chest and abdomen.
The pelvic nerve innervates the bladder detrusor muscle.
Causes of a dog's neurological disordersCauses of dog neurological disorders
The causes of neurological disorders in dogs can be varied. There is a pattern in neuroscience that helps to identify the category of disease causing neurological disorders and then helps to make the appropriate diagnosis.
We are talking about the so-called. diagram VITAMIN D, and the letters of this acronym identify the first letters of the causes of neurological disorders.
Based on the VITAMIN D regimen, the causes of neurological disorders can be classified into the following groups:
- V (eng. vascular) - vascular diseases, e.g.:
- fibrocartilage embolism,
- spinal cord infarction;
- I (eng. inflammatory, infectious) - inflammatory, infectious diseases, e.g.:
- inflammation of the brain and meninges,
- inflammation of the intervertebral disc and vertebrae;
- T (eng. trauma) - traumatic diseases, e.g.:
- Head damage,
- spine fracture;
- A (eng. anomalies) - birth defects, e.g. hydrocephalus;
- M (eng. metabolic) - metabolic and toxic disorders, e.g.:
- hepatic encephalopathy,
- uremic condition,
- lead poisoning,
- poisoning with carbamates;
- I (eng. idiopathic) - idiopathic diseases, e.g. idiopathic epilepsy;
- N (eng. neoplasia) - neoplastic diseases, e.g. intracranial or spinal cord tumors;
- D (eng. degenerative) - degenerative diseases, e.g. cauda equina syndrome).
As you can see, neurological disorders may result from a disease directly affecting the nervous system (central or peripheral) or may be related to other diseases in which neurological symptoms are also observed.
Symptoms of neurological diseases in a dogSymptoms of neurological diseases in a dog
As your pet's keeper, you are the first to spot signs that something is wrong.
These warning signs include, but are not limited to, the following:
- Neck pain and / or pain in the spine area.
The dog may squeal or whine while stroking the sore area.
Notice if there are other clues that may suggest pain in these areas, such as: reluctance to turn your head, jump, climb stairs, or reluctance to move at all.
You may also notice low tail carry, reduced tail mobility (e.g. the dog avoids wagging its tail), as well as difficulties in adopting an appropriate stance for defecation.
- Balance problems.
This includes lack of motor coordination, tilting the head, tilting to one side, circling or even falling to the side.
- Abnormal eye movements.
You may notice staring into space, getting stuck in a corner, etc.
- Walking in circles, walking aimlessly.
Your pet may look confused or act as if it doesn't recognize you.
- Mobility problems, especially with the hind limbs.
Note stumbling, obvious weakness, lameness, problems getting up or standing, and even paralysis (in extreme cases).
- Phantom scratching.
Scratching air, often near the ear, neck, or shoulder area without touching the body.
- Convulsions, epileptic seizures.
If your pet shows one or more of the above warning signs - even intermittently - or anything else that seems unusual, contact your veterinarian as soon as possible.
Depending on the severity of the symptoms observed, the next steps may include a complete clinical examination and consultation with a veterinary neurologist.
Diagnosis of neurological diseases in dogsDiagnosis of neurological diseases in dogs
For animals with neurological disorders, a methodical approach to the clinical trial is necessary.
A neurological examination is usually described as a very complicated process, completely separate from the physical examination, however, during a routine examination, a clinician may observe some symptoms, the presence of which requires further diagnosis and a full neurological examination.
There are several key elements in the diagnosis of neurological disease, as described below.
Description of the animal
The description of the animal at the very beginning of the diagnostic process is very important as it allows the first list of differential diagnoses to be made.
Due to the presence of certain species, age, racial and even gender-related predispositions, information on species, race, sex and age may help in finding a predilection for various diseases and syndromes.
The prevalence of some diseases varies widely between breeds, and certain conditions are diagnosed at a certain age.
- Genre-related predilections:
- distemper in dogs;
- Age-related predilections:
- young animals: they are more likely to have congenital and hereditary disorders, malformations, storage diseases, as well as infectious diseases,
- older dogs: tumors, degenerative diseases;
- Racial predilection, for example:
- Irish wolfhound: idiopathic epilepsy,
- German Shepherd Dog: Degenerative Myelopathy,
- pug: pug encephalitis,
- dachshunds: prolapse of the intervertebral disc,
- epilepsy in golden retrievers,
- hydrocephalus in chihuahuas;
- Gender-related predilections:
- e.g. prostatitis in males can cause inflammation of the intervertebral disc in the lumbosacral region (due to the proximity of the disease process),
- epilepsy is more common in males than in females.
These criteria are not absolute and you should always be vigilant (e.g. in young dogs, cancers of the nervous system are also possible).
However, in the initial evaluation of the animal, and sometimes even in the final diagnosis, it is important to organize the probabilities.
In an older brachycephalic dog, a tumor in the central nervous system is more likely to cause seizures than a birth defect.
Information obtained during the interview may be of great diagnostic importance.
When reviewing the history of the disease, the veterinarian takes into account the observations of the animal caretaker and the main problem underlying the veterinary consultation.
The medical history is nothing more than a series of questions asked the guardian of the dog to help determine the most likely cause of the main symptom and determine the appropriate treatment.
Examples of questions for the caregiver of the neurological patient may include the following:
- When did the first symptoms appear and what was the course of the disease?
The duration of the disease and the rate of progression of symptoms are important because already at this stage of the diagnostic process they can provide clues as to the suspected nature of the disease. For example:
- sudden onset of symptoms - injuries of the brain and spine, vascular changes;
- very rapid build-up of symptoms - CNS infections;
- slow and progressive development of symptoms - tumors, degenerative changes.
- Whether symptoms are acute or chronic / progressive or non-progressive / permanent or intermittent? Or maybe they appeared shortly after birth?
Based on the history, the disease is identified as acute or chronic, progressive or stabilized, permanent or with periods of remission (recurrent).
The doctor takes into account previous illnesses, vaccination data and the results of previous tests.
- Does the dog feel pain? What kind of character is he (sharp / blunt)? Can I be petted? Whether or not limb or limb paresis is present?
In the case of the presence of hyperesthesia of the spine (hyperesthesia - the animal reacts violently to stroking), its location is determined (e.g. in the cervical, thoracolumbar, lumbosacral and limbs), duration (acute, chronic), progression (progressive, constant - i.e. static), persistence (permanent, intermittent / recurrent) and nature (acute, blunt).
If the patient has pararesis (paresis), it is important to determine whether it is acute or chronic, progressive or stabilized, and permanent or intermittent / recurrent.
The lesion causing the neurological disturbance may be localized inside the spinal canal (e.g. extra-scleral, intraspinal-extra-spinal and intramedullary).
In patients with epidural spinal lesions, sudden onset of persistent, sometimes increasing pain and.
Patients with intra-extrospinal lesions usually have chronic, dull pain with a slowly progressive pararesis.
In the case of intramedullary lesions, pain and pareza may be present; pain - if present - is usually short-lived, while paresis is permanent, but not progressive.
- Is an injury possible?
If the answer is affirmative and the animal is in a critical condition, life-saving procedures are implemented, and only after the patient's condition is stabilized, the examination is possibly continued.
- Has the dog been exposed to drugs or poisons (e.g. antifreeze, pesticides, lead)?
- Is the dog away from home (unattended)?
- Whether the dog recognizes and reacts to the handler?
- Whether your dog has seizures (seizures) or other neurological disorders (e.g. head pushing, circulation, aimless walking, increased or decreased activity)?
- Are there symptoms from other systems (e.g. lack of appetite, increased thirst and urination, bulimia, coughing, sneezing, vomiting, diarrhea, fever?
- vomiting, diarrhea, sub-normal temperature - possibility of poisoning;
- continuous or slowing fever - bacterial infections;
- intermittent and recurrent fever - viral infections;
- pruritus - Aujeszky's disease;
- Whether the dog is currently ill or has been ill before? What is / has been treated? What was the response to treatment?
- What the dog is fed? (monodiet, shortages)
- What environment does the dog live in?? Does he have contact with other animals? (exposure to infectious diseases)
- What is the origin of the dog (shelter, bazaar - increased risk of an infectious disease)?
- What is the status of preventive vaccinations?
- Whether similar symptoms occurred in the animal's family and siblings?
During the interview, it is extremely important to accurately interpret the tutor's words.
It often happens that the animal's keeper describes a symptom he has noticed by naming it incorrectly.
“My dog is in pain. "
A symptom that gives rise to this suspicion is trembling.
However, such a symptom may indicate not only pain sensations, but also:
- movement disorders,
- intentional tremors,
- strong emotional arousal,
In such a situation, it is worth considering what other symptoms - apart from tremors - may indicate that the animal is experiencing pain?
Is the trembling accompanied by barking, squeaking, whining??
The doctor will most likely ask you to state exactly under what circumstances the dog is trembling.
“My dog sleeps more, probably because he is getting older. "
However, this symptom can also be a sign of depression or depression.
Consider when your pet started sleeping more?
Or when the dog is awake, behaving as before?
"My dog has difficulty getting up ".
The caregiver usually attributes this symptom to joint disorders. However, it may also result from a generalized weakness or be the result of:
- back problems,
- orthopedic problems other than arthritis,
- metabolic disorders.
You will probably be asked when you noticed that the dog is having trouble standing up?
Does the problem worsen after rest or after exercise?? Does the animal appear healthy apart from the difficulty of standing up?? Whether the dog is vomiting?
"My dog has a stroke. "
This conclusion is often made to the caregiver when the dog has had an episode of collapse (with or without stiffness).
It is quite likely that your pet has had a stroke, but this symptom could be a sign of:
- metabolic problems.
Therefore, it is important to determine if the dog was behaving normally immediately prior to the attack?
What was it like after the attack?
Are you able to describe the course of the attack?
When attacks occur?
Following an interview, the first step in making a diagnosis is to classify the problem as acute or chronic, and progressive or non-progressive.
Thanks to such information, the problem is automatically divided into individual groups of diseases.
The choice of diseases and conditions likely to cause neurological disorders is later narrowed down by indicating whether the lesions and disorders are focal or diffuse.
- Acute diseases
- Progressive diseases:
- young animals (
- focal lesions: birth defects, neoplastic diseases,
- inflammatory changes (e.g. abscess);
- diffuse changes: inflammatory, degenerative, toxic, nutritional.
- adult animals (> 1 year):
- focal lesions: cancerous;
- diffuse changes: inflammatory, toxic, degenerative.
- Progressive diseases:
- Non-progressive diseases:
- young animals (
- focal changes: birth defects,
- post-traumatic changes,
- vascular changes;
- diffuse changes are rare.
- adult animals (> 1 year):
- focal changes: post-traumatic, vascular changes;
- rare diffuse changes.
- Progressive diseases:
- young animals (
- focal lesions: inflammatory (e.g. abscess);
- diffuse changes: degenerative, metabolic, nutritional, toxic, immunological;
- adult animals (> 1 year):
- focal changes: degenerative (e.g. intervertebral disc), cancerous, inflammatory (e.g. abscess);
- diffuse changes: degenerative, metabolic, inflammatory, nutritional.
Based on the data obtained from the dog's guardian, the doctor proceeds to systematize the reported clinical symptoms and other information.
Recognition of the most common symptoms of neurological disordersThe most common symptoms of a dog's neurological disorder
Symptoms, as a rule, related to the central nervous system:
- Epileptic seizures (brain, interbrain).
Seizures always indicate the location of the lesion in the forebrain, although their etiology may be secondary to a metabolic or toxic state.
It can be difficult to distinguish between seizures and syncope, especially for the pet's caregiver.
- Altered mental state (brain, limbic system, dumbrain):
- Dementia or coma (brainstem reticular formation) are symptoms of abnormal brain or brainstem activity.
- Abnormal behavior (limbic system).
Behavioral changes may be caused by primary abnormalities in the brain or may be secondary to environmental factors.
- Paresis, paralysis, proprioception deficits (different areas).
- Paresis, paralysis - symptoms of primary motor dysfunction - are caused by neurological abnormalities.
These symptoms should be distinguished from lameness of musculoskeletal origin (in the further procedure - during physical and neurological examination).
- head tilt, nystagmus - vestibular system,
- intentional tremor, dysmetry (cerebellum),
- general proprioceptive deficits, no cerebral symptoms (spinal cord),
- Hypesthesia, anesthesia.
Sensory deficits such as loss of proprioception or hypesthesia (decreased feeling) are always the result of an abnormality in the nervous system.
Symptoms that may or may not be related to the central nervous system:
- Fainting (usually cardiovascular or metabolic causes).
- Weakness, muscle weakness (metabolic or muscular origin).
- Lameness (orthopedic disorder).
- Pain, hyperesthesia.
Pain (a subjective reaction to a harmful stimulus) may be associated with nervous changes.
E.g. Nerve root irritation may cause local pain and lameness and information from the dog handler may be helpful in determining the location.
- Pain can be generalized (thalamus, meningitis, lesions that affect multiple joints, muscles, and bones) or localized.
Vision deficits can be caused by abnormalities in the eye or the nervous system.
In order to make a diagnosis, it is necessary to undergo a thorough ophthalmological examination.
History information may be misleading in case of visual impairment.
An animal in a domestic environment, in a familiar environment, can function normally, even if it is blind:
- normal pupils (interbrain or occipital lobe of the brain),
- abnormal pupils (retina, optic nerve, optic crossing).
- Hearing deficits.
Hearing defects are usually undiagnosed unless they are bilateral.
Bilateral hearing loss is usually caused by an abnormality in the inner ear.
Brain damage resulting in deafness is rare.
- Disturbance or loss of smell can occasionally be accompanied by a lack of appetite.
- no vestibular symptoms (cochlear labyrinth),
- vestibular symptoms (VIII nerve, vestibular labyrinth).
- Lack of smell (nasal passages, olfactory nerve).
- Urinary incontinence (vulvar nerve, spinal cord, brainstem).
AND. Physical examination
Certain metabolic, cardiovascular and musculoskeletal diseases may resemble neurological disorders in their clinical picture.
An example might be:
- addison's disease,
- pyomyxia with intoxication,
- cardiovascular failure,
- bilateral rupture of the cruciate ligament.
Therefore, in the case of a patient with neurological disorders, the doctor will perform a physical examination, including body temperature measurement, auscultation and palpation.
Already when the dog enters the office and later - during the medical interview - the doctor closely observes the animal.
The visual disturbance may become more noticeable if the dog finds himself in a new, strange environment.
Proprioceptive deficits may also be more pronounced, especially on a slippery floor.
The researcher pays attention to deliberate movements (e.g. is the dog trying to move its limbs by itself).
The physical examination also includes some elements of the neurological examination, such as assessment of:
- mental state,
- traces of trauma,
- facial expressions,
- respiratory track.
If the patient is injured, movement (especially walking) should be limited until spine fractures are excluded.
The purpose of a physical examination is to rule out (or confirm) the presence of symptoms that may indicate a multi-system disease.
Any abnormalities, such as: fever, jaundice, pallor, cyanosis, ecchymosis, haemorrhage, chorioretinitis, abnormal respiratory murmurs, presence of heart murmurs, palpable tumors in the abdominal cavity, enlarged lymph nodes, changes on or under the skin may be about an ongoing pathological process that affects not only the nervous system, but in principle may be the cause of neurological disorders.
If there is a breathing disorder, its type is determined.
The presence of a Cheyne-Stokes breath (periodic very deep breaths followed by apnea) indicates deep bilateral brain damage.
In turn, neurogenic hyperventilation (deep, fast, regular breaths) - about the involvement of the pathological process of the midbrain.
Breaths that are irregular in rhythm and depth may indicate involvement of the respiratory center, threatening respiratory arrest.
Additionally, during this examination, the general clinical condition of the patient is assessed.
To assess the symmetry of the body, a thorough palpation of the musculoskeletal system, skin and subcutaneous tissue is performed with the simultaneous comparison of both sides.
Attention is paid to worn claws, bumps under the skin or deeper, altered body shape, unusual movement or creaking (crepitus), and the size, tension and strength of the muscles are assessed.
Although the skin is usually not involved in a neurological disease, assessment of the skin may provide some clues for the diagnosis.
Scars may indicate a previous trauma.
Incorrectly worn claws can be associated with paresis or proprioceptive deficits.
The color of the coat and eyes may be associated with an inherited abnormality.
The meningeal hernia may be palpable when it is located in the lumbosacral area of the skin.
The temperature of the extremities can be significantly lowered due to the obstruction of the arteries.
Dermatomyositis is an inflammatory disease of the skin of the muscles of Shetland Sheepdogs and Collies.
Skin lesions occur on the face, lips and ears, and above the bones.
Examination of the skeleton may reveal tumors involving the skull or spine, deviation from normal contour, abnormal movement, or crepitus.
The doctor palpates the spinous processes of the vertebrae for irregularities in their outline.
Deviations may indicate a dislocation, fracture or congenital anomaly.
Recessed or elevated skull fractures are often palpable.
Persistent fontanel and suture lines in the skull may indicate congenital hydrocephalus.
In the case of fractures and dislocations, abnormal movement is detectable.
Peripheral nerve injuries may be associated with fractures of the long bones.
Muscles are judged for size, tone, and strength.
All muscle groups are systematically palpated, starting from the head, through the neck and torso, all the way to each limb.
When palpating the muscles, it assesses muscle tension, soreness (e.g. during the inflammatory process) and possible asymmetries or disappearances.
There are two types of muscle wasting:
- neurogenic atrophy - it occurs quickly (up to 2 weeks) due to the loss of the influence of nerve impulses on the muscle,
- atrophy due to inactivity - it occurs slowly and results from the lack of use of a given muscle or group of muscles.
Changes in tension, both increased (spasticity) and decreased (laxity) can be detected by palpation and passive limb manipulation.
Increased extensor muscle tone (common in upper motor neuron disease) is manifested by increased resistance to passive flexion of the limb.
Muscle strength is difficult to quantify.
Extensor muscles can be assessed during postural responses such as bouncing in which the animal must support the weight on one limb.
Flexor muscles can be assessed by comparing the relative flexion force during the flexion reflex.
Loss of muscle strength is usually a sign of lower motor neuron disease, but is sometimes seen in upper motor neuron disease.
The test of sensation
The test of sensation (sensitivity) in a physical examination is performed by palpating the entire body of the animal, and then individual sections (especially those suspected of changes).
First the pelvic limbs are checked, then the spine.
The spine is compressed symmetrically on both sides along its entire course, starting with moving the tail in all directions, and ending with the neck (the neck is bent sideways, dorsal and abdominal).
Under normal circumstances, the dog is able to touch his nose to the chest on the sides of the body, and the lower jaw to reach the sternum without showing any pain symptoms.
Proper palpation does not produce a reaction in normal areas and a behavioral response in areas that are painful.
Animals that experience extreme pain may react no matter where they are touched.
When touching an animal, areas of increased sensitivity (hyperesthesia) can be observed.
Pain hypersensitivity (hyperpathy)
Pain hypersensitivity is observed when pain and behavioral reaction occur after compression of the spinous processes and paravertebral muscles of the thoracic and lumbar region, as well as the transverse processes and paravertebral muscles of the cervical region.
Pain hypersensitivity occurs at sites of spinal cord injury, therefore demonstrating it during the examination helps to precisely locate the lesion.
During the physical examination, some cranial nerves are assessed:
- The doctor assesses the symmetry of the face (nerve VII), the symmetry of the position of the eye and pupils (nerves III, IV, VI and sympathetic nerves).
- A threatening gesture is made next to each eye causing a blink (nerves II and VII).
The doctor also touches the medial and lateral corners of both eyes, causing a blink (V nerve - eye and jaw branch, VII nerve).
- The examiner turns the dog's head sideways, observing the coordinated eye movements (nerves III, IV, VI and VIII), then shines a light into each eye observing the pupil's reflex to light (nerves II and III).
- The nose and jaw are touched or pinched, and the doctor observes facial movements and possible behavioral reactions (V-maxillary and mandibular nerves, VII nerves).
The temporal and masseter muscles are palpated, and the dog's mouth is opened to assess the tonus of the jaw (V nerve - mandibular branch).
- When assessing the mucous membranes and tonsils during a physical examination, the doctor assesses the symmetry of the larynx and pharynx and touches the throat, causing a gag reflex (IX, X and XI nerves).
The assessor observes the symmetry of the tongue and, after the dog closes the mouth, assesses the nose - most animals lick at this point and the doctor can assess the symmetry of the tongue movements (XII nerve).
When palpating the patient, the trapezius and brachiocephalic muscles are assessed for muscle atrophy (XI nerve).
The only unchecked cranial nerve (unless a forebrain deficit is suspected) is the olfactory nerve, which, however, can be checked by an aversive reaction to alcohol.
B. A neurological examination
A neurological examination is an extension of the physical examination. It should determine the presence of a neurological disease and help in determining the location of the lesions.
In order not to overlook the often subtle disorders, a uniform and methodical approach to research is necessary, which is to be achieved by a standardized scheme of neurological examination.
In order to assess the patient's condition, terms such as:
The test should be conducted in a quiet and calm place and it is important that the patient is as relaxed as possible.
Conducting a neurological examination and conclusions drawn on the basis of the obtained results allow the doctor to:
- defining whether the dog has a neurological problem at all,
- determining the location of the disease process,
- determining the nature of the disease process (deficits or excessive activity of the nervous system),
- determining the cause of the disease,
- making a list of differential diagnosis of possible diseases (based on an interview, clinical symptoms, course of the disease and results of neurological examination),
- estimating the degree of damage to the nervous system, and thus determining the prognosis for the patient.
The way the test is performed depends to a large extent on the patient's condition - some tests should not be performed if, for example,. a spine fracture is suspected.
The examination begins with the determination of the patient's mental state, his attitude and the way he walks.
AND. Assessment of the mental state of the dog
When assessing the mental state of the dog, attention is paid to its behavior (temperament, alignment) and awareness (i.e. consciousness, wakefulness and the ability to receive stimuli from the environment).
In the beginning, the consciousness, behavior, posture and walking behavior of the animal are determined. The dog should move freely around the office.
The veterinarian assesses the animal's awareness and behavior by observing its responses to environmental stimuli and to humans.
Certain physiological differences, such as. intense puppies curiosity about elderly dogs' indifference is usually normal behavior.
Symptoms of aggression and fear are often visible in the office.
Consciousness is a function of the cerebral cortex and the brain stem.
Sensory stimuli from the body, such as touch, temperature or reaction to nociceptive stimuli (damaging, pain) and coming from outside, such as sight, sound and smells, provide information to the reticular formation.
Consciousness is held by the diffuse appendages of the reticular formation into the cerebral cortex.
This arousal system is called the ascending reticular excitatory system (ARAS).
A common cause of a lowered level of consciousness is disruption of the pathways between the reticular formation and the cerebral cortex.
The system that influences behavior is the limbic system, which is the arrangement of the cortical and subcortical structures of the brain.
The mental state can be defined (depending on the level of consciousness) as:
- Alive / alert (correct) - the animal reacts correctly to the environment, the guardian and other animals;
- Depressed / sad (conscious but inactive).
The dog is calm, too calm according to the handler, but reacts correctly;
- Appearance / depression is characterized by a conscious but inactive state.
The patient reacts only to direct, strong stimuli (e.g. loud sounds, touch, calling by name);
the animal is relatively unresponsive to the environment and tends to sleep when not disturbed.
Such severe apathy may be caused by systemic (extracranial) disturbances such as fever, anemia, or metabolic disturbances.
If it is associated with primary brain problems (intracranial), it indicates diffuse cerebral cortex disease or damage to the brainstem.
- Confused / bewildered; stupor is a state of sleep-daze in which the response to most environmental stimuli (except pain) is reduced; confusion, pushing your head against a wall, walking in a circle, aimlessly walking, self-mutilation, stereotypes may indicate a neurological disease.
- Dull - sleeps when not disturbed, does not respond to harmless stimuli such as noise, but wakes up to pain stimuli.
The dog is conscious but muffled and reacts inappropriately.
Dementia is usually associated with a partial disconnection of the reticular system and the cerebral cortex, as is the case with generalized brain disease or pressure on the brain stem.
- Delirium - is a hysterical behavior (e.g. the dog catches non-existent flies);
- Coma - is a long-term loss of consciousness, lasting several hours to days.
The comatose animal lies inert and shows no reaction to external stimuli.
The dog cannot be awakened even by a pain stimulus, although simple reflexes may remain intact. E.g. the squeezing of the foot causes a flexor reflex, but will not stimulate it.
Animals that do not respond to their environment tend to have generalized lesions of the cerebral cortex.
Coma is caused by a lack of connection between the reticular formation and the brain, which may be due to: head trauma, hypoxia (e.g. as a result of melting, suffocation), poisoning with drugs or toxic compounds (hypnotics), infectious or parasitic encephalitis (e.g. rabies), adrenal insufficiency (rare), hydrocephalus, brain tumors, cerebral vascular disorders, metabolic causes: hepatic encephalopathy, uremic state, plasma osmolarity disorders, acid-base imbalance, hypoglycaemia, hyperglycaemia.
Its most common cause in small animals is acute head trauma with haemorrhage within the pons and midbrain.
- Excitement (excitacio) and frenzy (mania) are increased psychomotor activity during which the dog is overly aroused.
Rage or aggression is often observed in the office, but in many cases it is a behavioral rather than a neurological disorder.
Nevertheless, aggression can be observed in the course of primary cerebral disease.
When assessing the patient, the doctor looks at the animal's behavior and its reactions in various situations (e.g. at home, in the office, in the waiting room, during the examination). Some of this information is obtained from the dog handler.
Behavioral disorders are often functional, that is, related to the environment and training.
However, primary brain disease can also cause behavioral changes. They indicate damage to the brain or diencephalon.
Behavioral changes may include:
Other symptoms related to abnormal behavior include:
- pushing his head,
- compulsive walking,
- "Star gazing ".
B. Assessment of the dog's posture
Correct posture is maintained by coordinated motor responses to sensory signals from receptors in the limbs and body, visual and vestibular systems.
Vestibular receptors sense changes in the position of the animal's head in relation to gravity and detect movement.
Sensory information is processed by the brainstem, cerebellum and the brain. The cerebellum and vestibular system are especially important.
An integrated exit through the motor paths to the muscles of the neck, torso and limbs maintains normal posture.
All pets can maintain their upright posture shortly after birth; however, they differ in their ability to stand and walk.
The posture is assessed when the animal moves freely around the room. Under proper conditions, the dog should stand upright with its head raised.
Then, the examination is continued, forcing various positions that allow to determine the ability to return to normal posture.
Postural disorders include:
- Head tilt.
It occurs when the head is tilted to one side and one ear is closer to the ground.
The constant tilt of the head is associated with vestibular anomalies.
Intermittent head tilting, especially if it involves ear friction, can be caused by otitis externa or ear mite infestation.
The constant tilt of the head and resistance to forced straightening by the doctor are almost always caused by dysfunction of the vestibular system.
- Head twist.
When the head is twisted, the ears are on the same level.
The turning of the head towards the lesion is caused by disorders in the brain and diencephalon. It is often accompanied by walking around.
Head tilt and twist must be distinguished from cervical muscle spasm caused by spinal cord disease or nerve root disease.
The head and neck can be held in a steady position when there is neck pain.
Dogs with focal neck pain and weakness in the pectoral limb often flex their spine and put their nose on the ground, apparently trying not to put stress on the pectoral limbs.
- Head coordination abnormalities and tremors may be noticeable with head movements (e.g. trying to eat and drink). They usually indicate changes in the cerebellum.
Abnormal torso posture may be related to congenital or acquired lesions of the spine, or abnormal muscle tone resulting from changes in the brain or spinal cord.
Body posture abnormalities
- lordosis (ventral curvature of the back),
- kyphosis (dorsal curvature of the back),
- scoliosis (lateral curve of the spine),
- head down (centroflexia),
- dorsal head curvature (opisthotonus),
- turning of the head in its axis or turning to the side (torticollis).
Incorrect positioning of the limbs is caused by deficits in proprioception.
Abnormal limb posture includes improper limb positioning and an increase or decrease in extensor tension.
The posture with widely spaced limbs is typical of all forms of ataxia (ataxia, motor coordination disorders). It is also observed in cases of generalized weakness.
Proprioceptive or motor deficiencies can cause the dog to stand upside down (rests the foot on the dorsal surface of the foot).
In the event of changes in the lower or upper motor neurons, the animal often tries to reposition the limb.
Uneven weight distribution in the limbs may indicate weakness or pain. Animals try to shift most of their weight to the pectoral limbs when the pelvic limbs are weak or painful and vice versa.
Reduced muscle tone in the extremities (flaccidity - clonic) is often associated with changes in the lower motor neuron and causes poor posture.
The limbs are passive, often with knuckling fingers.
Increased muscle tone (spasticity)
Increased tension in the thoracic limbs with flaccid paralysis of the hind limbs is called the Schiff-Sherrington phenomenon and is associated with changes in the spinal cord between the T2 and L4 segments of the spinal cord.
Increased tension in both extensors and flexors is observed in poisoning with tetanus and strychnine.
Cerebral stiffness syndrome is characterized by the straightening of all four limbs and the torso (increased tension of the extensor muscles).
This is due to damage located in the brain stem.
Opisthotonus, i.e. the backward bending of the head and neck, may accompany these changes if the nasal lobes of the cerebellum are damaged.
Mental functions also change frequently.
Increased extensor muscle tone is a sign of upper motor neuron disease. Partial changes can overstretch the knee and ankle joints.
Crescent stiffness is an extreme form of increased rectifier voltage.
C. Traffic evaluation
The animal is observed for abnormal movements while walking and when resting.
It is very important to observe your pet closely as movement can be the most important part of the neurological examination, especially in large and giant dogs where postural responses are more difficult to study.
Adopting a proper posture and movement are complicated in terms of neurology - they require the participation of the brain, spinal cord and peripheral nerves.
Proprioception (the sense of position of the body) is the ability to recognize the location of the limbs in relation to the rest of the body.
In order to hold the weight, the limbs are kept in extension by means of reflexes from the spinal cord.
Walking movements are also programmed at the level of the spine.
The organization of the various paces (trot, gallop, walk) for proper and normal movement takes place at the level of the brainstem in the reticular formation.
The regulation flowing from the cerebellum makes the movement smooth and coordinated.
Vestibular influence ensures balance.
The influence of the cerebral cortex is necessary for deliberate movement, voluntary control, and precise coordination, especially for learned movements.
The gait test is performed on a surface providing adequate adhesion (e.g. carpet, grass).
The doctor may also ask you to lead the dog up the stairs or from them, or to cover the animal's eyes.
When assessing the gait, the animal is observed from the side, from the front - when the dog walks towards the examiner and from the rear when it moves away from him, as well as when it moves in a tight circle and moves backwards.
Each limb is scored both in normal gait and trot.
The animal should be led on wide and tight circles, and it should also be turned around.
Gait abnormalities may include paresis and general proprioceptive, vestibular or cerebellar ataxia or lameness (seen in orthopedic disorders).
Proprioception (or sense of position) is the ability to recognize the position of your limbs in relation to the rest of your body.
Proprioceptive deficiencies (deficits) that cause wrist walking (stiffening / knuckling), incorrect foot positioning and / or claw shuffling (this may not be noticeable at every step) - may be associated with changes in the brainstem and damage to any section of the spinal cord and peripheral nerves.
General proprioceptive pathways in the spinal cord are found in the dorsal and dorsolateral pillars and extend into the cerebellum (unconscious process) and into the cerebral cortex (conscious process).
Paresis / paralysis / parezia - this is a deficit of conscious movements.
This is known as a partial loss of sensation and a complete or partial loss of the limb's motor functions.
Affected limbs are unable to adequately support the weight of the body, and voluntary movement is absent or incorrect.
Paresis is caused by the disruption of the conscious / intentional movement from the brainstem to the spine.
Pareza is clinically evident only when the descending pathway of the upper motor neuron is disrupted caudally from the midbrain and in the spinal cord, or in the case of changes affecting the lower motor neuron unit.
Therefore, the paresis may be of the GNR or DNR type.
- flaccid paralysis, when the lower motor neuron (DNR), i.e. the reflex arc in the limbs, is damaged,
- spastic paralysis, during damage to the upper motor neuron (GNR), i.e. the system of higher centers that controls the voltage of the lower neuron.
Weakness or lack of spinal reflexes in the limbs indicates damage to the DNR, while normal, increased reflexes or spasms in the limbs indicate damage to the DNR.
Due to the anatomical aspect, the following are distinguished:
- monoparesis - when only one limb is affected by paresis,
- paraparesis - paresis of both pelvic limbs,
- tetraparesis - dysfunction affects all four limbs,
- hemiparesis - when the disorder affects the thoracic and pelvic limbs of the same side of the body.
It is a complete loss of sensory and motor functions (i.e. motor functions) in the affected limb.
The dog is unable to consciously make any movement with the affected limb.
Spinal reflexes may still be present, but are not indicative of spinal cord integrity above reflex level.
Due to the anatomical aspect, the following are distinguished:
- monoplegia - paralysis of one limb,
- paraplegia - paralysis of both pelvic limbs,
- tetraplegia - paralysis of all four limbs,
- hemiplegia - paralysis of the thoracic and pelvic limbs on the same side of the body.
A neurological disease may cause the animal to circulate. Circulation ranges from drifting in a wide circle to spinning in a tight circle.
Walking in a tight circle is usually caused by lesions in the back of the brainstem.
If it is accompanied by a head tilt, it may indicate that the vestibular system is covered by the disease.
Wide circles are usually caused by changes in the forebrain.
The direction of circulation is usually in the direction of the change (i.e. left circulation - left side change), but there are exceptions, especially if the change is intranasally from the midbrain.
Ataxia (ataxia, disorder)
Means a disturbance of coordination in the movement of the animal, without the accompanying paresis and spastic or involuntary movements.
It may result from proprioceptive disorders when the animal "doesn't know" where its limbs are.
Inoperability can be caused by damage at any level of the nervous system, but usually involves changes in:
- cerebellum (dysmetric disorders in the form of hypermetry, i.e. exaggeration of steps or hypometry, i.e. reduction of the stride length),
- atrium (then the balance is disturbed),
- spinal cord.
Trunk ataxia is characterized by poorly controlled swaying.
Limb movement is uncoordinated. The feet may cross or be placed too far apart.
Dysmetry is characterized by steps that are too long (hypermetry) or steps that are too short (hypometry) and is usually caused by changes in the cerebellum.
A common symptom of dysmetria is the so-called. "Goose walk ". The step may stop abruptly and the animal wobbles from side to side.
Head and neck dysmetry may be best noticeable when the dog tries to drink or eat but misses the bowl.
Atony - a sudden reduction or loss of muscle tone
Catalepsy is a sudden, complete loss of muscle tone that causes an animal to go limp. It is usually seen in conjunction with narcolepsy.
Purposeful / conscious movement
Deliberate movement is caused by the conscious intention of the animal to move its limbs.
The evaluation of purposeful movement is usually carried out in weakened animals that are unable to walk or are too weak to walk.
The dog tries to pull the limbs up to assume the correct posture.
Attention is paid to limb movements, hip flexion and ground pushing.
In paretic animals that do not make an evaluation of the deliberate movements, one can grasp the base of the tail with one hand, pick the animal up and try to walk with it.
If your dog's limbs hang down randomly and he doesn't show deliberate movements, it may indicate severe but not necessarily irreversible damage to the spinal cord.
They arise as a result of alternating, rhythmic contractions of opposite muscle groups. Tremors can be:
- Intentional (intentional, intentional) - when the animal is about to make some conscious movement.
Intentional tremor is very pronounced when movements are initiated.
This is an important symptom of cerebellar disease.
- Resting, observed in the course of many diseases of muscles and nerves.
Tremor can also be caused by fatigue, fear, chills, drug reaction, or a muscle disease, so it is important to distinguish these conditions from neurological tremors.
Constant tremors are usually associated with an abnormality in the locomotor system.
Sudden, involuntary contractions (jerks, jerks) of the muscles.
They can affect a single muscle (focal myoclonus) or whole groups of muscles (generalized / multifocal myoclonus).
Two forms of myoclonus can be found in dogs:
- In acute encephalitis, the lesion is likely associated with the destruction of areas in the basal ganglia.
- The chronic form (more common) is associated with interneurons or the inferior motor neuron at the segmental level.
Distemal myoclonus are the most common, although the pathogenesis is not fully understood.
The myoclonus seen in canine nasal encephalomyelitis is usually a rhythmic jerk of one muscle group, such as the elbow flexor or the temporal muscle.
If the myoclonus recurs, they are clinically seen as tremors.
Tetanus or tetany
Spastic contraction of all body muscles, which is observed in the course of tetanus and electrolyte disturbances (e.g. magnesium deficiency, calcium deficiency).
Seizures (convulsions, seizures) - this is the clinical manifestation of excessive and / or hypersynchronous neuronal discharges in the brain.
They can manifest as episodic reduction or loss of consciousness, abnormal motor behavior, mental or sensory disturbances, or symptoms from the autonomic nervous system, such as:
- urination and defecation.
The most commonly observed clinical signs in animals with seizures are:
- disturbances of consciousness,
- dilated pupils,
- eyes wide open,
- involuntary passing of faeces and urine,
- generalized tonic-clonic convulsions.
Sustained muscle contraction lasting from a few seconds to several minutes; during seizures it may cause facial grimaces, jaw opening, back extension of the head and neck and extension of the limbs.
Regular, short, involuntary muscle contractions; during contractions, they can cause facial twitching, snapping jaws, jerky movements of the neck and limbs.
These are alternating periods of tonic and clonic contractions.
Two or more seizures occurring in a 24-hour period.
The preview period
These are behavioral changes that precede the onset of seizures; the animal may hide, follow the handler, show anxiety or fear.
D.Study of reflexes
Postural reactions (postural reactions / postural reflexes / postural reflexes; postural reactions)
Postural reflexes are a set of reflexes that allow the animal to maintain a correct standing posture.
If the animal's body weight is shifted from one side to the other, front to back, or back to front, the load on the limb or limbs currently supporting the body weight will increase.
This requires increased tension in the extensor muscles to prevent the limb from collapsing.
Partial regulation of such muscle tone is achieved through the reflexes of the spinal cord, but for the changes to be smooth and coordinated, it is necessary to engage the motor and sensory systems of the brain.
Functioning of postural reactions requires the cooperation of the higher centers of the forebrain, spinal pathways, and motor, sensory and muscle nerves.
These are conscious reactions, and because in veterinary medicine there is a limited possibility of cooperation with the patient, we have to check them by means of various tests and exercises.
The presence of atypical postural reactions does not provide accurate information on the location of the lesions (as changes in one of several areas of the nervous system may affect the response), but it may indicate a neurological disease.
Therefore, assessing postural responses is an important part of the neurological examination.
Minimal deficits in brain function can cause significant changes in postural responses that are not detected when gait is observed.
All postural responses make it possible to evaluate the functioning of proprioceptive sensation.
In the reactions of posture and position, the phases of initiation (initiation) and movement adaptation are distinguished.
Generally, in the case of sensory disorders, the phase of initiation of movement is impaired, while in the case of movement disorders, a delay in the adaptation phase is observed.
Proprioceptive positioning (or correction reaction / conscious proprioceptive positioning) - i.e. checking awareness of the location of body parts in space.
The animal is placed so that it symmetrically loads all four limbs, and the head is directed forward.
The doctor bends the dog's paw so that its dorsal surface rests against the ground.
The limb is held in this position for a moment and then released.
Under correct conditions, the dog should return the limb to its natural position immediately.
Most animals do not allow the weight of the body to be supported in the abnormal position of the limb.
When the paw is in an incorrect position, the animal should reposition the paw in order to obtain a normal load.
Delayed correction of the foot thimble is indicative of a neurological disease.
If the dorsal surfaces of the claws are rubbed and / or there is damage to the skin or calluses on the dorsal surface of the fingers, this may indicate prolonged proprioceptive disorders.
Alternatively, this test can be performed by placing a sheet of paper under the paw and slowly sliding it to the side.
A dog that is aware of the placement of its limbs will make a corrective movement.
In general, proprioceptive information is transmitted in the dorsal columns and by the spinal-thalamic route in the dorsolateral cord of the spinal cord through the brainstem to the sensorimotor cortex and fibers entering the cerebellum.
The motor response is initiated by the cerebral cortex and is transmitted to the inferior motor neuron in the spinal cord.
Since proprioceptive pathways are sensitive to compression, disturbances in proprioceptive positioning may occur before detecting motor dysfunction (paresis).
The response is abnormal if there is significant paresis, but other postural responses such as jumping are also altered.
Some healthy dogs do not move their paws after turning the paw.
In such a situation, you should always evaluate the bouncing response.
Jumping (jumping / hopping reaction)
It is a reliable test for postural response.
Assesses all components involved in voluntary limb movements.
Normal bouncing responses require intact sensory receptors, peripheral nerves, ascending long pathways in the spinal cord and brainstem, sensory cortex, upper sensory neuron systems, and integration with the lower sensory neuron in the spinal cord.
This test is performed while the dog is standing.
The doctor lifts the three limbs of the animal, pushing the dog to the side to observe the ability to "walk", or rather jump on each limb separately.
In the case of a pectoral limb test, the bouncing response is checked with one pectoral limb lifted off the ground.
While it is easy to raise the three limbs in small dogs, it is not necessary in larger dogs.
A dog's pelvis should only be sufficiently supported to increase the pressure on the straightened limb.
As the load on the upright (support) paw increases, the dog's ability to maintain full extension is assessed.
When the dog is facing away from the examiner, the weight of the animal is shifted to the side - over the straightened limb, and then initiation, movement and support while jumping are assessed.
Medial Jumping is more difficult, but this maneuver detects more subtle abnormalities.
Pelvic bouncing is done by supporting the chest and lifting one pelvic limb.
When the patient is facing the examiner, the weight is shifted to the side over the assessed limb - initiation, movement and support are assessed.
Giant breed dogs are examined by lifting one limb and shifting the animal's weight to make it jump to the opposite limb.
Alternatively, large animals can be pulled by the tail or pushed sideways (rocking reaction) to produce movements similar to a bouncing reaction.
The bounce response is more sensitive than other postural responses for detecting minor deficits.
A poor onset of the reaction suggests a sensory (proprioceptive) deficiency, while poor continuation and initiation of movement suggests an abnormality in the locomotor system (paresis).
A normal animal can walk forward and side to side with coordinated movements of both pectoral limbs.
Movement is forced sideways or inwards, and the entire body weight is supported on one limb only.
Traffic asymmetry can help you identify the side on which the change is located.
A thoracic limb examination usually provides more information than a pelvic limb examination.
Rolling (wheelbarrowing reaction)
This test allows the assessment of proprioceptive sensation in the forelimbs and the comparison of the two forelimbs.
This test is done by propping the dog under the belly, lifting the hind limbs, and forcing him to transfer all his body weight to the pectoral limbs.
Then you take a few steps forward.
A healthy dog will move forward thanks to the coordinated movements of both front legs.
If the movements seem normal, the maneuver is repeated with the head held high and the neck stretched.
The raised head position prevents the dog from looking ahead, which makes the animal dependent on proprioceptive information.
When the neck is stretched, animals may develop subtle abnormalities in the pectoral limbs that otherwise appear normal.
This reaction is especially useful for detecting compressive changes in the caudal part of the cervical spinal cord that primarily cause paraparesis.
Weakness in the pectoral limbs can be detected on examination as the dog is forced to shift most of its weight to the two limbs by only standing on one limb while moving.
If the forward movement is delayed, it may indicate proprioception deficits or paresis caused by changes in the cervical spinal cord, brain stem or cerebral cortex.
Exaggerated / over-expressed movements (dysmetry) may indicate changes in the cervical spinal cord, lower brain stem, or cerebellum.
Postural thrust of the extensors (support reaction / support reaction - extensor postural thrust)
The support reaction is carried out by lowering the animal supported under the rib cage to the ground.
When the animal is lowered to the floor, it should extend its limbs awaiting contact with the ground.
This is an vestibular reaction and may be impaired or uncoordinated in animals with vestibular changes.
When the pelvic limbs touch the ground, they should (trying to gain support) move backwards in symmetrical movements (as when walking).
The assessment of the patient's condition is the same as in the case of barrowing.
You may observe asymmetrical weakness, incoordination and dysmetria.
This reaction is difficult or even impossible to perform in large animals.
Half standing / jumping (jumping reaction on a pair of limbs, jumping on one side of the limbs, half-gait reaction - hemistanding / hemiwalking)
This reaction makes it possible to compare the functions of both sides of the body.
The half-standing and half-walk test is performed by lifting the pectoral and pelvic limbs on one side of the dog's body so that the entire body weight is based on the opposite limbs.
In this way, the animal is judged to be able to support its body weight, then the patient shifts and observes the forward and sideways movement (bouncing), and the interpretation of the test result is the same as for wheelbarrow.
Symptoms can be seen with this test as with any postural response.
This test is most useful in animals with forebrain lesions.
Such dogs have a relatively normal gait, but have deficits in postural response in both the pectoral and pelvic limbs contralateral to the change.
Placement reaction (table edge test - placing). This is an exercise that allows you to evaluate proprioception in dogs of small and medium breeds (and in cats)
Placement first is done without the dog's eyesight being involved (touch test, touch placement).
During this test, the examiner supports the animal under the chest, with one hand (or a blindfold) covering its eyes.
The animal's wrists are touching the edge of the table. The correct reaction is to immediately place the paws on the table surface in a body-supporting position.
If you do not react after contact with the obstacle, it may be a symptom of abnormal sensation or a lack of awareness (proprioception).
Tactile localization requires the integrated actions of tactile receptors in the skin, sensory pathways through the spinal cord and brainstem to the cerebral cortex, and motor pathways from the cerebral cortex to the lower motor neuron of the thoracic extremities.
The same test is then carried out by letting the dog look (visual placing).
When the animal sees the edge of the table, it should raise the pectoral or pelvic limbs in order to place them on the table before they touch the table top.
A dog that cannot see or realize that it is approaching the edge will not make any movement or the movement will be clumsy.
Some dogs used to being handled may ignore the table.
Such dogs will respond better if kept in a less comfortable position, away from the examiner's body.
Correct results of this test require the proper functioning of the visual pathways of the cerebral cortex, the connection between the visual cortex and the motor cortex, and the motor pathways to the peripheral nerves of the thoracic limb.
A disturbance in any part of this conduction pathway can cause abnormalities in the placement reaction.
The test can also be performed by lifting the patient by the hind limbs and then slowly lowering the patient head down onto the ground. Attention is paid to the positioning of the body - the animal should tilt its head up and spread its front limbs in order to place them on the ground.
Giant breed dogs can be judged by pointing them to a curb or step with or without viewing.
A normal tactile test result with an abnormal optical test result indicates a change in the optical system of the eye, while a normal tactile test result indicates a sensory change.
Changes in the brain and diencephalon cause disturbances in the opposite side (contralateral) limb.
Changes below the midbrain usually cause disorders on the same side (ipsilateral).
Neck tonic reaction
The dog is in a normal standing position and the doctor raises his head and stretches his neck.
The normal reaction is a slight straightening of the pectoral limbs and a slight flexion of the pelvic limbs.
Lowering the head causes the pectoral limbs to flex and straighten the pelvic limbs.
Turning the head to the side causes a slight extension of the ipsilateral pectoral limb and a slight flexion of the contralateral pectoral limb.
The tonic reactions of the neck are initiated by receptors in the cranial cervical region and are transmitted through the reticular formation of the brainstem.
In healthy animals, the response is subtle and is often voluntarily suppressed by cortical control.
Abnormalities in the sensory (proprioception) or motor system may cause abnormal responses.
Changes in the cerebellum cause exaggerated tonic reactions in the neck.
The study of spinal reflexes examines the sensory and motor integrity of all elements of the reflex arc and the influence of descending motor paths on the reflex.
The study of spinal reflexes allows the assessment of the lower motor neuron (DNR) and the effect on it of the upper motor neuron (GNR).
The lower motor neuron consists of:
- ascending (sensory) nerve,
- alpha-motoneuron lying in the spinal cord,
- descending (motor) nerve,
- motor plate and muscle, forming the reflex arc.
By checking spinal reflexes, the examiner can obtain three types of response:
- normal reflex - indicating the continuity of sensory and motor nerves;
- lack of reflex or reduced reflex, indicating complete or partial loss of integrity of the sensory or motor nerves responsible for reflex (lower motor neuron - DNR);
- an intense reflex, indicating a disorder in the descending pathways of the brain and spinal cord that inhibit the reflex in a healthy animal (upper motor neuron - GNR).
Due to strength, it is distinguished by:
- normal reflex (value 0),
- increased (+1),
- clonic (+2),
- weakened (-1),
- lack of reflex (-2).
Positive values indicate damage to the GNR, while negative values indicate damage to the DNR.
If the gait and posture responses are normal, spinal reflexes are usually also normal.
Since each of the spinal reflexes corresponds to an anatomically specific segment of the spinal cord, it is possible (in case of spinal cord injury) to determine the location of the lesion relatively precisely on the basis of disturbances in spinal reflexes.
Examination of spinal reflexes is performed with the animal lying on its side.
Initially, the muscle tone is reassessed, this time in the supine position.
The doctor first checks the pelvic limbs. Passive limb manipulation assesses the degree of muscle tone, especially in the extensor muscles.
Extending the fingers with light pressure on the pads causes the extensor resistance reflex.
Then the myotatic reflexes (own muscle) are assessed.
Only the patellar reflex is routinely assessed.
The tibialis and gastrocnemius muscles can also be assessed, but these reflexes are more difficult to elicit and assess.
The flexor reflex is then tested by gently squeezing the toes.
The most predictable myotatic reflex in the pectoral limb is that caused by the radial extensor muscle of the wrist (causing the wrist to straighten slightly).
The triceps and biceps reflexes are difficult to elicit in many healthy animals.
After examining the limbs on one side, the doctor turns the dog over and examines the opposite limbs.
Myotatic reflexes (muscle self or stretching) are the basis of reflexes that regulate posture and movement.
The reflex arc is a simple two-neural pathway (monosynaptic).
The sensory neuron has a receptor in the muscle spindle and its cell body is in the spinal ganglion.
Motor neurons have cell bodies in the abdominal horn of the gray matter of the spinal cord.
Axons form the motor components of peripheral nerves that end in the muscle (neuromuscular junction).
Patellar reflex (L4-L6 segments, femoral nerve)
It is the most reliable reflex of the pelvic limb.
The test is performed with the animal lying on its side.
The upper limb is supported under the thigh bone with the knee joint slightly bent. The doctor strikes the patellar ligament vigorously with a neurological hammer, and the response should be a vigorous, single straightening of the knee.
The patellar reflex is the most reliably interpreted myotatic reflex.
It is interpreted as:
- absent (0),
- weakened (+1),
- normal (+2),
- exaggerated (+3),
- overdone with clonus (+4).
Correct responses may vary between representatives of different breeds of dogs, for example large dogs respond less quickly than small dogs.
Absence (0) or weakening of the patellar reflex and a decrease in muscle tone (relaxation) indicate a change in the sensory or motor component of the reflex arc (a symptom of the lower motor neuron or a segmental symptom).
A unilateral lack of reflex indicates damage to peripheral nerves, e.g. damage to the femoral nerve.
A bilateral lack of this reflex indicates a segmental lesion in the spinal cord that affects segments (neuromers). This damage affects the motor neurons of both limbs, located in the L4-6 segments of the canine spinal cord.
Final differentiation between peripheral nerve injuries and spinal cord injuries may require an evaluation of the sensory examination and the presence or absence of other neurological symptoms.
Old dogs sometimes lose their patellar reflex but retain the ability to walk.
A weakened (+1) reflex has the same meaning as a lack of reflex except that the lesion is incomplete.
Reflex weakness is more common in spinal cord lesions in situations where some, but not all, segments of the spinal cord are affected (L4-6).
Other reflexes should also be investigated as generalized reflex weakness may occur in patients with polyneuropathies or neuromuscular junction abnormalities (botulism, tick palsy).
Animals that are tense or keep their limbs straight may have reduced or no reflexes.
Intensified reflexes and increased muscle tension (spasticity), occurring simultaneously with other symptoms of upper motor neuron disorders, indicate a cranial locus of the lesion from the L4 segment (GNR).
Normal (+2) or exaggerated (+3, +4) reflexes and increased tension result from the loss of descending inhibitory paths.
These pathways support the flexor muscles and inhibit the extensor muscles.
Their damage releases the myotatic reflex, causing an exaggerated reflex and increased rectifier voltage.
Clonus is your muscles repeatedly contracting and relaxing in response to a single stimulus.
Clonus is often seen in patients with chronic (weeks to months) loss of downstream inhibitory pathways. Clonus has the same localization significance as exaggerated reflexes.
Bilateral exaggerated reflexes are most often associated with damage to the descending craniofacial inhibition pathways to the reflex level.
Damage to the upper motor neuron causing exaggerated myotatic reflexes also causes paresis.
The tibial-cranial reflex (L6-7 segments, sciatic nerve)
This reflex is checked by hitting the tibial cranial muscle with a hammer.
The correct reaction should be to flex the foot.
The tibial accessory muscle is the flexor of the ankle and it is innervated by the sagittal branch of the sciatic nerve (derived from the L6-7 segments of the canine spinal cord).
This reflex may be more difficult to elicit in a healthy animal than the patellar reflex, therefore absent or diminished reflexes should be interpreted with caution.
Exaggerated reflexes indicate damage cranially to the L6-7 spinal cord segments.
The gastrocnemius reflex
The gastrocnemius muscle is primarily an extensor of the ankle and is innervated by the tibial branch of the sciatic nerve (derived from the L7-S1 segments of the canine spinal cord).
In order to keep the muscle slightly tense, a slight flexion of the ankle joint is necessary.
The doctor then strikes the gastrocnemius tendon with a neurological hammer.
The correct answer should be to straighten the ankle joint.
You may also notice spasm of the posterior thigh muscles.
The gastrocnemius reflex is interpreted in a similar way to the tibialis cranial reflex.
Flexor reflex (L6-S1 segments, sciatic nerve)
The flexor reflex is more complex than the myotatic reflex.
All flexor muscles of the limb are involved in the response, so it requires the activation of motor neurons in several segments of the spinal cord.
The flexor reflex is a reflex originating in the spinal cord and does not require activation of the brain.
If an animal steps on a piece of glass, it immediately withdraws its foot before it consciously feels pain.
If the continuity of the spinal cord is completely broken intracranially from the segments responsible for this reflex, the reflex is present even if the animal has no conscious perception of pain.
The pelvic limb retraction is assessed in the animal lying on its side.
The plantar area of the foot is stimulated with the most gentle stimulus - the doctor uses fingers or forceps to press against the folds between the fingers.
The expected response is to withdraw the limb towards the body (flexion of the limb - including the hip, knee and ankle joint).
This reflex is mainly associated with the L6 to S1 sections of the spinal cord and the sciatic nerve.
Lack of (0) or weakening (+1) of the reflex indicates damage to the L6-S1 segments or branches of the sciatic nerve.
A unilateral lack of reflex is most likely the result of an alteration in the sciatic nerve, while a bilateral deficit or weakness occurs due to an alteration in the spinal cord.
A normal flexor reflex (+2) indicates that the spinal cord segments and nerves are working.
Increased withdrawal reflex is associated with the presence of a craniocephalus injury from the L6 segment of the spinal cord.
An exaggerated (+3) flexor reflex is rarely seen with acute changes in the descending pathways.
Chronic and severe damage to the descending pathway can exaggerate the reflex.
This manifests itself as a permanent withdrawal of the limb upon stimulation.
Mass reflex (+4) is seen as permanent flexion of both limbs with contraction of the muscles of the tail and perineum in response to a stimulus applied to only one limb. This is more evidence of the chronicity than the severity of the change.
Rectifier resistance reflex
It is important for maintaining posture and is part of more complex responses such as jumping.
The reflex may be triggered in the animal lying down (on its side) or in an animal suspended by its arms with free pelvic limbs.
The fingers are spread out and there is little pressure between the pads.
The reaction is to stiffly extend the limb.
The reflex is initiated by stretching the spindles in the interosseous muscles of the foot. At the same time, skin sensory receptors are stimulated.
The reaction is dominated by the extensors, forcing the limb to straighten stiffly.
Sensory fibers are found in the sciatic nerve (L6-S1 spinal cord segments) and the response involves both the femoral nerve and the sciatic nerve (L4-S1 segments).
Excessive stimulation of the sensory fibers of the flexor reflex (e.g. a harmful stimulus) causes the dominance of the flexor reflex and the limb withdraws (flexes).
The extensor resistance reflex is necessary to elicit in healthy animals (especially in a horizontal position). Induction of a reflex generally indicates an intracranial injury from L4.
The wrist radial extensor reflex.
The radial extensor muscle of the wrist is the extensor of the wrist and is innervated by the radial nerve (coming from the C7-T1 segments of the dog's spinal cord).
This reflex is more difficult to elicit than the patellar reflex, but can usually be recognized in dogs.
The animal lies on its side, the pectoral limb is supported under the elbow with the elbow and wrist bent.
This muscle is hit with a neurological hammer just behind the elbow. The answer is to straighten your wrist a little.
The absence or decreased reflexes should be interpreted with caution. Strong reflexes are usually exaggerated (+3) and indicate damage to the cranial to the L7 segment.
The triceps muscle of the arm straightens the elbow and is necessary to support the weight of the body on the forelimb.
It is innervated by a radial nerve that derives from the C7-Th1 neuromers of the canine spinal cord.
The triceps reflex is assessed in the animal lying on its side.
The limb is held under the elbow which should be fully extended and the entire limb pulled back.
The doctor strikes a neurological hammer against the tendon of the triceps muscle of the arm, close to the ulna. The correct response should be a slight extension of the elbow or a visible contraction of the triceps muscle.
Radial nerve damage can be identified by loss of muscle tone and inability to hold weight. The triceps reflex is difficult to elicit even in healthy animals, so the absence or weakening of reflexes does not necessarily mean that there is a malfunction.
The intensified reflex indicates a lesion located in the head from the C7 neuromer (GNR).
The biceps muscle of the shoulder and the brachial muscle are the flexors of the elbow joint. They are innervated by the musculocutaneous nerve that comes from the C6-8 spinal cord segments in the dog.
The veterinarian holds the animal's forearm and places the index finger on the tendon of the biceps muscle, near the elbow.
The elbow joint must be slightly straightened and the doctor hits his own finger with a hammer.
The correct reaction is a slight flexion of the elbow joint.
This reflex is difficult to elicit even in a healthy animal. The absence or weakening of it suggests a change in the C6-Th8 segments of the spinal cord (DNR), but may be the norm in some animals.
An intense reflex (exaggerated +3) indicates a cephalic lesion from the C6 segment of the spinal cord (GNR).
Retraction (flexor) reflex (C7-T1 and radial, axillary, musculo-cutaneous, median and ulnar nerves)
The branches of the radial nerve innervate the cranial surface of the foot and exit the C7-T1 spinal cord segments.
The medial palmar surface is innervated by the ulnar and median nerves that originate from the C8-T1 segments of the spinal cord.
The lateral palmar surface and most of the lateral fingers are innervated by the branches of the ulnar nerve.
The doctor squeezes the phalanges with a finger or forceps, and the correct response should be to flex the shoulder, elbow, wrist and sometimes fingers.
The sensory stimulus passes through the radial, median and ulnar nerves, and the motor stimulus passes through the C7-T1 segments of the spinal cord and nerve roots as well as the axillary, musculo-cutaneous, median and ulnar nerves.
Absence or weakening of reflexes indicates damage to the C6-T1 segments of the spinal cord or peripheral nerves.
Increased reflexes, occurring with other symptoms of GNR disorders, appear as a result of changes located in the head from the C6 segment of the spinal cord (GNR).
Anal sphincter reflex (perianal reflex, perineal reflex - anal sphincter reflex; segments S1-2 (3), vulvar nerve)
The anal sphincter reflex is the best indicator of the functional integrity of the sacral sections of the spinal cord and the roots of the sacral nerves.
Its evaluation is especially important in animals with bladder dysfunction.
The anus is sensory and motor innervated by the vulva nerve (the perineal nerve is the sensory nerve, the posterior rectal nerve - the motor nerve) and the S1-S2 (sometimes S3) segments of the spinal cord.
The caudal nerves are involved in the flexion of the tail.
The perineal reflex is triggered by gentle stimulation of the perineum with a needle or forceps.
The correct response is contraction of the anal sphincter and flexion of the tail.
A similar reaction can be obtained by squeezing the penis or the vulva (bulbocavernous reflex).
Reflex loss or weakness (anal contraction deficit) indicates changes in the sacral spinal cord or the labia nerve (DNR).
An enhanced reflex occurs due to changes above the S1 segment of the spinal cord.
Emptying the bladder
The innervation of the bladder comes mainly from the autonomic (sub-gastric and pelvic) and somatic (vulvar) nerves.
The vulva nerve innervates the striated muscles of the urethra and helps with urinary incontinence.
Bladder disorders may accompany spinal cord injuries with damage to the vulvar nerve (S1 and S2 segments).
Above the sacral lesions in the spinal cord cause the detrusor muscle to contract, causing difficulty in emptying the bladder (GNR).
The change in the sacrum of the spinal cord causes the sphincter muscles to lose tension and the bladder to empty too easily (DNR).
Crossed extensor reflex (extensor-flexor reflex, crossed extensor-flexor reflex)
This reflex is part of the animal's normal weight bearing mechanism.
The weight of the standing animal is evenly distributed over the limbs.
If one of them is bent, increased support is required from the opposite limb.
Sensory fibers of flexor reflexes send beams to interneurons on the opposite side of the spinal cord that stimulate extensor motor neurons.
This reflex can be observed when inducing the withdrawal (flexor) reflex.
The animal lies on its side, limbs relaxed, then the fingers of the upper limb (thoracic or pelvic) are slightly (gently) pinched with the fingers, causing the withdrawal reflex.
The incorrect response is bending the limb at the top and straightening the lower limb at the same time (such a reflex occurs physiologically in young animals up to 2-3 weeks of age).
The cross reflex is generally considered abnormal, except in the standing position.
In a healthy recumbent animal, the extensor response is inhibited by descending pathways.
Crossed extensor reflexes result from changes in the ipsilateral inhibitory descending pathways, which is a sign of upper motor neuron disease.
The crossed extensor reflex was considered evidence of severe spinal cord injury.
However, this is not a reliable indicator of the severity of the lesion.
This reflex is often associated with chronic conditions, but is not associated with poor prognosis.
The animal lies in a horizontal position (as in myotatic reflexes), the pelvic limb is held proximally to the ankle joint (ankle joint and fingers slightly bent).
The neurological hammer strokes the limb on the tail-lateral surface from the ankle joint to the toes.
A normal animal shows no reaction and does not bend its fingers.
The incorrect answer is extension and "fan-shaped" finger movements.
The tail wagging reflex
Animals with a broken spinal cord above the sacral and caudal sections can tail wag.
This reflex swing is usually seen when emptying the bladder or triggering an anal sphincter reflex.
Tail wagging can also be a conscious response to pleasurable stimuli, such as stroking the head or seeing a caregiver.
This conscious response suggests some continuity in the spinal cord.
Therefore, it is important to distinguish between spontaneous (reflex) tail wagging and conscious (deliberate) tail wagging.
Therefore, it should not be assumed that a dog that is wagging its tail has preserved spinal cord continuity.
It might just be a reflex action.
Subcutaneous reflex (skin reflex of the torso)
It enables a more precise localization of the spinal cord injury.
This reflex is checked by pricking or pinching the skin of the back on both sides of the spine, starting from the lumbosacral area and continuing towards the head.
The correct response to these stimuli is the twitching of the cutaneous muscle of the torso on both sides of the back (at the point where the stimulus is applied and head to it).
No response to the stimulus is observed in 1 or 2 caudal segments from the location of the lesion in the spinal cord.
This reflex can be unbelievable and should therefore be interpreted very carefully.
The constant lack of reflex only on the affected side occurs with injuries with a brachial plexus detachment.
Clonus is an effect of persistent contraction or tremors that may be seen or felt when triggering spinal reflexes (especially patellar and cross extensor reflexes).
The occurrence of clonic contractions is often observed in chronic diseases.
E. Assessment of cranial nerves
The examination of the cranial nerves is of great importance especially when suspecting changes in the brain.
Abnormalities in these nerves are evidence of the presence of a specific, localized area of lesions that has not been revealed by postural reactions.
The olfactory nerve (I, n. olfactorius)
The olfactory nerve is the sensory nerve for the conscious perception of smell.
Chemoreceptors in the nasal mucosa give rise to axons that pass through the holes in the ethmoid bone to the synapses in the olfactory bulb.
From the olfactory bulb, axons pass through the olfactory tract into the ipsilateral olfactory cortex. Behavioral responses to odors are controlled by connections to the limbic system.
A dog's sense of smell can be difficult to assess, and its deficiencies are difficult to quantify.
Important information about this sense can be obtained from the guardian, as well as by observing the animal in the office.
For an overall olfactory test, a behavioral response to pleasant or noxious odors can be used, inferred from the interview, or assessed by direct testing.
Alcohol, cloves, xylol, benzol, or cat food containing fish appear to stimulate the olfactory nerves.
Irritants such as ammonia or tobacco smoke cannot be used as they stimulate the trigeminal nerve endings in the nasal mucosa.
The most common causes of loss of smell (anosmia) include:
- nasal inflammation,
- tumors of the nasal passages,
- plate disease.
Inflammatory diseases such as distemper virus and parainfluenza will also impair your sense of smell.
The optic nerve (II, n. opticus)
It is a sensory nerve for the organ of vision and the reaction of the pupils to light.
The retina of the eye functions as a digital scanner. It contains photosensitive cells (cones and rods), bipolar neurons and ganglion neurons.
The axons from the ganglion cells make up the optic nerve. Intranasally in relation to the diencephalon, the optic nerves connect at the optic junction.
Generally speaking, the fibers from the medial half of the retina of both eyes intersect at the optic junction, while the fibers from the lateral surface of the retina remain on the same side.
After passing the optic junction, the fibers continue in bilateral visual pathways located on the surface of the diencephalon.
The optic nerve is examined in conjunction with the oculomotor (III) nerve, which provides the motor path for the pupil-to-light reflex, and the facial nerve, which provides the motor path for the threatening reflex.
Vision can be assessed by observing the animal's movements in an unfamiliar environment, avoiding obstacles and following moving objects.
A more objective evaluation requires three tests:
- Checking the threat response (threat reflex, threat reflex, threat reaction, threat attempt - menace response / assessment of the retina, optic nerve, visual pathways, cerebral cortex and facial nerve).
This reflex is tested by making a threatening hand gesture towards each eye.
The normal reaction is a blink and sometimes an aversive movement of the head.
The absence of this reflex may indicate damage to the retina, optic nerve, visual pathways, cerebral cortex, or facial nerve.
- The visual response to placement (one of the postural responses) is an excellent method of assessing eyesight.
- Check pupil response to light - A doctor directs light to each eye and checks the pupil's response to light.
Changes indicating disorders of the optic nerve and loss of vision are pupil dilation and lack of their response to light (in direct and cross-over test) when the light source is directed towards the affected eye.
The oculomotor nerve (III, n. oculomotorius)
The oculomotor nerve has parasympathetic motor fibers responsible for the contraction of the pupil.
It is the motor nerve for the extraocular muscles and the muscle of the upper eyelid lifter.
The evaluation of this nerve consists of:
- Pupil examination (II cranial nerve, III nerve parasympathetic fibers, Th1-3 sympathetic nerve are evaluated).
Pupil size, symmetry and reaction to light are compared.
After directing the light to one of the pupils, both pupils should narrow symmetrically (cross reflex). Possible changes are:
- diversity (anisokoria),
- narrowing of both pupils (miosis - indicates damage to the sympathetic innervation of the pupil)
- dilatation of both pupils (mydriasis - indicates damage to the parasympathetic innervation of the pupil).
- Eye movement (III, IV, VI nerve) is also assessed by observing the dog's eyes when he looks in different directions.
The movement of the eyeballs can also be checked by observing the dog's reaction to the movement of (some object) in the peripheral field of view (the doctor checks if the animal is following the moving object).
The doctor observes the convergence of the eyeballs' movement and their symmetry.
- damage to the oculomotor nerve is caused by ventrolateral strabismus,
- damage to the block nerve (IV) - twist of the eyeball in the axis,
- damage to the abductor nerve (VI) - ventrico-centripetal strabismus.
- A more direct method is to induce physiological nystagmus, i.e. an oscillating movement of the eyeballs with a quick phase in the direction of moving the head.
The oculo-cerebral reflex (the "doll's eye" test) is triggered by moving the dog's head sideways and up and down.
The rapid rhythm of nystagmus occurs in the direction of the head movement. The eyes should move in a coordinated manner with each other (conjugated movements).
This test allows you to evaluate the functioning of the III, IV, VI, and VIII nerves.
Physiological nystagmus appears correctly. Lack of reflex may indicate severe damage to the nuclei of the III, IV and VI nerves in the brain stem.
If nystagmus appears spontaneously (without provoking head movements), it may indicate damage to the vestibular system (peripheral or central).
Incorrect reactions include:
- no pupil reaction on the affected side (even when shining to the opposite side),
- permanent lateral deviation of the eye (strabismus),
- pupil dilation.
A drooping upper eyelid (ptosis) indicates paresis of the levator eyelid muscle.
The compound nerve (IV, n.trochlearis)
The block nerve is the motor path for the dorsal oblique muscle of the eyeball.
It is difficult to assess.
Changes in this nerve trigger lateral rotation of the eye.
The trigeminal nerve (V, n. trigeminus)
The trigeminal nerve is the motor path for the chewing muscles and the sensory path for the face.
The motor branch is located on the mandibular nerve and innervates the muscles:
- the mandibular-hyoid.
The nerve of the mandibular muscles is the sensory nerve for the facial part of the head.
The motor function of the trigeminal nerve is studied by assessing the muscle mass and muscle tone of the mandibular masticatory muscles.
Palpation of the masseter muscles (the jaw branch of the V nerve) is a test that allows the detection of asymmetry or atrophy of these muscles, resulting from possible damage to the trigeminal nerve.
Bilateral motor paralysis manifests itself in the form of a "dropped jaw", which cannot be closed voluntarily, atrophy of the temporal muscles and a lack of the dog's chewing reflex.
One-sided paralysis causes temporal muscle atrophy, reduction of tension and strength of the mandibular muscles on the affected side.
Sensory function is assessed by testing pain sensation in the face, eyelids, cornea and nasal mucosa.
Feeling is checked by touching or gently pinching specific areas of the skin of the face.
The eyelid and corneal reflexes (the ophthalmic branch of the V nerve and the VII nerve) are triggered by touching the medial corner of the eye and the cornea with a tissue or cotton swab, and the effect should be to close the eyelid.
The eyelid reflex, checking the ophthalmic branch of the trigeminal nerve, is a response to a touch of the medial corner of the eye.
Touching the lateral corner of the eye checks the maxillary branch.
The blink response depends on the innervation of the muscles through the facial nerve (VII).
The response to stimulation of the nasal mucosa checks the jaw and eye branches, and the response should be evident even in dull and very calm animals.
Mandibular pinch assesses the mandibular branch.
The abduction nerve (VI, n. abducens)
The abduction nerve is the motor nerve for the retractor muscle and the rectus muscle of the eyeball.
Eye movements are examined by the method described for the oculomotor nerve.
The retractor muscle of the eyeball can be examined by the eyelid or corneal reflex.
The response to stimulation is usually by pulling the eyeball in, which results in the third eyelid being pulled out.
Changes in the abduction nerve result in convergent strabismus, loss of vision, inability to withdraw the eyeball.
The facial nerve (VII, n. facialis)
It is the motor nerve for the facial muscles and the sensory nerve for the inner surface of the auricle, the palate and 2/3 of the mouth of the tongue (taste sensation).
Facial nerve palsy causes facial asymmetry (e.g. lip, eyelid, ear may droop) and loss of blinking and lip retraction.
The nose may be slightly inclined from its normal position and the nostrils may widen when you inhale.
The fissure of the eyelid may be slightly widened and will not close during the eyelid or corneal reflex.
A pinch of the lip causes a behavioral response, but the lip may not back away.
With long-term paralysis of the VII nerve, the facial muscles atrophy and contract, which is manifested by pulling the lip or eyelid on the paralyzed side and curvature of the nose to the paralyzed side.
You can test your animal's sense of taste by applying a little bit of atropine to the tip of the tongue.
First, the affected side is checked.
Healthy dogs react immediately to the bitter taste.
A delayed response may appear when atropine reaches healthy areas of the tongue.
The vestibulocochlear nerve (VIII, n. vestibulocochlearis)
It is divided into the vestibular part (which provides information about the orientation of the head in relation to gravity) and the cochlear part (which is responsible for hearing).
The cochlea is a receptor of the hearing organ and is located in the inner ear.
The movement of special cells in the cochlea activates the fibers in the cochlear nerves.
The cochlear nerve connects with the vestibular nerve to form the VIII cranial nerve (vestibulocochlear nerve) that goes to the medulla. The cochlear nerve neurons are located directly in the spine.
Conscious sound perception is bilateral and is located in the temporal lobes of the cerebral cortex.
Most hearing tests are based on a behavioral response to sound, which is extremely subjective and can be misinterpreted.
General examination in the office is to surprise the dog with a loud noise (sudden clap, whistle).
Similar responses can be monitored by electroencephalogram (EEG) or by observation or direct measurement of the respiratory cycle.
An objective hearing test is an audiometric test.
The equipment includes a signal averaging computer that measures the electrical activity of the brainstem in response to auditory stimuli (brainstem auditory-evoked response / BAER).
This test not only detects hearing deficits, but can also indicate the location of the lesion.
One-sided deafness can only be confirmed by an audiometric test
The vestibular system is a special proprioception system that maintains the animal's orientation in relation to gravity and its position in the event of an acceleration or tilt of the head.
Thanks to it, it is possible to maintain the correct position of the eyes, torso and limbs in relation to the position of the head or movement.
Neurons are located in the vestibular nuclei of the brainstem and connect to receptors in the inner ear via the VIII nerve.
Equilibrium receptors are located in semicircular canals.
To maintain correct posture and coordinated eye movements, vestibular stimuli are transferred from the vestibular nuclei to the cerebellum and to the nuclei of the III, IV and VI nerve.
The motor fibers from the vestibular nuclei travel to all levels of the spinal cord via the vestibulospinal tract and synaptize on the abdominal gray matter interneurons.
The effect is to support the ipsilateral extensor muscles (located on the same side) and inhibit the ipsilateral flexor muscles and contralateral extensor muscles.
This is important for maintaining the extensor tone and facilitating the stretch reflex mechanism. Both are important components of the animal's antigravity system.
Disorders related to the dysfunction of the vestibulocochlear nerve include:
- head tilt,
- walking in a circle,
- hearing loss.
Abnormalities of the vestibular system produce several characteristic signs.
Most vestibular lesions are unilateral, except for congenital anomalies and occasionally in inflammatory diseases.
Unilateral vestibular disease usually causes ataxia, nystagmus, and tilting the head to the side of the lesion.
The doctor may emphasize the tilt of the head by preventing the dog from seeing or by removing tactile proprioception.
Usually there is atrial ataxia (uncoordinated, dizzy gait) with a broad posture and a tendency to fall or circulate to the side of the lesion.
Nystagmus is the involuntary rhythmic movement of the eyes.
Two of its forms are recognized.
Nystagmus with different phase lengths has a slow phase in one direction and a phase of rapid recovery.
This fast component is important and its direction should be observed.
This type of nystagmus can be vertical, horizontal or rotary.
It is associated with vestibular diseases and diseases of the brainstem.
Pendulum nystagmus is the small oscillation of the eyes with no slow or fast components.
It is associated with visual impairment and diseases of the cerebellum.
Vestibular syndromes are classified as peripheral (inner ear, vestibular nerve) and central (medulla and cerebellum).
The glossopharyngeal nerve (IX, n. glossopharyngeus), vagus nerve (X, n. vagus) and accessory nerve (XI, n. accessorius)
They are most often considered together because of their common origin and intracranial route.
The glossopharyngeal nerve is the motor nerve for the pharyngeal muscles, and it also supplies the parasympathetic motor fibers to the zygomatic and parotid salivary glands.
It is the sensory nerve of the caudal 1/3 of the tongue and the pharyngeal mucosa (sense of taste).
The vagus nerve is the motor nerve for the muscles of the pharynx and larynx.
The vagus nerve sensorially innervates the back of the throat (including part of the tongue), larynx and palate, and supplies parasympathetic motor fibers to the guts of the body (except the pelvic organs).
The accessory nerve has two roots - cranial and spinal.
The cranial roots come from the same nucleus as the vagus and glossopharyngeal nerves.
As the accessory nerve leaves the cranial cavity, its fibers join the vagus nerve to innervate the muscles of the pharynx and larynx.
The glossopharyngeal nerve and the vagus nerve control the act of swallowing.
The simplest functional test is to observe the palate and larynx for asymmetry and to induce the gag and swallow reflexes.
The swallowing reflex is tested by inserting a finger or a spatula into the throat, which raises the base of the tongue, spasms this area of the throat, and pulls up the larynx.
The reflex can also be triggered by light pressure from the outside on the hyoid area (or by giving the dog a treat or water).
The swallowing reflex and tongue movements are observed simultaneously.
The gag reflex is triggered by inserting a spatula into the back of the throat and applying pressure to the vagus triangle at the back of the tongue.
Taste can be judged as when testing the VII nerve.
Disorders caused by lesions of the glossopharyngeal and vagus nerves include loss of the gag reflex, dysphagia (inability to eat), problems with vocalizing, voice changes, and laryngeal paralysis.
Heavy breathing may be observed during laryngeal paralysis.
The functioning of the XI (accessory) nerve is difficult to assess.
Muscle atrophy in the neck area are possible, but most often disorders of the XI nerve occur together with disorders of the IX, X and XII nerves.
Difficulty or inability of the dog to swallow (information obtained from the history) may suggest abnormalities in the IX, X and XI nerves. Dysphagia is one of the symptoms of rabies.
The sublingual nerve (XII, n. hypoglossus)
The sublingual nerve is the motor path for the internal and external muscles of the tongue and the hyoid muscle, so it is responsible for the mobility of the tongue.
The muscles of the tongue stick out and hide the tongue.
Each side of the tongue is innervated independently.
The examination measures the muscle tone of the tongue, its movement and symmetry.
Tongue extension is tested by moistening the nose and observing the possibility of the tongue sticking forward.
The pullout force can be checked by catching the tongue through gauze.
In the case of denervation of the XII nerve, the tongue is initially tilted to the opposite side, then the denervated muscles atrophy and contract, which causes the tongue to shift to the affected side.
Atrophy can be observed if the lesion has been present for 5-7 days.
F. Assessment of feeling
The sensory examination provides information related to the anatomical location of the lesion and its severity.
Assessment of the conscious response of an animal to a noxious stimulus is performed only in animals exhibiting infestation.
A dog that is able to voluntarily move on its own (even if it cannot support its weight or walk) should be able to feel the stimulus of pain.
Sensory testing is done by assessing the cranial nerves, spinal reflexes and proprioceptive positioning.
So at this stage of the neurological examination, the doctor already has some information about the dog's ability to sense.
Additionally, the patient is checked for the presence of hyperalgesia, superficial pain and deep pain in the limbs and trunk.
Sensory pathways that are clinically relevant include those responsible for general proprioception (sense of position) and general somatic afferent information (especially response to noxious stimuli).
In animals, two types of information-carrying fibers pass through the spinal cord. Due to the location of the receptors, they are called superficial and deep pathways.
Superficial nociceptive pathways (to receive discrete pain stimuli in the skin, e.g. pin prick) are found in the abdominal (primates) or dorsolateral (cat) spinal cord, with a transmitter in the thalamus.
The pathway leads to the contralateral cerebral cortex for conscious pain recognition.
Deep nociceptive pathway (for experiencing severe pain in bones, joints or internal organs, e.g. crushing pain) is a bilateral system that affects:
- reticular formation,
- the cerebral cortex.
In general: to block the conscious sensation of pain stimuli distant from the lesions, the damage must be bilateral and severe.
The study of superficial sensation
The area of skin innervated by one spinal nerve is called a dermatome.
The dermatomas are arranged in a regular segmental fashion, except for some changes in the limbs.
Each spinal nerve carries a sensation of superficial pain from a specific dermatome.
The presence of abnormalities in the sensation of a given dermatome can be used to locate the lesion in the spinal nerve or dorsal root.
Checking for superficial pain is provoked by gently pinching the skin with forceps or pricking with a needle, starting from the back of the animal and moving forward.
The goal is to elicit a behavioral response in the dog that indicates that it is in pain.
The doctor checks the skin just off the midline and then repeats it on the sideline.
The opposite side is checked similarly.
During this study, three responses can be observed:
- behavioral reaction,
- reflex limb withdrawal,
- skin twitching.
A behavioral reaction, such as an anxiety, trying to flee, turning your head over or vocalizing, indicates you are in superficial pain.
The withdrawal of the limb is a reflex and only indicates an intact reflex arc.
The skin reflex is a contraction of the skin muscle, causing the skin to twitch along the dorsal and lateral parts of the trunk.
Depending on the response, feeling can be described as:
- absent (0),
- weakened (+1),
- normal (+2),
- increased (hyperesthesia, +3).
Lack of or decreased sensation indicates damage to a nerve or sensory pathway:
- Lack of sensation (0) - Known as anesthesia, it indicates complete damage to the nerve or the sensory pathway;
- Weakened feeling (+1) - hypesthesia, i.e. reduced perception of harmful stimuli, anesthesia; indicates partial damage;
- Increased sensitivity may indicate nerve irritation or, more commonly, irritation of adjacent structures (e.g. herniated disc with meningeal irritation).
- Hyperalgesia (+3) - hyperesthesia, increased sensitivity to nociceptive / noxious stimuli; irritating damage.
Behavioral responses to a harmless stimulus are interpreted as pain.
Sensation level - determined by pricking or pinching the skin on the back, from the L7 vertebrae and towards the head.
The sensory level is defined as the place between the area of decreased or no feeling and the area of normal feeling.
Since the nerve roots go caudally and abdominally, the sensory level is shifted by 2-3 caudal vertebrae in relation to the lesion in the spinal cord.
Nervous system damage reduces caudal sensation from the lesion, sometimes increases sensation at the lesion site and leaves the normal feeling closer to the lesion.
Feeling of the face
Facial sensation is examined by touching different areas of the face with the tip of the hemostatic forceps.
Failure to respond may be due to damage to the branches of the trigeminal or facial nerve.
The most pronounced reaction can be observed when touching the medial part of the nostrils (the jaw branch of the V nerve) - this is the most sensitive area.
The inner part of the auricle and the nasal part of the tongue are sensually innervated by the facial nerve.
The feeling of the tongue can be checked by introducing a small amount of a bitter substance - the correct response is salivation, licking and moving the tongue.
Facial feeling is assessed by examining the cranial nerves.
Examination of deep feeling
The presence or absence of deep sensation is one of the most important prognostic factors in a neurological examination as well as a reliable indicator of the integrity of the spinal cord.
This trial ends the neurological examination.
It is carried out by applying a pain stimulus to each of the limbs and the tail.
A significant behavioral reaction (vocalization, attempting to bite or move away, turning towards the pain stimulus) indicates the presence of sensation.
The withdrawal of the limb is not a behavioral reaction, but only a spinal reflex.
Pain stimuli are triggered by forceps, which forcefully pinch the interdigital folds or fingers of the limbs and tail.
Loss of spinal cord function after injury develops in the following sequence:
- loss of proprioception,
- loss of independent motor functions,
- loss of superficial pain sensation,
- loss of deep pain sensation.
Therefore, an animal with spinal cord compression that has lost proprioception and independent motor functions, but has the ability to superficially and deeply feel pain (pareza), has less spinal cord injury than an animal that has lost all four functions (resulting in plague and paralysis).
Loss of deep pain sensation indicates severe spinal cord damage and is poor prognosis.
During recovery, feeling returns first, then motor functions, and proprioception last.
G. Localization of changes
After the neurological examination is completed, it is necessary to locate the lesion in the nervous system, which is responsible for all the identified symptoms.
First, the lesion is located above or below the foramen magnum.
The great foramen is the caudal opening in the skull at the junction of the brain and spinal cord.
Above the great foramen lesions are further classified into one of five brain structures:
- cerebral cortex,
- diencephalon (thalamus and hypothalamus),
- brain stem (bridge, medulla),
The lesions located below the great foramen are classified as one of the five sections of the spinal cord:
- cervical to cervical (anterior) - C1-C5
- cervical caudal (posterior) - C6-Th2
- thoracolumbar - Th3-L3
- lumbosacral - L4-S3
- cross (S1-S3).
Brain lesion location and neurological disorders:
Symptoms of changes in the brain
- convulsive attacks,
- behavioral changes,
- the constant movement of the animal in a circle,
- sensory deficits,
- slight changes in the way you walk.
It is made of the forebrain and diencephalon.
The lesions affecting these areas generally cause contralateral clinical signs (i.e., appearing on the opposite side to the brain lesion causing them) and are generally similar.
Forebrain symptoms include:
- contralateral loss of body posture response,
- contralateral sensory deficits.
An animal with a lesion in the forebrain or diencephalon is able to walk, but does not have the precision of a healthy animal's movement. However, postural responses are not correct.
the cerebral cortex
The brain contains areas of cognition (thinking), learned responses, and behavior.
Generalized brain disease can cause changes in mental status (dementia, coma), loss of learned responses and responses (e.g. during training) and aimless wandering.
Seizures can also be a sign of brain disease.
Change in mental state:
- Walking in a circle one way, tramping around, pushing your head forward;
- Postural and proprioceptive deficiencies on the side opposite to the lesion;
- Cortical blindness on the side opposite to the lesion (normal pupils and their reflex to light);
- GNR hemiparesis on the contralateral side;
Interbrain (thalamus and hypothalamus)
- Mental state change:
- Postural and proprioceptive deficiencies on the side opposite to the lesion;
- Bilateral vision deficit;
- Disorders of eating, drinking, sleeping, body temperature (hypothalamus);
- No changes in sensation, muscle tone, spinal reflexes.
Changes in the midbrain cause:
- abnormal mental activity,
- disorders of the eyeball movements (nystagmus) and their position (strabismus),
- dilated (parasympathetic) or narrowed (sympathetic) pupils,
- weak or absent pupil reflexes to light,
- gait deficits,
- contralateral or ipsilateral (i.e., on the same side as the change) postural response deficits.
Hindbrain and medulla extended
Anatomically, the brain stem contains:
- secondary hindbrain,
- medullary brain (medulla).
It functionally includes all of these structures except the diencephalon.
Most clinicians confine the brainstem to the pons and medulla.
The bridge and core contain the upper motor neurons responsible for generating gait.
Damages within them cause ipsilateral motor and sensory deficits, vestibular disorders, deficits in the functions of cranial nerves and mental disorders:
- From normal mental state to dementia and coma; changes in consciousness are seen when the disease involves elements of the ascending, activating reticular system;
- Advanced gait and posture disorders:
- Side of the lesion GNR hemiparesis or tetraparesis; walking in a circle, if the animal is able to move;
- Cranial nerve deficits from V to XII:
- tricuspid - motor and sensory deficits;
- abductive - convergent strabismus;
- facial - facial paralysis;
- vestibulo-cochlear - central vestibular symptoms, deafness;
- glossopharyngeal / vagus - dysphagia, impaired swallowing, laryngeal disorders;
- sublingual - tongue movement disorders.
- Vestibular disorders:
- Restlessness or normal mental state;
- Head tilt on the side of the lesion, circular movements, rolling, falling, asymmetric ataxia and incoordination;
- Nystagmus (spontaneous or positional) with a fast fraction in the direction opposite to the lesion;
- Abdominal-lateral squint towards the lesion.
- Severe changes in the brainstem (midbrain and pons) cause post-cerebral stiffness because the motor pathways that inhibit extensor activity are lost.
Changes in the cerebellum and neurological disorders
The cerebellum acts as a coordinator of movements originating in the upper motor neuron system.
It is also responsible for maintaining balance, posture, and supporting the body in response to gravity and eye movements.
For the cerebellum to function, it must receive sensory information related to the position of the head, torso and limbs.
After receiving this information, the cerebellum compares or "measures" which parts of the body are involved in performing coordinated movements.
Clinical symptoms of cerebellar dysfunction include:
- Lack of coordination, cerebellar ataxia with dominance of hypermetry, in which there is excessive flexion of the joints of the limbs during the external phase, "goose gait ".
This may be accompanied by intentional tremors - they appear before the animal performs the intended activity (e.g. will take food).
- Head trembling, trembling with deliberate attempts to move.
- Broad posture with correct muscle tone and postural responses.
Since the cerebellum does not initiate motor activity, paresis and paralysis are not symptoms of cerebellar disease.
Movement may be uncoordinated to the extent that severely affected animals are unable to move, but these animals are not paretic because they can initiate movement and hold weight against gravity.
Postural and gait responses can be initiated and muscle tone is normal.
Feeling and spinal reflexes are normal.
Since the cerebellum has a direct connection with the vestibular system, disorders of the cerebellum can also cause symptoms of vestibular dysfunction.
Changes in the cerebellum can also cause deficits in the threat reflex in normal vision.
The loss of reaction to the threat occurs on the side of change.
Changes in the spinal cord with neurological disorders
The presence of symptoms of the upper or lower motor neuron also helps in locating changes, which may indicate changes in different parts of the spinal cord.
Generally, spinal cord injuries are accompanied by symptoms of upper motor neuron disorders (e.g. increased segmental reflexes, caudal from the site of damage) and lower motor neuron (weakness or lack of reflexes and withdrawal reactions at the site of damage), if the changes concern the cervical (C6-T2) or lumbosacral thickening (L4-S3).
A single spinal lesion may belong to both DNR and GNR for different groups of nerves and muscles, so special care should be taken in interpreting the symptoms.
Symptoms of the lower motor neuron
Damage to the lower motor neuron, whether it is a cell, axon, motor plate or muscle, produces a characteristic set of clinical symptoms.
Symptoms of DNR changes can be easily recognized during a neurological examination.
Paresis or paralysis, loss of muscle tone, and reduction or absence of reflexes occur immediately after damage to the DNR unit.
Rapid muscular atrophy becomes noticeable within 1 week and becomes severe.
Atrophy is limited to denervated muscles.
Correct interpretation of these symptoms allows the physician to locate lesions precisely in the specific segment of the CNS from which the affected DNR unit originates.
E.g. DNR symptoms affecting the pectoral limb are localized in the C6-T2 spinal cord segments, peripheral nerves, or muscles.
Most muscles are innervated by nerves from more than one segment of the spinal cord, e.g. the quadriceps are innervated by neurons from the L4-6 spinal cord segments.
The loss of one segment or one root causes a partial loss of muscle innervation.
The clinical symptom is paresis but not paralysis of the affected muscles.
Reflexes may be impaired.
Peripheral nerve damage can cause severe loss of function and all muscles innervated by the nerve are affected.
In these changes, reflexes are usually absent.
- Motor function:
- paresis for paralysis:
- flabby muscles.
- paresis for paralysis:
- hyporeflexia (weakness of reflexes) to areflexia (lack of reflexes).
- Muscle atrophy:
- early and severe:
- limb contracture.
- early and severe:
- Muscle tonus:
- Electromyographic changes:
- abnormal potentials after 5-7 days.
- Associated sensory symptoms:
- anesthesia of the innervated area (numbness);
- paraesthesia (misguided feeling - usually tingling, numbness etc.)
- hyperesthesia of adjacent areas;
- proprioception reduced to absent.
Symptoms of the upper motor neuron
GNR lesions produce a characteristic set of clinical symptoms caudally from the level of the injury.
The main symptom of motor dysfunction is paresis.
In the case of a disease of the upper motor neuron, paresis or paralysis is associated with normal or increased extensor voltage and normal or exaggerated reflexes.
In some cases, abnormal reflexes (e.g. crossed extensor reflex).
Such effects result in the loss of descending inhibition on the lower motor neuron.
Muscle atrophy (inactivity) may develop which develop slowly, are incomplete and in most cases involve the entire affected limb.
Since lesions at many different levels of the CNS cause symptoms of the upper motor neuron, it is usually not possible to match the lesion to a specific segment of the spinal cord (if only GNR symptoms are considered).
However, the correct interpretation of these symptoms and other related symptoms allows you to locate the damage in a given region, e.g. GNR paresis of the pelvic limbs indicates damage localized cranially to the L4 segment of the spinal cord.
If the lesion was in the L4-S2 segments (more caudal), DNR paresis would be present.
If the thoracic limbs are normal, the lesion must be caudal to the T2 segment of the spinal cord.
Therefore, a pelvic limb paresis (GNR) with normal pectoral limbs indicates damage between the T3 and L3 spinal cord segments.
- Motor function:
- paresis for paralysis:
- spastic muscles.
- paresis for paralysis:
- normal to hyperreflexia (excessive or exaggerated reflexes).
- Muscle atrophy:
- late and mild (inactive).
- Muscle tonus:
- normal to increased.
- Electromyographic changes:
- no change.
- Associated sensory symptoms:
- reduced or absent proprioception;
- reduced perception of harmful stimuli caudally from the change.
Distinguishing the symptoms of the upper and lower motor neurons is extremely important for locating lesions in the spinal cord and brainstem.
GNR symptoms locate lesions in areas of the spinal cord, while DNR symptoms help locate lesions in specific nerves, nerve roots, or spinal cord segments.
Diseases of the peripheral nerves or neuromuscular connections
Disturbances in peripheral nerves show symptoms of damage to the lower motor neuron with or without disturbed sensation.
After obtaining basic medical information (including the results of a general physical exam, neurological exam, and blood tests), you may need to undergo additional medical tests.
There are many diseases, such as infections, endocrine disorders, cancer, toxin poisoning, birth defects, degenerative diseases, and allergies that are believed to be related to neurological symptoms.
Therefore, in the absence of an unequivocal diagnosis, the diagnostic process continues with a series of tests.
H. Differential diagnosis
Based on the information obtained from the interview and the results of previously performed tests (physical and neurological examination), the veterinarian creates a list of differential diagnoses.
It may use the acronym VITAMIN-D for this purpose.
Diseases of the central nervous system in dogs based on the acronym: VITAMIN-D
Inappropriate urination / genitourinary diseases
- V - no data,
- And - distemper,
- T - diseases of the intervertebral disc,
- A - smoothbrain (angina), hydrocephalus, syringohydromielia,
- M - hepatic encephalopathy, uremic syndrome, hypercalcemia, hyperthyroidism, hyperadrenocorticism, hypoadrenocorticism,
- I - neurogenic cystitis, idiopathic cystitis,
- N - tumor of the basal ganglia, thalamus, cerebellum, vulvar nerve,
- D - neurodegenerative diseases of the basal ganglia, thalamus, cerebellum, vulva nerve, disease of the upper and lower motor neurons.
- V - cerebral hypoxia, cerebrovascular disorders,
- I - distemper, rabies, cryptococcosis, toxoplasmosis, steroid-responsive arteritis / meningitis, reflex sympathetic dystrophy,
- T - brain trauma,
- A - angina, hydrocephalus, porencephaly,
- M - hepatic encephalopathy, uremic syndrome, hypercalcemia, hyperthyroidism or hypothyroidism, hypo- or hyperadrenocorticism, heavy metal poisoning,
- I - neurogenic cystitis, idiopathic ganglioradiculoneuritis, idiopathic epilepsy,
- N - intracranial tumors: temporal lobes, limbic system, hypothalamus,
- D - poliencephalomalacia of the pear-shaped lobe and hippocampus, lysosomal storage diseases, mitochondrial encephalopathies.
Depression, decreased activity, drowsiness, apathetic behavior
- V - cerebrovascular disorders, cerebral hypoxia,
- I - distemper, cryptococcosis, prototecosis, ehrlichiosis, canine encephalitozoonosis, bacterial meningitis, necrotizing meningitis, granulomatous meningitis, steroid-responsive meningitis,
- T - brain trauma,
- A - angina, hydrocephalus,
- M - hepatic encephalopathy, uremic syndrome, hypercalcemia, hyperthyroidism or hypothyroidism, hyperadrenocorticism, hypoglycaemia, heavy metal poisoning, marijuana poisoning,
- And - no data,
- N - intracranial neoplasms: thalamus, frontal lobes, mesencephalic and ponsal midsection,
- D - lysosomal storage diseases, spongy gray matter degeneration, necrotizing encephalopathy.
Behavioral changes related to food intake
- V - brain hypoxia,
- And - rabies,
- T - no data,
- A - no data,
- M - hyperadrenocorticism, hyperthyroidism, lead poisoning, hepatic encephalopathy, uremic syndrome,
- And - no data,
- N - intracranial neoplasms,
- D - no data,
Cognitive disorders, learning and memory deficits, dementia
- V - brain hypoxia,
- I - distemper, fungal meningitis, rabies, toxoplasmosis, neosporosis,
- T - trauma to the frontal lobe,
- A - hydrocephalus, syringohydromyelia and Arnold-Chiari malformation,
- M - organic aciduria, lead poisoning, hepatic encephalopathy, uremic syndrome,
- And - no data,
- N - tumor of the frontal lobe,
- D - age-related brain damage, lysosomal storage diseases.
Stereotypes and compulsive disorders
- V - brain hypoxia, polycythemia,
I - rabies, Aujeszky's disease, granulomatous meningitis, tetanus, ehrlichiosis, necrotizing meningitis, prototecosis,
T - frontal lobe injury, reflex sympathetic dystrophy,
A - hydrocephalus, Arnold-Chiari malformation, syringohydromyelia,
M - hypocalcemia, lead and thallium poisoning, loperamide toxicity, hepatic encephalopathy, uremic syndrome, hypothyroidism, hyperadrenocorticism,
And - idiopathic ganglioradiculoneuritis,
N - intracranial tumors: frontal lobes, basal ganglia,
D - spongiform degeneration of gray matter, axonal neuropathy, cauda equina syndrome.
Unusual anxiety and fear
- V - cerebrovascular disorders, cerebral hypoxia,
- I - distemper, rabies, cryptococcosis, arthropod-borne diseases, toxoplasmosis, neosporosis,
- T - brain trauma, reflex sympathetic dystrophy,
- A - hydrocephalus, syringohydromyelia, Chiari-like syndrome,
- M - hepatic encephalopathy, uremic syndrome, hypothyroidism, hyperadrenocorticism, hypoadrenocorticism, heavy metal poisoning,
- And - no data,
- N - intracranial tumors (frontal lobes, basal ganglia),
- D - no data.
- V, I, T, A, M, I - no data,
- N - intracranial tumors (temporal lobes, limbic system, hypothalamus),
- D - axonal neuropathy.
Differential diagnosis of spinal cord diseases based on the VITAMIN-D scheme
- V- vascular:
- fibrocartilage embolism,
- spinal cord infarction.
- I - Inflammatory / infectious:
- T - Traumatic:
- vertebra fracture / dislocation.
- A - Anomalies:
- peak-rotational instability.
- M - Metabolic, I - Idiopathic:
- no data
- N - neoplasmatic:
- spine tumors,
- spinal cord tumors,
- tumors of the meninges.
- D - Degenerative:
- intervertebral disc disease,
- instability syndrome,
- horse tail syndrome,
- degenerative myelopathy.
Laboratory tests, such as blood count and serum chemistry, urinalysis - in conjunction with the results of a physical examination - are the absolute minimum necessary for the initial diagnosis.
Depending on the initial diagnosis and information obtained from the neurological examination, additional tests may be necessary:
- additional laboratory tests,
- X-ray of the chest and abdominal cavity,
- ultrasound and others.
In patients with suspected intracranial changes, it is necessary to perform:
- additional blood tests,
- cerebrospinal fluid tests,
- X-ray images of the skull,
- computed tomography and / or magnetic resonance imaging.
In patients with suspected spinal lesions, it may be necessary to perform:
- review series of x-rays of the spine,
- cerebrospinal fluid tests,
- computed tomography and / or magnetic resonance imaging.
These tests help to locate the lesion inside the skull or spinal cord, determine the most effective course of action (conservative or surgical treatment), and pinpoint the cause of neurological disorders in dogs.
Additional blood tests that are carried out at this stage of the diagnosis of neurological diseases are most often:
- serum bile acid test for hepatic encephalopathy,
- serum cholinesterase testing in case of suspected poisoning with organophosphorus preparations,
- determination of the level of thyroid hormones (diagnosis of hypothyroidism),
- immunological testing for specific microorganisms (meningitis, encephalitis and spinal cord inflammation),
- toxicological study (e.g. phenobarbital, bromide, lead),
- testing for tick-borne diseases (eg. Lyme disease).
X-ray examinationX-ray examination
As a method widely available and inexpensive - it is still an important research in neurology, especially when it comes to diseases of the spine or changes in the bones of the skull (e.g. post-traumatic, inflammatory or proliferative changes).
However, X-ray in many neurological cases is an insufficient examination (overlapping of various structures and difficult or even impossible assessment of the brain, spinal cord and nerve roots).
Surveillance radiographs of the spine allow the localization of changes when they directly affect the vertebrae or their ligamentous attachments, e.g.:
- congenital disorders,
- vertebral fractures / dislocations,
- vertebral body tumors,
- osteomyelitis of the vertebral body,
- displacement of the calcified intervertebral disc.
Radiographic symptoms of spine diseases are most often changes in shape, size, position and translucency.
However, overview x-rays do not allow direct visualization of the spinal cord.
In symptomatic patients who do not have visible changes in the vertebrae (e.g. with fibrocartilaginous embolism, tumors of the spinal cord or meninges, displacement of the intervertebral disc, cauda equina syndrome or unsteadiness), myelography, CT scan or magnetic resonance imaging are necessary to accurately locate the lesion.
Review skull x-rays can help evaluate patients with cranial vault injuries, otitis media, tumors involving the cranial vault, its mineralization, or any changes directly affecting the bones of the head.
Review photos, however, may not show changes in animals with neurological disorders that are secondary to intracranial diseases (e.g. hematoma, tumor, abscess, hydrocephalus and inflammation).
Functional radiography (load radiograph)
The test is performed on different sections of the spine using cautious dorsal hyperextension, abdominal flexion and / or linear stretching.
The reaction should be to intensify or remove pressure changes.
Functional radiography is most often used to identify peak-rotational instability, cervical and lumbosacral instability.
This examination shows the outline of the spinal cord, thanks to which changes (e.g. compression of the spinal cord, swelling or other disorders, defects in the structure of the vertebrae or spine, trauma, cancer or damage to the intervertebral disc).
It consists in subarachnoid injection of a contrast agent (from the lumbar or occipital access).
The myelography is performed under general anesthesia.
Lesions identified by myelography are classified as extra-scleral or intra-scleral (the latter may be extra-spinal or intramedullary).
Epidural changes are visible in the form of a contrast column raised and moved away from the spinal canal.
Intra-sclero-extra-spinal changes cause the contrast column to become wider in one of the projections.
Intramedullary changes cause a narrowing of the contrast column in both projections (ventral-dorsal and lateral).
Functional (with stress) myelography can help in the exact location of changes in the spine, as well as in planning therapy. It is usually used in the diagnosis of Unsteadiness Syndrome.
Functional myelography is performed by straightening, bending and stretching individual sections of the spine, thus increasing pressure on the spinal cord.
Epidurography and discography
Epidurography is a contrast test involving the injection of a non-ionic contrast agent into the caudal extracheal space and the radiographic recording of the image.
Discography, in turn, is performed by injecting contrast into the disc space between the vertebral bodies. Both methods are most often used in diagnosing cauda equina syndrome.
Radiographic changes on the epidurogram include elevation or compression of the contrast column by a lesion in the spine.
Changes on the discogram are irregular contrast distribution in the nucleus pulposus L7-S1 and the displacement of the contrast to the spinal canal of the lumbosacral section.
CT scan - due to its high sensitivity to changes in bone structures - is often used to assess the spine.
They are also used to assess changes in the brain and spinal cord.
Epidural lesions of the spinal cord are often assessed tomographically after epidural contrast administration.
Similarly, when recognizing specific soft tissue structures in the skull (e.g. intracranial tumors), a combination of CT with intravenous contrast can be used.
Tomograms can be used to determine the size of the lesion and determine whether the cranial vault is affected.
Magnetic resonance imaging (MRI)
Like computed tomography, it also provides cross-sectional imaging, but does not use ionizing radiation to obtain the image.
It is the diagnostic method of choice for brain lesions, intraspinal lesions and any other soft tissue (intervertebral discs) causing neurological disorders, because it allows for perfect imaging of these structures.
MRI is a non-invasive examination and is more accurate in soft tissue imaging than CT.
It is also more sensitive in the diagnosis and location of cerebral lesions.
In patients with lesions in the brain or in the spine, intraoperative ultrasound can be used until the final location of the lesion and assessment of whether it has been fully removed.
Examination of the cerebrospinal fluid
The parameters assessed during this study are:
- Physical properties:
- Under normal circumstances, the cerebrospinal fluid should be colorless, clear, and non-clotting. Possible incorrect results:
- blood fluid - caused by bleeding,
- cloudy - increase in cell count> 500 / μl,
- greenish and cloudy - purulent meningitis,
- clotting - inflammation of the meninges.
- Under normal circumstances, the cerebrospinal fluid should be colorless, clear, and non-clotting. Possible incorrect results:
- Number of cells (cytosis):
- under proper conditions
- protein - should be 25-30 mg / dl. > 60mg / dl + moderate pleocytosis - viral diseases of the central nervous system, tumors of the central nervous system,
- about 1000 mg / dl - bacterial inflammation of the central nervous system.
If necessary, inoculation for bacteria and fungi, immunological testing for microorganisms, the content of immunoglobulins and albumin is determined.
This test is used in the diagnosis of functional disorders of the central nervous system.
It is of particular importance in the diagnosis of epilepsy in dogs.
It is used to differentiate between neurological seizures and behavioral disturbances.
This test assesses the electrical activity of the peripheral nerves and muscles.
This test is used to diagnose diseases of the peripheral nervous system and muscles.
Diagnosis - the cause of neurological diseases in the dog
After a physical and neurological examination, and the necessary additional examinations, the veterinarian determines the most likely diagnosis.
Diseases with neurological symptoms are classified into several main groups.
Classification of neurological diseases
V (Vasculopathiae - vascular diseases)
Vascular diseases can appear at any age of the dog.
Their course is usually acute, sometimes there is noticeable improvement.
Sometimes non-neurological symptoms are present. The localization of lesions is usually focal.
Cerebrospinal fluid test: protein + to +++, possibly blood.
I (Inflammatio - infectious and inflammatory lesions)
The changes can appear at any age, sometimes they are also accompanied by extra-neurological symptoms.
The course is acute to subacute, rarely chronically progressive. The localization of the lesions is focal to multifocal.
In the cerebrospinal fluid, the presence of cells (+ to ++++), and protein (+ to +++).
T (Trauma - trauma)
Injury can occur at any age of the dog.
In fact, head or spine injury is one of the most common reasons for consultation in animals with neurological disorders.
The course is most often acute (or progressive), sometimes it may improve.
Sometimes the trauma is accompanied by extra-neurological symptoms. Focal to multifocal location.
Puncture in the case of post-traumatic changes is contraindicated.
A (Anomalous - developmental / acquired disorders)
They are most common in newborns and young animals.
The waveform is static and improvement is sometimes seen.
No extra-neurological symptoms. Focal location.
There is no change in the cerebrospinal fluid.
M (Metabolic - metabolic diseases / poisoning)
They can occur at any age.
The course is sharp, with a quick course.
Possible gastrointestinal, cardiovascular or other symptoms. Focal-diffuse location.
In the cerebrospinal fluid, protein (+ to +++), cells (absent to ++).
I (Idiopathic - idiopathic diseases)
Age - everyone.
Acute course with variable course.
No extra-neurological symptoms. Focal-diffuse location.
There is no change in the cerebrospinal fluid.
N (Neoplasia - cancer)
Nervous system tumors usually affect elderly dogs, rarely young ones.
The course of subacute to chronic, progressive.
As a rule, there are no extra-neurological symptoms. Focal location.
In the study of cerebrospinal fluid, protein (+ to ++), tumor cells.
D - (Degenerative - degeneration)
As a rule, degenerative diseases affect young or young adult dogs.
Diseases are usually chronic.
No extra-neurological symptoms. Focal-diffuse location.
In the cerebrospinal fluid, proteins are absent to +.
The most common neurological diseases / conditions in dogs
- Injury of the nervous system, caused by trauma to the head, spinal cord, brachial plexus detachment.
- Seizures caused by paroxysmal disturbances in the electrical activity of the neurons that make up the brain.
- Intervertebral disc disease - pressure on the spinal cord caused by degeneration, protrusion or prolapse of the intervertebral disc.
- Fibrocartilaginous embolism - ischemic disease of the spinal cord, caused by embolism caused by fragments of the degenerated nucleus in the blood vessels supplying the spinal cord.
- Muscle weakness - reduction in the number of acetylcholine receptors, leading to disturbances in neuromuscular transmission.
- Inflammation of the brain, spinal cord, and meninges that is sensitive to steroids.
- Tick-tick infestation caused by the toxin secreted by female ticks of the genus Dermacentor and other.
- Focal disorders of the cranial nerves (e.g. facial nerve palsy, damage to the trigeminal nerve).
- Central nervous system poisoning, e.g. organophosphorus / carbamate agents, metaldehyde, strychnine, lead and many others.
- Acute vestibular syndrome (in the course of otitis media / inner ear, idiopathic labyrinthitis).
- Inflammation of the vertebrae and intervertebral discs - bacterial or fungal infection of the intervertebral vertebrae and adjacent vertebral bodies.
- Hydrocephalus - accumulation of excessive amounts of cerebrospinal fluid in the ventricular system of the brain and in the subarachnoid space.
Most often it is a birth defect.
- Nodular lesions of the brain and spinal cord.
- Hereditary and congenital disorders of the central nervous system.
After the final diagnosis is made, the veterinarian proceeds to develop a therapeutic plan.
Treatment of neurological diseases is closely related to their root cause and may include conservative therapy, surgery, or a combination of both.
Since the management of canine neurological conditions can vary significantly from disease to disease, treatment of these conditions is far beyond the scope of this paper.
Prognosis of neurological diseasesPrognosis of neurological diseases
Many variables influence the prognosis for the health and life of a patient with neurological disorders and / or diseases.
The main prognostic factors are the location of the lesion, its extent and cause.
Diseases that progress slowly, such as cancer or degenerative conditions, have a much worse prognosis than those that are past their peak and are improving.
Clinical symptoms are also important guidelines for prognosis.
Compression of the spinal cord causes symptoms that change as compression increases.
The symptoms are not related to the position of the ducts in the spinal cord, but are related to the diameter of the fibers. Due to compression of the spinal cord, large fibers lose their function before the small fibers are affected.
Improvement in activity is possible until pain is lost.
An animal that fails to respond to a painful stimulus for more than 48 hours is unlikely to recover. Recovering animals may have severe movement deficits.
The duration of the lesion is also a significant prognostic factor, as the nervous tissue tolerates damage only for a short time.
Compression on the spinal cord that is strong enough to withstand voluntary motor function but not strong enough to withstand a noxious stimulus response is associated with a fairly good prognosis for recovery if spinal decompression occurs within 5-7 days.
The longer the compression time, the slower the recovery.
The location and nature of the change are also important.
Spinal cord infarction, e.g. it can range from mild to severe.
Forecasts differ equally seriously only because they differ, for example, in. location. e.g. an animal with an infarction attacking mainly gray matter in the L1 segment, with intact feeling in the pelvic limbs, has a fairly good prognosis.
The same degree of damage in the L5 segment is likely to cause permanent disruption due to destruction of the lower motor neurons supplying the femoral nerve.
When considering your dog's abnormal behavior, you should always bear in mind that it may not be caused by problems with the nervous system, but rather by behavioral abnormalities.
In fact, many neurological disorders can lead to behavioral modifications, and for many atypical behaviors, there is not yet a clear distinction between neurological and behavioral disorders.
This is a case of compulsive disorder, some of which may benefit from antiepileptic drugs while others are treated with psychoactive medications, usually used to treat behavioral problems.
The line between neurological disease and behavioral disorder is often blurred, and these abnormalities often coexist.
For example, all disorders of the central nervous system, especially the forebrain, have consequences in changing the behavior of an animal.
In addition, perceptual diseases such as blindness are responsible for marked behavioral changes.
Therefore, in some cases, close collaboration between veterinary doctors and neurologists and behaviorists is advisable.
Veterinarians, thanks to the use of advanced diagnostic methods and the exclusion of neurological, metabolic or infectious diseases, can take into account behavioral aspects and, if necessary, consult the patient with a behaviorist.
On the other hand, behaviorists should take into account that a patient with a behavioral disorder should first be carefully examined, also in terms of neurology.
However, it should be remembered that a routine neurological examination may not rule out the presence of neurological problems: for example, an intracranial tumor may give normal neurological examination results, and the only noticeable symptom may be behavioral change.
Such situations make the diagnosis and treatment of some diseases associated with neurological disorders extremely difficult and requires not only considerable financial outlays (specialist consultations, diagnostic tests), but also close cooperation between the animal's guardian - veterinarian / neurologist - behaviorist.
This article was intended to present issues related to neurology in general and show how complicated the diagnosis of neurological diseases can be.
The next step should be treatment and - possibly - rehabilitation.
An illness involving changes in the central nervous system does not necessarily mean a sentence.
Advances in veterinary neurology and increased access to certified veterinary neurologists, combined with improved imaging and other diagnostic techniques, offer new hope for proper diagnosis and treatment.
Of course, there are cases in which - due to poor prognosis or the aggressiveness of the disease process - the treatment is withdrawn, but there are a large number of neurological diseases that can be successfully treated.
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