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Constipation in your dog: symptoms and treatment of constipation [vet advice

Constipation is defined as the rare, difficult or incomplete excretion of dry, too hard and sometimes brittle faeces that the animal tries to forcefully "squeeze out" during defecation. This is what makes it different from constipation, which is a complete inability to pass stools and is a form of severe constipation. Constipation can therefore be defined as difficult to control or unresponsive to treatment constipation, caused by prolonged retention of hard, dry faeces, in which defecation is impossible.

Constipation in a dog

In general, it is believed that a healthy dog ​​should have a bowel movement at least once a day, although two stools a day or defecation every other day are generally normal, provided the animal shows no disturbing symptoms.

The frequency of bowel movements as well as the size and consistency of stools are individual features, however, they depend to a large extent on the type of diet, the size and frequency of meals, as well as physical activity.

Of course, there are occasional bowel irregularities in animals that are not cause for concern.

However, if constipation occurs frequently or lasts a long time, it should prompt the handler of the dog to consult a veterinarian.

Chronic constipation or constipation not only affects your pet's overall health and quality of life, but can also contribute to complications that are much more serious than simply being unable to pass stools.

In this study, I will discuss the important issue of factors predisposing to defecation problems, the early identification of which may spare the animal many unpleasant experiences.

I will also briefly characterize the most common complications of constipation, describe diseases and disorders in which the presence of feces in the colon is often observed, and I will mention the methods of treating both constipation, as well as the underlying diseases.

However, before we move on to pathological processes that predispose to constipation, in a few words I will mention the structure and functions of the large intestine.

This will come in handy for later considerations for treating and preventing constipation.

  • Structure and functions of the large intestine
    • Moving food content in the large intestine
    • Defecation - defecation
  • What is constipation in a dog?
    • Etiopathogenesis
  • The causes of constipation in the dog
    • Dietary reasons
    • Behavioral / environmental causes
    • Refusal to defecate
  • Changes seen in a dog with constipation or constipation
  • Identifying the causes of constipation
  • Means for the treatment of constipation
    • Characteristics of means used in constipation
  • Treatment of constipation in a dog
    • Treatment of mild to moderate constipation
    • Treatment of recurring or prolonged constipation
  • Treatment of constipation in a dog
    • Supportive treatment and preventive measures
  • Key nutritional recommendations
    • Digestibility and caloric density
    • Feeding plan
    • Assessment and choice of food
    • Assessment and determination of the method of feeding
  • Patient monitoring
  • Prognosis for constipation in the dog
  • Possible complications of constipation / constipation in your dog
    • Diseases and complications related to constipation in dogs

Structure and functions of the large intestine

There are three main sections of the dog's large intestine:

  • cecum,
  • colon,
  • rectum (i.e. straight intestine, or rectum).

The final segment of the rectum is the rectum, in which there is an external sphincter, made of striated muscles, and the internal sphincter muscle, which is a smooth muscle and is a cluster of circular fibers of the rectal muscle.

As a result of the contraction of these sphincters, the final segment of the rectum is kept closed.

Moving food content in the large intestine

Smooth muscles, which make up the walls of its individual sections, play an extremely important role in the efficient functioning of the digestive tract.

Food that enters the mouth, and then through the throat and esophagus, goes to the stomach, thanks to the efficient motor movement, it is moved further to the small intestine, then to the large intestine, and in its final part is excreted.

At each stage of this process, specific enzymes are secreted that digest specific nutrients.

The proper course of the digestive and excretion process depends largely on the motor efficiency of individual parts of the gastrointestinal tract.

If the contractile function of its smooth muscles is impaired, the food cannot be transported properly.

The large intestine shows different types of contractile activity, the most important of which are contractions:

  • mixing,
  • propulsive,
  • retropulsive.

Stirring contractions

They consist in the occurrence of a sequence of strong contractions of the circular muscle layer of the large intestine over a distance of 3-4 cm.

They are important for the fermentation processes that take place in the intestine.

Retropulsive or anti-peristaltic contractions

They rely on the migration of a contractile wave along the muscular membrane of the intestine, but in the opposite direction to typical peristaltic contractions.

As a result of retropulsive contractions, the contents are moved back towards the small intestine, thanks to which the mixing of the chyme is intensified.

Propulsive (peristaltic) contractions

Ingestion from the hip intestine means that some of the contents present in the colon must be moved so that a new portion can fit.

This is due to propulsive contractions, which are intensified from time to time, aimed at moving the entire contents to the end of the colon.

Canine colon consists of three segments, the colon:

  • ascending,
  • transverse,
  • descending.

The cecum is small and does not play a major role in digestive processes.

In the resting phase, on the border of the transverse and descending colon, retropulsive contractions arise that move the contents of the intestine to the ascending part of the colon and to the cecum.

In the descending part, in turn, weak peristaltic contractions occur, and the muscle of the proximal colon and rectum continues in contraction.

The liquid content reaching the colon is strongly dehydrated here, and a significant part of the electrolytes is also absorbed.

Defecation - defecation

The internal anal sphincter remains in a tonic contraction most of the time, thanks to which it is responsible for holding the faeces.

The external sphincter is kept in a permanent contracture, but is not as strong as the internal sphincter.

Defecation (defecation) is regulated by a reflex, which causes the relaxation of the internal anal sphincter and the appearance of peristaltic contractions in the rectum.

This reflex is known as the recto-sphincter reflex, and its appearance usually leads to the initiation of defecation.

This process is supported by the reflex contraction of the muscles of the abdominal press and the diaphragm.

The most important tasks of the large intestine include:

  • absorption of water and electrolytes,
  • stool storage,
  • carrying out the bacterial fermentation of organic substances that remained in the food content after passing through the small intestine.

The time it takes for feces to pass through the large intestine is usually 12-24 hours, but it may increase temporarily without major long-term consequences.

Extending the time it takes for the contents to pass through the colon results in dehydration of the stool and its hardening.

When stool is retained for a long time, it gradually becomes harder and drier, and eventually becomes trapped in the colon, while the mucosa continues to absorb water from the stool.

Diseases that significantly extend this transit time cause constipation, while chronically prolonged transit time of faeces leads to constipation, which in turn can result in enlargement of the colon.

What is constipation in a dog?

When we talk about constipation?

The term constipation applies to those patients who pass stool infrequently or who exhibit painful urge to defecate. Constipation is a clinical symptom, like vomiting or diarrhea, and not a disease, and may result from several disorders - either alone or in combination.

It is therefore only a fragment of the diagnosis that forces us to look for the underlying causes and to try to eliminate them.

WITH constipation the following medical terms are related:

  • Constipation - is a state of persistent constipation in which the colon and rectum are so overloaded with excessively hard fecal mass that the animal cannot defecate.
    It is a condition that, in addition to managing your diet, also requires pharmacological treatment.
  • Megacolon - is a condition in which the colon becomes extremely and often irreversibly enlarged and its motor function is significantly impaired.
    Megacolon in dogs is usually viewed as a consequence of severe chronic constipation resulting from obstruction (e.g. perineal hernia, pelvic canal strictures) and / or an underlying innervation defect.
  • Dyschezia - is a clinical symptom often associated with constipation, characterized by difficult and / or painful evacuation of feces from the rectum.
    In other words, it is difficult defecation, which is often associated with changes in the anus or its immediate vicinity.
  • Tenesmus - is a clinical symptom characterized by straining to defecate, which is usually ineffective and / or painful.
    It is often accompanied by dyschezia.
    Stool pressure is often confused with constipation, especially in an animal with an episode of diarrhea (the dog is dead, but the gut is empty).


Various mechanisms may be involved in the development of constipation, e.g. neuromuscular, mechanical, inflammatory, metabolic / endocrine, pharmacological, environmental or behavioral, so it is important to consider a comprehensive list of differential diagnoses.

Mechanical obstruction can result in constipation due to masses inside or outside the lumen of the large intestine, strictures of the anus and pelvic canal (improperly healed pelvic fractures).

Dehydration and electrolyte imbalance can also induce constipation.

Dehydration increases the absorption of water in the colon, thereby promoting the formation of dry, hard fecal matter.

Electrolyte disturbances (e.g. hyponatraemia, hypokalaemia, hypocalcaemia and hypercalcaemia) may alter the muscular activity of the colon, leading to stool retention in the large intestine.

The colon is innervated by the parasympathetic nervous system and the internal muscle and submucosa plexuses. Destruction or damage to any of these pathways reduces the mobility of the colon and increases constipation.

Normal colonic motility includes both propulsive and non-propulsive movements.

Eating, digesting and related somatic activity stimulate propulsive (driving) contractions, which are used to move the contents of the colon further - in the caudal direction.

Motor activity unrelated to propulsive movements, also known as segmental rhythms, mixes the colon content and supports the absorption of water and electrolytes.

In addition, a number of neurological disorders may reduce colon motility.

These include, among others:

  • cauda equina syndrome,
  • dysautonomia,
  • diabetic polyneuropathy of the diabetic and thyroid background.

The causes of constipation in the dog

Constipation is the result of a variety of factors that impair the passage of contents through the colon in various ways.

These causes can impair a bowel obstruction or reduce the need for a bowel movement, thus delaying the movement of the fecal masses.

The longer the stool remains in the colon, the longer it lasts for its contact with the mucosa of the large intestine, which means that most of the salt and water is "extracted" from the faeces.

This causes the stools to dry out and harden.

Colon overload with fecal matter, ingested foreign objects, or other undigested materials is the most common cause of constipation in dogs.

In some patients, constipation may be recurrent and may result in secondary giant colon syndrome.

Dietary reasons

  • Incorrect diet that may contain too little or too much fiber.
    In dehydrated animals, an excessive supply of dietary fiber may lead to constipation.
  • Swallowing inedible objects or materials such as: hair, bones, stones, socks, part of toys, plants, plastic, wood and much more.
    Ingested indigestible materials are incorporated into the fecal mass and can produce hard, blocking fecal masses that are painful and difficult to evacuate from the colon.
  • Insufficient fluid intake.
    Constipation can also occur when too much moisture is absorbed from food in relation to the water you drink.
    Therefore, a very good supporting action in the case of constipation tendencies is adding water to food.

Behavioral / environmental causes

  • Change in the household, routine activities, hospitalization.
    Environmental conditions that are not conducive to defecation or that differ from the dog's daily routine may cause the animal to inhibit its pressure, thereby causing faeces to accumulate abnormally in the intestine.
    This is what happens, for example. when an animal is kept in an unusual environment, e.g. at a dog hotel or veterinary hospital, or when the daily routine of outdoor exercise changes.
  • Lack of activity.
    Dogs with a "sedentary" lifestyle may be at greater risk of constipation.
    Pets that are trained to take care of their needs outdoors, but are confined to their homes for long periods of time, may stop their bowel movements for fear of getting dirty in the home.
    If these conditions persist, your dog may have problems with bowel movements.
  • Prolonged immobilization, e.g. for health reasons, during which the dog must stay in a small space for a long time (e.g. in a cage, carrier) can lead to constipation.
    Elderly animals with mobility problems often become constipated.

Refusal to defecate

  • Pain in the rectum or perineum may cause the animal to hold up bowel movements just to avoid discomfort.
    This happens so often with the following disorders:

    • inflammation of the anal glands,
    • anal abscess,
    • perianal fistulas,
    • anal constriction / anal spasm,
    • foreign body in the rectum or anus,
    • rectification (prolapse) of the rectum,
    • pseudo-prosthesis - this is a condition where feces become trapped and tangled in the hair around the anus,
    • proctitis,
    • bite wound or wounds in the anus,
    • abscess in the perineum area,
  • Inability to assume the defecation position, which is most often due to neurological or orthopedic reasons.
  • Painful orthopedic disorders such as trauma (e.g. pelvic fracture, limb fracture, dislocated hip) or degenerative changes in bones or joints.
    In such situations, the animal tries to reduce the need to walk, causing voluntary inhibition of defecation, which in turn leads to constipation.
  • Neurological problems:
    • disorders of the central nervous system:
      • hind leg paralysis (paraplegia),
      • spinal cord disease,
      • intervertebral disc disease,
      • brain disease (e.g. lead poisoning and even rabies);
    • disorders of the peripheral nervous system:
      • dysautonomia (abnormal function of the autonomic nervous system),
      • sacral nerve injury (e.g. tail fracture, pull trauma);
    • smooth muscle dysfunction of the large intestine:
      • enlarged large intestine of unknown cause (megacolon).
  • Obstruction of the colon, rectum or anus, which leads to a mechanical obstruction of the passage of the feces.
    The obstruction may result from lesions located inside or outside the lumen of the intestine:

    • Disorders located in the lumen of the intestine or its wall:
      • a tumor or polyp in the colon or rectum,
      • granuloma,
      • scar,
      • foreign body in the rectum,
      • congenital stenosis of the rectum,
      • rectal diverticulum,
      • rectal prolapse,
      • congenital absence of anus,
      • changes in the position of the rectum (perineal hernia).
    • Disorders located outside the intestinal lumen:
      • a tumor, granuloma or perianal abscess,
      • fused pelvic fracture with a narrowed pelvic canal,
      • prostatic hyperplasia, tumor, abscess, or inflammation,
      • prostate or periglandular cyst,
      • enlargement of the lumbar lymph nodes,
      • pseudo-coprostasis.
  • Colon weakness that may be due to a neuromuscular disorder.
    They can lead to constipation by disrupting the innervation of the colon, affecting smooth muscle function.
    Neuromuscular disorders also frequently result in the inability of the animal to assume its normal defecation posture.
    Faecal incontinence may be an accompanying clinical symptom when rectal innervation is also impaired.
  • Systemic disease (metabolic, hormonal) may lead to dysfunction of the smooth muscles of the large intestine.
    It happens in the course of the following disorders:

    • hypothyroidism (low levels of thyroid hormones),
    • hypercalcemia (hyperparathyroidism, etc.),
    • dehydration,
    • hypokalemia (e.g. in the course of chronic renal failure),
    • overactive parathyroid glands (parathyroid hormone regulates the level of calcium in the blood by causing calcium to be absorbed from the bones),
    • exhaustion, cachexia (e.g. in the course of general muscle weakness, dehydration, cancer)
    • diabetic gastroparesis.
  • Local neuromuscular damage:
    • spinal cord disease in the lumbosacral region (trauma, deformity, degeneration, cancer),
    • bilateral damage to the pelvic nerve,
    • dysautonomia,
    • chronic massive dilatation of the colon causing irreversible stretching of the muscle of the colon (idiopathic megacolon).
  • Iatrogenic causes:
    • opioid drugs (e.g. tramadol),
    • anticholinergic drugs, e.g. drugs for premedication or for the treatment of diarrhea, e.g. atropine,
    • adrenergic antagonists,
    • calcium channel blockers,
    • antihistamines,
    • sucralfate (a drug that creates a protective barrier on the gastrointestinal mucosa, usually used in ulcers),
    • barium sulfate,
    • antacids,
    • use of anti-diarrheal drugs,
    • iron supplements,
    • diuretics,
    • phenothiazines and benzodiazepines; anticonvulsants (e.g. phenytoin),
    • chemotherapy drugs (e.g. vincristine),
    • kaolin, pectins,
    • iron,
    • laxatives (abused or used chronically).
  • Other causes and predisposing factors:
    • Diseases causing dehydration.
      Dehydration may cause the faeces to become excessively dry and hard, which will predispose the animal to constipation.
    • Idiopathic giant colon syndrome.
      The condition known as megacolon mainly affects cats, but can occasionally occur in dogs.
      The smooth muscle of the colon - under normal conditions causing the fecal masses to move towards the rectum - loses its ability to move properly and feces remain in the large intestine.
      This is presumed to be due to the lack of conduction of electrical impulses from the nerves to the smooth muscles.
    • Constipation after surgery;
    • Invasion of internal parasites such as roundworms.
      As a rule, ascariasis causes diarrhea, however, with massive infestation, the lumen of the intestine may be blocked by a bundle of worms, especially in puppies.
    • Neoplastic obstruction of the gastrointestinal tract;
    • Advanced age;
    • Obesity;
    • Inflammatory bowel disease;
    • In non-castrated dogs - perineal hernia, prostate disease;
    • Perianal fistula;
    • Distorted appetite resulting in the consumption of inedible materials;
    • Excessive care, hair licking (possibility of consuming a significant amount of hair);
    • Lack of grooming, especially in long-haired dogs, resulting in tangling of the hair around the anus and induction of a pseudo-prostatic condition;
    • A fracture of the pelvis.

Changes seen in a dog with constipation or constipation

Constipation is an obvious symptom that is easily noticed by a dog handler.

The change in the frequency of bowel movements, the consistency of the stool and possible problems with defecation are noticed relatively quickly.

The most frequently observed changes in dogs with constipation are:

  • Reduced or absent defecation.
    This is one of the main reasons for a veterinary consultation regarding the digestive system.
    In animals, no bowel movements are observed for several days, and there may be a noticeable pressure on the faeces or frequent attempts to pass the faeces.
  • The classic clinical sign of constipation is high pressure and a characteristic defecation posture.
    However, this pressure is ineffective or results in very little stool.
  • Walking on the grass and looking for a place to defecate for a long time.
  • Dogs with constipation usually show tenesmus, dyschezia, and abdominal pain.
    Difficult or painful bowel movements usually indicate rectal disease.
    The animal may squeal or whine when trying to defecate, and these attempts are strenuous.
    He may then stop exercising, walk anxiously and repeatedly make fruitless attempts to expel his faeces.
  • Animals with chronic constipation may show systemic signs of the disease, including weight loss, anorexia, vomiting, and depression.
    Long-term inability to defecate may result in other systemic symptoms such as anorexia, lethargy, vomiting, and poor coat quality.
  • Infrequent bowel movements and the presence of hard, dry stools are also symptoms of constipation.
  • Paradoxical diarrhea - a small amount of liquid stool with mucus (sometimes with blood present), excreted after prolonged and severe urgency.
    Mucosal irritation caused by colonic stool retention can provoke the secretion of fluid and mucus that squeezes around the retained fecal mass and is excreted paradoxically as diarrhea when trying to push the stool out.
  • In addition to exertion, there may also be signs of general discomfort, irritability, anxiety, resignation, decreased appetite, and a frequent need to defecate with proper posture and tail lift.
  • Redness and swelling may appear around the anus, and fresh blood may be visible in the stools (this symptom is called. hematochezia, i.e. the presence of fresh red blood in the stool).
  • Faeces unusually smelly (more intense than usual).
  • Belt droppings.
  • Stool incontinence.
  • Occasional vomiting, lack of appetite, apathy.
  • Reduced activity and lethargy, most likely from pain and severe discomfort
  • The colon is filled with hard fecal masses.
  • Painful and / or distended abdomen, indicating abdominal discomfort.
    In animals, a hunched appearance may appear.
  • Dullness or discoloration of the hair around the anus.
  • Inflammation of the skin around the anus.
  • Decreased interest in eating.
  • Long-term constipation can lead to complete lack of food intake, weight loss, lethargy, vomiting, and dehydration.
  • Other changes depend on the cause of the constipation.

Identifying the causes of constipation

Identifying the cause of constipation

The presence of constipation is usually determined on the basis of information obtained from the animal's handler and confirmed by palpation of the abdominal cavity and rectal examination, in which the enlarged colon filled with fecal masses is palpable.

The purpose of diagnostics is to show the underlying cause and factors that predispose to constipation.

  • In the interview with the dog handler, iatrogenic, nutritional, environmental, and behavioral causes of constipation are primarily taken into account.
  • A clinical and rectal examination is performed to demonstrate any obstruction or infiltration.
    • During the general examination, the patient appears dull and usually dehydrated.
    • The animals adopt a relieved posture: hunched over, with a curved back, suggesting pain in the abdominal cavity.
    • When palpating the abdominal cavity, there is a noticeable presence of hard, kneadable, irregular, roller-shaped masses in the colon that can fill it along its entire length.
    • Rectal examination may show painful or obstructive changes in the anus and pelvic canal.
      On this examination, the rectum is usually empty and the hard fecal masses may be at the level of the pelvic entrance.
      In male dogs, prostate size and tenderness can also be assessed in this test.
      Light anesthesia may be required for rectal examination due to possible pain and strong defenses of the animal.
      When performing this test, it is a good idea to collect some stool from the handpiece to make sure it does not contain bone, hair, plastic, or other similar materials.
    • Rectal examination may reveal:
      • mass in the rectum or in the large intestine,
      • stricture of the large intestine (known as colon stricture),
      • a hernia of the perineum, which develops when the muscles that support the anus weaken and separate, allowing the rectum or bladder to slide under the skin and form a visible swelling around the anus,
      • perianal gland disease,
      • the presence of a foreign body,
      • enlarged prostate,
      • pelvic canal narrowing.
    • It is also important in a clinical examination to evaluate the pelvic limbs, hips, pelvis and lumbosacral spine for orthopedic problems that may cause painful bowel movements or difficulty in adopting a proper defecation posture.
    • A neurological examination may be required to identify any possible neurological deficits that may be involved in causing constipation.
  • Blood counts, serum chemistry and urine tests can reveal metabolic or hormonal causes of colon atony (hypercalcemia, hypokalemia, hypothyroidism).
    • Serum chemistry, urinalysis, and complete blood counts should be performed in dogs that are either suffering from recurrent constipation or during an episode of severe constipation.
      This test can identify an underlying systemic disease that may be causing constipation related to dehydration or electrolyte disturbances (e.g. in the course of chronic renal failure).
    • In severely "constipated" animals, especially those suffering from apathy and vomiting, laboratory tests may reveal the metabolic consequences of prolonged stool retention (e.g. fluid and electrolyte imbalance, endotoxaemia and azotaemia) and allow the introduction of supportive treatment.
  • A general x-ray of the abdomen and pelvis may reveal anatomical abnormalities or an obstruction in the colon (e.g. prostate hypertrophy, enlarged lumbar lymph nodes).
    This study also allows:

    • determine the extent of colon enlargement with densely packed, obstructive feces,
    • identify maximum colon dilatation that may be indicative of a megacolon,
    • identify foreign material, impervious to X-rays (e.g. "Bone splinters ") in the retained faeces, which indicates a dietary cause of constipation,
    • identify damage to the pelvis, femur, or spine that may be causing constipation,
    • identify an underlying enlarged prostate that may be causing constipation.
  • In some patients with recurrent constipation, it may be necessary to extend the diagnosis:
    • Thyroid function test, with the determination of the level of thyroid hormones.
    • Abdominal ultrasound to show infiltrates.
      This examination is indicated for the evaluation of the genitourinary system when prostate disease, prostate cysts or pelvic canal cancer are suspected.
    • Contrast-enhanced radiography is used to assess the lumen of the large intestine when an intra-lumen stenosis is suspected (e.g. stenosis or cancer of the rectum).
    • A colonoscopy is performed after any residual feces are removed and is used to assess the lumen of the colon.
    • Neurodiagnostics - myelography, magnetic resonance imaging (MRI), electromyography and nerve conduction studies to assess the lumbosacral segment of the spinal cord in selected patients suspected of impaired innervation of the rectum and anus.

If all the studies mentioned above fail to answer the question of what is the cause chronic constipation, this could be a case of idiopathic giant colon syndrome.

Means for the treatment of constipation

Means to increase the volume of feces

Fiber-based laxatives are added to the diet to provoke the formation of soft faeces and promote the normal mobility of the colon.

It is an initial approach to long-term control of mild constipation in dogs.

Stool expanders are non-absorbable polysaccharides, cellulose derivatives that exhibit hydrophilic properties in the intestine (they attract water).

This form of treatment is available as a commercial high-fiber dog food or as a fiber supplement to your regular diet, such as unprocessed cereal grains, wheat bran, or psyllium (psyllium seed).

The effectiveness of administration of this type of preparations depends on the proper hydration of the dog and the right consumption of water.

  • Psyllium - psyllium seeds, whose place of action is in the small and large intestines.
    The time during which the effect is visible is 12-24 hours.
    The dose of the powder is 1-5 teaspoons per day with food.
  • Unprocessed whole grain cereals and other bran (1-5 teaspoons daily with food).
  • Pumpkin pulp or ground pumpkin seeds (1-5 teaspoons daily with food).
    Place of impact: small and large intestine.
  • Commercial, high-fiber veterinary diet as a daily food source.

Lubricants, coatings

Laxatives such as mineral oil and white petroleum jelly are used to soften and lubricate the faeces to help evacuate the faeces.

  • White petroleum jelly - oral fluid administered at a dose of 5-25 ml 2 times a day.
    Paste: 1-5 ml once a day.
    Site of impact: colon, and the time needed to produce the effect is 6-12 hours.
    Vaseline is the preferred lubricant laxative.
    However, it is only effective in preventing (or treating) mild constipation.
    It should be administered between meals so as not to interfere with the absorption of fat-soluble vitamins.
  • Mineral oil, e.g. liquid paraffin (1-5 ml per day orally).
    Used with great caution as it can cause aspiration pneumonia caused by oil aspiration and also impair the absorption of fat-soluble vitamins.
    Combined use with docusan may cause undesirable absorption of mineral oil.

Laxatives and fecal softeners

Sodium docusate, calcium docusate and potassium docusate are mild laxatives available in oral forms and as rectal enemas.

They promote the penetration of water into the fecal masses, thereby softening the feces.

Their effectiveness requires proper hydration of the patient.

Docusan must not be mixed with mineral oil.

  • Sodium docusate at a dose of 50-200 mg per day orally.
    Place of action: small and large intestine.
  • Calcium docusate in a dose of 100-240 mg per day orally.
    Place of action: small and large intestine.

Osmotic stool expanders

These measures consist of:

  • poorly absorbed disaccharides (e.g. lactose or lactulose),
  • ions (e.g. magnesium hydroxide or magnesium citrate) or neutral osmotic agents (e.g. polyethylene glycol).

They osmotically trap water in the intestinal lumen, promoting the production of soft or liquid excrements.

Some animals may achieve a mild osmotic effect by adding milk (lactose) to the diet in an amount that exceeds the digestibility of the small intestine lactase.

  • Lactulose - is a non-absorbable disaccharide laxative, metabolized by colon bacteria to lactic acid and other organic acids that exert an osmotic effect and stimulate colonic fluid secretion and propulsive movements.
    Lactulose is administered as a syrup every 8-12 hours at a dose of 1-3 ml / kg m.c. orally.
    The effect appears 6 hours after administration, and the site of action is the large intestine.
    Lactulose is a very safe drug, even for long-term use.
    It is also the most clinically useful and effective osmotic laxative.
  • Magnesium hydroxide at a dose of 2-8 tablets daily orally.
    It is a human drug, rather not used in animals.
    Magnesium is contraindicated in patients with renal insufficiency.
  • Glycerine.
  • Polyethylene glycol at a dose of 25-40 ml / kg m.c. orally, repeat after 2-4 hours (mainly used to prepare the colon for radiographic or endoscopic examination).
  • Sorbitol.
  • Mannitol.

Intestinal motility stimulants

Stimulating laxatives are agents that increase the intestinal motility.

Bisacodyl is the most effective drug in this group.

These drugs are contraindicated if any obstructive changes in the intestine are suspected.

This group includes:

  • Aloe.
  • Anthraquinones:
    • Cascara Sagrada - is a natural preparation obtained from the bark of the American Buckthorn tree.
      It has a mild laxative effect and stimulates the motility of the large intestine.
    • Senna - This is a natural herbal laxative.
      Senna contains glycosides that stimulate the motility of the colon.
      Used in a dose of 1-4 tablets orally every 12-24 hours.
    • Castor oil - it is metabolized in the intestines to ricinoleic acid, which stimulates the motility and secretion of the colon.
      It is mainly used to prepare the colon for radiographic and endoscopic examination.
      Administered at a dose of 5-30 ml orally.
      Castor oil is not useful in outpatient treatment due to poor patient tolerance.
  • Diphenylmethanes:
    • Phenolphthalein,
    • Bisacodyl is available for oral, rectal and suppository administration.
      It works by stimulating the smooth muscle of the colon and the muscle plexus of the intestine.
      Although its action - in combination with stool softeners - is beneficial in the short term of administration, its long-term use may damage the muscle plexus.
      Administered in a dose of 5-20 mg per day orally.
      The site of influence is the colon, and the effect appears after 6-12 hours.
    • Sodium picosulfate.

Prokinetic therapy

Drugs that increase the mobility of the colon are contraindicated in the case of obstructive changes in the large intestine.

  • Cisapride at a dose of 0.25-0.5 mg / kg m.c. every 8-12 hours orally.
    The site of action is in the colon, and the time needed to produce the effect can be as long as 1-2 weeks.
    Medicines modifying intestinal motility are indicated in the early stages of colon enlargement (megacolon).
  • Prucalopride.

New use of other drugs

  • Acetylcholinesterase inhibitors.
    Ranitidine and nizatidine are H2 receptor blockers that stimulate the motility of the gastrointestinal tract and colon by inhibiting synaptic acetylcholinesterase, which increases the concentration of acetylcholine.
    These drugs are less prokinetic than cisapride.

    • Ranitidine at a dose of 2.0 mg / kg m.c. orally every 12 hours;
    • Nizatidine at a dose of 2.5 mg / kg m.c. orally every 24 hours;
    • Neostigmine;
  • Erythromycin.
  • Metoclopramide.
  • Prostaglandin E1 analogs (misoprostol).

Laxatives for rectal infusion

  • isotonic warm saline (or water) 5-20 ml / kg m.c. rectally,
  • Lactulose 5-30 ml rectally,
  • sodium docusate 5-30 ml rectally,
  • mineral oil (liquid paraffin) 5-30 ml or 1-2 ml / kg m.c. rectally,
  • magnesium citrate,
  • magnesium hydroxide,
  • magnesium sulfate,
  • sodium phosphate (not for use in small dogs) 1-2 ml / kg m.c rectal or 1 dose recommended by the manufacturer,
  • bisacodyl 1-2 ml / kg m.c. rectally or 1 dose recommended by the manufacturer.

Rectal suppositories

They can be used as a substitute for enemas.
Unfortunately, most dogs are reluctant to cooperate with their owner when attempting to apply a suppository to the anus, which makes their use rare.

  • glycerin suppositories 1-3 pediatric suppositories prosthetically,
  • suppositories containing bisacodyl, 1-3 pediatric suppositories, rectally,
  • suppositories containing docusate sodium 1-3 pediatric rectal suppositories.

Characteristics of means used in constipation

Mineral oil (e.g. Liquid paraffin)

It is a laxative with a lubricating effect, facilitating the passage of fecal masses and increasing the water content of the stool.

For short-term use, it is an appropriate option, but in chronic constipation, constipation often reappears as soon as laxatives are discontinued.

Side effects include greasy stool and abdominal cramps.

When administered orally, there is a high risk of choking with oil, which poses a risk of very serious and often fatal aspiration pneumonia.

Therefore, preparations of this type should be administered very carefully; it is unacceptable to inject oil under high pressure into the throat.


It is a disaccharide containing fructose and galactose.

Since it is not absorbed from the gastrointestinal tract after oral administration, it reaches the large intestine in unchanged form, where, under the influence of bacteria, it is broken down into carbon dioxide and organic acids (mainly lactic, acetic and formic).

These acids acidify the content of the large intestine and cause an osmotic laxative effect, i.e. they retain water and increase its content in the large intestine and soften the fecal masses.

Increased stool volume stimulates the motility of the colon, and increased stool water content facilitates defecation.

Side effects of excessive use of lactulose include loss of fluid and electrolytes, resulting in dehydration.

Care should be taken with long-term use as it may lead to electrolyte disturbances.


This macrolide antibiotic can be administered to "restart" the stomach during acute episodes of gastric congestion where oral medication is not tolerated.

Erythromycin causes stomach contractions by stimulating motilin receptors which increase smooth muscle activity.

This helps to remove solid and indigestible elements from the stomach.


This is another macrolide antibiotic that has been used as an alternative to the aforementioned erythromycin.

Azithromycin does not appear to interact with other medications seen with erythromycin and is also associated with fewer side effects.

However, there is only a limited amount of research into the use of this antibiotic to treat delayed gastric emptying.

There is also concern about its higher cost, and most importantly, it is controversial to use it to empty the stomach rather than to treat the actual infection with antimicrobials, as this may result in the development of antibiotic resistance.

Side effects include vomiting and diarrhea, but the antibiotic is better tolerated than erythromycin.

Ranitidine and Nizatidine

Both of these drugs are histamine receptor antagonists called H2 blockers.

However, they are unique in their class as they have the ability to improve gastrointestinal stasis thanks to prokinetic properties that improve gastric emptying.

Side effects are generally mild and occur at higher doses, but can include dizziness, nausea, diarrhea, and muscle aches.


It is a prokinetic drug that increases the motility of the upper gastrointestinal tract.

It is an agonist of 5-HT4 receptors and a weak antagonist of 5-HT3 and 5-HT1 receptors.

Side effects in veterinary patients are minimal and may include vomiting, diarrhea and abdominal discomfort.


This drug is a serotonin agonist with a selective affinity for 5-HT4 receptors.

In human clinical trials, prucalopride has provided constipation patients with increased daily passage of food from the stomach, through the intestines and colon.

Side effects in these studies showed effects such as headache, nausea, abdominal pain or cramps, diarrhea.


This drug is an antiemetic and prokinetic benzamide that acts as a dopamine antagonist.

Metoclopramide works by blocking dopamine receptors in front of the synapse (a synapse is a junction of two nerve cells).

The effect of this action is to facilitate the release of the neurotransmitter acetylcholine from neurons.

Acetylcholine, in turn, acts on the M2 muscarinic receptors in smooth muscle cells of the gastrointestinal tract, inducing contraction.

This improves the functioning of the digestive tract and facilitates the transfer of food to its other parts.

At higher doses, it also has an antagonistic (inhibitory) effect on 5-HT3 serotonin receptors.

Thanks to this, it has antiemetic properties and inhibits nausea.

Metoclopramide eventually improves the acetylcholine response in the tissues of the upper gastrointestinal tract, which increases motor activity and reduces gastric emptying time.

However, as this drug crosses the blood-brain barrier, it may have effects on the central nervous system, causing side effects that limit the use of this drug.

They include:

  • anxiety,
  • depression,
  • gait disturbance,
  • muscle tremors or stiffness and other neurological symptoms


It is a cholinergic agonist usually used in urinary retention because it increases the tone of the bladder muscles.

However, since it stimulates the parasympathetic system as a whole, it also stimulates gastric motility.

Possible side effects may include:

  • low blood pressure,
  • accelerated heart rate,
  • abdominal cramps,
  • diarrhea,
  • nausea,
  • vomiting,
  • drooling,
  • increased tearing,
  • throat spasm.


This drug is an acetylcholinesterase inhibitor that is usually used as an antidote for anticholinergic poisoning and for the treatment of myasthenia gravis and urinary retention.

There is also limited evidence of stimulation of gut motility.

Neostigmine also has a number of related side effects, including:

  • bradycardia,
  • low blood pressure,
  • seizures,
  • somnolence,
  • weakness,
  • diarrhea,
  • muscle cramps,
  • nausea,
  • drooling,
  • stomach cramps,
  • vomiting,
  • breathing difficulties,
  • increased secretion of mucus in the throat,
  • increased tear production.


This drug is a gastrointestinal dopamine antagonist.

It works by stimulating the activity of the upper gastrointestinal tract by inhibiting dopamine receptors, enhancing the action of acetylcholine in the gastrointestinal tract, increasing gastric motility and increasing peristalsis to facilitate gastric emptying and speed up small intestinal transit time.

Domperidone does not cross the blood-brain barrier and therefore has no tendency to induce effects on the central nervous system.

Side effects that may be noticed include dry mucous membranes, dizziness and increased heart rate.


This drug is a cyclic fatty acid that acts locally at the top of the gut as a chloride channel activator, increasing intestinal fluid secretion and increasing intestinal motility.

Although it is only approved in humans, and currently no studies have been conducted in dogs, cats and horses, a pilot study has been conducted that has proven its effectiveness in reversing opioid constipation in guinea pigs.

Side effects in humans include:

  • headache,
  • nausea,
  • diarrhea,
  • flatulence,
  • stomach pain,
  • dizziness.


It is a peptide agonist of the guanylate cyclase C receptor.

It is minimally absorbed, and by attaching to the receptors found in the intestines, it increases the secretion of fluid in the intestinal lumen, which causes the stool to relax and accelerate bowel movements.

The most common dose-related adverse reaction in humans was diarrhea.

Treatment of constipation in a dog

The specific treatment plan will depend on the severity of your constipation and the underlying cause.

The choice of therapy will be selected on the basis of the exact type of ailments the animal is experiencing.

As chronic constipation is painful, it is difficult for the patient to relax the abdomen, which makes defecation more difficult.

Therefore, in addition to treating constipation itself, it is also necessary to focus on pain management.

Surgical therapy, if justified, can be very helpful, and in some cases even key to improving the patient's clinical condition.

There are several options for treating constipation in a dog.

Most of these procedures (such as surgery for mechanical obstruction of faeces or fluid therapy for dehydration) focus on the underlying cause of fecal retention in the colon.

Sometimes it is necessary to stabilize the patient's condition beforehand.

However, you should always try to relieve your pet from constipation and, if necessary, treat pain.

Initial relief from constipation

The use of rectal suppositories, enemas, or manual fecal extraction under anesthesia initially relieves constipation.

Rectal suppositories

  • sodium docusate (docusate) - they soften the faeces and have a laxative effect,
  • glycerin - a laxative with a lubricating effect,
  • bisacodyl - stimulating laxative.

To support bowel movements in patients with mild constipation, 1-3 pediatric rectal suppositories containing docusate, glycerin or bisacodyl should be given.

Rectal suppositories can be used alone or in combination with an oral laxative.

The use of suppositories is often restricted due to the reluctance of the dog (or its guardian).

Enema therapy

Rectal enemas commonly used include:

  • warm isotonic saline or water (5-10 ml / kg m.c.);
  • lactulose as an osmotic stool softener;
  • docusat as a softening agent;
  • mineral oil as a lubricant;
  • sodium phosphate has a softening, volumizing and irritating effect.

Enema solutions are used to soften hard, wedged feces, favoring their evacuation.

Before starting the enema, the infusion solution should be warmed to body temperature.

Thereafter, a rubber or plastic catheter is lubricated with a lubricant and inserted into the handpiece.

The fluids are given slowly so as not to cause vomiting.

Mineral oil and docusate should not be mixed.

Dokusat supports the absorption of mineral oil by the mucosa, and the oil, in turn, covers the faeces, preventing docusate from working.

Sodium phosphate solution should only be used in medium and large dogs with adequate hydration and renal function.

Phosphate enemas cannot be used in small dogs (and in cats) due to life-threatening hypernatraemia, hyperosmolarity, hyperphosphataemia and hypocalcaemia.

Manual extraction of retained feces

In severe constipation or constipation, first the fluid and electrolyte balance should be parenterally restored, and then - under general anesthesia - the colon should be emptied of residual feces.

For this, colon lavage with warm isotonic saline is used to soften the faeces.

Then the residual masses are moved by gentle manipulation through the abdominal wall to push them gently towards the anus.

The feces are then extracted by hand or with the help of special forceps.

In animals with extensive stool retention, to avoid excessive intestinal trauma, it is advisable to manually empty the colon in stages - a little for 2-3 days.

Oral laxative therapy

Oral laxatives and dietary supplements may be introduced as needed to control constipation and prevent relapse.

Laxatives act as a lubricant (coating the faeces with a slippery layer, facilitating their excretion), support the penetration of water into them to soften hard masses, improve the transport of fluids and electrolytes through the intestinal mucosa and stimulate propulsive movements of the colon.

They are classified according to the properties and mechanism of action as means:

  • increasing the weight of the stool,
  • lubricating,
  • softening,
  • osmotic,
  • stimulating,
  • prokinetic.

Many oral laxatives require that the animal be adequately hydrated and have constant access to fresh water for optimal effect.

The use of these drugs is often individual and the dose must be adjusted to the desired frequency of defecation and the consistency of the stools.

The most effective and clinically useful laxatives are:

  • dietary fiber,
  • lactulose,
  • prokinetic drugs such as cisapride.

Management of constipation should be in stages

  1. Combating water and electrolyte imbalances.
  2. Removal or reduction of the root cause.
  3. Use of laxatives or laxatives.
  4. Performing post-rectal infusions.
  5. Determining how to prevent.

Clinically constipated patients can be classified into one of two main groups:

  1. The first are animals suffering from acute obstruction or chronic constipation for the first time.
    In patients with acute and moderate constipation, initial therapy is aimed at restoring the fluid and electrolyte balance.
    After correcting the water and electrolyte disturbances, post-rectal infusions are made and the compacted feces are removed manually.
    The procedure is performed under general anesthesia.
  2. The second are animals with recurrent and prolonged constipation.
    Severe constipation and constipation may initially require the evacuation of stools from a blocked large intestine (with enemas, manual extraction, or both) and correction of complicating the patient's condition - dehydration and electrolyte imbalance.

Treatment of mild to moderate constipation

Treatment for mild to moderate constipation may include enemas, stool softeners, laxatives, and colonic motility modifiers.

The first episodes of constipation are often transient and usually resolve without the need for pharmacological treatment.

Mild to moderate and recurrent episodes of constipation (but without systemic symptoms such as apathy, vomiting or dehydration) usually require medical attention:

  • In addition to dietary management, these cases can be treated, often on an outpatient basis, with enemas, laxatives (oral or suppository), and prokinetics.
    • Enemas: You can relieve constipation symptoms by using warm water enemas with a water-soluble lubricant.
      Rectal infusions can be assisted by manual stool removal.
      An attempt to empty a colon filled with faeces can be done with soapy solutions or by:

      • sodium citrate
      • lactulose
      • dioctyl sodium sulfosuccinate,
      • phosphate enemas (not in small dogs).
    • Repeated infusion attempts and the simultaneous kneading of the intestines by the abdominal wall facilitate the extraction of the fecal masses outside.
      However, removing them should be done with great care.
      After the procedure, it is recommended to introduce an antibiotic-steroid ointment (preferably mixed with lignocaine ointment in a 3: 1 ratio) into the rectum.
    • After removing the stools, steps should be taken to prevent the constipation coming back.
      Prophylaxis consists in enriching the diet with bran, methylcellulose or other fillers.
      Many of the poorly absorbed carbohydrates can prove useful as laxatives.
      Sugars, e.g. sorbitol and lactulose are hydrolyzed to fatty acids by the colonic microflora.
      The metabolites of these sugars exert osmotic pressure and draw fluid into the lumen of the large intestine.
  • Additionally, laxative treatment may sometimes be required to increase stool hydration and increase "slippage".
    If necessary, laxative drugs are used, e.g. lactulose.
  • The patient should be reassessed after 48 hours.

Treatment of recurring or prolonged constipation

In animals with recurrent, long-term constipation, one should strive for a detailed identification of the cause of constipation and reduction of defecation.

If possible, it should be eliminated.

  • Symptomatic action also consists in the mechanical removal of residual feces, the use of enemas, and then the administration of pharmacological agents and strict adherence to dietary and environmental recommendations.
    Symptomatic treatment is often effective at first and relieves the animal, but it is important to look for the causes of constipation at the same time.
    When treatment to mask constipation symptoms is too long, some problems that initially respond well to treatment may become irreversible.
    Laxatives, in the form of stool softeners:

    • Bulking agents such as: bran, methylcellulose, pumpkin seeds, psyllium, Hill's food w / d, y / d. Dietary supplementation with products that increase stool volume is often helpful, although these measures can sometimes increase the distension of the colon by fecal matter and make the situation worse.
      In this case, you should follow a low-residue diet.
    • lubricants: mineral oil,
    • hyperosmotic agents: lactulose, magnesium sulfate,
    • prokinetics can be useful, although they rarely provide a long-term solution to the problem: cisapride, bethanechol, tanitidine.
  • Surgical treatment.
    If enemas and medications are ineffective, it may be necessary to manually remove residual fecal matter from the colon of an anesthetized animal.
    Occasionally, surgery to partially remove the colon may be necessary.
    In general, such treatment is recommended in dogs with recurrent constipation.
    Surgical treatment is indicated in the following cases:

    • Pelvic canal stenosis: Pelvic injuries can cause pelvic canal narrowing and ultimately the development of megacolon.
      Correcting these changes within three months will resolve colon dilatation, but more chronic trauma may require partial colon removal.
    • Cancer.
      Tumor masses in the posterior abdominal or pelvic region can cause severe compression of the colon and require surgical removal.
    • Colon diseases.
      Changes inside the large intestine (e.g. torsion of the large intestine, rectal cancer) are treated by resection of the affected intestine.
    • Megacolone: ​​Up to 95-98% of the colon can be removed during surgery.
    • Post-operative care.
      After the colectomy procedure for several days (usually 3-5), you may feel a painful urge to stool.
      A semi-solid stool will form within a few days.
      Colon surgery is associated with a higher risk of postoperative infections, but perioperative antimicrobial prophylaxis is sufficient to minimize this problem (if care has been taken to minimize intraoperative infection).
      It is mandatory to carefully monitor the dog for any signs of postoperative leakage into the peritoneal cavity, especially in the first 24-72 hours after surgery.
  • Healthcare:
    • the cause of constipation or constipation should be removed or treated if possible,
    • medications that can cause constipation should be discontinued,
    • if you suffer from constipation and / or dehydration, you may need to be hospitalized,
    • fluid therapy in the case of dehydrated animals.
    • increasing the dog's physical activity and encouraging him to move.

Treatment of constipation in a dog

Treatment of constipation in a dog

Constipation often requires inpatient treatment to correct metabolic abnormalities and evacuation of feces using an enema, manual extraction of residual feces, or both.

Further goals of therapy are the elimination or control of all causes of constipation, the correction of predisposing factors, and the prevention of relapse with dietary modification, laxatives and prokinetic medications as needed.

In the case of tumors blocking the passage of the feces, pelvic strictures or some diseases of the anus, surgical intervention is sometimes necessary.

Supportive treatment and preventive measures

After removing the retained feces from the colon, all measures should be taken to prevent the recurrence of constipation and, if necessary, to monitor them.

The main issue is to identify and eliminate the root cause of constipation and the predisposing factors.

  • Prevent ingestion of constipating materials such as bones, plastic bags, toy fragments, etc.
  • In long-haired dogs, prevent hair ingestion through regular grooming.
  • Providing daily activity and frequent bowel movements.
  • Providing constant access to fresh water at all times.
  • Along with plenty of water, increasing the amount of fiber in your diet and reducing the amount of carbohydrates is very important to the health of your digestive system.
  • Eliminate or adjust the dose of any medications that may be causing constipation.
  • Treatment of predisposing disorders such as prostate, endocrine (hypothyroid), orthopedic and neurological diseases.

Heal painful or obstructive perianal lesions (if necessary surgically).

Key nutritional recommendations

Dietary recommendations


Keeping hydrated is important when treating patients with chronic constipation or constipation.

Water is a key nutrient and its consumption is often overlooked.

Various methods should be used to encourage a dog to consume water.

These include providing multiple bowls of water in prominent locations around the animal, serving moist (> 75% water) rather than dry foods, adding small amounts of flavorings (such as broth) to the drinking water, and offering ice cubes as treats or snacks.

The addition of canned pumpkin and / or sweet potatoes to food has been used successfully in some cases of constipation.

These vegetables mainly consist of water (90%), which adds moisture to the digestive process.

The beneficial effects of using this type of vegetables are rather due to the increase in the daily water consumption, although the consumption of fiber is also increased thanks to them.


Many constipation patients experience clinical improvement when the fiber content of food increases.

Dietary fiber is poorly digestible polysaccharides from various sources.

Fiber sources commonly used in commercial pet products include:

  • sugar beet pulp,
  • wheat seeds,
  • cellulose,
  • soybean husks,
  • nut shells,
  • pea fiber.

Increased fiber intake increases stool water content, colon motility, and intestinal transit rate.

All of these elements can be beneficial in constipated patients.

Both soluble and insoluble fiber are recommended for treating constipation.

Fiber acts as a laxative to increase stool volume.

Insoluble (poorly fermentable) fiber (e.g. purified cellulose, peanut husks) normalize the mobility of the colon by expanding the lumen of the intestine, increasing the lumen content in the colon, diluting the toxins present in the lumen of the large intestine (e.g. bile acids, ammonia) and increasing the rate of intestinal transit.

This acceleration of the passage of fecal masses through the gut reduces the exposure of colonocytes (colonic epithelial cells) to toxins, while softening the stool and increasing the frequency of bowel movements.

Soluble (fermentable) fiber such as fruit pectin, guar gum, psyllium is easily fermented by bacteria, resulting in short chain fatty acids that benefit colon health.

These fibers, introduced with food into the gastrointestinal tract, swell to form gels that soften and facilitate the passage of fecal masses.

However, fermentable fibers may not be as laxative as insoluble or mixed because they have little ability to add bulk to stool or dilute toxins.

Potential side effects of the fermentable gel-forming fibers are:

  • flatulence,
  • diarrhea,
  • stomach pain.

These side effects can be reduced by gradually switching to fiber supplementation, slowly increasing the amount of soluble fiber added until it is effective with minimal side effects.

Such fiber should be added in an amount no greater than 5% of the total ration, as soluble fiber can significantly reduce the availability of minerals, including zinc, calcium, iron and phosphorus.

Ingredients such as beet pulp, bran (rice, wheat or oat), pea fiber, soy fiber, soybean husks or mixtures of soluble and insoluble fiber sources are indirectly fermentable and have moderate properties of both fermentable and poorly fermentable fibers.

They are referred to as mixed fibers.

For patients with chronic constipation who have some degree of mobility of the colon, the crude fiber content of the food should initially be at least 7% dry weight and the fiber source should be insoluble or mixed.

Fiber sources can be added to the patient's current diet, but it is better to switch to fiber-enriched foods.

Feeding extra dietary fiber is better than using laxatives alone.

Dietary fiber is more physiological, better tolerated, and often more effective than other laxatives.

For patients in whom colonic motility is completely depleted, fiber-enriched foods and fiber supplements are no longer effective stimulants of colonic motility and, worse, may contribute to constipation.

Food for patients with megacolon should contain no more than 5% fiber by dry weight.

Digestibility and caloric density

In constipated patients in whom colonic motility is completely compromised, feeding on a highly digestible diet with increased energy density will provide adequate nutrition and significantly reduce fecal matter.

Energy density and digestibility are inversely proportional to the fiber content.

The reduction in fiber increases the caloric density, which helps to meet the small food volume requirements.

Calorically dense food can reduce the housekeeping responsibilities of the owner (such as administering stool reducing agents, using enemas, etc.).

In these cases, stool production is reduced to the point where owners can generally remove feces through cleansing enemas once or twice a week.

In many cases, this type of nutrition is used when a dog's handler is considering a surgical colectomy option.

Energy density and digestibility are less important in constipated dogs.

Feeding plan

Initial treatment of chronic constipation includes educating the caregiver, encouraging increased water intake, appropriate dietary changes, and judicious use of laxatives and enemas.

If the animal is overweight, a weight reduction program should be instituted.

Constipation often requires multiple cleansing enemas with or without mechanical faecal evacuation before making dietary changes.

Assessment and choice of food

In patients with constipation, the content of key nutrients in the currently fed diet should be assessed.

Such information is essential for any change to the food.

A switch to a more appropriate food is advisable if the levels of the key nutritional factors in the current food are not strictly within the recommended levels.

Many "constipated" patients respond positively when given the right food, especially if it is moist.

Animals should be well hydrated prior to increasing their fiber content to maximize the therapeutic effect of the fiber and minimize the fiber's potential to retain feces in the colon.

It is prudent to gradually increase the fiber content of the diet over several weeks until clinical symptoms improve or resolve.

The fiber content can also be increased by adding foods with a higher fiber content to the actual food.

Most commercial foods and specialty pet foods contain less than 5% crude fiber.

Foods enriched with fiber contain 8 to 25% crude fiber.

Adding fiber supplements like psyllium, coarse wheat bran, grain bran, and pumpkin to regular food is another method of increasing fiber intake for constipation in dogs.

However, this is a less desirable approach.

Fiber supplements can be inconvenient to use, can make foods less palatable, and in some cases can significantly reduce the bioavailability of minerals.

Fiber supplements work best when added to moist foods.

For patients with persistent constipation and loss of colonic mobility, feed them foods that are highly digestible and have an increased energy density.

Assessment and determination of the method of feeding

As it is sometimes necessary to change the feeding method in patients with constipation, an evaluation of the current diet of the dog should be made.

It should take into account the frequency of feeding, the amount of food given and access to other foods.

In some cases, smaller and more frequent meals can help support the natural contractions of the colon.

Dogs should be walked immediately after a meal; both gentle exercise and the gastro-colic reflex often result in a postprandial bowel movement.

Feeding three to four meals a day also minimizes the amount of food entering the large intestine simultaneously.

Of course, the consumption of water should be encouraged and it should be readily available in the animal's surroundings at all times.

Patient monitoring

Assessment of body condition and weight, as well as regular stool evaluation, are needed to monitor patients with constipation.

Regaining or maintaining an optimal body weight, normal activity levels, normal behavior and the absence of clinical symptoms are a measure of an effective diet.

  • Monitoring the frequency of bowel movements and stool consistency at least twice a week, then once a week or once every two weeks.
  • Relapse prevention in the form of a proper diet and increased physical activity.
  • In order to maintain the condition and body weight at an optimal level, the method of feeding and the amount of food given should be adjusted to the animal's needs.
  • Consider additional drug therapy if dietary management alone is inadequate to improve stool quality and maintain weight.
    Although treatment is specific and individualized on a case-by-case basis, many patients may eventually be treated with diet alone after gradual reduction of initial therapies.
  • Occasionally you may develop constipation, abdominal distension, or constipation while feeding on a moderate (8-15%) or high (greater than 15%) dietary fiber.
    It is then wise to halve the fiber content, reassess the patient after about a week and - if necessary - reduce the amount of fiber administered again.

Prognosis for constipation in the dog


Once there are problems with intestinal motility, they may or may not be troublesome for the rest of their lives.

In constipated animals, the outcome of treatment always depends on the underlying cause and duration of the disease.

In non-advanced cases, the effects of treatment are usually good, but if the dog develops secondary giant colon syndrome, or if there is an irremovable cause, the dog may need to continue treatment with laxative agents.

Such patients are at increased risk of developing secondary colon diseases.

The prognosis is then doubtful, and the results are uncertain.

It is very important to increase your dog's hydration by feeding more humid food.

The key is also to increase the amount of fiber in your diet and reduce the amount of carbohydrates.

Possible complications of constipation / constipation in your dog

  • Chronic constipation in a dog causes severe pain symptoms, buildup of toxins, damage to intestinal tissue.
  • Long-term (chronic) constipation or recurrent constipation can lead to acquired colon enlargement or megacolon.
  • Excessive use of laxatives and enemas can cause diarrhea and serious bowel complications such as. intussusception of the intestine.
  • The mucosa of the colon can be damaged by the repeated mechanical action of residual fecal masses, their pressure on the colon wall, and by improper enema.
  • Faecal incontinence (the dog's inability to control its bowel movements).

Diseases and complications related to constipation in dogs

Mild narrowing of the anus or rectum

The cause of mild rectal stricture is not fully understood.

It is suspected that it may have an inherited background.

The most common secondary stenosis in the rectum is:

  • trauma caused by the passage of foreign bodies (especially bones),
  • post-operative scar formation following anal surgery,
  • chronic inflammation associated with a disease of the anal glands, anal fistula or proctitis,
  • anorectal adenocarcinoma causing stricture of the anus.

The main symptom of the disease is constipation, painful urge to defecate and obstructed defecation.

The onset of symptoms usually occurs 2-3 weeks after the rectal injury.

On handpiece examination, a stricture is palpable, although it may not be recognized if it is too cranial.

A proctoscopy is recommended to confirm rectal stricture.

The diagnosis is also made on the basis of contrast radiography with a barium enema.

In order to exclude the cancerous nature of the lesion, a biopsy is recommended.

In some animals, simple dilation with a dilator or a balloon can reduce the constriction and allow for proper bowel movement.

However, some dogs require surgical intervention.

Unfortunately, during the healing process, constriction may occur again and, additionally, faecal incontinence may develop as a result of the procedure.

Glucocorticosteroids (prednisolone 1.1 mg / kg m.c. daily) can prevent the stenosis from re-occurring.

The prognosis is cautious to good.

Constipation as a result of an incorrect diet

Distorted appetite and ingestion by animals of inappropriate, inedible objects (e.g. paper, hair, bones) can lead to constipation.

Excessive fiber addition to food can also be a cause, especially if the animal is dehydrated.

This type of constipation often occurs in dogs that eat garbage or are fed an excessive amount of bones.

A colon stool test can be performed to find out if your dog's diet is adequate.

Treatment in this case is not difficult.

You should control eating habits, introduce an appropriate diet with the correct content of dietary fiber, diversify the food and add wet food. Encourage your dog to drink.

In more serious cases, intensive irrigation and cleansing enemas are recommended (solutions must not be hypertonic).

Mechanical removal of residual masses from the colon and rectum should be avoided, but if such surgery is necessary, the animal should be anesthetized beforehand in order to avoid possible damage to the colon during the procedure.

The prognosis is usually good.

After the bowel is emptied, the function of the colon should return to normal.

The exceptions are cases of long-term, severe, chronic dilation of the colon.

Fecal stones in a dog

Fecal stones are a final and severe form of constipation.

They arise as a result of the long-term presence of feces in the rectum, as a result of which they dry out and clump into hard fecal lumps.

Normal propulsive movements of the colon are unable to expel the stones.

All the factors that play a role in constipation and / or constipation in a dog predispose to their formation.

Foreign bodies in the rectum

Swallowed foreign bodies, such as bones, toys, sticks, and even needles, can sometimes unobtrusively pass through the entire digestive tract but get stuck crosswise in the rectum or around the anal sphincter.

Unfortunately - there are also situations where foreign materials are sometimes placed in an animal's anus by humans.

The reason for the latter behavior is unknown to me.

Clinical symptoms

When a foreign body or fecal stone enters the rectum or the anal canal, defecation becomes very painful or even impossible.

It is accompanied by dyschezia, stool pressure and secondary stool retention.

The diagnosis is usually made on the basis of rectal examination and stool analysis, but sometimes it is necessary to perform a radiographic examination.

Most foreign bodies and fecal stones can be detected and removed by palpating the rectum.

Since this is an unpleasant procedure for the animal, it should be performed under anesthesia.

Idiopathic giant colon syndrome (megacolon)

It is a primary, congenital or acquired condition of the colon that leads to constipation.

It is more common in cats, but dogs have also reported cases of the disease.

Usually, animals under the age of 6 are sick.

The essence of the disease

The essence of this disease is that the walls of the colon stretch and the muscle membrane degenerates.

As a result, a large, sack-like structure is created, filled with fecal material hardened like stone.

In the case of congenital megacolons, there is a lack of ganglion cells in the nerve plexuses of the intestinal muscle membrane, while in acquired cases, the ganglion cells degenerate to varying degrees.

Acquired Giant Colon Syndrome can develop as a consequence of any disease that leads to problems with passing stools.

Therefore, it is rather an effect (complication) of constipation and constipation that lasts longer, although in the longer term it will be an important factor of impaired defecation.

The cause of this condition is unknown, but it is expected to be affected by altered behavior (e.g. omission of bowel movements) or impaired function of colon neurotransmitters.


Idiopathic giant colon syndrome occurs sporadically in dogs.

This pathological colon enlargement can affect them:

  • spicy,
  • chronic,
  • toxic.

Chronic megacolon can be classified as congenital (equivalent to human Hirschsprung disease) or acquired, which can be primary or secondary.

The cause of the primary megacolon is unknown and is therefore referred to as idiopathic.

Primary megacolon

The pathogenesis of primary colon enlargement is still controversial, although attributed to primary neurogenic or degenerative neuromuscular disorder.

  • Idiopathic megacolone - affects mainly cats and is an idiopathic motor disorder involving smooth muscles of the colon.
    The condition is usually irreversible.
    In vitro studies have shown a reduction in active colonic smooth muscle contraction in response to neurotransmitters (acetylcholine, substance P, cholecystokinin), depolarization of the cell membrane (in which potassium plays an important role) and electrical stimulation.
    The innervation of the colon is intact, and the histological features of the muscles and nerves show no major abnormalities.
  • Obstructive megacolon - in 25% of cases, megacolon occurs secondary to the underlying cause of persistent colon obstruction.
    Examples of such conditions are perineal hernia, rectal stricture, rectal cancer, or pelvic canal stricture caused by bone fracture.
    This hypertrophic condition is potentially reversible if the cause that caused the blockage is removed in time.
  • Neurological megacolon.
    Neurological dysfunction, e.g. in lumbosacral disease, it may constitute 5% of cases of the giant colon syndrome.

Secondary megacolon

Secondary megacolon can occur as a result of damage to the intestinal wall or various conditions that prevent bowel movements for extended periods of time.

Two mechanisms are involved in the development of megacolon: expansion and hypertrophy.

An extended megacolon is the final stage of colonic dysfunction in idiopathic cases.

In turn, hypertrophic megacolon refers to a functional disorder that develops as a result of chronic obstructive lesions, e.g.:

  • pelvic canal strictures,
  • tumor,
  • foreign body etc.

Diagnosis of megacolon

The diagnosis of megacolon is based on the history of the disease and clinical examination, and is most often confirmed by means of review pictures of the abdominal cavity.

It is also important to exclude nutritional, behavioral, metabolic and anatomical factors.

History will usually get information about lethargy, decreased appetite, vomiting and lack of bowel movements for an extended period of time in the dog.

As a rule, clinical examination reveals:

  • dehydration,
  • abdominal pain,
  • mild enlargement of the mesenteric lymph nodes.

When palpating the abdominal cavity, the presence of hard fecal masses in the colon area is found.

A complete neurological examination is also performed to identify the neurological causes of constipation, e.g. spinal cord injury or nerve injury.

The diagnosis should also include the results of laboratory tests to rule out any metabolic abnormalities.

In animals with advanced symptoms, hypokalemia and anemia, leukocytosis, and neutrophils with toxic granules are frequently observed.

Radiographs can confirm the presence of a large colon and can also be used to determine if there are any old pelvic fractures, spine masses, or deformities.

Contrastive radiographs with barium sulfate are usually contraindicated.

Megacolon is a so-called exclusion diagnosis - meaning that the final diagnosis of idiopathic colon enlargement is usually made by excluding all other causes of constipation and / or constipation.

Taking this into account, differential diagnosis is extremely important.

Treatment of a megacolon in a dog

The goal of treatment is to keep your stools soft and improve colon motility.

Initially, laxatives and prokinetics are used.

Administration of cisapride may improve the motility of the gastrointestinal tract, including the colon.

In practice, it is recommended to administer cisapride orally at a dose of 0.1-0.5 mg / kg m.c. every 8-12 hours.

Some cases of megacolon have been shown to respond poorly to treatment - in such patients surgery is the treatment of choice.

Surgical intervention is also indicated in the case of persistent dilatation of the colon and associated complications.

There are many treatment options, and the most effective treatment usually involves a combination of treatment options.

One surgical technique is to remove a large portion of the colon and spare only a short portion of the distal intestine to allow for anastomosis.

However, some authors have suggested that the entire colon is likely to be histopathologically altered and that any part left behind after partial colectomy may continue to expand, causing a recurrence of clinical symptoms.

Treatment with megacolon depends on several factors, including the severity of constipation and stool retention, as well as the immediate underlying cause of the condition.

  • Initial treatment is aimed at stabilizing the water and electrolyte balance as well as eliminating possible causes of constipation, so it works in the same way as treating constipation.
  • The first-line treatment is therapy with fecal softeners.
    Therefore, animals should be adequately hydrated.
    Then an enema is performed.
    Fecal masses remaining in the colon should be removed.
    Cleansing warm water enemas for 2-4 days are usually effective.
  • Treatment with laxatives (Bisacodyl), prokinetics (cisapride) and stool volume expanders (lactulose) should be started at the same time.
    Cisapride has been frequently used to treat disorders of gastric emptying, intestinal transit and other motor disorders in dogs and cats.
  • If it turns out that the degenerative changes in the colon wall are irreversible and the organ cannot contract sufficiently to move the fecal masses into the rectum, and medical therapy is not effective, the treatment of choice is incomplete colectomy and prophylactic measures for the rest of the dog's life.
    Although surgery is often performed as a partial or total colectomy (i.e. colectomy), in some cases colonotomy with residual fecal matter is removed.
  • Postoperative management is based on the combination of an appropriate diet and aggressive antibiotic treatment with vitamin therapy.
    Patients with constipation are usually fed a standard high-fiber diet to increase water attraction to the stool, improving its consistency.
    Consuming high-fiber foods contributes to the optimal treatment effect and helps prevent postoperative constipation.
  • To prevent re-constipation, fiber is fed into moist food (e.g. Metamucil, pumpkin pulp or seeds), the use of osmotic laxatives (e.g. lactulose) and / or prokinetic drugs (e.g. cisapride).
    Lubricants are not useful as they do not change the consistency of the fecal masses.
    Bisacodyl is rarely as effective as lactulose.
    If such treatment is ineffective and constipation continues, surgery may be required.
  • The prognosis depends on early diagnosis and treatment of megacolon, and is usually good to cautious.

Although megacolon mainly affects cats, it can also happen in dogs.

Unfortunately, the exact prevalence of this condition in dogs is unknown.

Given the small number of publications on megacolon in dogs, most case reports and literature data come from numerous studies on the condition in cats.

However, one study examined 28 dogs affected by megacolon, aged 5-9 years, and 26 of them underwent surgical treatment for the condition.

According to the medical history, clinical and radiographic findings, 7 dogs (25%) had idiopathic acquired megacolone, while 75% of cases had secondary acquired megacolone of various etiology.

The results of this study regarding the breed, age and sex of the test dogs are in line with the literature data showing that both canine and feline megacolone was present in animals of any age or breed, but is often seen in middle-aged males.

In this study, nearly half of the megacolon cases were secondary to lumbosacral spine injuries or leg fractures (13/28 dogs, 46%), while in 25% of the cases the cause remained unknown and these cases were classified as acquired idiopathic megacolone.

The role of environmental and / or behavioral factors in colonic motility disorders is also important.

In the cited study, 28% of the dogs tested had environmental and behavioral causes, which is consistent with the literature data.

All dogs included in this study had normal laboratory results with the exception of two severe cases.

The results of laboratory tests in the field of reference standards exclude metabolic and hormonal causes.

However, in all dogs, radiography showed pathognomonic features of megacolon (an abnormally dilated segment of the large intestine filled with hard fecal masses).

However, radiographic features of colon dilatation cannot be used to differentiate between constipation, constipation and megacolon in idiopathic cases.

Rectal prolapse

Rectal prolapse is most commonly seen in puppies and kittens, although it can also occur in older animals.

It is the consequence of an underlying disorder that causes persistent efforts to defecate.

The following factors predispose to rectal prolapse:

  • All illnesses with prolonged constipation and the accompanying urge to stool, e.g.:
    • strong worming, especially in young animals,
    • bowel diseases that cause diarrhea and tenesmus (inflammation of the rectum, colitis, internal parasites),
    • diseases of the anus and / or rectum, making it difficult and painful to pass stools,
    • birthing problems in bitches, dystocia,
    • diseases of the lower urinary tract (e.g. inflammation of the urinary bladder and urethra, obstruction of the urethra, urolithiasis),
      prostate disease.

Clinical symptoms:

Partial prolapse affects only the rectal mucosa.

It is visible as a red, swollen ring of a convex mucosa.

Complete prolapse covers all layers of the rectal wall.

It is visible as a swollen, cylindrical, moist, pink-red mass.

If there is tissue necrosis, it becomes blackened and dry.


Treatment is based on the surgical repair of the prolapse of the rectum and elimination of the cause that led to it, and since the prolapse was caused by a strong pressure, its removal should be sought to prevent recurrence.

The anus, rectum and genitourinary tract should be carefully assessed by palpation, urinalysis, stool examination, proctoscopy, and imaging examinations.

The procedure in the case of a minor prolapse of the rectum, in which the tissue is still alive, consists in delicately draining the mucosa into the rectum, and then placing a temporary suture (the so-called. puffin) for 2-3 days to prevent relapse, especially in animals with high pressure.

The seam is left loose enough to allow feces to pass through.

Following treatment, a highly digestible, low-fiber diet is given.

In the absence of this effect, or when the everted tissue is necrotic, surgery is required.

Colopexy (i.e., sewing the colon to the abdominal wall to prevent recurrence of prolapse) or amputation of a prolapsed part of the intestine that shows features of necrosis are performed.

To improve rectal tone in animals with diarrhea, loperamide (0.1-0.2 mg / kg m.c.)

Antispasmodics are used to relieve persistent cramps and stresses that are resistant to loperamide.

For proctitis, it may make sense to use an anti-inflammatory enema with hydrocortisone or mesalamine.

Perineal hernia

A perineal hernia occurs when the weakened musculature of the perineal area (the so-called pelvic diaphragm) does not support the rectal wall properly, causing its persistent distension and impaired defecation.

Most often it affects older, non-castrated male dogs.


The pathophysiology of muscle weakness is poorly understood.

In some animals, it may develop as a result of the continued stress of chronic constipation or prostate disease.

Neurogenic atrophy of the perineal muscles may also play a role in dogs.

Male hormones are also likely to contribute to the pathogenesis, as the perineal hernia is an extremely rare disorder in bitches and castrated dogs.

Chronic constipation with strong pressure and megacolon may also predispose to the formation of a perineal hernia.

The hernia can be unilateral (usually right-sided) or bilateral, and usually includes a displaced rectum.

The hernial sac may also contain retroperitoneal fat, the prostate gland and, rarely, abdominal organs such as the bladder or intestines.

Rectal defects associated with perineal hernia are classified as follows:

  • prominence - a loss of support on one side causes the rectum to widen to one side,
  • dilation - bilateral loss of support causes overall widening of the rectum,
  • deviation or flexion - the rectum bends, curves or folds to one side in the hernial sac,
  • diverticulum - protrusion of the mucosa that appears as a result of damage to the rectal wall.

Symptoms of a hernia in a dog

Clinical symptoms of a perineal hernia include:

  • Swelling or bulging around the perineum accompanied by symptoms of constipation, constipation, difficult and / or painful defecation and urge to defecate.
  • If the bladder enters the hernial sac and the urethra becomes obstructed, the dog may develop symptoms of obstructed urination or complete urinary retention.
  • Diagnosis is based on palpation of the perineal area.
    In doubtful cases, you can use ultrasound.

Treatment of a hernia in a dog

The purpose of initial treatment is to evacuate retained feces from the rectum.

Bladder catheterization or cystocentesis may also be necessary if the bladder is trapped to relieve urinary obstruction.

In a mild perineal hernia, laxatives and stool softeners and an adequate diet may be sufficient to maintain a normal bowel rhythm.

Castration can prevent aggravation of lesions in a benign perineal hernia.

Surgery to correct a hernia in combination with castration is the best long-term effect in most cases.

Anal spasm

It is a rare, idiopathic form of severe dyschezia.

It occurs when the anal sphincter spasms when the animal is trying to defecate.

Clinical symptoms

When attempting to defecate, the dog may squeal, whine or vocalize loudly in pain, move frantically before attempting another bowel movement, turn and stare at the hind limbs, be very restless and agitated.

There may be a cycle of painful defecations that lead to a defensive contraction of the anal sphincter, causing even more pain.

The disease most often affects German Shepherds with a lively temperament.


There is a strong muscular defense during rectal examination, and the anal sphincter itself is oversized and strongly contracted.

In order to make a diagnosis of anal spasm, other identifiable causes of dyscheiasis (e.g. perianal gland diseases, perianal fistulas, anal stricture).

This is the purpose of a thorough rectal examination under anesthesia and proctoscopy.


Conservative treatment, including evacuation of the secretion of the anal glands, the use of local painkillers, antispasmodics and stool softeners, usually fails.

The small rectal fistulas are easily overlooked and have similar clinical symptoms.

Hence, fistula treatment should initially be initiated to see if dyschezia is resolving, especially in high-risk breeds such as German Shepherds.

Ultimately, resection of one or both branches of the vulvar nerve may be necessary to relieve pain and anal spasm.

Faecal incontinence is a common complication with this method.

Anal sinus diseases

Anal sinus disorders are the most common perianal problem in dogs.

Sinus conditions are classified as:

  • clogging,
  • inflammation,
  • infection,
  • abscess,
  • rupture.

The obstruction of the anal sinuses can be bilateral or unilateral.

The sinuses are enlarged, painful to touch, and do not empty easily.

The contents of the sinuses are usually dense, pasty, dark brown or grayish brown.

Anal sinusitis can be unilateral or bilateral and is associated with moderate to severe pain when palpating.

In the sinuses there is less than usual yellowish or blood-stained purulent discharge.

Anal sinus abscess - this is usually one-sided and is characterized by significant sinus enlargement with pus, inflammation of the surrounding connective tissue, reddening of the skin over the affected sinus, and fever.

Rupture (perforation) of the anal sinus - filled with discharge - usually purulent - the sinuses may rupture, forming a fistula.

All dog breeds are affected by sinus disease.

The specific cause of anal sinus disease is poorly understood.

It may be associated with conditions conducive to the inappropriate emptying of the sinuses that would normally occur on defecation, when normal consistency faeces are pushed through the anal sphincter.

Abnormal retention of secretions in the anal sinuses initiates the cycle: obstruction-inflammation-infection.

However, anal sinus disease may be secondary to the primary dermatological or endocrine disease (e.g. hypothyroidism).

Clinical symptoms

The most common signs of anal sinus disease are related to anal discomfort and include:

  • tobogganing,
  • urge to defecate,
  • licking and biting around the anus, perineum or the base of the tail.

The diagnosis is made on the basis of data obtained from an interview and physical examination of the rectal sinuses.


  • For obstruction and / or inflammation of the anal sinuses, manual emptying to restore drainage is all that is required for most animals.
    After 1-2 weeks, it is recommended to re-examine and empty the sinuses.
    A high-fiber diet can prevent relapse.
  • In the case of recurrent blockage and / or inflammation of the anal sinuses, it may be helpful to rinse them with a betadine solution using a special needle and apply an antibiotic to the sinuses.
    The treatment is repeated every 3-4 days.
    In the case of troublesome relapses, antibiotic therapy is introduced based on the results of a bacteriological examination.
  • In the case of anal sinus abscesses, purulent discharge should be drained, the sinuses should be thoroughly rinsed with betadine and an antibiotic should be administered systemically.
    Surgical sinusectomy is sometimes the recommended treatment for recurrent inflammation or abscesses of the anal sinuses.

Anus obstruction

Anal furuncle (or anal fistula) is a chronic, progressive disease characterized by deep sinus ulceration and the formation of fistulas in the perianal tissues.

The most common disease affects German Shepherds and Irish Setters over 5 years of age, but can occur in Labradors and other large breed dogs.

The pathogenesis of this disease is not well understood. Its formation may involve infection and the ongoing purulent process of the apocrine glands and other glandular structures in and around the anus.

Inflammation may be further supported by the area's wet and polluted environment, as well as the wide, low-set tail typical of German Shepherds.

Cellular defense mechanisms are most likely involved in the pathogenesis.

Clinical symptoms

Dogs with rectal furuncle usually show symptoms of dyschezia, painful stool pressure, and severe anal discomfort (constant licking and sledding).

The disease may also be accompanied by:

  • hematochezia,
  • constipation,
  • fecal incontinence,
  • foul, purulent, perianal discharge.


An examination of the anus area confirms the diagnosis.

Due to the severe soreness, it may be necessary to anesthetize and sedate the animal.

  • Fistulas initially show up as small, draining holes in the skin around the anus.
    There is also inflammation and discoloration of the surrounding skin.
  • These small stretches grow in size and connect to form large interconnected sinuses and areas of ulceration and granulation tissue.
    Fistulas can extend deep into the perianal tissues and the rectal sinuses can become infected or ruptured.
  • In chronic cases, fibrosis can lead to narrowing of the anus


Drug treatment can be used alone or in combination with surgical treatment.

The treatment includes hair removal from the perianal area, thorough cleaning, systematic antibacterial therapy, diet therapy and immunosuppressive therapy using cyclosporine or azathioprine.

  • Ciclosporin at a dose of 5 mg / kg m.c. orally every 24 hours improves almost all dogs within 2-4 weeks and complete remission and healing in 85% of dogs within 16 weeks.
    Unfortunately, the relapse rate is as high as 40%, requiring additional treatment or surgery.
  • Tacrolismus (0.1% topical ointment) applied topically.
  • Azathioprine in combination with metronidazole is an alternative, cheaper form of immunotherapy that usually improves, but the rate of complete recovery may not be as fast as with cyclosporine or tacrolismus.
    The recommended dose of azathioprine is 2 mg / kg m.c. orally every 24 hours.
  • Novel protein diets combined with immunotherapy may benefit some dogs.
  • Often, therapy is enhanced with the use of broad-spectrum antibiotics.
  • In the absence of pharmacological treatment effects or relapses, surgery is recommended, which may include various degrees of excision and debridement of the diseased tissue, chemical ablation, laser excision, electrocoagulation, cryosurgery or tail amputation.
    The range and aggressiveness of the surgical technique depends on the extent of the lesions, but the aim is always to maintain as much normal tissue as possible in order to maintain the proper functions of the anus.


Pseudo-prosthesis is the apparent obstruction of the anal opening in which the surrounding hair is tightly entangled with the feces.

When trying to defecate, the anal area is severely irritated by pulling the hair, which causes pain and an unwillingness to pass faeces.

The condition occurs primarily in long-haired dogs, especially after episodes of diarrhea.

Obesity may be a predisposing factor in some animals.

Clinical symptoms

  • the animal is usually restless and tries to lick or nibble around the anus,
  • there is an unpleasant smell of the animal, especially around the tail,
  • Dermatitis often develops underneath matted hair.

Diagnosis is based on identifying tangled hairs in the anal area.


The procedure is based on cutting tangles and cleansing and disinfecting the skin with the use of mild antibacterial agents.

A soothing ointment is used for irritations (you can use a cream with D-panthenol).

After removing the hair, defecation should continue as normal.

If your dog has secondary fecal retention in the colon, it may also be necessary to treat constipation with enemas, laxatives and a proper diet.

An observant reader has certainly noticed that many of these disorders and diseases can be both a cause and a consequence of chronic constipation in dogs.

Sometimes it even leads to the formation of the so-called pathophysiological vicious circle, as is the case with the secondary megacolon.

Constipation is then caused by a disturbance of the motor function of the colon, which leads to even greater stool retention in the intestine, stronger stretching of its walls and intensification of pathological changes in its wall.

This in turn makes the intestine less efficient to perform its faecal excretion function, which promotes the accumulation of fecal masses.

Breaking this circle is of paramount importance, and the sooner it comes, the better the chances of a cure.


A dog's digestive tract is complex and various factors can interfere with this multi-faceted process of defecation, leading to faecal retention in the large intestine.

Constipation can be caused by any disease of the perineum or anus that causes pain (e.g. perianal furunculosis, perineal hernia, inflammation of the anal glands), obstruction or weakening of the colon and other disorders.

It happens that constipation accompanies metabolic or hormonal diseases, and being the motive for consultation, they contribute to the diagnosis of a given disease.

It turns out that chronic constipation is a very debilitating problem that affects not only human patients, but also our four-legged friends.

And while these abnormalities can affect all breeds of dogs, the incidence of constipation is higher in English Bulldogs, Boston Terriers, and German Shepherds.

Dietary factors are important in the treatment of constipation, and non-drug therapy is very often the first-line treatment in patients with mild to moderate constipation.

In each case, however, prevention plays an important role, i.e. proper dietary management and physical activity.

Finally, I would like to add that this problem should not be underestimated in animals.

If you notice any symptoms that indicate difficulty passing faeces, take your dog to the vet as soon as possible. The sooner the treatment is started, the greater the chances of resolving the problem and minimizing the risk of recurrence.

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