Colitis (Diarrhoea) in Pets

Colitis & Stress Colitis in Dogs & Cats

What is Colitis?

Colitis simply refers to inflammation of the large intestine (colon). Colitis is most commonly used to describe diarrhoea or loose stools associated with the large bowel and is also known as large bowel diarrhea. 

What are the clinical signs of Colitis?

Many pet owners report seeing frequent, small volumes of semi-formed to liquid faeces. Some pets will exhibit straining during and after defecation, and small amounts of bright red blood will often be passed near the end of defecation. Mucus or fat is seen in many cases of chronic colitis. Most dogs with colitis will exhibit a sense of urgency and need to defecate frequently. Vomiting occurs in less than a third of the cases of colitis. Weight loss is rare.

What causes Colitis?

The causes of colitis include stress, infections (including Salmonella, Clostridium, and E. coli), and parasites (including, Giardia, Cryptosporidium, and worms), trauma, allergic colitis, and primary inflammatory bowel disease (lymphoplasmacytic, eosinophilic, granulomatous, and histiocytic types). Colitis may also occur after a change in diet, ingesting contaminated or inappropriate food, being in contact with other infected pets, or after chronic exposure to a wet environment.

Stress Colitis & Sudden (Acute) Colitis

A pet that has sudden symptoms of colitis, especially where there is no indication of parasites or infection probably has a stress or dietary indiscretion related colitis.

Stress Colitis

Common after boarding, transport, severe weather or any other sudden changes or situations that may cause stress. This may be seen more often in puppies during or after transport because transport may come at the same time as or immediately after pups first leaving the litter, meeting new people and environments, veterinary checks or vaccination. Stress Colitis episodes are generally minor. They may disappear quickly on their own or can be cleared with a short course of medication such as metronidazole or sulfasalazine and/or dietary therapy.

Stress colitis is one of the leading causes of colitis or large bowel diarrhea in pets and especially in puppies & kittens. Treatment with a simple change in diet and medication to resolve the inflammation or infection in the colon is all that is required for most pets. The majority of pets experiencing stress colitis are back to normal within three to five days.

Dietary indiscretion-related Colitis

This may be caused by sudden changes in diet, treats or an animal raiding the garbage or eating a small amount of inappropriate food. Sudden & Dietary Colitis episodes are generally minor.

 Parasites, especially Giardia and whipworms, can also cause Colitis to appear quite suddenly and the pet may be tested for those to rule them out or be dewormed. (in the case of puppies & kittens this may occur if the pet has not been regularly wormed by the breeder with an appropriate product)

Whatever the cause, the inflammation in the colon results in reduced water absorption and decreased ability to store faeces in the colon. This causes the classic symptom of frequent small amounts of diarrhea, often with mucus or blood.

How is Colitis diagnosed?

The diagnosis of colitis is based on your pet’s clinical signs and history, microscopic evaluation of the faeces, rectal examination, cytology, and blood tests. Where the more common causes can be ruled out and the colitis does not disapear after a few days additional testing such as radiographs (X-rays) to examine the colon and intestinal tract, colonoscopy and colon biopsies, faecal cultures, barium enemas, or ultrasound evaluation of the abdomen may be necessary in some cases. These tests may be more relevant for older animals and are important to rule out conditions such as colonic tumors or polyps, irritable bowel syndrome, cecal inversion, and ileocecocolic intussusception (a rare condition in which the intestines ‘telescope’ or fold into themselves).

How is Colitis treated?

The specific cause of colitis will dictate the appropriate treatment. In general, particularly with Stress, Sudden or Dietary Indiscretion related Colitis a few days of medication and a bland diet should resolve the problem and the pet will be back to normal quickly. (often Vets will prescribe a cooked chicken and rice diet for puppies)

During recovery, it is common for the pet to have no stool at all for a couple of days. This is normal and not a sign of constipation. If, however, the pet’s diarrhea is not clearly improved in two to three days, contact the veterinarian to see if further testing is needed.

Non-specific treatment includes fasting for 24 to 48 hours, feeding a low residue or hypoallergenic diet, increasing dietary fibre content, and adding fermentable fibre such as psyllium, beet pulp, or fructooligosaccharides (FOS) to the food. Some dogs with colitis will do better on low-fibre diets.

Antimicrobial drugs may be indicated, depending on your dog’s diagnosis. Anti-inflammatory or immunosuppressive drugs may be used in cases of inflammatory or immune-mediated colitis. Drugs that modify the colon’s motility may also provide symptomatic relief.

For most dogs diagnosed with colitis, the prognosis is excellent for a speedy recovery. Chronic, severe, or recurrent cases should have further diagnostic tests performed to determine the exact cause and proper treatment. For many dogs with chronic colitis, strict dietary control and careful use of medications keep the condition under control.