Introduction

Colitis refers to inflammation of the colon, which also is called the large intestine or the large bowel and is the lower end of the gastrointestinal tract. There are a number of different types of colitis, each of which has different causes but similar clinical signs. One of the most common signs of colitis in cats is a change in the consistency of stool. Colitis in cats can be acute or chronic, and it can also wax and wane with time.

Symptoms of Feline Colitis

Cats with colitis tend to have some combination of the following symptoms:

• Diarrhea with traces of fresh (red) blood (hematochezia)
• Diarrhea with traces of mucus or undigested fat (slimy or greasy diarrhea)
• Straining to defecate (tenesmus), with or without success
• Difficult or painful evacuation of stool from the rectum (dyschezia)
• Increased frequency of defecation or attempts to defecate
• Passage of small amounts of fecal matter
• Increased urgency to reach the litter box

These are commonly referred to as signs of “large bowel diarrhea.” However, one or more of these symptoms can be associated with disorders that affect both the large and small intestines.

Cats with acute colitis, sometimes referred to as “stress colitis,” usually have large bowel diarrhea and tenesmus without signs of systemic illness. The diarrhea in acute cases is usually small in volume, semi-formed to liquid and contains mucus and bright red blood. In many cases, the first portion of stool looks somewhat normal but the bowel movement becomes cloudy and jelly-like at the end. Cats can be quite stoic. They may show no outward signs of abdominal pain, even when their condition comes on suddenly and severely. Nonetheless, colitis typically is extremely painful.

Cats with moderate to severe chronic or episodic colitis have virtually identical symptoms, but they persist for weeks instead of days. In chronic cases, the animal can also develop systemic signs of malnutrition due to malabsorption of dietary nutrients, although this is uncommon in domestic cats. Chronic colitis can cause one or more of the following symptoms, in addition to the signs of large bowel diarrhea:

• Shying away from being touched
• Hiding from people or other pets
• Sleeping more than usual
• Vomiting
• Dehydration
• Loss of appetite (inappetance, anorexia)
• Weight loss (uncommon)
• Poor hair coat
• Poor body condition
• Lethargy

If the upper part of the intestinal tract – called the small intestine or small bowel - is also involved, the cat may have black tarry stools, in addition to or instead of diarrhea with traces of fresh blood and mucus.

Cats at Increased Risk

Acute colitis can occur in any cat but predominantly is seen in young cats with intestinal parasites, gastrointestinal bacterial overgrowth or dietary indiscretion. Free-roaming outdoor cats are predisposed to developing acute colitis. Chronic colitis is more common in middle-aged and older cats and tends to be caused by malignant neoplasia (cancer) or inflammatory bowel disease (IBD). Purebred cats are predisposed to developing a particular type of IBD called lymphocytic-plasmacytic IBD.