Colitis simply means inflammation of the colon. The causes and treatment for colitis may or may not be a simple matter, however. It is a symptom rather than a disease. Diarrhea with mucous and blood are the first indicators of colitis, and it may occur acutely, chronically, or episodically. Usually, colitis describes diarrhea that is not associated with mal-absorption of nutrients and weight loss.
The colon is the last stop along the digestive tract before stool is eliminated. Its function is to remove water and process fiber. The colon is home to a dense but fragile flora of billions of beneficial bacteria. During inflammation, the delicate balance of certain species of bacteria becomes more weighted to pathogens (harmful bacteria). Pathogens produce toxins and cause excessive cellular sloughing of the intestinal wall, producing the mucous that is associated with colitis. Bleeding can occur which further feeds the harmful bacteria. Red blood is a symptom of colitis, whereas black tarry stools (digested blood) would be indicative of upper GI bleeding.
Diagnosis of colitis is made primarily by history and observation, but discovery of the underlying cause of inflammation is necessary to treat the problem and prevent relapse. If the pet seems otherwise healthy on examination, trial dosing with colon-active medications may be attempted. However, there are some rule-out tests that should be performed on all colitis patients. A fecal flotation test to check for intestinal parasites like Giardia and whipworms is requisite on all diarrhea cases. Next, a fecal cytology is examined under the microscope to look for pathogenic spore-forming bacteria called clostridia. These pathogens produce enterotoxins and large amounts of gas that lead to painful cramping and urgency to defecate.
The sudden onset of colitis (acute colitis) is usually attributable to stress or dietary indiscretion. A history of boarding, separation anxiety, or garbage-rooting may call for a short round of medication like metronidazole or sulfasalazine. These antibiotics also have anti-inflammatory effects on the colon. Beneficial bacteria called probiotics can be given to reestablish the normal flora of the colon. These “good” bacteria can themselves reduce inflammation as in-vitro studies demonstrate. Bland diets low in sugar and fat can also be prescribed to help firm up stools.
In the case of chronic, episodic, or refractory colitis (doesn’t respond to treatment), further diagnostics are warranted. Cats should be tested for Feline Immunodeficiency Virus and Leukemia. Biopsies of the colon wall may be taken with the use of a colonoscopy to diagnose Inflammatory Bowel Disease, a condition where white blood cells invade the lining of the intestine. In this disease, prednisone may be added to antibiotics to treat the autoimmune response that is causing the inflammation. Food allergies can also cause colitis, especially in cats, and novel protein / novel carbohydrate foods may be curative. These types of diets are not available over-the-counter, as their indiscriminant use would introduce new food allergies into the dog and cat population.
The prognosis for colitis is generally good, as long as the underlying cause is discovered and treated.