Inflammatory Bowel Disease in Cats
This is the most common inflammatory bowel disease in cats. Lymphocytes and plasma cells are the predominant inflammatory cells seen on biopsy of the small and large intestines. The disease has been associated with giardiasis, food allergy or intolerance, and an overgrowth of intestinal bacteria. Vomiting is a common sign but is not present in all cases.
Treatment: An antibiotic (metronidazole) is given to treat bacterial overgrowth and giardiasis. Immunosuppressant drugs such as azathioprine (Imuran) and/or prednisone are used if other treatments are not successful. As a general measure, the cat should be placed on a hypoallergenic diet, either homemade (baby foods or boiled chicken) or commercially obtained from your veterinarian. The diet should be highly digestible and low in fat. If colitis is present, fiber may need to be added. A homemade diet may be developed by consulting a veterinary nutritionist. Raw diets are not recommended because the cat already has a stressed immune system.
On biopsy, eosinophils may be found in the stomach, small intestine, or colon, and the eosinophil count in the blood may be elevated. Some cases are thought to be associated with food allergy or the tissue migration of roundworms and hookworms.
Treatment: Treatment involves the use of high-dose corticosteroids, such as prednisolone, that are tapered as symptoms are controlled. The cat should be tested for food allergies and intestinal parasites and treated accordingly. Dietary changes, as described for lymphocytic-plasmacytic enterocolitis, may be beneficial. This form of IBD is the most difficult to treat successfully and has the poorest outlook.
Granulomatous (Regional) Enteritis
This is a rare disease, similar to Crohn’s disease in humans. There is thickening and narrowing of the terminal small bowel due to inflammation of surrounding fat and lymph nodes. Macrophages, which are cells, found in tissues, that fight infections, are found when the colon is biopsied. The diarrhea contains mucus and blood. Biopsies are processed with special stains to exclude histoplasmosis and intestinal tuberculosis.
Treatment: Corticosteroids and immunosuppressive drugs are used to reduce inflammation and scarring. A course of metronidazole may be of benefit. Surgery may be required for a strictured bowel.