Inflammatory Bowel Disease in Dogs
This is a group of diseases of the small and large intestines, characterized by chronic and protracted diarrhea, malabsorption, weight loss, anemia, and malnutrition. They are all treatable, but are seldom cured. In each specific disease, a different type of inflammatory cell is found in large numbers in the lining of the small and/or large intestines. These cells distinguish the specific diseases. Diagnosis is made by endoscopy and biopsy of the intestine wall, or by exploratory surgery.
This is the most common inflammatory bowel disease in dogs. Lymphocytic-plasmacytic enterocolitis has been associated with giardiasis, food allergy, and overgrowth of intestinal bacteria. Lymphocytes and plasma cells are the target cells seen on biopsy.
Certain breeds are predisposed, suggesting a genetic influence. They are the Basenji, Soft Coated Wheaten Terrier, German Shepherd Dog, and Chinese Shar-Pei. In the Basenji, the disease is known to be related to an autoimmune disorder. While signs can show up in younger dogs, most dogs are middle-aged when diarrhea starts.
Lymphocytic-plasmacytic enterocolitis produces a small bowel type of diarrhea (see page 283). Vomiting is common. Involvement of the colon produces signs of colitis.
Treatment: This is an illness for which the realistic goal is control, not cure. Hypoallergenic diets bring about partial or complete resolution of symptoms in some dogs. The Purina h/a and d/d veterinary diets may be useful, as well as Hill's z/d and z/d Ultra, and Royal Canin IVD. Antibiotics are used to treat bacterial overgrowth and giardiasis. Immunosuppressant drugs such as azathioprine (Imuran) and/or prednisone are used if other treatments are not successful.
This is a relatively uncommon form of inflammatory bowel disease in dogs. 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: High-dose corticosteroids are used to treat this disease. They are tapered off as symptoms diminish. The dog should be tested for intestinal parasites and placed on a hypoallergenic diet.
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 on biopsy of the colon. The diarrhea is the chronic large bowel type, containing mucus and blood. Biopsies are processed with special stains to exclude histoplasmosis and intestinal tuberculosis.
Treatment: This involves the use of corticosteroids and immunosuppressive drugs to reduce inflammation and scarring. A course of metronidazole may be of benefit. A strictured bowel requires surgery.
This inflammatory bowel disease produces acute and chronic large bowel diarrhea (see page 284). The inflammatory infiltrate is composed of mature white cells in the tissues and blood vessels. Diagnosis is based on a colon biopsy and stool cultures to exclude bacterial infection.
Treatment: Antibiotics and/or corticosteroids are used to control the disease.
Histiocytic Ulcerative Colitis
This inflammatory bowel disease occurs almost exclusively in Boxers. Signs usually appear before age 2. Affected dogs develop severe, unrelenting diarrhea that contains mucus and blood, and corresponding weight loss. The diagnosis is based on a colon biopsy.
Treatment: Treatment is similar to that described for lymphocytic-plasmacytic enterocolitis.
This article is excerpted from
“Dog Owner’s Home Veterinary Handbook” with permission from Wiley
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