Inflammatory Bowel Disease
Inflammatory bowel disease is not so much a disease as it is a group of clinical signs related to a large number of underlying causes. The clinical signs primarily involve the gastrointestinal tract and can vary somewhat based on what part of the GI tract is affected. Vomiting is the primary sign if the stomach is affected. If the small bowel is affected the signs are related to a protein-losing enteropathy – diarrhea or loose stools, weight loss, loss of appetite, etc. If the large bowel (colon) is affected signs are related to colitis such as loose stools (cow-pie type), mucous and/or bloody stools, straining to defecate and increased frequency of defecation. The underlying pathology in IBD is infiltration of the gut wall by various types of inflammatory cells such as eosinophils, macrophages, lymphocytes and plasma cells. This infiltration causes thickening of bowel wall which interferes with digestion of food and absorption of nutrients – malabsorption/maldigestion syndrome. ANY SHAR-PEI WITH A NON SPECIFIC ILLNESS SHOULD BE WORKED UP FOR IBD! Laboratory findings are non-specific, but may include a low albumin and globulin due to intestinal loss of these proteins mild anemia due to GI hemorrhage and electrolyte abnormalities due to chronic vomiting and diarrhea. Special testing such as B12/Folate levels may be useful. Fecal alpha-1 protease inhibitor is a new test which may prove useful in the diagnosis of IBD. The primary mode of diagnosis is intestinal biopsy which may be done via gastrointestinal endoscopy which is non-invasive or via exploratory laparotomy abdominal surgery. These procedures should be considered early in the course of the disease when the dog is the best anesthetic candidate. Waiting too long increases the risk. Bear in mind also that there is a 5-7 day delay in getting the biopsy results back. Therapy and prognosis does vary somewhat based on the type of IBD seen on the biopsy. Exploratory surgery also allows the veterinarian to rule-out other causes of GI disease and chronic illness such as cancer, bacterial or fungal disease, liver disease and intestinal foreign objects.
The cause of IBD in Shar-Pei is probably related to two breed predispositions – food allergy and IgA deficiency. Anywhere from 70% – 90% of Shar-Pei are deficient in IgA which is an immunoglobulin found in secretions of the GI tract, reproductive tract and the respiratory system. IgA has an important immune system function in these areas. It helps prevent infectious agents and antigens in the diet from crossing the lining of the gut. When atigens in the diet gain access to the gut wall an immune response is stimulated which eventually results in inflammantion and damage to the gut wall. Allergic responses to substances in the diet can also elicit a severe inflammatory reaction. Other causes have yet to be elucidated.
Therapy of IBD involves the use of specific drugs and dietary management. Drug therapy consists of immunosuppressive therapy with prednisolone or other corticosteroid. These are used to decrease inflammation and suppress the immune response so healing can occur. Other drugs are often combined with corticosteroids because of a synergistic effect. Sulfasalazine is often used for immune-mediated colitis as an anti-inflammatory medication. It is converted to aspirin in the colon. Sometimes other more potent chemotherapeutic agents are needed such as azathioprine. Dietary therapy is also extremely important. The use of novel protein sources is paramount as is the use of simple diets with minimal additives. There are a variety of diets available through your veterinarian specifically formulated for use in IBD. They often use lamb, chicken, rabbit, duck, turkey or venison as their protein source. All natural diets are sometimes used as well. IBD should be one of the major considerations in any Shar-Pei with weight loss and normal laboratory findings.
The special GI functions tests described in this article are done at the Gastrointestinal Function Test Lab. The address is:
College of Veterinary Medicine
College Station, TX 77843-4473
Fax: (979) 862-2864
Web site: www.cvm.tamu.edu/gilab