Inflammatory Bowel Disease

In cats, inflammatory bowel disease (IBD) is the most common cause of chronic vomiting and diarrhea. The term actually refers to a group of diseases that are characterized by the invasion of inflammatory cells into the cat's intestinal wall.
One or many of the following symptoms can be found in a cat with inflammatory bowel disease (IBD):

Vomiting
Diarrhea
Weight loss
Normal/increased appetite
Stomach rumbling
Belching
Black, tarry stools
Flatulence (from digested blood)
Halitosis
Increased thirst
Abdominal pain
Weight loss

In severe cases, weight loss can be extreme. Vomiting cats will seldom produce food in a cat's vomit. Instead, the vomit usually consists of bile-stained mucus. The presence of hair or partially digested food in the vomit indicates that the disease also involves the cat's stomach. The most common form of inflammatory bowel disease in cats is the presence of lymphocytes and plasma cells, which produce a diagnosis of lymphocytic-plasmacytic enteritis (LPE). This disease can develop in one of two ways. The inflammatory cells can enter the intestinal wall in response to an injury or infection. Or, parasites, food intolerance, bacteria, fungi, or cancer can cause activation of the immune system and subsequent inflammation. Cats that are affected with LPE may have a defective intestinal wall barrier. This defect allows normal intestinal bacteria to leak into the deeper layers of the intestinal wall, and the body mounts an immune response to remove them. Subsequent inflammation damages the gut wall even further, allowing more bacteria to enter the deeper tissues.
 
Appropriate tests must be chosen by your veterinarian to rule out infectious disease, parasites, obstructions and cancer. Metabolic disease (especially, hyperthyroidism), concurrent large bowel disease, and pancreatic insufficiency must be eliminated. It is also important that your cat is screened for feline leukemia and feline immunodeficiency because both diseases can be associated with IBD.
 
Dietary therapy for treating IBD is very important. Inflammatory response can be triggered by an abnormal immune reaction to normal intestinal components. Therefore, it may be possible that one or more ingredients in the cat's food may be one of the underlying causes. Even if dietary therapy alone doesn't resolve the cat's symptoms, it can allow other treatments to be more effective. Occasionally, a cat can be completely weaned off oral medication and maintained on dietary therapy alone. One possible explanation for the efficacy of dietary therapy is that it helps the intestinal tract to compensate better, despite ongoing inflammation. Effective dietary therapy for feline IBD involves feeding the cat a diet that is unlikely to trigger an immune response within the intestinal tract.