Inflammatory Bowel Disease Brochure
What is inflammatory bowel disease?
Feline inflammatory bowel disease (IBD) is not a single disease, but rather a group of chronic gastrointestinal disorders caused by an infiltration of inflammatory cells into the walls of a cat’s gastrointestinal tract. The infiltration of cells thickens the wall of the gastrointestinal tract and disrupts the intestine’s ability to function properly. Cats of any age can be affected by IBD; however the disease occurs most often in middle-aged and older cats.
Chronic inflammation of the gastrointestinal tract can occur as a result of a specific disease, such as a parasitic or bacterial infection or a specific food allergy. However, the cause of IBD in many cases is considered to be “idiopathic” or unknown. Current theories suggest that these cases of IBD may be due to a breakdown in the relationship between the normal bacteria that reside in the gastrointestinal tract and the immune system of the gastrointestinal wall.
IBD can present in different forms depending on the type of inflammatory cells and the region of the gastrointestinal tract involved. The most common form of IBD involves an inflammatory infiltrate consisting of lymphocytes (small white blood cells) and plasma cells (cells that produce antibodies) and is called lymphocytic-plasmacytic enteritis. Enteritis refers to the small intestine. If the stomach is involved, the inflammation is described as gastritis, and if the colon (large intestine) is involved, the term colitis is used. Eosinophils are another cell type commonly present in feline IBD. Eosinophils may be present as the predominant cell (for example, eosinophilic gastroenteritis), but are more commonly seen as part of a mixed population of other inflammatory cells. Two less common forms of IBD are called neutrophilic and granulomatous.
What are the symptoms of IBD?
Some common signs of feline IBD include vomiting, weight loss, diarrhea, and lethargy. Appetite can be variable, ranging from ravenous to anorexic. While some cats will show obvious symptoms of disease, such as vomiting after every meal, other cats may exhibit symptoms much less frequently, such as vomiting or producing hairballs once or twice a month. The symptoms of IBD can also vary depending on the area of the digestive tract affected by the disease. For example, if the inflammatory cells are affecting the stomach or higher areas of the small intestine, then the cat may exhibit symptoms of chronic vomiting. If the inflammatory cells are in the colon, then the cat may have diarrhea or blood in the stool. The symptoms may not always correspond to the area affected, especially if the entire digestive tract is involved.
How is feline IBD diagnosed?
Making a diagnosis of feline IBD requires an extensive work up because many of the common symptoms of IBD, such as vomiting and diarrhea, are also common symptoms of other diseases. First, specific causes of gastrointestinal inflammation must be ruled out. Your veterinarian will likely recommend blood work, fecal examinations, radiographs, and/or an ultrasound check for metabolic disease, feline leukemia, parasitic or bacterial infections, and certain types of cancer. A hypoallergenic food trial may also be conducted to rule out food allergy.
A definitive diagnosis of feline IBD can only be made based on microscopical evaluation of tissue collected by means of an intestinal (or gastric) biopsy. In a patient with IBD, the tissue sample will show increased numbers of inflammatory cells in the intestinal wall. The types of cells found will indicate what type of IBD is present and help to guide treatment. Gastrointestinal biopsies may be performed with the use of an endoscope or during abdominal surgery. Endoscopy is a less invasive procedure; however, surgery may be recommended for patients in whom liver or pancreatic disease is also suspected, so that those organs can be biopsied as well. Both procedures require general anesthesia, and the associated risks must be considered when deciding whether to perform these tests.
How is IBD treated?
The treatment of inflammatory bowel disease usually involves a combination of change in diet and the use of various medications. Because there is no single best treatment, your veterinarian may need to try several different combinations in order to determine the best therapy for your cat.
Because dietary allergens may play a role in inflammatory bowel disease, a food trial using hypoallergenic diets may be recommended by your veterinarian. In using a hypoallergenic diet, the key is to use a protein and carbohydrate source that the cat has never eaten before. Rabbit, duck, or venison-based diets are often tried initially.
If the symptoms of IBD are not improved with a hypoallergenic diet, other diets may be tried. Diets high in fiber, low in fat, and easily digestible can be beneficial and are generally better tolerated in cats with IBD. It is important to note that it may take several weeks or longer for cats to improve after a diet change, and during a food trial, all other food sources (including table food, flavored medications, and treats) must be eliminated from the diet.
Cats that have been diagnosed with IBD may be put on a course of corticosteroids, usually prednisolone. Corticosteroids have potent anti-inflammatory and immunosuppressive properties. Diabetes and excessive immunosuppression are among the serious side effects these drugs can produce. Cats should be monitored closely while they are on corticosteroids, although they tend to tolerate these drugs well as long as they are given at an appropriate dose and schedule. Corticosteroids are usually given orally, and are started at a higher dose, with a gradual reduction in dose over several weeks. In cats that are difficult to medicate orally or in cases where the vomiting is severe, your veterinarian can give the medications as an injection.
If combinations of dietary management and corticosteroid therapy have failed to adequately control feline IBD, then antibiotics may also be added to the treatment regimen. Metronidazole is a common medication that is used by itself or in conjunction with corticosteroids to control IBD. Metronidazole has antibacterial, anti-protozoal, and immunomodulatory properties. Although side effects are uncommon, some cats may experience loss of appetite and vomiting when given metronidazole. This is likely a response to the unpleasant taste of the medication.
If none of these medications successfully controls the symptoms of IBD, more potent immunosuppressive drugs, such as chlorambucil or azathioprine, may be necessary. These drugs can suppress the bone marrow, so a veterinarian must carefully monitor cats taking these drugs. Because the gastrointestinal microflora (bacteria) may play a role in the development of IBD, newer therapy considerations include using prebiotics (substances that promote certain bacterial populations) and probiotics (bacterial strains that promote gastrointestinal health) to help maintain beneficial bacterial populations in the gastrointestinal tract.
What is the prognosis for cats with inflammatory bowel disease?
Inflammatory bowel disease can often be controlled so that affected cats are healthy and comfortable. However, even with proper management, the disease may wax and wane; and animals may have periods during which they are symptomatic. Optimal control is dependent upon the proper selection of diet and medications. Vigilant monitoring by the veterinarian and owner is critical so that relapses can be assessed and managed and appropriate adjustments in the dosing of long-term medications can be made.