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.
Symptoms of IBD
One or many of the following symptoms can be found in a cat with inflammatory bowel disease (IBD):
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).
Causes of 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.
History and Clinical Signs
The most consistent clinical signs associated with feline lymphocytic-plasmacytic enteritis are those consistent with a small-bowel diarrhea syndrome.
LPE can occur in cats of any age, but most commonly appears in older cats. LPE can affect any area of the intestinal tract, and can also be very localized. Consequently, the symptoms of an affected cat are quite variable.
For example, clinical signs in some cats can appear suddenly, while in others, the signs can be more subtle and intermittent. Many cats experience exacerbation of symptoms only during times of stress, while others experience constant problems.
Vomiting may be the only symptom of LPE. Often, cats with chronic vomiting are misdiagnosed and treated symptomatically for stomach or pancreatic disease, when the disease is actually located in the small intestine.
Diagnosis and Treatment
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, since each can closely mimic the symptoms of LPE. It is also important that your cat is screened for the viral infections feline leukemia and feline immunodeficiency because both diseases can be associated with IBD.
In severe cases of LPE, cats may have one or more abnormal test results that indicate advanced intestinal wall damage. In these cases, protein leaks into the intestinal tract and subsequently, cats can have abnormally low serum protein levels.
Definitive diagnosis of feline LPE can only be made by examining biopsy samples from the intestinal tract. Lymphocytic-plasmacytic enteritis lesions can be very localized, leaving the surface of the intestinal wall normal. If only grossly abnormal tissues are sampled, the diagnosis may be missed.
The pathologist will usually report cases of LPE as mild, moderate, or severe. A diagnosis of mild lymphocytic-plasmacytic enteritis may just indicate a reaction to an underlying parasitic or infectious disease, and the underlying causes should be addressed. A diagnosis of moderate to severe LPE tells the veterinarian that more aggressive therapy should be considered.
Dietary therapy for feline LPE may or may not help, but it is certainly worth trying. 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 LPE involves feeding the cat a diet that is unlikely to trigger an immune response within the intestinal tract. To accomplish this, the cat must be fed a home-cooked elimination diet composed of a protein and carbohydrate source. Commercial hypoallergenic diets are not effective.
A careful dietary history should be obtained to find out which ingredients the cat has eaten over its lifetime. Once known, a food can be formulated consisting of a protein and carbohydrate source that the cat has never had. During the dietary trial (ideally five to six weeks), nothing but that special diet and water must be ingested by the cat, including treats, chewable vitamins, or chewable medications. If the cat has improved by the time the trial period ends, you can try switching to a commercial diet based on the protein source used.
Some cases of feline LPE may benefit from additional dietary manipulation. Adding extra fiber into the diet may help cats with large bowel involvement. Although the increased fiber doesn't have any anti-inflammatory effect, it can help to improve fluid balance inside the intestine and relieve diarrhea. Severe cases may benefit from additional vitamin and mineral supplementation.
A severely inflamed small intestine cannot absorb vitamins and minerals efficiently, which can result in a deficiency. Vitamin deficiencies can adversely affect the course of the disease. For example, folic acid and cobalamin may contribute to the small intestine's ability to repair itself. Therefore, supplementation of these important vitamins should be considered.
There is no set treatment regimen for every case of lymphocytic-plasmacytic enteritis in the cat. The appropriate choice of immune-suppressing drugs for treating feline LPE is up to your veterinarian. Treatment must be tailored to each cat's needs.
Prednisone (a potent corticosteroid) is usually the initial drug of choice for treating feline LPE. As a class, the corticosteroids are powerful immune suppressive and anti- inflammatory agents. In addition, treatment with corticosteroids may improve the fluid and electrolyte balance within the intestine. This can have a significant role in decreasing diarrhea.
If prednisone alone is given, then improvement should be noted within the first one to two weeks of therapy.Most cats with lymphocytic-plasmacytic enteritis will require life-long prednisone therapy to avoid a relapse.
In severe cases of LPE, azathioprine can be useful as a very potent immunosuppressive drug. Adding this drug to the treatment should be considered in cats that are not responsive to prednisone alone. Also, azathioprine can be used in cats that just cannot tolerate the adverse effects of prednisone. However, cat owners must wait three to four weeks before azathioprine will take effect.
Several other drugs can be tried for treating feline LPE. There is evidence that metronidazole may have a direct immune suppressing effect. Cyclophosphamide is a chemotherapy drug that also has potent immune suppressing qualities. Again, it is important that your veterinarian choose the appropriate treatment for your cat.
Most cases of feline lymphocytic-plasmacytic enteritis cannot be cured, although the disease is not usually life threatening. With aggressive therapy, many cases can be adequately controlled.