Inflammatory Bowel Disease in Cats

Inflammatory bowel disease (IBD) is a relatively common disorder in cats. This is actually a group of conditions that are characterized by thickening of the large and/or small intestines. The thickening of the intestinal wall is a direct result of inflammation, which consists of edema or swelling and an influx of the inflammatory cells that exceeds a normal inflammatory reaction. This abnormal immune response is the result of an out of control cascade that the body normally mobilizes at a much lower level to deal with a number of inciting irritants.

This excessive inflammatory reaction actually damages the tissues and interferes with the normal delicate balance in the gut wall that allows proper absorption of nutrients. This leads to maldigestion and diarrhea and the bowel irritation also triggers the vomiting reflex. Vomiting is the most common sign in cats, and may be present without diarrhea signs. There may be increased gas production and gut sounds (flatulence, borborygmus). The belly may appear swollen and sometimes the cats seem sensitive when the belly is examined. The condition may lead to weight loss and a poor haircoat, though some cats keep a normal condition and appearance.

Though some infectious agents such as Giardia, Salmonella or an overgrowth of normal bacteria of the gut are suspected to play a role, others believe dietary sensitivity is the primary inciting factor. It is likely that this is a condition with multi-factorial causes. In cats, the condition may be associated with pancreas inflammation (pancreatitis) and liver inflammation (cholangiohepatitis) in a syndrome termed triad disease.

Diagnosis of this condition requires that many other causes of digestive disease be ruled out. In cats, cancers of the intestine such as lymphosarcoma can lead to general thickening of the gut and maldigestion. Hormone imbalances such as hyperthyroidism can lead to many similar clinical signs. Viral infections, parasites and food allergies need to be ruled out also. Testing will include complete blood count (CBC), urinalysis, stool sample, blood chemistry profile, viral screen (*FIP, FeLV), and thyroid hormone levels. Imaging (ultrasound, X-ray) may be done to help rule out other conditions, but many of these tests will be normal in IBD cats. The diagnosis may only be confirmed by performing an endoscope biopsy or surgical biopsy. The tissue is sent to the laboratory where the section is examined under a microscope. This allows the pathologist to identify the hallmarks of exuberant inflammation seen in IBD. Based on the major inflammatory cell type, IBD may for example, be classed as eosinophilic or lymphocytic-plasmacytic.

Treatment may consist of hypoallergenic diet and prophylactic deworming initially. Some cases do respond to this basic approach, while most require medications such as anti-inflammatory or immune-modulating drugs. A commonly selected medicine is called metronidazole, which appears to have many effects including immune-modulation, anti-parasitic and antibiotic. Cats hate the taste, and it is not without side effects, so veterinarians will discuss use of this drug thoroughly with their clients if they decide to include it in the treatment plan. Often a combination of drugs is prescribed.

Cats with IBD are usually not cured, but often can be well controlled with appropriate nursing, dietary and medical care. Sometimes, IBD waxes and wanes with or without therapy. It may take a while to get the disease under control, and a few drug trials or dosage adjustments are often needed before control is optimized. The veterinarian handling the case will adjust therapy based on the individual needs of the patient, and based on the response to therapy. There is no magic bullet, but with patience, most cats will be controlled. Follow up assessments are an integral part of case management, so clients should be prepared to follow their veterinarians treatment plan and follow up visit schedule.

*FIP= Feline infectious peritonitis virus
FeLV=Feline leukemia virus