Canine Inflammatory Bowel Disease

What is inflammatory bowel disease?

Inflammatory bowel disease (IBD) is the name used for a nonspecific condition that involves chronic inflammation in the stomach or intestines. It occurs when inflammatory cells accumulate in the lining of the intestinal tract. One of the medical terms for this disease is lymphoplasmacytic gastritis or colitis. IBD is most often found in middle-aged or older dogs.

What are the signs of IBD?

Depending on the site of inflammation, the most consistent sign is chronic vomiting (stomach) or diarrhea (intestines). Inflammation of the intestines is the most common form; so chronic diarrhea is the most common sign. Weight loss may also be present if the dog has had IBD for several weeks or more. Dogs with chronic gastritis may be picky eaters or have a poor appetite.

How is IBD diagnosed?

To diagnose IBD, your veterinarian must take a biopsy (tissue sample) of the affected bowel. In most cases, the biopsy can be performed using an endoscope. The dog is anesthetized and the endoscope is passed into either the dog's stomach (through the mouth) or colon (through the rectum). The endoscope allows the veterinarian to see the lining of the stomach or intestine. It also allows a small sample of tissue to be collected from the by passing a biopsy instrument down the endoscope.

The tissue sample is examined by a veterinary pathologist. The diagnosis is made when abnormal accumulations of inflammatory cells are found in the mucosa. The cause of the inflammatory reaction must then be determined, if possible. Internal parasites, tumors, infections, hyperthyroidism, diabetes, and diseases of the liver, kidney, and pancreas need to be considered. Specific tests or response to specific treatment may be used to determine the cause. In some cases a definite cause cannot be found. In this situation, the disease is called idiopathic, meaning that the cause is not known. A significant percentage of IBD cases are idiopathic.

One specific cause of chronic gastritis and vomiting in dogs is Helicobacter infection. These spiral-shaped bacteria are often found in people with stomach ulcers. Helicobacter infection in dogs can be diagnosed by biopsy of the stomach lining. These bacteria can be found in the stomachs of healthy dogs (and humans), so finding them in the stomach is meaningless without evidence of inflammation.

Can IBD be treated?

If a cause for the inflammatory reaction can be found, specific treatment is directed at that condition. Idiopathic cases are usually treated in two ways. First, your veterinarian may recommend dietary changes. Options include changing to a food that contains a protein source the dog has never been exposed to, and feeding a high-fiber diet. The new diet must be strictly followed for at least 6 weeks before deciding if it is effective. There are a number of prescription diets available from your veterinarian. These diets have been specially formulated to treat IBD.

Some cases may require medical therapy. Corticosteroid ("cortisone") therapy is commonly used

to treat IBD. High doses of corticosteroids given for several days may cause side effects, so the goal is to get and keep the condition under control using the lowest effective dose. Your veterinarian will begin treatment with a moderate-to-high dose, and then taper the dose down over the next several days. The most commonly used corticosteroid for this condition is prednisolone or prednisone. It is given orally every other day, in the morning. Low-dose prednisolone therapy is given for a few months. The drug is then gradually withdrawn. If the vomiting or diarrhea return, drug therapy is continued. Occasionally, a more potent drug is needed to get the condition under control. Once the dog's symptoms have resolved, therapy can be continued with prednisolone. Some cases require antibiotic therapy. Metronidazol and sulfasalazine are two popular antibiotics used to control IBD.

How is Helicobacter infection treated?

Treatment of this infection in dogs is similar to that used in people: a combination of antibiotics and anti ulcer medications. This approach seems to be successful in most cases. (Incidentally, it is doubtful that dogs with Helicobacter infection can spread the bacteria to you or your family. It is equally doubtful that a person gave it to your dog.)

What is the prognosis for IBD?

The prognosis is good for dogs that respond to a change of diet, provided you are able to continue feeding that diet for the rest of the dog's life and the diet is well balanced. The prognosis is also good for dogs that respond to medication for Helicobacter infection.

Dogs that respond well to corticosteroids may also have a good prognosis, especially if the dog remains healthy after the drug has been withdrawn. If there is no response to dietary change and corticosteroids, the prognosis is guarded. Further testing should be performed to identify any underlying disease.

by William M. Fraser, D.V.M.

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