Having a cat with a chronic vomiting or diarrhea, or both, is absolutely no fun, for you or your cat! One of the important parts of the medical history we will take at the Animal Clinic at Thorndale is “How long has the problem been going on?” Chronic problems, even when they occur intermittently, are often due to different causes than short term problems.
Inflammatory bowel disease (IBD) is an important and relatively common medical problem of cats. It is not a specific disease; rather, the term IBD represents several processes which are manifested as inflammation of the bowel. It may involve only the small intestine, large intestine, or stomach; in some cases, all parts of the gastrointestinal tract are affected.
Contributing Factors
Ingestion of hair can occur with grooming and may lead to development of hairballs, especially in cats who are prolific groomers. While this hair does not lead to IBD, it can be contributory as a source of gastric (stomach) or intestinal irritation.
Prevalence
IBD is most common in middle-aged to older cats. The age of onset is generally 5-12 years.
Causes/Transmission
For the most part, the cause (or causes) of IBD in the cat are unknown. When a cause is not identified, it is called “idiopathic IBD.” Some of the identified causes include infection with certain types of bacteria or other parasites, toxins, dietary intolerance, or immune reactions.
There are some spiral-shaped bacteria that can cause vomiting in cats and may be a cause of IBD. The most common is Helicobacter. These bacteria have been shown to be the cause of disease, including stomach ulcers, in humans and are also pathogens in cats. However, they are also found in many normal cats and humans. Therefore, just finding spiral-shaped bacteria on a biopsy is not always meaningful. It is considered a pathogen only if an associated inflammation is present in the stomach mucosa.
Clinical Signs
Three general presentations have been identified for IBD: (1) cats with primarily vomiting, (2), cats with primarily diarrhea, and (3) cats with both vomiting and diarrhea. Of these presentations, the most common in vomiting. It often begins as an intermittent event but, over months to years, progresses to the point that medical care is sought. IBD is one cause of chronic vomiting in cats.
Diagnosis
Chronic inflammation stimulates immune cells, primarily lymphocytes and plasma cells, to invade the stomach and/or intestinal wall. Occasionally, eosinophils and neutrophils will be found. The disease is diagnosed when these cells are identified in abnormal levels in the tissue. A pathologist is responsible for this part of the diagnosis; his or her report usually calls the disease lymphoplasmacytic gastritis (stomach), lymphoplamsamcytic enteritis (intestine), or lymphoplasmacytic colitis (colon) .
In order to obtain these cells, a biopsy is required. In most cases, an endoscope is passed into the cat’s stomach, small intestine or colon (with the cat under anesthesia). A tiny biopsy instrument is passed through the endoscope and used to take small samples of the lining (mucosa) of the affected organ. These biopsies, while fairly superficial, are extremely helpful in determining the type of cells present.
While the presence of an inflammatory process is determined with a biopsy, isolating the cause of the inflammation will usually require other tests. Tests or treatments should be performed to rule out stomach and intestinal parasites, cancer, and infections. Diseases such as hyperthyroidism and diabetes are considered. In addition, diseases of the kidney, liver, and pancreas should also be ruled out. In many cases, the cause cannot be determined.
Treatment
When possible, an underlying cause is identified and treated. Sometimes the above mentioned tests will do that, and sometimes a cause cannot be found. Unfortunately, many cases of IBD are considered idiopathic.
Spiral-shaped bacteria may be an important part of IBD in some cats. When they are found in humans, successful treatment may require several medications or combinations of medications. Currently we are using what is effective in humans to treat cats. This approach is successful in most cats, but we have quite a great deal to learn about the most effective means of treatment.
Some cats with IBD respond to a change in diet. This is done in two ways. First, a food is chosen that contains a protein source that the cat has not eaten in the past. If changing protein sources is not helpful, a high-fiber diet is tried. Unfortunately, a true food trial requires that the test diet be fed exclusively for 6-10 weeks.
If dietary therapy is not successful or feasible, drugs are used to suppress the inflammatory reaction. Corticosteroids (“cortisone”) are the most effective, so they are typically used first. Prednisolone is the most effective of the corticosteroids and has the least side effects. However, it is not effective in all cats. Sometimes a stronger drug is used initially to gain control of the disease. Then, prednisolone is tried again as a maintenance drug. Other drugs can be tried if corticosteroids are not successful.
Corticosteroids are renowned for causing a variety of side effects in humans. Fortunately, cats are relatively resistant to these side-effects as compared to humans. Regardless, to minimize any possible adverse effects, our goal is to use the lowest possible dose that is effective and to administer it on an every other day schedule. By giving prednisolone every other day, the last dose is out of the body for about 12 hours before the next dose is given. During this 12 hour period, the adrenal glands are stimulated to function and the body does not forget how to manufacture its own corticosteroids.
The cat’s adrenal glands function primarily in the morning hours. By giving prednisolone in the evening, the 12 hour off period will occur when the adrenal glands are ready to work. Thus, the preferred way to give prednisolone on a long-term basis is to give it every other evening.
It will be necessary to begin therapy with a rather high dose, but once response occurs, the dose is gradually tapered to the point that the signs are controlled. Long-term therapy is required for many cats. Generally, a cat is treated for a few months then prednisolone is discontinued to see if it is still needed. If the signs of vomiting or diarrhea recur, it is resumed.
Prognosis
In most cases, it is reasonable to hope for control of the disease. However, unless a specific cause can be identified, a cure is not expected. Also, the intestinal biopsies taken with the endoscope can be helpful in determining the severity of the IBD, which helps in considering prognosis.
Transmission to Humans
IBD is not transmitted to humans. Potentially, some of the parasitic causes of IBD could be infectious to humans but, in most cases, a cause is not identified.