Lymphocytic Plasmacytic Gastroenteritis in Cats

By Malcolm Weir, DVM, MSc, MPH; Robin Downing, DVM, DAAPM, DACVSMR, CVPP, CRPP

What is lymphocytic plasmacytic gastroenteritis?

Lymphocytic plasmacytic gastroenteritis is a form of inflammatory bowel disease in which inflammatory cells infiltrate the lining of the stomach and intestine as the result of an abnormal immune response. While the exact cause is not known, it is possible that the intestinal bacteria themselves may actually be involved in stimulating the immune response. That is, the body reacts to the intestinal bacteria as though they were foreign, releasing cells that cause inflammation. Environmental, dietary and immune-system factors likely also play a role in disease development.

While most cats with lymphocytic plasmacytic gastroenteritis are middle-aged, this disease has been diagnosed in cats as young as 5 months. The signs and symptoms can vary in intensity and frequency, but generally, cats exhibit signs of disease intermittently at first, with the frequency of episodes increasing over time.

What are the signs of lymphocytic plasmacytic gastroenteritis?

Diarrhea is the most common symptom in most cats, but vomiting occurs when the stomach is most affected. Other possible signs include loss of appetite, long-term weight loss, and blood in the stool and/or vomit.

What are some other conditions that can look like lymphocytic plasmacytic gastroenteritis?

There are several conditions that share similar signs of lymphocytic plasmacytic gastroenteritis, including granulomatous inflammatory bowel disease, gastrointestinal infections (e.g., histoplasmosis, Salmonella, Giardia, and bacterial overgrowth), gastrointestinal cancers, and pancreatic disease.

What diagnostic tests are used to diagnose lymphocytic plasmacytic gastroenteritis?

A complete blood count and blood chemistry panel are often normal in these cats, although the cat may have a mild anemia (low red blood cell count) or a low protein level. Tests for pancreatitis may be recommended in order to rule out a problem with pancreatic function. Levels of vitamin B12 (cobalamin) and folate may also be assessed to help determine the presence of intestinal absorption. Plain abdominal radiographs (X-rays) typically look normal, but barium radiographs may demonstrate thickened loops of bowel. An abdominal ultrasound may also be recommended and may be more diagnostic than radiographs.

"Your veterinarian may recommend a hypoallergenic diet
to rule out a nutritional intolerance."

Your veterinarian may recommend a hypoallergenic diet to rule out a nutritional intolerance. Some forms of immune-mediated gastrointestinal disease in cats may respond to changes in diet, in which case the diagnostic plan is complete. Independent of the path to a diagnosis, most cases of lymphocytic plasmacytic gastroenteritis are helped when nutrition is part of long-term management.

The definitive diagnosis of lymphocytic plasmacytic gastroenteritis involves a biopsy that is evaluated by a surgical pathologist. Most often, the biopsy is taken via the less invasive technique of endoscopy, rather than by an open abdomen surgical procedure.

How is lymphocytic plasmacytic gastroenteritis treated, aside from managing the cat nutritionally?

If there is any dehydration or ongoing vomiting, the cat may need to be admitted to the hospital for anti-nausea medication and IV fluid therapy. Immunosuppressive medications (such as prednisone) are used to control the symptoms of lymphocytic plasmacytic gastroenteritis. Once the cat is feeling better, the immunosuppressive therapy can be tapered down to the lowest dose that keeps the cat’s symptoms under control.

Other treatments can include antibiotic therapy, cobalamin supplementation, as well as prebiotics and probiotics to help improve gut bacterial flora.

What kind of follow-up will be needed for my cat once her symptoms are under control?  Will she ever be normal again?

Cats with severe clinical signs require more frequent monitoring. The end point of treatment is the resolution of clinical signs. Most cats are monitored every two to three weeks initially, and then every month or two until the immunosuppressive medications can be withdrawn. Cats with a mild case of lymphocytic plasmacytic gastroenteritis have an excellent prognosis. Those with a more severe case have a more guarded prognosis. Some patients may need to remain on immunosuppressive drugs.

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