Lymphocytic Plasmacytic Gastroenteritis in Dogs

By Courtney Barnes, BSc, DVM; 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. Inflammatory cells infiltrate the lining of the stomach and intestine as the result of an abnormal immune response.

While the exact cause is unknown, it is possible that intestinal bacteria may be involved in stimulating the immune response. That is, the body reacts to the intestinal bacteria as though they were foreign, releasing immune cells that cause inflammation. Environmental, dietary, and immune-system factors also likely to play a role in disease development.

Most dogs with lymphocytic plasmacytic gastroenteritis are middle-aged, but this disease has been diagnosed in dogs as young as 8 months. The signs and symptoms vary in intensity and frequency, but generally, dogs 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 dogs, but vomiting occurs when the stomach is most affected. Other possible signs include loss of appetite, weight loss, blood in stool and/or vomiting. If severe protein loss occurs, signs of ascites (fluid in the abdomen) or edema (fluid in the subcutaneous tissues) may be present. Abdominal pain may be present.

What other conditions can look like lymphocytic plasmacytic gastroenteritis?

Several conditions have signs like lymphocytic plasmacytic gastroenteritis, including granulomatous inflammatory bowel disease, lymphangiectasia, gastrointestinal infections (e.g., histoplasmosis, Salmonella, Giardia, and bacterial overgrowth), gastrointestinal cancers, and pancreatic disease.

What tests are used to diagnose lymphocytic plasmacytic gastroenteritis?

A complete blood count and blood chemistry panel are often normal in these dogs, although the dog may have mild anemia (low red blood cell count) or low protein levels. Tests for pancreatic disease may be recommended to rule out pancreatitis or a problem with pancreatic function (exocrine pancreatic insufficiency). Levels of vitamin B12 (cobalamin) and folate may also be measured to assess the ability of the intestines to absorb nutrients.

Plain abdominal X-rays (radiographs) typically look normal, but barium X-rays may reveal thickened loops of bowel. An abdominal ultrasound may also be recommended and may be more diagnostic than X-rays, as it allows bowel wall thickness to be more accurately measured.

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

Your veterinarian may recommend a hypoallergenic diet trial to rule out a nutritional intolerance, such as an immune reaction to a specific protein. Some forms of immune-mediated gastrointestinal disease in dogs 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 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 nutrition?

If there is any dehydration or ongoing vomiting, the dog may need to be admitted to the hospital for anti-nausea medication and IV fluid therapy. Immunosuppressive medications are used to control the symptoms of lymphocytic plasmacytic gastroenteritis. Prednisone is the most prescribed medication, but other corticosteroids and immunosuppressive medications may be tried. Once the dog feels better, the immunosuppressive therapy can be tapered down to the lowest dose that keeps the dog’s symptoms under control.

Other treatments can include antibiotic therapy and cobalamin (B12) supplementation, as well as prebiotics and probiotics to help improve gut bacterial flora.

What kind of follow-up will be needed once my dog’s symptoms are under control? Will he ever be normal again?

Dogs with severe clinical signs require more frequent monitoring. The end point of treatment is the resolution of clinical signs. Most dogs are monitored every two to three weeks initially, and then every month or two until the immunosuppressive medications can be withdrawn. Some patients, however, may need to remain on immunosuppressive drugs.

Dogs with a mild case of lymphocytic plasmacytic gastroenteritis have an excellent prognosis. Those with a more severe case have a more guarded prognosis. Those dogs who recover quickly initially seem to do the best.

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