What is protein-losing enteropathy?
The word “enteropathy” means any disease of the intestinal system.
Protein-losing enteropathy (PLE) is not a specific disease, but is described as a group of diseases that cause the loss of proteins from the bloodstream into the gastrointestinal (GI) tract. Primary GI disease, heart disease, and diseases of the lymphatic system can all cause PLE.
When the body is functioning normally, plasma proteins that end up in the GI tract are broken down and re-absorbed by the body. When disease occurs, protein loss may exceed protein manufacturing by the body. This is called “hypoproteinemia.” When hypoproteinemia is severe, fluid may leak from the circulatory system in to the abdomen, chest, or out of the tiny blood vessels in the limbs, causing swelling of the legs.
What breeds most commonly get PLE?
The Soft-coated Wheaten Terrier, Yorkshire Terrier, Maltese, Chinese Shar Pei, Rottweiler, Basenji, Irish Setter, and Norwegian Lundehund breeds are over-represented among PLE patients. There may be a genetic predisposition in some of these breeds.
Is diarrhea the only sign of PLE?
Diarrhea is one common sign of PLE. The diarrhea may come and go, may be continuous, or may be the consistency of water. But some dogs with PLE have normal stools. Dogs will also have a difficult time holding their weight, and they may become lethargic.
Fluid in the abdomen, fluid under the skin on the under-side of the body or in the limbs, difficulty breathing from the pressure of fluid build-up inside the chest cavity, and thickened loops of intestine, are also signs of PLE.
What diseases cause PLE?
The lymphatic vessels carry a clear fluid containing white blood cells, called “lymph”, throughout the body. Lymphatic diseases that can lead to PLE include:
- Lymphangiectasia—dilation of the lymphatic vessels in the GI tract
- GI lymphoma/lymphosarcoma—cancer of the lymphoid tissues around the body, including the lymphoid tissues within the GI tract
- Infiltration of the GI tract by granulomatous tissue which interrupts lymphatic flow
- Congestive heart failure causing increased pressure within the lymphatic system
Diseases that directly affect the GI tract and can lead to PLE include:
- Bacterial gastroenteritis—eg. salmonella
- Fungal gastroenteritis—eg. histoplasmosis
- Parasitic enteritis—eg. whipworms
- Inflammatory bowel disease (IBD)
- Adverse food reactions—eg. food intolerance
- Mechanical GI disease—eg. chronic foreign body irritation (without creating a blockage)
- Intestinal cancer—eg. carcinoma
- Ulcers in the stomach or intestines
- Viral gastroenteritis – eg. parvovirus
Diagnosis may depend on a biopsy of the stomach or intestine.
How is PLE treated?
Severe hypoproteinemia may require hospitalization for plasma transfusions, or the use of intravenous fluids to keep fluid within the vasculature (blood vessels in the body). If a dog has difficulty breathing, it may become necessary for the veterinarian to remove fluid from the chest or abdomen.
In general, treatment of PLE is determined by the underlying disease. Ongoing monitoring will help determine what it may be. Modified nutrition is also part of ongoing management because the primary, underlying disease may not be treatable.
The long-term prognosis in most dogs is largely determined by the underlying cause of the PLE.