Protein-Losing Enteropathy (PLE) in Cats

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


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 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 into the abdomen, chest, or out of the tiny blood vessels in the limbs, causing swelling of the legs.

Could my cat’s genetic profile or breed have led to PLE?

No. There has not been any genetic predisposition proven to date.

Is diarrhea the only sign of PLE?

Diarrhea is one common sign of PLE. The diarrhea may come and go. It may be continuous or may be the consistency of water. But some cats with PLE can have normal stools. Cats with PLE generally have a difficult time holding their weight, and may become lethargic. 

Fluid in the abdomen (ascites), fluid under the skin (edema) on the under-side of the body or in the limbs, difficulty breathing from the pressure of fluid build-up inside the chest cavity (pleural effusion), and thickened loops of intestine are all 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:

  • Gl ymphoma/lymphosarcoma -cancer of the lymphoid tissues around the body, including those 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
  • Lymphangiectasia – dilation of the lymphatic vessels in the GI tract

Diseases that directly affect the GI tract and can lead to PLE include:

  • Viral gastroenteritis—eg. panleukopenia
  • 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

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 cat 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 also be determined by the underlying cause of the PLE. Modified nutrition is also part of ongoing management because the primary, underlying disease may not be treatable.

The long-term prognosis in most cats depends largely on the underlying cause of the PLE.


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