Intestinal Protein Loss in Cats

By PetMD Editorial on Jul. 31, 2009

Protein Losing Enteropathy in Cats

Nutrients make their way through the body by way of the bloodstream. From the stomach, the food that has been eaten enters into the intestines, where it is divided into what is useful for the body and what is not. The useful, nutritious bits are picked up by the bloodstream as it passes through the intestines, carrying them to the rest of the body, where they are converted into various types of energy.

As the bloodstream picks up these nutrients, a small amount of protein leaks from the blood vessels back into the intestines. Usually these proteins are digested in the intestines, absorbed back into the blood, and used by the body to make more protein, but when the intestines are damaged, more protein leaks out into the intestines than the body can replace. This condition is referred to as protein losing enteropathy (enteropathy being any abnormal condition relating to the intestines). There are a number of diseases that can damage the intestines enough to cause this extra protein loss.

Protein losing enteropathies can occur in any cat breed and at any age.

Symptoms and Types

  • Occasional bouts of diarrhea
  • Chronic diarrhea
  • Weight loss
  • Lack of energy (lethargy)
  • Difficulty breathing (dyspnea)
  • Enlarged abdomen
  • Legs and feet may be puffy or swollen (edema)


  • Cancer in the intestines
  • Infection in the intestines
  • Bacteria such as salmonella
  • Fungal infection
  • Intestinal parasites like hookworms and whipworms
  • Inflammation of the intestines (inflammatory bowel disease)
  • Food Allergies
  • Stomach or intestinal ulcers
  • Congestive heart failure
  • Problems with the movement of lymphatic fluid out of the intestines (lymphangiectasia)


You will need to give a thorough history of your cat's health and onset of symptoms. A thorough physical examination will be performed, and will include standard laboratory work – a complete blood count, biochemical profile and urinalysis. Your veterinarian will use these samples to determine your cat's blood protein level and blood calcium level. There are several causes that will need to be ruled out in order to make a diagnosis. Your veterinarian will order stool (fecal) tests to check for intestinal parasites, intestinal infections, and other indicators that your cat is losing protein from its intestines.

Your veterinarian may also check the blood vitamin levels, which will be low if your cat is losing protein from its intestines. X-ray and ultrasound images of your cat's chest and abdomen will allow your veterinarian to visually examine these internal structures for evidence of internal ulcerations or tumors, and will also display the heart's capabilities, and whether its performing abnormally. If your veterinarian needs a better visual of the stomach and intestines than external devices can provide, an endoscopy may be performed for a better view. In this test, a small camera, attached to a tube, is passed through the mouth or anus into the intestines so that the walls of the stomach and intestinal tract can be closely inspected for ulcers, tissue masses (tumors), or abnormalities in the wall or cell structure. The endoscopic device also allows for taking samples of tissue while it is inserted, and is a much less invasive method for performing a biopsy. Bioptic analysis is an especially useful diagnostic tool for determining why an animal is losing protein through its intestines.


Treatment will depend on the underlying disease that is causing your cat to lose protein through its intestines. If your cat's protein level is dangerously low, it may need a transfusion to replace some of the blood protein.

Living and Management

In most cases there is no cure for protein loss through the intestines. Your veterinarian will work with you to develop a treatment plan to help you manage your cat's symptoms, including a diet that will ensure that the best possible amount of nutrients are being absorbed by your cat's body. During follow-up visits, complete blood counts and biochemical profiles will be done to make sure that your cat's blood protein level is stable and not becoming dangerously low. Your veterinarian will also check your cat to make sure it is not having trouble with breathing and does not have fluid built up in its belly.

Encourage your cat to relax by giving it a quiet space in which to withdraw when the house is active, away from children and other pets.

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