Protein-Losing Enteropathy in Dogs

What happens when a dog has protein-losing enteropathy?

In a normal, healthy dog, protein from ingested food is digested into smaller protein molecules, called amino acids, and then absorbed as the food travels down the intestinal tract. It’s also normal for a dog to lose some protein from its bloodstream but this lost protein is digested and reabsorbed again. Absorbed amino acids will then be rearranged into different proteins with various functions in the dog’s body.

Some proteins will stay in the bloodstream and make up the liquid component of the blood, called plasma. Plasma proteins are divided into 2 main types: albumins and globulins. These plasma proteins play an important role in the dog’s immunity, cell functions, and transport of different molecules.

When a dog suffers from an intestinal disease, it often causes inflammation along the intestinal lining, resulting in damaged intestinal tissue. This break in the intestinal lining leads to leakage of plasma proteins from the bloodstream into the intestinal lumen. Absorption of protein is also compromised in cases of intestinal problems, which worsens the decline in protein levels of the affected animal.

Both plasma proteins albumin and globulin are lost when a dog suffers from protein-losing enteropathy. But albumin is lost at a faster rate than globulin, leading to a wide range of clinical signs. Albumin is produced by the liver, and a decline in albumin levels will often trigger an increased rate of albumin production. Protein losing-enteropathy happens when the rate at which protein is lost is significantly greater than the production of replacement proteins.

Symptoms of Protein-Losing Enteropathy in Dogs

The most common clinical signs associated with protein-losing enteropathy are primary GI signs like vomiting and diarrhea. Chronic cases often result in excessive weight loss, dehydration, and generalized weakness.

Other symptoms observed in dogs with protein-losing enteropathy happen as a consequence of excessive protein loss, specifically albumin. Albumin plays an important role in holding water molecules inside blood vessels through oncotic pressure.

A significant decline in albumin levels leads to drastic changes in cellular oncotic pressure, causing water molecules from blood vessels to leak into body tissues and cavities such as the abdomen. This results in generalized edema (fluid build-up within skin tissues), pleural effusion (fluid build-up in the chest cavity), or ascites (fluid build-up inside the abdominal cavity).

Secondary signs like respiratory distress appear as fluid accumulates in the chest cavity, causing compromised lung inflation. Swelling or edema of the skin, especially in the hindlegs, can also cause movement problems in dogs with protein-losing enteropathy.

Common Causes of Protein-Losing Enteropathy in Dogs

Any intestinal disease can potentially result in protein-losing enteropathy in dogs, however, there are conditions in which there is an increased risk for protein loss. The most common causes of protein-losing enteropathy in dogs are infectious intestinal diseases.

Viral infections such as canine parvoviral enteritis (parvo) cause severe diarrhea and damage along the intestine’s mucosal lining, resulting in severely compromised protein absorption and an increased rate of protein leakage. Dogs with severe parvovirus infection will eventually develop ascites or edema as albumin and globulin levels drop. Bacterial enteritis, such as spirochete infections, can also result in protein-losing enteropathy if left untreated.

Tumors and cancer growing anywhere along the intestinal tract can also lead to protein-losing enteropathy in dogs. Intestinal malignancies, like lymphoma, can cause leakage of protein from blood vessels to the lumen or abdominal cavity. The presence of tumors can also hinder the proper absorption of protein molecules, leading to more protein loss.

Intestinal parasites such as worms or protozoal organisms often cause diarrhea severe enough to result in protein leakage and compromised protein absorption.

Anatomical changes such as intussusception (telescoping of intestinal segments) and obstruction are also reported to be causes of protein-losing enteropathy in dogs.

Inflammatory conditions such as inflammatory bowel disease (IBD) also cause protein-losing enteropathy in dogs. Chronic inflammatory response of the mucosal lining of the intestines leads to progressive damage, severe protein leakage, and improper nutrient absorption in dogs.

How is Protein-Losing Enteropathy Treated and Managed in Dogs?

Successful treatment of protein-losing enteropathy will depend highly on determining the underlying cause. Diagnostic tests must be done to figure out the cause of the condition. This may include blood work, urinalysis, fecal testing, and imaging such as abdominal x-rays or ultrasound.

In cases where the patient has developed ascites or edema from severe protein loss, IV fluid therapy using colloids can help increase oncotic pressure and help hold fluid inside the blood vessels. Albumin replacement, via intravenous albumin infusion, is the fastest way to replace lost albumin in the blood and improve oncotic pressure. Human albumin is a suitable replacement for lost albumin in dogs with severe protein-losing enteropathy.

Use of diuretics, like furosemide, may be needed in individuals with progressively worsening edema or ascites. Care must be taken when using diuretics as they can cause dehydration and electrolyte imbalances, leading to more serious clinical signs.

For dogs with severe ascites and extremely distended abdomen, the increased pressure can potentially damage internal organs. A fast way to remove this accumulated fluid may be indicated. The fastest way to remove fluid from the abdominal cavity is through draining, call abdominocentesis. Abdominal draining must be done by an experienced vet to avoid injuring internal abdominal organs.

Keep in mind though that protein-losing enteropathy can be fatal in dogs even with treatment, even more so if left untreated. It’s important to bring your dog to a vet as early as possible if you suspect that your dog may be suffering from this condition. Early detection and treatment can significantly increase the chances of recovery for dogs.

Read more:

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Pancreatitis in Dogs

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