Protein-Losing Enteropathy in Dogs

It is important to note that Protein-losing enteropathy (PLE) is not a distinct illness, but refers to a set of disorders that result in the loss of proteins from the circulation into the intestine. Primary GI disease, heart disease, and lymphatic system diseases can all induce PLE.

Dr. Justine A. Lee, described PLE as “a fancy way of saying that excessive protein is lost from the gastrointestinal tract.” She went on to explain further that ‘protein that normally leaks into the intestines is digested into amino acids, then reabsorbed and made into protein again.’

While uncommon in humans, protein-losing enteropathies are seen more frequently in dogs. They can be a primary disease or secondary to other diseases.

Excessive loss of protein can occur through the gastrointestinal tract as a result of certain conditions.

The following three conditions can occur through the gastro tract causing excessive loss of protein;

• Gastrointestinal disease
• Lymphatic diseases
• Congestive heart failure

When the body is healthy, plasma proteins that end up in the GI tract are broken down and reabsorbed by the body. When disease occurs, protein loss may exceed protein formation by the body. This is known as “hypoproteinemia.” Fluid may leak from the circulatory system into the abdomen, chest, or out of tiny blood vessels (capillaries) into the tissues. This is called “third-space fluid accumulation.”

Protein-losing enteropathy occurs when there is an increased loss of proteins from the gastrointestinal tract or when the body does not make enough protein. The most common symptom of protein-losing enteropathy is weight loss.

What dog breeds are susceptible to PLE:

According to VCA Blog, over-representation of certain dog breeds, including the Soft-coated Wheaten Terrier, Yorkshire Terrier, Maltese, Chinese Shar Pei, Rottweiler, Basenji, Irish Setter, and Norwegian Lundehund, is seen among PLE patients. Some of these breeds may have a genetic propensity.

What causes PLE?

PLE can be caused by any type of GI disease, whether mild or severe such as inflammatory bowel disease (IBD), neoplasia (particularly lymphoma), lymphangiectasia, histoplasmosis, GI parasites, and pythiosis.

Parasites and chronic intussusception are the most common causes of PLE in juvenile dogs. All of these cause primarily small-bowel diarrhea, but they can also result in vomiting or large-bowel diarrhea. GI abnormalities are not uncommon (e.g., parvovirus), and acute gastrointestinal illnesses.

The most common GI diseases that lead to PLE are:

• Inflammatory bowel disease (IBD)
• Lymphangiectasia
• Neoplasia
• Histoplasmosis
• Pythiosis

Symptoms of protein-losing enteropathy:

According to dvm360.com, diarrhea, vomiting, and weight loss are the most common clinical symptoms of PLE in dogs. It’s worth noting that not all dogs with PLE vomit or have diarrhea; they frequently but not always have weight loss as a result of this disease. Other clinical symptoms might be caused by a loss of serum proteins, especially albumin.

Albumin is the primary protein in serum, and it plays an important role in oncotic pressure. When albumin levels are low, fluid leaks out of the vasculature into the interstitial spaces and tissues. This can cause edema (fluid retention), which is often seen in dogs with PLE.

Dyspnea (labored breathing) and ascites (fluid in the abdomen) can also be seen with protein-losing enteropathy, as a result of low oncotic pressure and fluid retention.

Clinical signs are quite subtle in the beginning but they may include any of the following:

• Decreased appetite
• Being a “picky” eater
• Vomiting
• Diarrhea
• Lethargy
• Weight loss
• The abdomen appears to be pot-bellied (due to fluid accumulation within the abdominal cavity)
• Blood-tinged, mucoid diarrhea
• Difficulty breathing (due to fluid accumulation in the chest cavity)

Upon further examination by a vet, below are some other possible symptoms;

• Muscle wasting
• Thickened intestines on palpation
• Fluid in the abdomen
• Abnormal rectal exam
• Increased lymph nodes A heart murmur

What Diseases are associated with protein-losing enteropathy?

Intestinal lymphangiectasia:

This is a dilation of the lymph vessels in the intestine. It can be caused by various conditions, including heart disease, intestinal parasites, and cancer.

Heartworm disease:

Heartworms are parasitic worms that live in the heart and pulmonary arteries of dogs (and other animals). They are transmitted by mosquitoes. Infected animals may have a mild cough, decreased appetite, and tire easily during exercise. As the disease progresses, heart failure can occur.

Intestinal parasites:

Many types of intestinal parasites can cause protein-losing enteropathy. These include hookworms, roundworms, and whipworms.

Cancer:

Various types of cancer, including lymphoma and stomach cancer, can cause protein-losing enteropathy.

Treatment of protein-losing enteropathy:

The goal of treatment is to identify and treat the underlying cause. If your dog has intestinal lymphangiectasia, he may need to be on a special diet. If heartworm disease is the cause, your dog will need to be treated with heartworm preventative medication and may need to be hospitalized. Intestinal parasites will need to be treated with deworming medication. If cancer is the cause, your dog may need surgery, chemotherapy, or radiation therapy.

The mainstay of therapy for PLE is dietary modification. Many dogs respond well to a diet that is low in fat and highly digestible. In some cases, a hypoallergenic or hydrolyzed protein diet may be necessary.

In addition to dietary modification, other therapies that may be used include:

• Antibiotics
• Corticosteroids
• Immunosuppressive drugs
• Intravenous (IV) fluids
• Vitamins and minerals
• Surgery may be necessary in some cases.

As reported by veterinary-practice.com, Dr. Armstrong uses a low dose of aspirin (0.5-1 mg/kg/day) to treat PLE because of its antithrombotic property, but she warns that it may not be sufficient to prevent a thromboembolic event.

Prevention of PLE:

There is no known prevention for PLE. However, prompt treatment of any underlying GI disease is important to help minimize the protein loss.

PLE can be a serious condition for dogs. If you notice any of the above symptoms, please contact your veterinarian.

How is PLE Diagnosed?

A veterinarian will take a complete history and perform a physical examination. Diagnosis of PLE can be difficult since there are no specific tests for the condition. A variety of tests may be performed to rule out other diseases and to try to identify the underlying cause of the protein loss. These tests may include:

• Complete blood count: A CBC may be done to check for anemia and to evaluate the overall health of your dog.
• Chemistry panel: A chemistry panel will be performed to assess organ function and to look for evidence of infection.
• Urinalysis: This test will be done to check for evidence of kidney disease or urinary tract infection.
• Fecal exam: A fecal exam will be performed to look for evidence of intestinal parasites.
• X-rays: X-rays may be taken of the chest and abdomen to look for evidence of fluid accumulation or tumor growth.
• Ultrasound: An ultrasound may be performed to evaluate the organs in the abdominal cavity. This can help to identify tumors or fluid accumulation.
• Endoscopy: An endoscopy may be performed to evaluate the GI tract. This involves passing a small camera through the mouth and into the stomach and intestines.
• Biopsy: A biopsy may be performed to identify the underlying cause of the protein loss. This can be done via endoscopy or surgery.PLE can be a serious condition for dogs. If you notice any of the above symptoms, please contact your veterinarian.

Does Hydrolyzed protein diet help dogs with PLE?

A diet that is low in fat and highly digestible is the mainstay of therapy for PLE. Many dogs respond well to a diet that is low in fat and highly digestible. In some cases, a hypoallergenic or hydrolyzed protein diet may be necessary.

Hydrolyzed protein diets are made with proteins that have been broken down into smaller pieces. This makes them easier to digest and less likely to cause an allergic reaction. These diets may be helpful for dogs with PLE who are also allergic to certain proteins.

If your dog has PLE, work with your veterinarian to choose the best diet for him.

My dog is dying with PLE, what should I do to help?

If your dog is clearly dying and not responding to diet changes and any medication, euthanasia is the kindest option. No one wants their dog to suffer, and at this point, there is no cure. Putting your dog down will help them to avoid any further pain and suffering.

Before making the decision, be sure to speak with your veterinarian about all of your options and what you can expect. This is a difficult decision to make, but sometimes it is the best thing for your dog.

Take some time to grieve your loss. This is a difficult time, and you will need time to process your emotions. There are many resources available to help you through this tough time. Speak with your veterinarian or a grief counselor if you need help.

Check out this detailed manual on euthanasia.

FAQs

Q: Is PLE the same as heart disease?

A: No. PLE is a condition that affects the protein levels in the blood. Heart disease is a condition that affects the heart muscle.

Q: Can humans get PLE?

A: PLE is only seen in dogs. Humans cannot get this condition.

Q: What is the prognosis for dogs with PLE?

A: The prognosis for dogs with PLE depends on the underlying cause. Some causes are more serious than others. In general, the prognosis is poor to fair.

Q: My dog has PLE. Can I breed her?

A: No. Dogs with PLE should not be bred. This is because PLE is considered to be a genetic condition. Breeding dogs with PLE will only perpetuate the condition in future generations.

Q: Can I feed my dog table scraps if he has PLE?

A: No. Dogs with PLE need to be on a special diet. Table scraps are not appropriate for dogs with this condition. Speak with your veterinarian about the best diet for your dog.

Q: I think my dog has PLE. Should I take him to the vet?

A: Yes. If you think your dog has PLE, please take him to the vet right away. This is a serious condition that requires prompt treatment.

Q: What should I and my vet be monitoring to check the progress of PLE?

A: Blood chemistry, specifically albumin and globulin, should be monitored every 2-4 weeks. Complete blood count (CBC) and urinalysis should be performed every 2-4 weeks. Thoracic radiographs (chest x-rays) should be performed every 2-4 weeks to check for evidence of heart failure. Echocardiography should be performed every 6-12 months to assess heart function.

If you have any additional questions, please feel free to contact us. We are always happy to help!