Protein Losing Enteropathy in Dogs (PLE)

Overview of Canine Protein Losing Enteropathy (PLE)

Protein losing enteropathy (PLE) is a nonspecific term referring to conditions associated with excessive loss of plasma proteins into the gastrointestinal tract. There are numerous causes in dogs lymphatic disorders and mucosal diseases. Details of these conditions are below including:

Disorders of Lymphatic System

• Intestinal lymphangiectasia, or blockage of the lymphatics of the gastrointestinal tract
• Cancer
• Congestive heart failure
• Granuloma (a non-cancerous mass of tissue) of the small intestines or the tissue that attaches abdominal organs to the body wall

Diseases Associated with Increased Mucosal Permeability:

(Increased mucosal permeability is the passage of fluid through tissue.)

• Lymphoplasmacytic enteritis, a type of inflammatory bowel disorder
• Intestinal cancer
• Intussusception, which is telescoping of one part of the bowel into an adjoining segment
• Chronic intestinal foreign body
• Ulcerative gastroenteritis
• Histoplasmosis (fungal infection)
• Intestinal parasitism
• Immune-mediated diseases
• Hemorrhagic gastroenteritis (HGE) is a disorder with no known cause. It has a predilection for small breed dogs, and it is not recognized in cats. HGE is characterized by the sudden onset of profuse bloody diarrhea and occasional vomiting

PLE is seen in both dogs and cats. PLE can be seen in any age animal and equally in both genders. Although PLE affects all breeds, dogs with familial predisposition to lymphangiectasia (the most common cause of PLE) include soft-coated Wheaten terriers, basenjis, Lundehunds and Yorkshire terriers.

Although some patients may be asymptomatic (have no clinical signs), some may have life threatening manifestations of PLE.

What to Watch For

• Diarrhea
• Anorexia
• Lethargy
• Weight loss
• Ascities (fluid in the abdominal cavity)
• Edema (abnormal fluid accumulation in any part of the body)
• Respiratory difficulty secondary to fluid in the chest cavity

Diagnosis of Protein Losing Enteropathy in Dogs

• Complete blood cell count (CBC)
• Biochemical profile
• Urinalysis
• Fecal examinations
• Chest and abdominal X-rays
• Abdominal ultrasound
• Gastroduodenoscopy

Treatment for Protein Losing Enteropathy in Dogs

Treatment of patients with PLE should be directed at the underlying cause. Most of these individuals can be treated as outpatients.

• Dietary management is often recommended and varies depending on the underlying cause.
• MCT oil is a source of calories that is well tolerated by patients with PLE that may be indicated in patients who are severely emaciated.
• Fluid therapy may be necessary in some patients with severe vomiting and diarrhea, and is directed toward correction of dehydration and acid-base derangements, replacement of electrolyte deficits and to provide for ongoing losses.
• Diuretics that help remove excess fluid from the body may be indicated in some patients with PLE.
• Oncotic agents help maintain normal fluid distribution in the body.
• Antibiotic therapy, anti-inflammatory drugs, and/or antifungal agents may be indicated depending on the underlying cause of PLE.

Home Care and Prevention

Administer all medication and dietary recommendations as directed by your veterinarian. Follow up as directed.

If your dog’s condition is not improving and is getting worse, seek veterinary attention at once. There is no preventative care for protein losing enteropathy.

Information In-depth on Protein Losing Enteropathy in Dogs

The term protein losing enteropathy (PLE) refers to a variety of intestinal diseases that are associated with hypoproteinemia (low protein levels) caused by an excessive loss of protein into the gut. It is important to note that the initial step in the diagnosis is to exclude non-intestinal causes of hypoproteinemia, specifically related to the liver or kidneys.

Many different disease processes can cause or are associated with PLE. The clinical signs seen are quite varied, ranging from mild non-specific intermittent signs, to profound weight loss, emaciation, and in some cases, life-threatening respiratory difficulty secondary to fluid accumulation in the chest cavity. Many disorders must be considered initially. These disorders in dogs include liver disease, kidney lymphatic disease, and gastrointestinal disease. Details below include:

Liver Disease

Severe hepatic disease must be ruled out as a contributing cause of hypoproteinemia. These include:

• Hepatitis (inflammation of the liver)
• Cancer
• Cirrhosis

Kidney Disease

Protein losing kidney disorders need to be considered in hypoproteinemic patients. These include:

• Glomerulonephritis, an type of kidney inflammation involving the glomeruli, which are a mass of capillaries
• Amyloidosis, the deposition or collection of a type of protein in organs and tissues that compromises their normal function

Lymphatic Diseases

Disorders of the lymphatic system need to be considered. These include:

• Intestinal lymphangiectasia – blockage of the lymphatics of the gastrointestinal tract – is one of the most common causes of PLE.
• Cancer of any sort must be ruled out. Lymphosarcoma is a malignant cancer that is the most common cancer causing PLE. It most often takes the form of a microscopic infiltration into the bowel, although it may form mass lesions.
• Granuloma, a non-cancerous mass of tissue, of the small intestines or tissue that attaches abdominal organs to the body wall may be associated with profound protein loss.
• Congestive heart failure may be associated with hypoproteinemia. Constrictive pericarditis is a condition where the tissue covering the heart cannot expand for a variety of reasons.

Gastrointestinal Diseases

Diseases associated with increased permeability of mucosa commonly cause PLE. These include:

• Lymphoplasmacytic enteritis is a form of inflammatory bowel disease characterized by the infiltration of cells into the intestinal wall, causing a disruption of normal intestinal function and protein loss.
• Intestinal cancer of any kind may cause or contribute to protein loss in the gut.
• An intussusception, especially chronic, will often be associated with protein loss. This is a telescoping of part of the bowel into an immediately adjacent segment of bowel, and is most often associated with the presence of inflammation, foreign bodies, parasites or tumors.
• Chronic foreign bodies of the intestinal tract are often associated with a number of gastrointestinal signs including diarrhea, vomiting and weight loss, and occasionally hypoproteinemia.
• Ulcerative gastroenteritis is an inflammation of the lining of the gastrointestinal tract and is often associated with hypoproteinemia. It may be secondary to inflammation, drug administration, cancer or foreign bodies.
• Small intestinal bacterial overgrowth (SIBO) is characterized by an overgrowth of normal intestinal bacteria usually secondary to various gastrointestinal diseases, but occasionally as a primary entity.
• Histoplasmosis is a fungal infection that affects many systems, including the gastrointestinal tract. It has been associated with profound hypoproteinemia.
• Intestinal parasitism has been associated with PLE, especially in young puppies that are anemic as well.
• Roundworms, hookworms, whipworms, coccidia and giardia.
• Hemorrhagic gastroenteritis (HGE) is a dramatic, potentially fatal disorder with no known cause. It has a predilection for small breed dogs, and it is not recognized in cats. HGE is characterized by the sudden onset of profuse bloody diarrhea and occasional vomiting.
• Immune-mediated intestinal diseases may cause PLE.
• Food allergies and gluten-induced diseases of the intestines, which are a sensitivity to a component of wheat and other grains.

Miscellaneous

• Blood loss for any reason will decrease the protein level.
• Inadequate protein intake will contribute to hypoproteinemia.

Diagnosis In-depth of Canine Protein Losing Enteropathy

Certain diagnostic tests must be performed to make a definitive diagnosis of the underlying disorder and to exclude other disease processes that may cause similar symptoms. A complete history, description of clinical signs, and thorough physical examination are all an important part of obtaining a diagnosis. In addition, the following tests are recommended in dogs to confirm a diagnosis:

• A complete blood count (CBC) may be within normal limits but may reveal anemia (low red blood cell count), and in cases of lymphangiectasia, a decreased lymphocyte (type of white blood cell) count.
• A biochemical profile can help evaluate the kidney, liver, protein, and electrolyte status. Hypoproteinemia is the hallmark of this group of diseases. Hypocalcemia (low calcium) is often seen secondary to low protein levels. Additionally, in cases of lymphangiectasia, hypocholesterolemia (decreased cholesterol) is common.
• A urinalysis is most often within normal limits, and is helpful in ruling out protein loss associated with kidney disease. If there is any suspicion of kidney related protein loss, a urine protein:creatinine ratio should be evaluated. It is a simple test that can be performed on the urine.
• Fecal examinations should be performed to rule out parasitism. Chest and abdominal X-rays, although often within normal limits, may be of benefit in ruling out other disorders.
• Abdominal ultrasound may be indicated if the previous diagnostics have been inconclusive. It helps to evaluate the size, shape and integrity of the abdominal organs, and is especially helpful in evaluating for an intussusception or pancreatitis. It is a non-invasive procedure, although it may require a referral facility.
• An upper gastrointestinal (GI) barium series may be considered to help rule out foreign bodies that can be seen on X-ray and other causes of intestinal blockage. It also helps evaluate for intestinal ulcers, and can assess intestinal wall thickness. A safe dye is given to the pet by mouth and is watched as it travels through the GI tract. It is non-invasive and most often able to be performed by your veterinarian, although sometimes it may necessitate a referral facility.
• Gastroduodenoscopy is often indicated. This test allows direct visualization of the stomach and the duodenum by means of an endoscope that is passed through the mouth and esophagus into the stomach. With this procedure, biopsies can be obtained without an abdominal incision and submitted for microscopic evaluation. General anesthesia is necessary, but endoscopy is considered a relatively low risk procedure. It most often necessitates the expertise of a specialist and specialized instrumentation.

Your veterinarian may require additional tests to insure optimal medical care. These are selected on a case by case basis:

• Serum folate and cobalamin are blood tests, which generally increase and decrease respectively, in those cases with small intestinal bacterial overgrowth (SIBO).
• Cytologic examination of feces and the rectal tissue may reveal histoplasmosis.
• Cardiac ultrasound may be performed in those patients where heart disease is felt to play a part in the hypoproteinemia.
• Laparotomy, which is an incision into the abdominal, allows surgical biopsies of intestines, lymph nodes, and other organs to be obtained. Laparotomy is not recommended unless all prior procedures are inconclusive, and/or the patient is not responding well to appropriate therapy. There are moderate risks associated with doing surgery on hypoproteinemic animals, and should be performed only if absolutely necessary.

Therapy In-depth for Dogs with Protein Losing Enteropathy

Appropriate therapy for protein losing enteropathy is largely dependent on the underlying cause, and varies according to the type and severity of clinical illness. Depending on the severity of clinical signs and/or stage of disease in your dog, hospitalization may or may not be recommended.

Dogs with severe vomiting and/or diarrhea, dehydration, or hypoproteinemia and associated inappropriate fluid accumulation are hospitalized for aggressive treatment and stabilization. Stable patients can be treated as outpatients as long as they are monitored closely for response to therapy. With appropriate therapy, many dog do quite well. It is important that all recommendations by your veterinarian are followed very closely, and any questions or concerns that arise during treatment are addressed immediately.

• Dietary management is often recommended and varies on the underlying cause. For lymphangiectasia, low fat diets are recommended. For gluten-induced enteropathy, diets with no gluten (wheat, grains) are recommended. For immune-mediated inflammatory bowel disease, easily digestible and/or non-allergenic diets are recommended. For lymphoplasmacytic enteritis, easily digestible and/or non-allergenic diets are recommended.
• MCT oil is a source of calories that is well tolerated by dogs with PLE (specifically, lymphangiectasia) that may be indicated in patients who are severely emaciated.
• Fluid therapy may be necessary in some dogs with severe vomiting and/or diarrhea, and is directed toward correction of dehydration and acid-base derangements, replacement of electrolyte deficits, and to provide for ongoing losses.
• Diuretics to help remove excess fluid from the body may be indicated in some patients with PLE.
• Oncotic agents (plasma, dextran, hetastarch) are products that help maintain normal fluid distribution in the body.
• Antibiotic therapy, anti-inflammatory drugs, and/or antifungal agents may be indicated depending on the underlying cause.

Home Care of Dogs with Protein Losing Enteropathy (PLE)

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve. Administer all prescribed medication as directed. Alert your veterinarian if you are experiencing problems treating your dog.

Observe your dog’s general activity level, body weight, appetite and evidence of return of clinical signs such as the accumulation of fluid in the chest (pleural effusion), accumulation of fluid in the abdomen (ascities), and accumulation of fluid under the skin (edema). Follow serum protein level as directed by your veterinarian.