Lymphangiectasia in Dogs

Overview of Canine Lymphangiectasia

Lymphangiectasia is an obstructive disorder characterized by marked dilation and dysfunction of the intestinal lymphatic system. This disorder affects the gastrointestinal tract, resulting in a protein-losing enteropathy, and eventually, profoundly low blood protein levels develop. Impaired intestinal lymph drainage is presumably caused by obstruction to the normal flow.

Primary or Congenital Causes of Lymphangiectasia in Dogs

• Focal (intestinal only) lymphangiectasia
• Diffuse (widespread) lymphatic abnormalities
• Chylothorax (collection of high fat lymphatic fluid in the chest cavity)
• Lymphedema (swelling of any part of the body due to insufficient lymphatic drainage)
• Chylous ascites (collection of high fat lymphatic fluid in the abdominal cavity)
• Thoracic duct obstruction (blockage of the lymphatic system that drains the chest cavity)

Secondary Causes of Lymphangiectasia in Dogs

• Right heart failure
• Constrictive pericarditis (covering of the heart cannot expand)
• Budd-Chiari syndrome (blockage of the liver veins)
• Cancer

The average age of onset is 5 years of age, however this disorder can be seen in older or younger dogs. There appears to be a slight increased incidence in females over males. Although lymphangiectasia can affect all breeds, dogs with a familial predisposition 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 lymphangiectasia.

What to Watch For

Symptoms of Lymphangiectasia in Dogs may include:

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

Diagnosis of Lymphangiectasia in Dogs

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

Treatment of Lymphangiectasia in Dogs

• Dietary management is often recommended and one of the most important parts of therapy.
• Oncotic agents like plasma, dextrans, hetastarch help maintain normal fluid distribution in the body and may be of benefit in critical cases that are severely hypoproteinemic and need immediate attention.
• Corticosteroids (anti-inflammatory drugs)

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 or is getting worse, seek veterinary attention at once.

There is no preventative care for protein losing enteropathy.

In-depth Information on Lymphangiectasia in Dogs

Lymphangiectasia is the blockage of lymphatic vessels that carry lymph fluid through the body. It is the most common intestinal disease that causes low protein levels in dogs. Although most often a primary intestinal disorder, it is interesting to note that gastrointestinal signs (vomiting, diarrhea) are not present in all cases, and the clinical signs 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 pleural effusion (fluid accumulation in the chest cavity). The initial step in the diagnosis of lymphangiectasia is to exclude non-intestinal causes of hypoproteinemia, specifically related to the liver or kidneys, and then to rule out other intestinal disorders that cause hypoproteinemia.

Many disorders must initially be considered:

• Severe liver disease must be eliminated as a contributing cause of hypoproteinemia. Examples include hepatitis (inflammation of the liver), cancer and cirrhosis (end stage liver disease).
• Protein-losing nephropathy (kidney disorders) need to be considered in hypoproteinemic patients.
• Glomerulonephritis is an inflammation of a part of the kidney.
• Amyloidosis is the deposition or collection of a type of protein in organs and tissues that compromise their normal function.
• Blood loss for any reason will decrease the protein level in addition to causing anemia.
• Inadequate protein intake or starvation will contribute to hypoproteinemia.
• Congestive heart failure may be associated with hypoproteinemia, specifically constrictive pericarditis, which is a condition where the tissue covering the heart cannot expand for a variety of reasons.
• 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. Lymphosarcoma is a malignant cancer that is the most common cancer causing protein loss into the gut.
• An intussusception (telescoping of part of the bowel into an adjacent segment of bowel), especially chronic, can cause protein loss.
• Chronic foreign bodies of the intestinal tract are often associated with a number of gastrointestinal signs (diarrhea, vomiting, weight loss) and occasionally hypoproteinemia.
• Ulcerative gastroenteritis, or interruptions in the lining of the gastrointestinal tract, may cause anemia and 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 flora (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 protein-losing enteropathy, especially in young pups that are anemic as well. Common parasites include roundworms, hookworms, whipworms, coccidia and giardia.
• Food allergies and gluten-induced enteropathy (sensitivity to a component of wheat and other grains), have been associated with hypoproteinemia.

Diagnosis In-depth

Certain diagnostic tests must be performed in dogs to diagnose lymphangiectasia and 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 to confirm a diagnosis:

• A complete blood count (CBC) may be within normal limits, but it often reveals a decreased lymphocyte count.
• A biochemical profile will help evaluate the kidney, liver, protein and electrolyte status. Hypoproteinemia is the hallmark of this disease. Hypocalcemia (low calcium) is often seen secondary to low protein levels. Additionally, 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 reveal fluid in the chest or abdominal cavity, or may be of benefit in ruling out other disorders.
• Abdominal ultrasound may be indicated if the previous diagnostics have been inconclusive. Although it cannot document lymphangiectasia, it helps to better 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, but it may require transfer to a referral facility.
• An upper gastrointestinal (GI) barium series may be considered. It will help rule out foreign bodies 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 X-rays are taken as it travels through the GI tract. It is non-invasive and can usually be performed by your veterinarian, although it may necessitate transfer to a referral facility.
• Evaluating a portion of the stomach and small intestine with proper instrumentation by gastroduodenoscopy is often indicated. Biopsies can be obtained, without an abdominal incision, and submitted for microscopic evaluation. Endoscopic biopsies are often diagnostic in cases of lymphangiectasia. General anesthesia is necessary, although 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:

• Bile acids should be performed on those patients whose hypoproteinemia is potentially secondary to liver disease. They are paired blood tests obtained before and after a meal that evaluates liver function. The test is very safe and can be performed at your local veterinary hospital.
• Serum folate and cobalamin are blood tests that 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 (abdominal surgery) allows surgical biopsy of intestines, lymph nodes and other organs to be obtained. Laparotomy may be the one test that confirms lymphangiectasia, as there is a characteristic appearance of the intestines and surrounding tissue, as well as the fact that obtaining a large, “full-thickness” biopsy may be necessary. There are moderate risks associated with doing surgery on hypoproteinemic animals, and should be performed only if absolutely necessary.

Therapy In-depth

Appropriate therapy for dogs with lymphangiectasia varies according to the type of signs and severity of clinical illness. Depending on the severity of clinical signs and/or stage of disease, hospitalization may or may not be recommended. Patients who have severe vomiting and/or diarrhea, 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. It is very important that all recommendations by your veterinarian are followed very closely, and any questions or concerns that arise during the treatment protocol are addressed immediately.

• Dietary management is an important part of therapy with lymphangiectasia. Low fat diets are recommended. Additionally, MCT oil (medium-chain triglycerides) is a source of calories that is well tolerated by patients with lymphangiectasia, and in those who are emaciated, help make up the calories missing in low fat diets.
• Diuretics that help remove excess fluid from the body may be indicated in some patients with lymphangiectasia where fluid accumulation in body cavities or tissues may be causing clinical problems. They should be used only as directed, and with caution.
• Oncotic agents (plasma, dextrans, hetastarch) help maintain normal fluid distribution in the body, and may be used in patients who are in immediate need of stabilization.
• Corticosteroids (anti-inflammatory drugs) may be of benefit in these patients.
• Other treatment options including surgical procedures may be indicated in those suffering from secondary lymphangiectasia. For example, a pericardectomy (removal of the covering of the heart) may be recommended in those with constrictive pericarditis.

Follow-up Care for Dogs with Lymphangiectasia

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 improve rapidly. Administer all prescribed medication as directed. Alert your veterinarian if you are experiencing problems treating your pet.

Observe your dog’s general activity level, body weight, appetite and evidence of return of clinical signs (pleural effusion, ascites, edema). Repeated serum protein level tests may be recommended.