LYMPHANGIECTASIA

About the Diagnosis

Cause: Lymphangiectasia is an intestinal disease of adult dogs. With lymphangiectasia, a disruption of the lymphatic system causes leakage of lymphatic fluid (also called lymph) into the gastrointestinal tract. The lymphatic system is a very complex network of fluid, vessels, lymph nodes, and organs throughout the body that has numerous functions. It often runs parallel to, although separately from, the blood circulation. The lymphatic system is a ferrying system that carries waste substances outward from tissues in the body to the bloodstream. It also provides immune defense in certain areas of the body such as the spleen, tonsils, and the lining of the gastrointestinal tract (stomach and intestines). Also in the intestine, the lymphatic system absorbs fats after they are digested (chyle). In addition to fats, lymphatic fluid contains proteins and white blood cells, which are vital for the body's functions. Unfortunately, with lymphangiectasia the white blood cells, proteins, and fats leak into the intestinal tract and are lost. As a result, the dog becomes malnourished. Over time, this potentially can become a life-threatening disease.

Primary lymphangiectasia is thought to be present at birth (congenital); however, symptoms are usually seen later. Although the intestinal lymphatic system is usually affected, other signs include the accumulation of a milky-looking, chylous effusion around the lungs (chylothorax), edema or swelling under the skin precipitated by decreased protein in the blood (peripheral edema), and fluid in the abdominal cavity (ascites).

Secondary lymphangiectasia has many potential causes. These include inflammation of the intestine, right-sided congestive heart failure, obstruction of the thoracic duct (the thin vessel that carries lymphatic fluid from the abdomen and part of the chest to the bloodstream), and certain types of intestinal cancer. The exact cause of lymphangiectasia is often not determined, and a large proportion of dogs with lymphangiectasia do not have any of the disorders listed above (no inciting cause is ever found).

Although soft-coated wheaten terriers, Yorkshire terriers, and Norwegian lundehunds are most commonly affected with lymphangiectasia, any breed of dog can be affected. This disorder is very uncommon in cats.

Diagnosis: When lymphangiectasia is suspected, a complete blood count (CBC), serum biochemistry profile, urinalysis, and fecal analysis are performed to look for characteristic changes associated with this disease, to assess overall health, and to rule out other possible causes that could be mimicking lymphangiectasia. X-rays of the chest and abdomen may be taken to screen for fluid accumulation or signs of any inciting causes. A fine-needle aspirate helps to characterize the type of effusion in the chest and/or abdomen when present. For this procedure, a very small needle is inserted into the body cavity without anesthesia; fluid is aspirated and examined under a microscope. Lymphangiectasia is diagnosed from a biopsy of the gastrointestinal tract that is obtained either endoscopically or, more commonly, during a surgical procedure. The tissue is submitted to a laboratory where a specialist examines it under a microscope to make the diagnosis.

Living with the Diagnosis

If your dog is diagnosed with lymphangiectasia, the cornerstone of treatment is your dog's food. It is important that the diet recommended by your veterinarian be given. Alternatively, you may make your dog's diet yourself, although it is critical to offer the correct balance of nutrients for dogs. You should seek the recommendations of a veterinary nutritionist (Diplomate of the American College of Veterinary Nutrition) because there are many, many terrific sounding diets on the market, in books, or on the Internet, but only a few of them have been tested and shown to be balanced and acceptable.

This disorder can lead to malnutrition because of the loss of nutrients in the intestines. An inappropriate diet can make this process worse. Medication must also be given exactly as directed, since it may lessen the degree of loss of protein and fat. However, there is no cure for lymphangiectasia; if an underlying disease (see "Secondary lymphangiectasia" above) is not found, then treatment for lymphangiectasia is usually lifelong.

Treatment

If an underlying disease can be identified, it must be treated. Because a cause is usually not determined, the symptoms are treated. A low fat and highly digestible diet that is calorie dense is an important part of therapy. An anti-inflammatory medication (corticosteroid or cortisone-derivative) may be given. Your veterinarian may need to give a transfusion of plasma or a colloid fluid to replace the blood's proteins and diuretics to help control effusion in the chest and/or abdomen by eliminating the excess fluid through the urine.

DOs

• Inform your veterinarian if your cat or dog has ever been diagnosed with a medical condition and is taking medication.

• Give medication exactly as directed by your veterinarian, and if you are concerned about possible negative effects, discuss them with your veterinarian immediately rather than simply discontinuing the treatment.

• Realize that getting to the point of having a conclusive diagnosis of lymphangiectasia is always challenging because of the tests and biopsies required to reach the diagnosis. Furthermore, the diagnosis can be disappointing since there is no cure. However, individual response to treatment is highly variable, and often the only way to know if treatment will work for a particular dog, once the diagnosis of lymphangiectasia is made, is to try treatment and monitor response. Some dogs do very well while others do poorly, and often the only way to know for sure is to try.

DON'Ts

• Do not substitute another diet without consulting your veterinarian. Malnutrition is a common, life-threatening complication of this disease.

When to Call Your Veterinarian

• If you cannot keep a scheduled appointment.
• If you are unable to give medication as directed.
• If your dog is not improving after treatment begins.
• If your dog's appetite is decreasing.

Signs to Watch For

• General signs of illness: lethargy, weakness, decreased appetite, other behavior changes.

• Signs of lymphangiectasia: profound weight loss, markedly increased appetite (polyphagia), respiratory problems (if pleural effusion is present), and less commonly, vomiting, diarrhea, and lethargy.

Routine Follow-Up

• Follow-up visits will be scheduled to monitor progress, especially involving measuring body weight and blood levels of protein and white blood cells.