Reviewed by Brian R. Robinson, MD
Lymphedema is a chronic swelling due to inadequate lymph drainage and accumulation of lymphatic fluid. Lymph is a clear fluid that travels through the body's arteries, circulates through your tissues to cleanse them and keep them firm, and then drains away through the lymphatic system. This condition usually develops in the legs or arms, but can occur elsewhere in the body.
Lymph nodes are the filters of the lymphatic system. Their job is to filter out and trap bacteria, viruses and other unwanted substances such as toxins or cancer cells, and to make sure they are safely eliminated from the body. Instrumental to the proper function of the lymph nodes is lymphatic fluid. Lymphedema is the result of a build-up of lymphatic fluid in a type of tissue called interstitial tissue, the tissue that supports organs and other structures in the body.
There are two main types of the condition. In primary lymphedema, the cause is either missing lymphatic vessels or lymphatic vessels whose function is impaired. In secondary lymphedema, the cause is lymph nodes that have been damaged or removed (possibly as a result of surgery in the area, or because they were cancerous and had to be removed to prevent the spread of the disease).
If left untreated, the buildup of fluid associated with lymphedema can result in irreversible, disfiguring enlargement of the affected limb, as well as hardening of the affected tissue. The affected tissue also becomes very sensitive to bacterial infection, skin deterioration and (in rare cases associated primarily with secondary lymphedema) cancer.
Primary lymphedema may be present at birth, or it may develop during the teen years even in adulthood. It can be associated with vascular defects such as hemangioma, lymphangioma, or Klippel-Trenaunay-Weber Syndrome (sometimes called “port wine stain,” because of the associated birthmarks).
Secondary lymphedema is associated with several risk factors, which include surgery, radiation therapy or exposure, infection and trauma. Surgeries for cancers such as melanoma, breast cancer, gynecological cancers, cancers in the head or neck, prostate or testicular cancer, bladder cancer, and colon cancer require the removal of lymph nodes, and are especially likely to cause the onset of the condition. When lymphedema occurs in the lower extremities, treatment with the anti-clotting medication Tamoxifen can also be a culprit, as can smoking, obesity, and diabetes.