Lymphedema is swelling in one or more of the arms or legs that arises due to damage or poor function of the lymphatic system. The lymphatic system is a network of vessels that course throughout the body to collect excess fluid as well as waste products. The fluid is filtered at the lymph nodes, which are important in fighting infection and are a key part of the lymphatic system. Eventually, the excess fluid removed from the tissues is drained into the bloodstream.
Lymphedema most commonly affects one of the extremities only, but in some cases both arms or both legs are affected.
Lymphedema may be classified as primary or secondary.
Lymphedema can occur due to a defect in the function of the lymphatic system, although this is not common. In this situation, the lymphedema is referred to as primary lymphedema. Depending upon when in life the signs and symptoms develop, primary lymphedema is termed congenital lymphedema (present from the time of birth), lymphedema praecox, or Meige disease. Milroy disease is a one specific type of primary lymphedema that is inherited in a sex-linked genetic pattern.
Much more commonly, lymphedema occurs because of damage or destruction of a lymphatic system that was previously functioning normally (secondary lymphedema). The most common cause of lymphedema in the U.S. is breast cancer surgery, especially in combination with radiation therapy, which can cause lymphedema of the arm on the side of the body affected by the cancer. Other surgeries, such as vein stripping, peripheral vascular surgery, scar excisions, or any procedure that potentially damages lymph nodes and vessels can result in lymphedema.
Worldwide, filariasis is the most common cause of lymphedema. Filariasis is infestation of lymph nodes by the parasite Wuchereria bancrofti, which is transmitted among humans by mosquitoes. Filariasis is a significant public health problem affecting millions in tropical and subtropical regions of Asia, Africa, the Western Pacific, and parts of Central and South America. In people suffering with filariasis, the entire leg, arm, or genital area may swell to several times its normal size, causing long-term disability.
Other conditions characterized by damage to lymph nodes can also cause lymphedema, including infiltration of lymph nodes by cancer or damage due to trauma, burns, radiation, compression, or infection.
The swelling of lymphedema may be so slight as to barely be noticed, or the swelling may be severe and disfiguring. Pronounced swelling can be accompanied by fatigue when moving the involved extremity, as well as embarrassment.
Over the long-term, the excess fluid and proteins in the tissues cause a chronic inflammation and scarring. The swelling is firm and does not retain an indentation (pit) when the skin is compressed by a finger (nonpitting edema). The skin in the involved area can become scaly or cracked, or may develop an orange-peel appearance (peau d'orange). Tenderness and soreness can accompany the swelling and skin changes. Loss of mobility may also occur.
Lymphedema also increases the susceptibility to infection in the affected area. Bacterial infections of the skin and of the subcutaneous tissues (the tissues underlying the skin) are the most common type of infections that occur in affected areas.
Medically Reviewed by a Doctor on 9/8/2014
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