Lymphedema is an accumulation of lymphatic fluid in the interstitial tissue that causes swelling, most often in the arm and/or leg, and occasionally in other parts of the body. Lymphedema can develop when lymphatic vessels are missing or impaired (primary), or when lymph vessels are damaged or lymph nodes removed (secondary).
When the impairment becomes so great that the lymphatic fluid exceeds the lymphatic transport capacity, an abnormal amount of protein-rich fluid collects in the tissues of the affected area. Left untreated, this stagnant, protein-rich fluid not only causes tissue channels to increase in size and number, but also reduces oxygen availability in the transport system, interferes with wound healing, and provides a culture medium for bacteria that can result in lymphangitis.
Primary lymphedema, which can affect from one to as many as four limbs and/or other parts of the body, can be present at birth, develop at the onset of puberty or in adulthood, all from unknown causes, or associated with vascular anomalies such as hemangioma, lymphangioma, port wine stain or Klippel Trenaury.
Secondary lymphedema, or acquired lymphedema, can develop as a result of surgery, radiation, infection or trauma. Specific surgeries, such as surgery for melanoma or breast, gynecological, head and neck, prostate or testicular, bladder or colon cancer, all of which currently require removal of lymph nodes, put patients at risk of developing secondary lymphedema. If lymph nodes are removed, there is always a risk of developing lymphedema.
Secondary lymphedema can develop immediately post-operatively, or weeks, months, even years later. It can also develop when chemotherapy is unwisely administered to the already affected area (the side on which the surgery was performed) or after repeated aspirations of a seroma (a pocket of fluid which occurs commonly post-operatively) in the axilla, around the breast incision, or groin area. This often causes infection and, subsequently, lymphedema.
Lymphedema develops in stages, from mild to severe and is defined below:
Stage 1 (spontaneously reversible):
Tissue is still at the "pitting" stage, which means that when pressed by fingertips, the area indents and holds the indentation. Usually, upon waking in the morning, the limb or affected area is normal or almost normal size.
Stage 2 (spontaneously irreversible):
The tissue now has a spongy consistency and is "non-pitting," meaning that when pressed by fingertips, the tissue bounces back without any indentation forming. Fibrosis found in this stage of lymphedema marks the beginning of the hardening and increasing size of the limbs.
Stage 3 (lymphostatic elephantiasis):
At this stage the swelling is irreversible and usually the limbs are very large. The tissue is hard (fibrotic) and unresponsive; some patients consider undergoing reconstructive surgery called "debulking" at this stage.
When lymphedema remains untreated, protein-rich fluid continues to accumulate, leading to an increase of swelling and a hardening or fibrosis of the tissue. In this state, the swollen limb becomes a perfect culture medium for bacteria and subsequent recurrent lymphangitis. Moreover, untreated lymphedema can lead into a decrease or loss of functioning of the limb, skin breakdown, chronic infections and, sometimes, irreversible complications. In the most severe cases, untreated lymphedema can develop into a rare form of lymphatic cancer called lymphangiosarcoma (most often in secondary lymphedema).
Microsurgical techniques for the anastomosis of blood or lymphatic vessels have introduced a possible method for treating lymphedema in the extremities. These techniques attempt to create a means for lymphatic fluid to by-pass the obstruction by being channeled through the venous system (lymphatic-venous anastomoses), or by using venous grafts between lymphatic collectors above and below the obstruction (lymphatic-venous-lymphatic plasty).