What is Lymphedema?

Lymphedema is a chronic medical condition where protein-rich fluid abnormally collects in the interstitium of any region of the body resulting in an upregulated inflammatory response and increased fibrosis that predisposes the afflicted individual to repeat infections and hindered function.

Lymphedema is classified as either primary or secondary. Primary lymphedemas reflect inborn or genetic disorders of the lymphatic system. Affected individuals present with a variety of abnormalities of lymphatic channels and/or lymph nodes, either i.) aplasia (absence of critical structures as in Milroy's Disease); ii.) hypoplasia (normal anatomy but reduced numbers of critical structures); or iii.) dysplasia (abnormal anatomy or function of critical structures). Interestingly, not all primary lymphedemas present at birth, but become evident in teenage years (lymphedema praecox) or later typically after the age of 35 (lymphedema tarda). Later presentations may or may not be associated with ipsilateral soft tissue trauma as the frequently reported "cheerleader syndrome". Further, there are a variety of congenital syndromes associated with lymphedema (i.e. Klippel-Trenaunay Syndrome, Turner's Syndrome, and Noonan's Syndrome) that may complicate diagnosis and treatment as lymphedema in these disorders may be mixed in nature.

Secondary lymphedema is a disorder that is acquired. This form of lymphedema reflects trauma to a previously intact lymphatic system either due to surgery, trauma, radiation or repeat infection. Lymphadenectomy (surgical removal of lymph nodes) with or without adjuvant irradiation therapy for cancer is associated with the largest numbers of secondary lymphedema patients in the United States. Repeat filarial infection is the most common cause of secondary lymphedema world-wide.

Discussion of lymphedema would be incomplete without noting the sub-category of mixed lymphedemas. Mixed lymphedemas can be thought of as abnormal lymphatic states that develop secondary to other medical conditions.

Phlebo-lymphedema is the most common mixed lymphedema of the lower extremity. It is associated with pre-existing chronic bilateral venous insufficiency but may present secondary to a pathologic deep venous thrombosis. This disorder likely reflects the long-term ill effects of venous valve and perforator incompetence. Thus, the lymphedema develops as a result of increased venous pressures that decrease rates of re-absorption of fluid from the interstitium.

Lipedema is a medical condition of primarily women where by an individual may present with an abnormal accumulation of "fragile fat" from the iliac crest to the ankles with sparing of the feet. Lipedema most often presents bilaterally with associated excessive skin laxity, intolerance to touch (hyperalgesia) and easy bruising that leads to an uncontrolled mixed lymphedema known as lipo-lymphedema. This abnormal accumulation of fat in lipedema has been found to be resistant to weight loss and presents with palpable lobules that are irregular. Skin folds are present at the ankle and knee even with progression of the mixed lymphedema component. There is no dorsal foot swelling and no Stemmer Sign. Many patients have associated psychosocial challenges to include depression and eating disorders. This condition appears to be inherited, however, a gene has not been identified. This condition is commonly miss-diagnosed as lymphedema secondary to morbid obesity. Clinicians are reminded to evaluate the upper body fat composition of individuals to distinguish these two disorders (lipedema vs. morbid obesity) as weight loss in the morbidly obese patient will likely improve lower extremity secondary lymphedema while the lipo-lymphedema patient will remain unchanged and should be managed aggressively.

Infrequently, patients may also present with self-induced or "artificial" lymphedema. This form of lymphedema presents with a noted proximal tourniquet mark that may initially be subtle to the inexperienced clinician. These patients are infrequent in the United States with greater numbers seen in European populations where such individuals may seek financial assistance for physical disability.

Lastly, not all swollen limbs represent protein-rich lymphedema but rather simple edema. Medical conditions as congestive heart failure /renal failure / liver failure (anasarca), thyroid disease (myxedema), inflammatory arthritis, complex regional pain syndrome, idiopathic cyclic edema and protein-wasting enteropathies may present with pitting interstitial fluid that must be managed medically, not with manual lymphatic drainage or compression bandaging.