What is lymphedema?

Updated: Mar 24, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: William D James, MD  more...
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Lymphedema is an abnormal collection of protein-rich fluid in the interstitium resulting from obstruction of lymphatic drainage. Lymphatic obstruction causes an increase in the protein content of the extravascular tissue, with subsequent retention of water and swelling of the soft tissue. The increase in the extravascular protein stimulates proliferation of fibroblasts, organization of the fluid, and the development of a nonpitting swelling of the affected extremity (see the image below). (See Pathophysiology and Etiology.)

Lymphedema in a patient with hypertension, diabete Lymphedema in a patient with hypertension, diabetes, and impaired cardiac function.

Fibrosis also obstructs the lymphatic channels and leads to increased protein concentration in the tissues, continuing this cycle. Lymphedema most commonly affects the extremities, but it can involve the face, genitalia, or trunk. (See Etiology, Pathophysiology, and Presentation.)

In addition to causing soft tissue swelling, lymphedema opens channels in the integument and allows bacteria to enter the subcuticular space, which overwhelms host defenses and leads to cellulitis of the extremity. (See Pathophysiology, Prognosis, Treatment, and Medication.)

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