Lymphedema Overview
Lymphedema results when the lymphatic system is overloaded, damaged, or defective. The lymphatic system helps fight infections and cancer, removes cellular waste, maintains fluid balance and controls blood pressure, and processes fats from foods. These functions are impaired in someone with lymphedema.
Lymphatic vessels are found near arteries and veins throughout the body. Tiny lymphatic collectors remove excess tissue fluid from the spaces between cells in the skin, the gut, and around other organs. This lymphatic fluid, or lymph, flows through a network of lymph nodes and progressively larger lymphatic vessels and trunks before emptying into the blood circulatory system at the base of the neck. Lymph nodes monitor the fluid for signs of infection, break down harmful microbes, and concentrate the fluid by removing excess water.
Lymphatic vessels contain segments with one-way valves at each end (lymphangions). Segments contract periodically, creating a pumping motion that pushes fluid into the next segment along the vessel. Fluid overload stretches the lymphatic vessels, causing one-way valves to fail, interfering with pumping, and allowing reverse flow (backflow) that increases dependent edema.
Lymphedema is characterized by swelling (edema) from excess tissue fluid trapped in the skin and tissues. Over time, stagnant fluid causes skin changes, fat accumulation, and progression to more advanced stages. In some cases, excess lymph may leak through the skin (weeping lymphedema) or accumulate in the abdomen (ascites).
Types of Lymphedema
There are two types of lymphedema, primary and secondary, based on different causes, although the cause may not be clear. These types are not exclusive; a person may have both because primary lymphedema increases the risk of secondary lymphedema. Treatment and care are the same for both types.
Primary lymphedema results from congenital lymphatic system defects that interfere with fluid removal. Swelling or other signs of lymphedema may be noticeable at birth, during infancy or appear around puberty, during pregnancy, or later in life. Inheritable genetic factors have been linked to certain types of primary lymphedema.
Secondary lymphedema results from lymphatic system damage or overload. Common causes of secondary lymphedema include cancer treatment, other trauma or injury, obesity, congestive heart failure, chronic venous insufficiency, lipedema, diabetes, etc.
One of the most common forms of secondary lymphedema in older people is phlebolymphedema, a combination of lymphedema and chronic venous insufficiency (CVI). Venous and lymphatic insufficiency results in swelling of the lower legs and feet. Reddish-brown skin discoloration and hyperpigmentation (hemosiderin staining) are common signs of venous involvement. See also the Photos of Lymphedema and Lipedema
The International Society of Lymphology (ISL) staging system uses stages 0 to III:
- Stage 0 (or Ia): a latent or sub-clinical condition where swelling is not yet evident despite impaired lymph drainage, subtle changes in tissue fluid composition, and changes in subjective symptoms. It may exist months or years before overt edema occurs (Stages I-III).
- Stage I represents an early accumulation of fluid relatively high in protein content (in comparison with venous edema) which subsides with limb elevation. Pitting may occur. An increase in various proliferating skin cells may also be seen.
- Stage II signifies that limb elevation alone rarely reduces tissue swelling and pitting is seen. Late in Stage II, the limb may or may not pit as excess fat and fibrosis replaces swelling.
- Stage III includes lymphostatic elephantiasis where pitting can be absent and abnormal skin changes such as thickening and pigment changes, further deposition of fat and fibrosis, and warty overgrowths have developed.
Portions adapted from Lymphedema and Lipedema Nutrition Guide, Lymph Notes 2016 by permission of the publisher.