Cath Lab Digest

Lymphedema, a disorder of the lymphatic system, affects at least 3 million Americans.1 The lymphatic system plays a role in both immune function and circulation. The system is comprised of lymphatic vessels located just under the skin and lymph nodes in areas around the neck, axilla, and groin. As the vessels transport fluid away from the tissues, waste products, bacteria, and large protein molecules are collected. The fluid is carried to the lymph nodes where the water products are degraded and eliminated, while the remaining protein-rich fluid is transported to the heart and back into circulation.2

When the normal lymphatic channels are disrupted, abnormal amounts of protein-rich lymphatic fluid collects in the interstitial tissue and causes swelling, most often in the arm and/or legs, and occasionally in other parts of the body. When the disruption becomes profound, the volume of lymphatic fluid exceeds the lymphatic transport capacity, leading to lymphedema.

Primary lymphedema is caused by connatal malformations of the lymphatic system, such as missing or impaired lymphatic vessels. This can affect any or all parts of the body but is usually seen in the legs. Secondary lymphedema, sometimes referred to as acquired lymphedema, occurs when lymphatic vessels are damaged or lymph nodes are removed. The lymphatic vessels can become damaged as a result of trauma, surgery, radiation, severe chronic venous insufficiency, morbid obesity, or infection. Without appropriate intervention, the protein-rich fluid increases the size and number of the tissue channels. This contributes to a reduction in the oxygen availability in the transport system, which interferes with wound healing and provides a culture medium for bacteria. This increased bacterial load can result in lymphangitis. When lymphedema continues unchecked, the protein-rich fluid continues to accumulate, swelling increases, and tissue becomes fibrotic. Untreated lymphedema can lead to a decrease or loss of limb function, skin breakdown, or chronic infections.

Risk Factors
Approximately 250 million people acquire lymphedema every year.3 Most commonly around the world, lymphedema is the result of a mosquito-born microfilia parasitic infection originating in the tropics. However, in industrialized nations, the onset of lymphedema is most commonly associated with complications following cancer treatment. Women are particularly at risk for lymphedema in the arm following surgery or radiation for breast cancer and in the legs following treatment for cervical or uterine cancer. Men are at risk of developing lymphedema in their legs following surgery for prostrate or testicular cancer. Both men and women are at risk following treatment for malignant melanoma or any other surgery or radiation affecting the lymph nodes or requiring lymph node dissection. For example, about 50% to 70% of patients having axillary lymph node dissection develop lymphedema. Of the 2 million breast cancer survivors alive today, 15% to 30% cope daily with lymphedema.4

Understanding the Differences between Lymphedema and Lipodema
Lymphatic accumulation and congestion—the clinical manifestation of lymphedema5—should not be confused with edema that results from venous insufficiency. However, untreated venous insufficiency can progress into a combined venous/lymphatic disorder that is treated in ways similar to treatment of lymphedema. Also, lipedema must be differentiated from lymphedema; however, treatment overlap also can occur.

Lipedema is characterized by a bilateral, symmetrical increase in stored fat. This condition usually affects the hips, buttocks, and thighs. Although the swelling can be extensive it seldom involves the feet. Lipedema often develops at the time of puberty, can be familial, and affects women. This hormone-driven condition is usually controllable as long the woman remains thin and active. Unfortunately, once the patient begins to gain weight the condition can progress rapidly. Many women with lipedema become morbidly obese because of weight gain coupled with difficulty comfortably achieving an adequate level of activity.6

One of the primary problems with lipedema is that it leads to inactivity. Physical fatigue can develop with a corresponding need for rest. Women with lipedema are likely to gain weight for a number of reasons. For example, many women avoid sports because they feel tired much of the time. It becomes difficult to climb stairs, wear regular clothing, or even walk. Others fail to engage in vigorous activity because they are embarrassed by the appearance of their body. Each of these factors works together to contribute to progressive weakness, additional weight gain, compulsive eating, increased reclusivity, and further development of lymphedema.

Another problem is the widespread misunderstanding of lipedema. Clinicians tend to misunderstand lipedema and its role in lymphedema. Lipedema often is confused with morbid obesity. Others fail to recognize the difference between cellulite and lipedema. Panniculopathia edematicosclerotica, often referred to as cellulite, is a related but different condition that occurs in young women and causes changes in the subcutaneous tissues of the thighs, buttocks, and hips.