The cure for lymphedema is unknown, and a single standard protocol for treatment has not been established, although a variety of management approaches are used, many of them successfully. Because both surgery and radiation can trigger lymphedema, cancer patients and cancer survivors are the biggest group of individuals with lymphedema in this country. Many of these individuals receive physical therapy. Thus, it is important for Understanding the lymphatic system The lymphatic system is an extensive drainage network of lymphatic vessels and organs throughout the body. Unlike the circulation system, however, it doesn’t have a central propulsion mechanism like the heart. Instead, the fluid in the system is moved around by contraction of muscles surrounding the larger lymphatic vessels. The lymphatic system has two overall purposes: 1. Helping the body fight infection and disease by producing and distributing lymphocytes (white blood cells), which are part of the body’s immune response. 2. Helping to move fluid from the tissues back into the bloodstream, thereby maintaining normal blood volume. The main structures of the lymphatic system are lymph nodes, lymphatic vessels and other lymphatic organs, which include the tonsils, spleen, appendix and thymus. This educational module focuses on the lymph nodes and vessels, which are important to an understanding of lymphedema. Lymph and lymphatic vessels The lymphatic vessels, which run through most of the body, interact with the circulation system. They are similar to veins but have thinner walls. These thin walls allow the lymphatic vessels to absorb water, proteins and other substances that are constantly leaking out of blood capillaries into the surrounding body tissues. The capillaries in the veins cannot transport the heavier protein cells, dead cells, bacteria and other waste products, but the lymphatic vessels have larger openings that are able to absorb these heavier fluids. The excess fluid that has leaked from arterial capillaries into the space outside the blood cells is called interstitial fluid . The interstitial fluid needs to be taken back into the circulatory Types of lymphedema and their causes There are two types of lymphedema: primary and secondary. The causes of the two types are different, but the treatment is the same. Primary lymphedema is present at birth. For reasons not yet known, in primary lymphedema a person’s lymphatic vessels or nodes do not develop. In most cases, symptoms of lymphedema – usually in the calf or foot – do not appear until adolescence. Most cases (87 percent) of primary lymphedema occur in females. 1 Symptoms may be triggered or made worse by pregnancy, heat, trauma or a wound infection. Secondary lymphedema , also called acquired lymphedema , is much more common than primary lymphedema and occurs as the result of an injury to the lymphatic system. In secondary lymphedema, the lymph vessels, lymph nodes, or both have been blocked or damaged, making them unable to manage the quantity of lymphatic fluid that accumulates in the affected body part. The most common causes of secondary lymphedema are: ● Surgery: In treating cancer of the breast, prostate, bladder, uterus, colon or skin, lymph nodes are usually removed. In some cases, even a limited surgery such as a lumpectomy can lead to lymphedema. ● Radiation therapy: Radiation can damage healthy lymph nodes and vessels, causing scar tissue to form. The scar tissue leads to decreased circulation of the lymph fluid. ● Trauma: An insult to the body, such as a pelvic fracture, liposuction or thermal injury, can reduce the ability of the lymphatic system to move lymph fluid.
physical therapists to be knowledgeable about lymphedema and its management, and to be aware of resources for referral and patient education as appropriate. The physical therapist should be able to recognize lymphedema, be aware of risk factors for lymphedema, and understand what constitutes appropriate and safe physical therapy interventions for those who have lymphedema or are at risk. system, and the lymphatic vessels help do that, cleansing it of impurities along the way. After the interstitial fluid enters the lymph capillaries, the fluid is called lymph . This colorless, watery fluid contains large proteins, white blood cells, and waste products. The lymph travels from the lymphatic capillaries into progressively larger vessels that ultimately take the fluid toward the trunk of the body and back to the heart. The larger lymphatic vessels drain into collecting ducts. The right lymphatic duct drains lymph from the right side of the head, neck, chest and right arm. Lymph from the legs and genitalia drains into lymph node basins in the pelvis and abdomen and then moves into the thoracic duct. The right lymphatic duct and the thoracic duct empty their contents into two veins located under the collarbones. These veins join to form the superior vena cava, the large vein that drains blood from the upper body into the heart. Any disruption or injury to the pelvis or abdomen, such as infection or scarring from surgery, can result in lymphedema of a leg or foot. Similarly, an injury along the lymphatic pathway from the arm to the axilla and then to the chest, can lead to lymphedema in the arm or hand. Lymph nodes All lymph passes through strategically placed lymph nodes, oval structures that can be up to an inch in diameter. The lymph nodes filter out bacteria, cancer cells and foreign particles. In addition, the lymph nodes produce new white blood cells to help fight disease. Clusters of lymph nodes are found in the underarms, groin, neck, chest and abdomen. ● Infection: Localized infection can lead to tissue destruction and scarring, which can result in lymphedema. ● Cancer of any lymph nodes: Cancer sometimes spreads to the lymph nodes in the neck, chest, underarm, pelvis or abdomen. ● Filariasis: This infection occurs in tropical countries and leads to elephantiasis. Larvae transmitted by mosquitoes live in the lymphatic system. Secondary lymphedema can develop at any time following a disruptive event. Cases have been reported from immediately following an event to as many as 30 years later. In the United States, the largest proportion of lymphedema cases is among women who have had breast cancer surgery, especially those who also have radiation therapy following lymph removal. The more lymph nodes a woman has removed, the higher the risk. Because of this, the modern trend toward removing only sentinel lymph nodes and leaving other lymph nodes intact is helpful in reducing the incidence of lymphedema. Discrepancies in diagnosis and reporting make it difficult to know the overall incidence, but researchers found that 42 percent of women who have had both surgery and radiation following breast cancer developed lymphedema. For women who had surgery only, the prevalence was 13 percent. 2 Worldwide, incidence of lymphedema is estimated at 140-250 million cases. 3 The biggest contributor to the prevalence of lymphedema worldwide is filariasis.
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