Lymphatic Diseases

Functions

The role of the blood vessels is to deliver oxygen and nutrients to different tissues where the molecular exchange of these compounds take place in capillaries. As blood moves through the tissues, blood pressure causes plasma to leak out from the capillaries into the surrounding tissues. This excess fluid, which is rich in protein, is then collected by the lymph system and returned to the circulatory system through the two subclavian veins under the collarbones. Consisting of lymph, lymphatic nodes, and lymphatic vessels, the lymphatic system also plays important roles besides keeping the fluid balance in homeostasis. Located throughout the body, lymphatic vessels have valves like those in veins to keep lymph flowing in one direction. Before returning back to the blood circulation, damaged cells, cancer cells, and foreign particles that might be present in the lymph are filtered out through the lymph nodes and destroyed by blood cells specifically made to initiate immune responses. As a result, the lymphatic system is important in removing damaged cells from the body and in protecting against the spread of infection and cancer cells. Furthermore, the lymphatic vessels located in the small intestine absorb dietary fat from food. Abnormality in the lymphatic system in the intestine can lead to malnutrition or excessive obesity.

Lymphedema

The lymphatic system might not function properly when there is excessive quantity of fluid or if there is a blockage of the lymph vessels or nodes because of a tumor or inflammation. The most prevalent lymphatic disease is lymphedema, which occurs when there is a buildup of excessive lymph fluid and swelling resulting in obstruction and destruction of lymph vessels. Lymphedema is caused by an abnormality preventing [Page 1043]lymph from being reabsorbed into the capillaries and drained from the tissues. The severity of this disease varies from very mild to a painful and debilitating state, and it remains a lifelong functional problem requiring daily treatment. Lymphedema may be either primary (congenital) or secondary (acquired). Primary lymphedema is an inherited condition more frequently seen in women. It occurs when the lymphatic vessels are either absent or impaired, resulting in swelling observed more commonly in the legs. Primary lymphedema can be present from birth (congenital lymphedema), occur during puberty (lymphedema praecox), or develop later in adult life (lymphedema tarda) either with unknown causes or associated with other vascular or lymphatic anomalies. The first indication of lymphedema may be swelling of the foot resulting in tightness in the shoe.

Secondary lymphedema is a common problem among adults and children, and it is acquired through infection or after major surgery or radiotherapy in which lymphatic tissues are removed. It is more common than primary lymphedema. One example of secondary lymphedema is lymphatic filariasis, a condition caused by microscopic parasites called filaria affecting hundred of millions of people worldwide. Patients with filariasis suffer from lymphedema in the arms, breast, and legs that might swell to several times their original size. Moreover, patients are more susceptible to further infections due to impaired lymph system. In rare situations, the swollen limb becomes extremely enlarged and the skin is so thickened and ridged that the infected area resembles elephant skin—this is a condition called elephantiasis that can be treated by an extensive operation to remove the swollen tissues under that skin or by antibiotics. There is no cure for patients wihth lymphedema. For people with mild lymphedema, the swelling can be reduced applying compression bandages. People who have more severe condition may have to wear pneumatic compression to reduce and control the swelling.

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