Lymphedema (PDQ®): Supportive care - Patient Information [NCI] - General Information About Lymphedema
Lymphedema is the build-up of fluid in soft body tissues when the lymph system is damaged or blocked.
Lymphedema occurs when the lymph system is damaged or blocked. Fluid builds up in soft body tissues and causes swelling. It is a common problem that may be caused by cancer and cancer treatment. Lymphedema usually affects an arm or leg, but it can also affect other parts of the body. Lymphedema can cause long-term physical, psychological, and social problems for patients.
The lymph system is a network of lymph vessels, tissues, and organs that carry lymph throughout the body.
The parts of the lymph system that play a direct part in lymphedema include the following:
- Lymph: A clear fluid that contains lymphocytes (white blood cells) that fight infection and the growth of tumors. Lymph also contains plasma, the watery part of the blood that carries the blood cells.
- Lymph vessels: A network of thin tubes that helps lymph flow through the body and returns it to the bloodstream.
- Lymph nodes: Small, bean-shaped structures that filter lymph and store white blood cells that help fight infection and disease. Lymph nodes are located along the network of lymph vessels found throughout the body. Clusters of lymph nodes are found in the underarm, pelvis, neck, abdomen, and groin.
The spleen, thymus, tonsils, and bone marrow are also part of the lymph system but do not play a direct part in lymphedema.
Anatomy of the lymph system, showing the lymph vessels and lymph organs including lymph nodes, tonsils, thymus, spleen, and bone marrow. Lymph (clear fluid) and lymphocytes travel through the lymph vessels and into the lymph nodes where the lymphocytes destroy harmful substances. The lymph enters the blood through a large vein near the heart.
Lymphedema occurs when lymph is not able to flow through the body the way that it should.
When the lymph system is working as it should, lymph flows through the body and is returned to the bloodstream.
- Fluid and plasma leak out of the capillaries (smallest blood vessels) and flow around body tissues so the cells can take up nutrients and oxygen.
- Some of this fluid goes back into the bloodstream. The rest of the fluid enters the lymph system through tiny lymph vessels. These lymph vessels pick up the lymph and move it toward the heart. The lymph is slowly moved through larger and larger lymph vessels and passes through lymph nodes where waste is filtered from the lymph.
- The lymph keeps moving through the lymph system and collects near the neck, then flows into one of two large ducts:
- The right lymph duct collects lymph from the right arm and the right side of the head and chest.
- The left lymph duct collects lymph from both legs, the left arm, and the left side of the head and chest.
- These large ducts empty into veins under the collarbones , which carry the lymph to the heart, where it is returned to the bloodstream.