Lymphedema and swelling in the body

What is the lymphatic system?

The lymphatic system is a central part of the body's immune defense and fluid balance. It consists of lymph fluid, lymphatic vessels and lymph nodes, as well as organs such as the spleen, tonsils and thymus.
The system carries the fluid—called lymph, which contains proteins, fats, waste products, dead cells, bacteria, and other foreign substances—back to the bloodstream. Along the way, the lymph is filtered in the lymph nodes, which act as the body’s cleaning stations. When the body fights infections, these glands can swell and become tender.

Unlike blood, which is pumped around in a closed system driven by the heart, lymph moves slowly in one direction – from the tissues back to the blood. The movement is supported by muscle activity and breathing, making physical activity and good circulation essential for a well-functioning lymphatic system.

What is lymphedema?

Lymphedema is a chronic condition that occurs when the lymphatic system fails to transport fluid effectively. The result is a buildup of lymph in the tissues, causing swelling – most often in the arms or legs. The condition can lead to a feeling of heaviness, discomfort, reduced mobility and an increased risk of skin infection.

There are two main types of lymphedema:

• Primary lymphedema is caused by a congenital or hereditary defect in the development of the lymphatic system. It can occur right after birth, during adolescence, or later in life. The condition affects women more often and usually occurs in the legs.

• Secondary lymphedema occurs when the lymphatic system is damaged or blocked, such as after surgery, radiation therapy, infection, injury, or inflammation. When the lymphatic vessels don't work properly, fluid builds up. Over time, proteins can build up in the tissue and form scar tissue (fibrosis), making the swelling firmer and harder to treat.