A disease impacting millions, known by a few
Lymphedema is the accumulation of protein-rich fluid, which usually causes chronic inflammation and reactive fibrosis. The lymphatic system runs throughout the body and parallels the arterial venous system. The lymphatic system can be thought of as the “garbage disposal” system of the body. The job of the lymphatic system is to pick up the excess fluid, which leaks out at the capillary level, take it to the lymph nodes where it is filtered and concentrated, and then dump it back into the cardiovascular system. The lymph nodes also serve as an important immune role to help prevent spread of infection and cancer.
The swelling that occurs in lymphedema is seen in the interstitial space between cells. Lymphedema fluid has a higher protein content than edema. These excess proteins hold onto water molecules due to their oncotic pressure, and thus cannot be pushed back across the capillary membrane simply by adding external compression and increasing the hydrostatic pressure.
The lymph fluid proteins must be processed by macrophages. This causes a variable amount of inflammation, and can lead to tissue fibrosis, fatty tissue deposition, and increased infection risk. Interstitial proteins can serve as nutrients for bacterial growth, which may worsen infection. Furthermore, the presence of proteins in the lymph fluid alters your body's immune system response and may increase infection risk.
When the lymphatic system does not work properly, whether it was poorly developed from birth, or damaged from surgery, radiation, or a trauma, the body cannot effectively transport lymph fluid. When transport is stopped and lymph fluid cannot drain properly, it causes swelling distal to the area where the drainage is disrupted. This swelling can be in any part of the body, most often in the arms and legs, but also the breast or chest wall, head and neck, or genitals.
Progression of Lymphedema
Progression of lymphedema to irreversible stages is due to the body’s inflammatory response over time as it tries to get rid of the proteins in the interstitial fluid. The inflammatory response leads to tissue fibrosis and deposition of fatty tissue. Some people develop fibrosis and fatty tissue deposition very quickly, and some go years and have very little irreversible changes. We do not understand all the factors. Some factors are likely genetic, but diet and healthy living may play a role in reducing the inflammatory response as well. Inflammation is also thought to lead to further damage to the remaining lymphatic vessels over time, as they are very fragile.