ABSTRACT
Lymphedema is the swelling of a body part due to an accumulation of lymphatic fluid
caused by an abnormality in the lymphatic drainage (1). It is thought that 38%–100% of
all circulating proteins leave the intravascular compartment every 24 hours (2). The
lymphatic system is responsible for return to the vascular system of these extravascular
molecules and colloids which are too large to re-enter directly (3). Lymphedema thus
occurs when the lymphatics are unable to cope with this protein rich fluid that is filtered
out of the vasculature but not reabsorbed. This happens because of three reasons: (1)
increased fluid filtered out of vascular capillaries, (2) reduced reabsorption into distal
capillaries and venules, and (3) failure of the lymphatics-i.e., lymphedema. Any of these
(or a combination) leads to an accumulation of fluid in the interstitial tissues. The normal
lymphatic system has some reserve to compensate for mild increases in fluid filtered or
reduction in fluid reabsorption, therefore edema is not usually clinically recognizable until
the normal interstitial volume has doubled (4). It is worth noting that lymphatic function
declines with age (especially after the age of 65 years) and may account for the relatively
late age at which some patients present (3).
