Although lymph circulates freely in the tissues of the body, it also has a capillary system, like the capillaries of blood. Most of the fluids that seep of of the arterial capillaries return to the bloodstream via the venous capillaries, but about 10% of if is picked up by the lymph.
The tissues in the body are constantly being supplied with clear fluid from the blood to both nourish and cleanse the tissues. Most of this fluid is again removed from the tissues by the blood, but approximately 10% of the fluid must be cleared away by another system called the lymphatic system.
The lymphatic system is made up of vessels which drain the clear lymph fluid, and nodes (or glands) which filter the lymph fluid to remove bacteria, dead or abnormal cells. This system plays an important role in the body's defence against infection.
When the lymphatic system fails to function normally, the lymph fluid does not drain away, and swelling occurs. This swelling in the tissues beneath the skin is referred to as Lymphoedema.
Who can develop lymphoedema?
There are a number of conditions which will place a person at risk of developing lymphoedema. In some individuals the lymphatic system is not properly developed and lymphoedema may be present at birth, or show up during teenage years or young adulthood. In others it may be acquired after a severe injury (such as burns), or after an infection or disease (such as cancer) which damages the lymphatic vessels or nodes.
Surgery to remove lymph nodes, or radio-therapy following cancer treatment can also interrupt the drainage of lymph fluid from the affected part of the body.
Whilst lymphodema can occur in almost any part of the body, it most commonly occurs in the arms and legs. It can appear soon after damage to the lymph system or it can occur months or years afterwards.