Primary and Secondary Lymphedema
There are two types of lymphedema - primary lymphedema and secondary lymphedema. Both types relate to lymph vessels or lymph nodes that are missing, damaged, removed or otherwise impaired.
The lymphatic system may be abnormal from birth. When a lymphatic system is no longer able to cope with the demands placed on it, primary lymphedema can develop. It is called 'primary' as the cause of the impairment is to be found in the structure of the lymphatic system itself. Primary lymphedema can be classified to age of onset.
Congenital: The lymphedema is noticeable at birth
Praecox: Lymphedema occurs after birth, but before age 35
Tardum: Lymphedema presents after age 35
Primary lymphedema can present as a variety of abnormalities:
- Aplasia: Portions of the lymph systems are missing.
- Hypoplasia: Lymph collectors are smaller in size, or the number of collectors is below normal levels. This is the most common abnormality seen in primary lymphedema.
- Hyperplasia: Lymph collectors are larger than normal, but don't always function as well as normal lymphatics.
Secondary lymphedema is caused when an outside factor directly impacts the lymph system. The lymphatic system is fully adequate and functions perfectly until it is damaged. Causes of secondary lymphedema include:
- Cancer surgery/radiation: Removal of lymph nodes that is often associated with cancer can disrupt lymph flow. Radiation treatment can also impair lymph flow.
- Malignant tumors: The tumors put pressure on lymph vessels, decreasing fluid flow.
- Trauma: The body sustains an injury, including burns or a crushing injury, which can inhibit the flow of lymph fluid.
- Infection: Recurrent infections can cause failure of lymphatic vessels.
- Chronic Venous Insufficiency: This venous disorder puts extra pressure on your lymphatic system, leading to a breakdown.
- Obesity: The increased lymphatic flow, and often time-increased pressure on lymph nodes, can impair lymphatic flow.
- Self-Induced: A patient uses a tourniquet to impair lymphatic and venous flow.
- Iatrogenic: This is lymphedema caused by a health care related procedure, such as an interventional procedure or tourniquet.
- Filariasis: A parasitic disease found mostly in third-world countries that impairs the lymphatic system.
There are other types of oedema which should not be forgotten
Often confused with lymphedema, lipedema is an adipose tissue disorder or abnormal accumulation of fatty tissue. It affects mostly women, often developing around the time of a hormonal change (i.e. puberty, pregnancy or menopause). The condition leads to tissue enlargement most commonly around the legs, hips and/or buttocks. Unlike lymphoedema, the enlargement usually stops at the ankles and the feet are spared. However, it tends to be in both legs. It mostly affects the lower limb but can develop in the arm (the hands are usually spared). It often leads to a sensation of the limbs being ‘heavy and tight’ and the skin may be tender to touch, cooler than unaffected areas, sensitive and/or bruise easily. Despite dieting or increasing physical activity, the volume of the limbs does not decrease and there is a distinct disproportion between the limbs and the trunk. Those who have had lipedema for many years often develop a lymphatic component, as the fatty tissues tend to obstruct lymphatic drainage. This is known as lipo-lymphoedema. The surface of the skin is more uneven, there may be ridges of fat under the skin, the limb is more distorted and mobility may be impacted. The foot can become swollen.
This condition results in both the venous lymphatic systems not functioning adequately due to an underlying venous problem/disease and results in a swelling. When valves weaken or there are abnormalities in the venous walls, blood can flow backward and increase the pressure in the veins, known as venous hypertension. If venous hypertension is sustained over time, the vein walls stretch and the valves no longer close. This further increases hypertension which can lead to a pooling of blood, discomfort and varicose veins. The common signs are staining of the skin, spider veins and varicose veins. A swelling occurs when the increase in lymphatic flow to the area is much greater than the lymph transport capacity.