Lymphedema, also known as lymphatic obstruction, is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system.
The lymphatic system returns the interstitial fluid to the thoracic duct and then to the bloodstream, where it is recirculated back to the tissues.
Tissues with lymphedema are at risk of infection.
Stages
Whether primary or secondary, lymphedema develops in stages, from mild to severe. Methods of staging are numerous and inconsistent. They ranged from three to as many as eight stages.
The most common method of staging was defined by the Fifth WHO Expert Committee on Filariasis:
- Stage 0 (latent): The lymphatic vessels have sustained some damage which is not yet apparent. Transport capacity is still sufficient for the amount of lymph being removed. Lymphedema is not present.
- Stage 1 (spontaneously reversible): Tissue is still at the "pitting" stage: when pressed by the fingertips, the affected area indents and holds the indentation. Usually upon waking in the morning, the limb or affected area is normal or almost normal in size.
- Stage 2 (spontaneously irreversible): The tissue now has a spongy consistency and is "non-pitting:" when pressed by the fingertips, the tissue bounces back without any indentation. Fibrosis found in Stage 2 Lymphedema marks the beginning of the hardening of the limbs and increasing size.
- Stage 3 (lymphostatic elephantiasis): At this stage, the swelling is irreversible and usually the limb(s) or affected area is very large. The tissue is hard (fibrotic) and unresponsive; some patients consider undergoing reconstructive surgery called "debulking". This remains controversial, however, since the risks may outweigh the benefits, and the further damage done to the lymphatic system may in fact make the lymphedema worse.
A new staging system has been set forth by Lee, Morgan and Bergan
and endorsed by the [http://www.lymphology.org American Society of Lymphology. This provides a clear technique which can be employed by clinical and laboratory assessments to more accurately diagnose and prescribe therapy for lymphedema. In this improved version there are four stages identified (I-IV). Physicians and researchers can utilize additional laboratory assessments such as bioimpedance, MRI, or CT to build on the findings of a clinical assessment (physical evaluation). From this results of therapy can be accurately determined and reported in documentation as well as research.
Risk is another measurement altogether. Current research using bioimpedance to measure risk of lymphedema is very promising.
Grades
Lymphedema can also be categorized by its severity (usually referenced to a healthy extremity):
- Grade 1 (mild edema): Lymphedema involves the distal parts such as a forearm and hand or a lower leg and foot. The difference in circumference is less than 4 centimeters, and other tissue changes are not yet present.
- Grade 2 (moderate edema): Lymphedema involves an entire limb or corresponding quadrant of the trunk. Difference in circumference is more than 4 but less than 6 centimeters. Tissue changes, such as pitting, are apparent. The patient may experience erysipelas.
- Grade 3a (severe edema): Lymphedema is present in one limb and its associated trunk quadrant. The difference in circumference is greater than 6 centimeters. Significant skin alterations, such as cornification or keratosis, cysts and/or fistulae, are present. Additionally the patient may experience repeated attacks of erysipelas.
- Grade 3b (massive edema): The same symptoms as Stage 3a except that two or more extremities are affected.
- Grade 4 (gigantic edema): Also known as elephantiasis. In this stage of lymphedema, the affected extremities are huge due to almost complete blockage of the lymph channels. Elephantiasis may also affect the head and face.
Further Reading
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