Lymphedema can affect any part of the body and can be of varying volumes. It occurs when there is an inability to remove lymphatic fluids, due to either genetic insufficiency or known cause of damage to the lymphatic system. In later stages there may be fibrotic tissue changes and increased fatty tissue. Lymphedema may be diagnosed by a primary care physician, general surgeon and/or vascular surgeon. Its prevalence worldwide is well over 100 million people, and in the U.S. exceeds 6 million. Individuals with lymphedema may be referred to a physical therapist who has received specialized training in Complete Decongestive Therapy for Lymphedema (DLT) treatment and management.
Anatomy and Function of the Lymphatic System
The lymphatic system collects excess interstitial fluid, protein, waste products and fat that have not been absorbed at the venous capillary level. From the body tissues, the lymphatic system transports and filters these constituents back to the venous system. There are lymph capillaries under the skin, and as the lymph transport vessels join and travel deeper in the skin, they are known as the lymph collectors. Collectors are characterized by having one-way valves and intrinsic contractibility to propel fluid towards the nearest lymph node bed. Lymph nodes filter noxious matter, such as dead cells and bacteria; produce white blood cells; and regulate the concentration of protein in the lymph.
The body is divided into the upper and lower body at the waist, and right and left at the midline; therefore, the flow of lymph to the regional lymph node beds is divided into four quadrants or watersheds. The regional lymph node beds are located in the inguinal groin for the lower quadrants, and in adjacent axillae for the upper quadrants. The head and neck drain separately into the supra clavicular area. From the regional lymph node beds, the lymph is transported deep into lymphatic trunks. From both legs and to left upper quadrant, drainage is into the thoracic duct, which lies in front of the spine. The R upper quadrant drains into the subclavian vein. The lymph is returned to the vascular system via the superior vena cava.
Types of Lymphedema
Primary Lymphedema is due to an insufficiency of the lymphatic system. The best estimates indicate that about 1 percent of the U.S. population presents with varying degrees of primary lymphedema. Primary lymphedema that is seen at birth or shortly afterwards is called congenital lymphedema, or Milroy's syndrome, and is most common in one leg of boys. Primary lymphedema that presents during puberty is known as Miege's syndrome and is most common in females, usually involving lower extremities.
Secondary Lymphedema is due to a known cause of damage to the lymphatic system. Damage can be either due to a medical condition or intervention. The most common form of secondary lymphedema worldwide is caused by an infection known as filariasis, which is caused by a mosquito-borne parasite that resides in some tropical regions of the world. Secondary lymphedema is the most common form of lymphedema in the U.S. and is normally seen secondary to cancer-related treatments or occlusion by cancer. Secondary lymphedema may also occur as a result of radiation treatment, scar tissue, history of multiple surgeries or obesity.
Combined Lymphedema is called phlebolymphostatic lymphedema and is due to chronic venous insufficiency. Damage to the lymphatic system is due to over-use over several years, often decades. Venous stasis ulcers are sometimes seen with combined lymphedema.
Stages of Lymphedema
Lymphedema is staged and starts with Latency, where the lymphatic system is compromised and subjective complaints occur. There may be no visible or palpable edema. Stage I, or Reversible Lymphedema, is an accumulation of fluid, and pitting edema may be present. Swelling at this stage reduces with elevation. Stage II, known as Spontaneously Irreversible Lymphedema is characterized by pitting becoming progressively more difficult because fibrosis of the tissues occurs. In Stage III, known as Lymphostatic Elephantiasis non- pitting fibrosis and sclerosis is present. There are skin changes, which include papillomas and hyperkeratosis. There is an increased risk for cellulitis, especially in Stages II and III due to high levels of interstitial protein, which are inviting to bacteria.
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