Lymphedema is a chronic and progressive condition caused by disruption in the function of lymphatic system. The disruption in the lymphatic system function leads to fluid accumulation in the tissues causing edema in various parts of the body where the lymphatic system is affected. The most commonly affected sites are the lower extremity and genitalia; however, upper extremity lymphedema is commonly seen secondary to breast cancer surgery.
Lymphedema can be classified into primary and secondary type. Primary lymphedema is hereditary and is caused by mutation in specific genes presenting as autosomal dominant trait leading to development anomalies in the lymphatic system. Primary lymphedema can be further subdivided into Milroy’s disease, lymphedema praecox and lymphedema tarda. Secondary lymphedema is acquired mainly due to surgery, trauma, infection-infestation, tumor or post-venous thrombosis. Both, primary and secondary lymphedema are clinically characteristic of chronic edema (swelling), localized pain or discomfort, atrophic skin changes and secondary infections.
How Is Lymphedema Diagnosed?
The diagnosis of lymphedema is made clinically by thorough evaluation and physical examination. Family history is crucial in the diagnosis of primary lymphedema. The characteristic symptoms include chronic swelling, progressive atrophic skin changes along with recurrent infections. History of trauma and surgery must be addressed properly.
The circumference and volume of the affected versus non-affected limb can be measured and circumference >2 cm and volume >200 ml may confirm the diagnosis. Volume can be measured by tape, water displacement or perometry. Perometry involves infrared optical electronic scanner to demonstrate minor changes in the volume of the affected limb. Tonometry is used to evaluate tissue resistance by applying compression with a tonometer and this can be used to measure fibrosis and skin texture. Bioimpedence spectroscopy (BIS) measures the water content of the body and helps assesses the electrical conductance of the extracellular fluid; it is effective for detecting the early stages of lymphedema.
Imaging techniques include lymphoscintigraphy, magnetic resonance lymphangiography (MRL), ultrasonography, computed tomography and Near Infra-Red Fluorescence Imaging (NIFR). Lymphoscintigraphy uses technetium 99m sulfur colloid for the assessment of lymph flow. NIFR uses indocyanine green for the visualization of superficial lymphatic flow and functioning lymphatic vessels; it is used to determine the seriousness of the condition. Magnetic resonance lymphangiography (MRL) is a new test, which involves injection of Gadolinium for the determination of lymphatic channels.
The treatment is based on the seriousness of lymphedema. However, accurate and early diagnosis is crucial as effective treatment for lymphedema can be established in the early stages of the condition.
Grading Of Lymphedema
Lymphedema and lymphedema-related fibrosis use guidelines supported by National Cancer Institute (NCI) for the diagnosis of lymphedema. Grading of lymphedema is based on measurement of the swelling as well as the changes in appearance of the affected skin.
Grade I: There is 5-10% difference between the affected and the unaffected limb in relation to volume and circumference. There is presence of pitting edema and on close inspection there is swelling or loss of anatomic architecture. Soft tissue response is minimal to moderate to limb elevation or compression and the texture is spongy to moderately firm.
Grade II: There is more than 10-30% difference between the affected and the unaffected limb in relation to volume and circumference. There is obvious loss of anatomic architecture, skin folds and normal shape of the affected limb. There is marked increase in density and firmness of the affected skin and the texture of the skin show signs of ‘tethering’.
Grade III: There is more than 30% difference between the affected and the unaffected limb with major changes in the shape of the limb. There is inability to perform daily activities and there might be leakage of lymph through skin surface. There is marked density and firmness of the skin with evident tethering.
Grade IV: The condition becomes disabling and there is diagnosis of lymphangiosarcoma, which is a rare tumor that develops in chronic, untreated severe lymphedema.
International Society of Lymphology uses staging system for the staging of lymphedema.
Stage 0: Latent or subclinical lymphedema
Stage I: Early or mild lymphedema with or without pitting
Stage II: Moderate lymphedema with pitting and skin changes
Stage III: Severe lymphedema without pitting and marked skin changes.