The first signs may be subjective observations such as a feeling of heaviness in the affected extremity. These may be symptomatic of early-stage lymphedema where accumulation of lymph is mild and not detectable by changes in volume or circumference. As lymphedema progresses, definitive diagnosis is commonly based upon an objective measurement of differences between the affected or at-risk limb at the opposite unaffected limb, e.g. in volume or circumference. No generally accepted criterion is definitively diagnostic, although a volume difference of 200 ml between limbs or a 4-cm difference (at a single measurement site or set intervals along the limb) is often used. Bioimpedance measurement (which measures the amount of fluid in a limb) offers greater sensitivity than existing methods.Chronic venous stasis changes can mimic early lymphedema, but the changes in venous stasis are more often bilateral and symmetric. Lipedema can also mimic lymphedema, however lipedema characteristically spares the feet beginning abruptly at the medial malleoli (ankle level). As a part of the initial work-up before diagnosing lymphedema, it may be necessary to exclude other potential causes of lower extremity swelling such as kidney failure, hypoalbuminemia, congestive heart-failure, protein-losing nephropathy, pulmonary hypertension, obesity, pregnancy and drug-induced edema. Classification
According to the Fifth WHO Expert Committee on Filariasis the most common method of classification of lymphedema is as follows: (The same classification method can be used for both primary and secondary lymphedema)
The International Society of Lymphology (ISL) Staging System is based solely on subjective symptoms, making it prone to substantial observer bias.
The tissue now has a spongy consistency and is considered non-pitting: when pressed by the fingertips, the affected area bounces back without indentation. Fibrosis found in Stage 2 lymphedema marks the beginning of the hardening of the limbs and increasing size. Stage 3: Swelling is irreversible and usually the limb(s) or affected area becomes increasingly 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. Stage 4: The size and circumference of the affected limb(s) become noticeably large. Bumps, lumps, or protrusions (also called knobs) on the skin begin to appear. Stage 5: The affected limb(s) become grossly large; one or more deep skin folds is prevalent among patients in this stage. Stage 6: Knobs of small elongated or small rounded sizes cluster together, giving mossy-like shapes on the limb. Mobility of the patient becomes increasingly difficult. Stage 7: The person becomes "handicapped", and is unable to independently perform daily routine activities such as walking, bathing and cooking. Assistance from the family and health care system is needed. Grades
Lymphedema can also be categorized by its severity (usually referenced to a healthy extremity):
Grade 1 (mild edema): Involves the distal parts such as a forearm and hand or a lower leg and foot. The difference in circumference is less than 4 cm and other tissue changes are not yet present.