The Diagnostic Unreliability of “Classic” Physical Signs of Lymphedema

Abstract

In Western populations, chronic venous disease is a major source of secondary lymphedema; as many as 30% of chronic venous disease patients may have phlebolymphedema. Proper diagnosis is particularly important in this population as clinical improvement in swelling (and even reversal of lymphatic damage in some) may be achieved by early correction of underlying venous disease. Diagnosis of lymphedema currently rests on “classic” clinical markers (dorsal hump, squaring of toes, Stemmer sign, and nonpitting edema) in most community practices. Isotope lymphangiography, which is objective, is performed infrequently to confirm the clinical impression. Once a diagnosis of lymphedema is made, the patient is invariably doomed to lifelong conservative therapy, which is often ineffective. The aim of this study was to evaluate the diagnostic accuracy of clinical signs compared with isotope lymphangiography. During a 1-year period (2016-2017), 2699 limbs with swelling (1396 left, 1303 right) were evaluated. All limbs were prospectively scored for the classic lymphedema signs listed before. Isotope lymphangiography was routinely performed for objective evaluation. Isotope lymphangiography was scored as positive for lymphedema on the basis of time of isotope appearance in the groin lymph nodes, number of visualized lymph nodes, isotope density, presence of lymph channels, and pooling of isotope (dermal backflow). A total of 2699 limbs were evaluated with swelling. Of those, 769 underwent lymphoscintigraphy; 320 (42%) were normal and 449 (58%) were abnormal. Also, of the swollen limbs, 401 (15%) had classic clinical signs of lymphedema (dorsal hump, 53%; square toes, 25%; Stemmer sign, 16%; nonpitting edema, 6%). Among the limbs with positive clinical signs (n = 401), lymphangiography was performed on 203; 141 (69%) were positive for lymphedema and 62 (31%) were normal. Conversely, among 449 swollen limbs with abnormalities on lymphoscintigraphy, only 141 (35%) had one or more classic clinical signs. Among those with dermal backflow or pooling (n = 114), clinical signs were present in only 30 limbs (26.3%). Classic clinical signs are notoriously unreliable for correct diagnosis of lymphedema. Objective lymphoscintigraphy is normal in 31% of limbs with classic clinical signs of lymphedema. This means that the edema is not lymphatic but probably of correctible venous disease; and similar clinical signs can be generated by venous disease without lymphatic damage. On the contrary, isotope lymphangiography detected an abnormality in 246 of 449 (55%) limbs with limb swelling but without classic lymphedema clinical signs. In these patients, venous intervention may be less efficacious, and the isotope test is of prognostic value. Routine use of lymphoscintigraphy is recommended in all patients with limb swelling for objective lymphatic evaluation. The practice of making a diagnosis of lymphedema on the basis of classic clinical signs should be abandoned.