LYMPHATIC ABNORMALITIES IN HUMAN FILARIASIS AS DEPICTED BY LYMPHANGIOSCINTIGRAPHY

Background: Investigation into filarial lymphedema has been hampered by the lack of a simple, safe, and easily repeated test to image the peripheral lymphatic system. Recent refinements in radionuclide lymphangioscintigraphy have established this noninvasive technique as the initial procedure of choice for visualizing lymphatics. Accordingly, we applied lymphangioscintigraphy to patients with filariasis and, for purposes of interpretation, compared the findings with those in patients with nonfilarial lymphedema. Methods: Thirty-three patients with classic symptoms or signs consistent with acute or chronic filariasis underwent lymphangioscintigraphy, and the findings were compared with those in five patients without lymphatic dysfunction and in 50 other patients with primary or secondary lymphedema without exposure to filariasis. Results: As in patients with nonfilarial lymphedema, scintigraphic abnormalities in the 33 patients with filariasis included delayed or absent tracer transport of the radiotracer (25 patients), tortuous and bizarre deep lymphatics (seven patients), dermal diffusion (15 patients), retrograde tracer flow (six patients), and faint or absent regional nodal visualization (14 patients). Even in patients with long-standing filarial lymphedema, peripheral trunks were often visualized (at least in part), and regional nodes and more central lymphatics sometimes filled after light exercise. In some of the latter patients, however, discrete lymphatic trunks were not detected. Conclusion: Lymphangioscintigraphy is a simple, safe, reliable, noninvasive method with which to examine the peripheral lymphatic system, including truncal and nodal abnormalities, in endemic populations with occult and overt lymphatic filariasis.