Levamisole-induced multifocal inflammatory leukoencephalopathy: clinical characteristics, outcome, and impact of treatment in 31 patients.

Levamisole (LEV) has been used as an immunomodulating medication in patients with recurrent aphthous ulcers and as an adjuvant for chemotherapy. LEV, with or without 5-fluorouracil (5-FU), induces multifocal inflammatory leukoencephalopathy (MIL). We identified 31 patients with LEV-induced MIL: 7 from our institution and 24 from a MEDLINE search. Twenty-one patients (67.7%) had been treated with a combination of LEV and 5-FU, while 10 patients had been treated with LEV alone. The onset of MIL was delayed in patients who took LEV and 5-FU in combination compared with the patients treated with LEV alone (11.7 +/- 3.7 vs. 4 +/- 2.5 wk, p < 0.001). Colon cancer (67.7%) was the most common indication for LEV administration. Gait ataxia occurred in 20 (64.5%) patients, and dysphagia was noted in 16 (51.6%) patients. Imaging studies revealed periventricular enhancement in 17 (54.8%) patients and supratentorial lesions in 16 (51.6%) patients. Cerebrospinal fluid studies showed lymphocytic pleocytosis in 10 of 21 (47.6%) patients. Early diagnosis of MIL and discontinuation of LEV is essential, yielding good recovery in most cases. Treatment with corticosteroids and/or intravenous immunoglobulin may be needed for this serious inflammatory encephalopathy. Twenty-nine patients exhibited improved clinical status and imaging findings after initial steroid or immunoglobulin treatment. Plasmapheresis may be an alternative regimen for patients with steroid resistance.