Gentamicin-induced Myoclonus

Abstract

Drug-induced myoclonus is a diagnosis of exclusion. Various drugs have been reported to induce myoclonus. Antibiotic-induced myoclonus (AIM) is very rare. We describe a case of multifocal myoclonus secondary to gentamicin toxicity and review the literature of AIM. A 59-year-old woman with end-stage renal disease developed generalized multifocal myoclonus within 1 hour after receiving only 1 supratherapeutic dose of gentamicin for a potential hemodialysis catheter infection. Myoclonus was completely resolved after 2 sessions of hemodialysis. We identified 22 patients of AIM in the literature. The median age of patients was 63 years. More than half of patients (12/22, 55%) had underlying chronic kidney disease. Cephalosporins were the most common drug class associated with AIM (12/22 patients; 55%). About two third of patients (15/22, 68%) received overdoses of antibiotics. Fifteen patients (71%) completely recovered after discontinuing or decreasing the dose of antibiotics. Five patients (24%) died of underlying medical conditions or of unknown etiology. Only 1 had persistent myoclonus. The potential mechanisms of AIM are discussed. AIM, although rare, should be considered as a potential cause of multifocal myoclonus in patients with advanced age or renal insufficiency. The prognosis of AIM appears favorable, with several cases resolving after withdrawal of the antibiotic.