MYOTONIA IN COLCHICINE MYONEUROPATHY

Colchicine may induce a myoneuropathy in patients with renal insuffici ency. To date, myotonia has not been described in this disorder, We re cently studied 4, patients treated with routine doses of colchicine wh o, in the setting of renal insufficiency, developed a severe myoneurop athy characterized by prominent myotonic discharges on electromyograph y. In addition, 1 of the 4 patients had profound clinical myotonia. in the 3 patients in wham biopsies were performed, marked myopathic chan ge with intracytoplasmic vacuolization was identified. All 4 patients improved rapidly with discontinuation of the medication. The patient i n whom electrophysiologic studies were repeated had a complete resolut ion of the myotonic discharges. Colchicine myoneuropathy can present w ith prominent clinical and electrophysiologic myotonia that resolves c ompletely with discontinuation of the medication. (C) 1996 John Wiley & Sons, Inc.