Neurogenic benign fasciculations, pseudomyotonia, and pseudotetany. A disease in search of a name.

We studied two patients with abnormal spontaneous muscular activity. The first had widespread fasciculations, painful spasms, delayed muscular relaxation, and hyperhidrosis. Improvement occurred after several years. The second case had generalized paresthesia, mild stiffness, a positive result from Trusseau's test, and was relieved by administration of carbamazepine. Both patients had abnormal conduction velocity. Examination of muscle biopsy specimens disclosed fiber type grouping and increased collateral ramification of motor axons. These observations exemplify symptoms and signs that resemble those of myotonia and tetany and occasionally occur in partial denervation. they provide additional evidence of the neurogenic nature of Isaacs-Mertens syndrome.