Transient myoclonic state with asterixis in elderly patients: a new syndrome?

We report 7 patients who developed acute co-occurrences of fragmentary generalized myoclonus and asterixis. All patients were elderly and had other chronic diseases. This condition appeared acutely, progressed over several hours and then disappeared in 2-3 days with diazepam administration. No sequelae were noted, although most cases developed recurrences. The myoclonus occurred spontaneously and was slightly enhanced by action. The myoclonus was widely distributed but predominated in the neck, shoulder girdle, and upper extremities. Opsoclonus was not noted. Clinically apparent myoclonus was not evoked by sensory stimuli. Asterixis was observed in the upper extremities in all cases. Asterixis-like movements of the protruded tongue were also observed. Neurological findings other than the myoclonus and asterixis were unremarkable. Neither metabolic nor organic abnormalities clearly responsible for this condition were identified. Cerebral potentials preceding the myoclonic jerks recorded in one case suggested that the myoclonus may have been a spontaneous cortical myoclonus. We named this condition a transient myoclonic state with asterixis (TMA). Awareness of this syndrome is clinically important because of its benign nature, although it can recur.