Generalized status myoclonicus in acute anoxic and toxic-metabolic encephalopathies.

Nineteen cases of generalized status myoclonicus (GSM) associated with acute anoxic and/or toxic-metabolic encephalopathy were studied. Generalized status myoclonicus was associated with coma in the overwhelming majority of patients (95%), although one patient had only clouding of consciousness. Generalized status myoclonicus occurred in 13 patients after cardiorespiratory arrest and in six patients after toxic-metabolic encephalopathy. Thirteen patients died, four survived in a chronic vegetative state, and two recovered without any permanent neurologic sequelae. Generalized status myoclonicus was preceded by generalized tonic-clonic seizures or generalized tonic-clonic status epilepticus in six patients (32%). The implications of these findings are discussed and a hypothesis that generalized status myoclonicus is a fragment of generalized tonic-clonic status epilepticus is proposed. Generalized status myoclonicus is a grave prognostic indicator that is often not compatible with useful recovery in spite of all therapeutic efforts. The final outcome is related to the underlying disease process. In our study, complete neurologic recovery was observed in two patients (11%).