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%).

Electroencephalographic activity after brain death.

Fifty-six consecutive patients clinically diagnosed as brain dead were seen at Loyola University Medical Center, Maywood, Ill, from January 1984 through May 1986. Eleven (19.6%) of the 56 patients had electroencephalographic (EEG) activity following the diagnosis of brain death. The mean duration of the observed EEG activity was 36.6 hours (range, two to 168 hours). Three patterns of EEG activity were observed: (1) low-voltage (4 to 20 microV) theta or beta activity was recorded in nine (16.1%) patients as long as 72 hours following brain death. Neuropathologic studies in one patient showed hypoxic-ischemic neuronal changes involving all cell layers of the cerebral cortex, basal ganglia, brain stem, and cerebellum; (2) sleep-like activity (a mixture of synchronous 30 to 40 microV theta and delta activity and 60 to 80 microV, 10 to 12 Hz spindle-like potentials) was noted in two (3.6%) patients for as long as 168 hours following brain death. Pathologic studies in both cases demonstrated ischemic necrosis of the brain stem with relative preservation of the cerebral cortex; and (3) alpha-like activity (monotonous, unreactive, anteriorly predominant, 25 to 40 microV, 9 to 12 Hz activity) was observed in one (1.8%) patient three hours following brain death. Regardless of activity on the EEG, none of the patients recovered. The occurrence of EEG activity following brain death would suggest reliance on the EEG to confirm brain death may be unwarranted. The use of the EEG as a confirmatory test of brain death may be of questionable value.