Neuropathologic findings in postmortem studies of sudden death in epilepsy.

Death in patients with epilepsy may occur suddenly and unexpectedly. When no anatomic or chemically demonstrable cause for such a death is found at postmortem examination, the death may remain unexplained. Previous studies of general autopsy features in cases of sudden unexpected death in epilepsy (SUDEP) have reported increased lung and liver weights, pulmonary edema, hepatic fatty change, and small increases in heart weights. Neuropathologic findings include cerebral edema, lighter brain weights compared with age-matched controls, and various other structural brain lesions in 34% to almost 50% of cases. In an ongoing United Kingdom study, brains from 25 cases of SUDEP have been examined. Macroscopic abnormalities were identified in 70% of cases and included contusions, old infarcts, hippocampal sclerosis, cortical dysgenesis, vascular malformation, oligodendroglioma, neurodegenerative brain disease, and microcephaly. Histopathologic findings include evidence of acute neocortical and brainstem hypoxic neuronal changes. Similar changes in hippocampal and basal ganglia neurones have also been observed. These changes indicate a cerebral event occurring at least 4-6 h before death and are at odds with a "sudden" death which, by definition, occurs within 1 h. Because many SUDEP cases are unwitnessed, the exact time sequence of events is often unknown. This study confirms the high incidence of structural brain lesions in SUDEP cases.