Abstracts

RATIONALE: Data are sparse concerning mortality following acute symptomatic seizures. We investigated mortality in the first 30 days (early mortality) and mortality among 30 day survivors (late mortality). METHODS: Acute symptomatic seizures (AS) occur in close temporal association with transient central nervous system (CNS) insults or transient systemic disturbance. These seizures are presumed to be an acute manifestation of the insult. We studied death among Rochester residents with an incident AS between 1/1/65 and 12/31/84 ascertained through the records-linkage system of the Rochester Epidemiologic Project. Medical records of all residents with a diagnosis of seizure, convulsion, epilepsy, or conditions known to be related to AS were reviewed. Children with febrile seizures were excluded from these analyses. Standardized mortality ratio (SMR) was used to compare observed to expected deaths based upon death rates from southeastern Minnesota for 1965-74 and 1975-84. RESULTS: Thirty day case fatality in the 428 incident cases of AS was 34.1%. Among 30 day survivors, case fatality was 16.6%. The SMR was 420 (95% CI 355-491) for early mortality and 2.5 (95% CI 1.8-3.2) for late mortality. The SMR for early mortality among people under 65 years of age was 1,206 (95% CI 800-1,279),dramatically increased when compared to the SMR for older individuals (4.0,95% CI=3.2-5.0). ( The SMR for late mortality in young people was 3.3, (95% CI=2.0-5.0) and for older people 2.4, (95% CI=1.6-3.4). Etiology was strongly associated with early mortality. CNS infections, trauma, cerebrovascular disease, metabolic problems, brain neoplasms, and encephalopathy were all increased (SMRs 73 to 2,209). The SMR for late mortality was significantly increased only for CNS infection, brain neoplasm, and encephalopathy (SMR 2.7, 24.0, and 7.1 respectively). CONCLUSIONS: Early and late deaths occur more often than expected following acute symptomatic seizure. Early deaths may occur among people with more severe underlying disorder or as a sign of impending death. Late deaths may represent deaths due to the underlying condition, independent of past seizure.