Ictal EEG: Etiology and Mortality in Older Adults With Nonconvulsive Status Epilepticus

Abstract

Clinical-electroencephalogram (EEG), as well as etiological and prognostic data on subtypes of nonconvulsive status epilepticus (NCSE) are yet to be established. Objective: Evaluate the clinical semiology and EEG findings and prognostic data of older adults with NCSE. Methodology: Characterize the clinical-EEG and prognostic data in the subtypes of NCSE in older adults consecutively admitted to the emergency room of the Pontifícia Universidade Católica de Campinas (PUC-Campinas) University Hospital. Results: When evaluating 105 older adults with altered consciousness, it was possible to diagnose NCSE in 50 (47.6%) older adults, with a mean age of 72.8 ± 8.8 years. NCSE-coma occurred in 6 cases, with NCSE-without coma in 44 cases. The etiology was structural in 41(82%) cases, metabolic in 5 cases, and unknown etiology in 4 cases. Twelve cases had a history of epileptic seizures. On the EEG, epileptiform discharges (EDs > 2.5 Hz) were present in 34(68%) cases and rhythmic delta activity /lateralized periodic patterns occurred in 35(70%) cases. There was clinical improvement after the initial pharmacological treatment in 36 cases and, within 30 days, 18 cases died. The better prognosis was associated with a good response to initial pharmacological treatment (n = 14) and with EDs > 2.5 Hz on EEG (Fisher's exact test; 26 vs 8; P = .012). Conclusion: Focal NCSE with impaired consciousness was the most frequent subtype. The most frequent finding on the EEG was the recording of focal/regional seizures. A high number of cases showed initial clinical improvement, but mortality was high. The favorable prognosis was associated with initial clinical improvement and the presence of EDs > 2.5 Hz. There was no relationship between EEG patterns and the etiology and subtypes of NCSE in older adults.