Non-convulsive status epilepticus is not a benign entity: The etiology determines mortality and its form of presentation predicts the functional prognosis.

Purpose

The prognostic significance of nonconvulsive status epilepticus (NCSE) compared with convulsive status epilepticus (CSE) remains uncertain. We compared clinical features, treatment burden and outcomes of both phenotypes in critically ill adults, and assessed independent predictors of mortality and functional outcome.

Methods

We conducted a retrospective study of 168 adults with status epilepticus admitted to a tertiary intensive care unit. After exclusion of 4 patients with undocumented semiology, the comparative cohort included 164 patients: 83 with CSE and 81 with NCSE. Five patients evolving from CSE to NCSE were classified as NCSE. NCSE was diagnosed using clinical assessment, EEG monitoring and the Salzburg Consensus Criteria. Outcomes were hospital mortality and modified Rankin Scale (mRS) >3 at discharge. Multivariable logistic regression identified independent predictors.

Results

Baseline age, APACHE II score and Glasgow Coma Scale did not differ between groups. Among NCSE patients, 35 fulfilled Salzburg criterion IIA and 36 criterion IIB. A benzodiazepine diagnostic trial was recorded in 27 patients, with EEG improvement in 25. Hospital mortality was similar in CSE and NCSE (34%vs 32%; p = 0.869). NCSE was associated with greater treatment burden, longer time to seizure control, longer ICU stay and worse functional outcome (mRS >3: 57% vs 84%; p < 0.001). Mortality was independently associated with age, anoxic encephalopathy and super-refractory status, but not NCSE. NCSE independently predicted poor functional outcome.

Conclusion

NCSE did not independently increase mortality, but was associated with greater therapeutic complexity and worse functional outcome at discharge, supporting early EEG monitoring and etiology-guided treatment.