Nonconvulsive status epilepticus in patients with brain tumors

The prevalence of nonconvulsive status epilepticus (NCSE) in brain tumor patients is unknown. Since NCSE has been associated with significant mortality and morbidity, early identification is essential. This study describes the clinical and EEG characteristics, treatment, and outcome in brain tumor patients with NCSE.

All patients admitted to Mount Sinai Hospital from 2009 to 2012 with an ICD-9 brain tumor code were cross-referenced with the epilepsy department's database. EEGs from matching patients were reviewed for NCSE. Relevant information from the medical records of the patients with NCSE was extracted.

1101 brain tumor patients were identified, of which 259 (24%) had an EEG and 24 (2%) had NCSE. The vast majority of seizures captured were subclinical with 13 patients (54%) having only subclinical seizures. Treatment resolved the NCSE in 22 patients (92%) with accompanying clinical improvement in 18 (75%) of those patients. Tumor recurrence or progression on MRI was associated with decreased 2-month survival (75% mortality, p=0.035) compared to stable tumors (20% mortality). Patients with metastatic disease had median survival from tumor diagnosis of 1.2 months.

NCSE in brain tumor patients may be under diagnosed due to the frequent lack of outward manifestations and highly treatable with improvement in the majority of patients. NCSE patients with progressing brain lesions, tumor recurrence, or metastatic disease are at serious risk of mortality within 2 months. Continuous EEG monitoring in brain tumor patients with recent clinical seizures and/or a depressed level of consciousness may be critical in providing appropriate care.