Spectrum of nonconvulsive status epilepticus in patients with cancer

Determine incidence, clinical presentation, electrographic correlates, and outcome of nonconvulsive status epilepticus (NCSE) in cancer patients on whom an EEG was performed.

Retrospective review of 947 EEG reports on 658 patients in whom any type of EEG was performed at Memorial Sloan-Kettering Cancer Center (July 2006 to March 2008). Using the Epilepsy Research Foundation criteria, patients were classified as definite or probable NCSE. Medical records were reviewed for diagnosis, causes of NCSE, response to treatment, and outcome. Mortality was determined for patients with NCSE.

Twenty-six episodes of NCSE were identified in 25 patients (25/658, 4%). Eleven patients had primary brain tumor, 12 patients systemic cancer, and two had both. At diagnostic EEG, 18 were awake, 3 were lethargic, and 5 patients were comatose. EEG revealed a seizure in 62% of the patients, periodic lateralized epileptiform discharges in 42%, and periodic epileptiform discharges in 7.7%. Neuroimaging revealed new intracranial pathology in 54% of the patients. Seventy-seven percent of the patients achieved control; 65% required ≥3 antiepileptic drugs, and 33% required intubation. Three patients died from NCSE.

In our cohort, awake NCSE was more common than comatose NCSE. Treatment was successful in patients with heterogeneous central nervous system disease. EEG evaluation should be considered in patients with cancer because NCSE is treatable despite a high prevalence of structural brain disease. Nonconvulsive status epilepticus control did not always require intubation and burst suppression, but frequently required three or more antiepileptic drugs.