Non-Convulsive Seizures and Non-Convulsive Status Epilepticus in a Neurological Intensive Care Unit: Risk Factors and Outcomes (S39.004)

OBJECTIVE: To describe risk factors and features affecting outcome in non-convulsive seizures (NCS) and non-convulsive status epilepticus (NCSE) in neurological ICU. BACKGROUND: NCS has been reported in 8-19% of ICU patients with altered mental status (AMS). NCSE may cause permanent neuronal damage via increased extracellular glutamate, leading to brain swelling and apoptosis. Delayed diagnosis and treatment of NCS may increase mortality. Little data exists regarding factors influencing outcome in ICU patients with NCS/NCSE. DESIGN/METHODS: Our prospective observational study recruited adults in our neurological ICU with unexplained AMS, unrelated to anoxia or hypothermia, between January and July 2012. After brain imaging, patients were placed on continuous EEG (cEEG) as medically indicated. NCSE was defined as continuous or recurrent ictal discharges for 30 minutes. We analyzed EEG pattern, clinical signs, risk factors (e.g. acute cerebral lesion, preexisting epilepsy), treatment response, and outcome in patients with and without NCS/NCSE. RESULTS: NCS/NCSE was detected in 20% of 139 patients(11 NCS, 17 NCSE). Factors associated with NCS/NCSE included history of epilepsy (p=0.039), seizure at presentation (p=0.001), intracranial tumor (p=0.007), and acute CNS infection (p=0.06). Subtle clinical signs such as twitching or eye deviation were found in 57% of the NCS/NCSE group (p=0.001). Mortality was higher in the NCS/NCSE group (29% vs12%, p=0.084). cEEG changed management of anticonvulsant in 39% of all cases. All six of the NCSE patients treated to burst-suppression with anesthetic infusions died. CONCLUSIONS: Subtle clinical findings, history of seizures, intracranial tumor, or acute CNS infection should raise suspicion for NCS/NCSE in ICU patients with AMS. However, cEEG remains essential in diagnosis and management. Mortality is high in NCSE; further study may help to understand the relationship between etiology, NCSE subtypes, treatment and outcome. A preliminary version of these data will be presented at the American Epilepsy Society meeting in December 2012. Disclosure: Dr. Laccheo has nothing to disclose. Dr. Sonmezturk has nothing to disclose. Dr. Bhatt has nothing to disclose. Dr. Barwise has nothing to disclose. Dr. Shi has nothing to disclose. Dr. Tomycz has nothing to disclose. Dr. Ringel has nothing to disclose. Dr. DiCarlo has nothing to disclose. Dr. Abou-Khalil has received research support from Valeant Pharmaceuticals International, UCB, Schwarz, King, Ortho McNeill, and Icagen. Dr. Haas has nothing to disclose.