Abstracts

Rationale: Status epilepticus (SE) is a major neurological and medical emergency that requires acute medical management. SE is routinely classified in convulsive status epilepticus (CSE) and nonconvulsive status epilepticus (NCSE), when impairment of consciousness is present with no overt signs of seizure activity. NCSE is diagnosed in up to 8% of patients with coma of unknown cause (Towne et al., 2000). Confirmation of NCSE requires EEG showing seizure activity. We evaluated the frequency of CSE and NCSE in patients in whom EEG was performed in order to confirm or exclude diagnosis of SE. For diagnosis of NCSE strict EEG criteria were applied (Kaplan, 2007). Methods: Patients older than one year submitted to EEG exams at the Neurophysiology Department of Hospital Israelita Albert Einstein, São Paulo, Brazil, between 2011 and 2012, were included in this study. EEG exams were ordered to investigate the diagnosis of SE in patients with clinically suspected SE, or in patients with impairment of consciousness of unknown cause. EEG records were reviewed by two independent observers. Diagnosis of CSE was firmed based on clinical and EEG findings. Diagnosis of NCSE, defined according to EEG characteristics, was confirmed only if 1) the criteria for SE were fulfilled, defined as continuous or nearly continuous electrographic seizure activity during the EEG record, without clinical seizure activity; and 2) at least two EEG interpreters independently agreed that the pattern represented seizure activity. Results: Four hundred and forty-eight EEG exams of 293 consecutive patients (128 women) were included in the study. Age varied from 1 to 98 years (mean 63.38 years, SD 25.30). Clinical diagnoses included impairment of consciousness with no apparent cause (132 patients), epilepsy and seizures (76), stroke (42), traumatic brain injury (11), encephalopathy (10) and others (22). A total of nine cases (2%) of SE were identified: 7 of them had CSE and 2 NCSE. Four patients presented focal SE and 5 generalized. Conclusions: Diagnosis of CSE can usually be confirmed based on clinical characteristics. NCSE, on the other hand, requires EEG for the confirmation of diagnosis. In patients with clinically suspected SE and in those with unexplained impairment of consciousness, EEG is mandatory for confirmation of this diagnosis. In this series, the use of strict criteria for definition of NCSE might have led to the low number of confirmed cases.