Abstracts

Status epilepticus (SE) from all causes is associated with a 25-30 % mortality rate. In patients with hypoxic-ischemic encephalopathy (HIE) and SE, the mortality is even higher. Effect of non-convulsive status epilepticus (NCSE) in this group have not been described previously. We, therefore, wanted to review the EEG features of SE in patients with HIE to correlate them with the clinical findings and also identify patients in which intervention may be associated with a better prognosis. The EEG database at Medical University of Ohio from 1999-2004 was reviewed. Patients with HIE and fulfilling the EEG criteria for status epilepticus were identified. EEG were reviewed by two Board Certified Electroencephalographers and charts were reviewed for clinical and EEG information. IRB approval was obtained for this study. Twelve patients were identified who fulfilled the criteria for for HIE and NCSE. There were six men and six women. Mean age was 60.5 years (range 38-85). Six patients had isolated cardiac arrest, two had purely respiratory arrest while four had simulatneous cardiorespiratory arrest. Six patients were comatose with no clinical evidence of seizures (50%), three patients (25 %) had intermittent myoclonus, while two patients (16 %) had focal clonic activity noted initially. One additional patient had generalized tonic clonic seizure that was followed by coma and EEG evidence of NCSE.
Irregular bifrontal generalized spike and wave discharges were seen in six patients (50%), generalized periodic epileptiform discharges with evolving pattern were seen in five patients (42 %), and focal rhythmic spike and wave activity was seen in one patient (8 %). Severe background suppression was noted in all patients. Three patients had intermittent theta activity but the background was unreactive. In nine patients NCSE resolved with treatment but in all twelve patients this did not result in improvement of the background EEG activity. All twelve patients died within 30 days of onset of NCSE. EEG features of non-convulsive status epilepticus are variable but most patients had generalized periodic epileptiform discharges with evolving frontal discharges or rhythmic frontal spike and wave activity. The EEG pattern did not influence outcome or correlate with specific clinical features.
In our series non-convulsive status epilepticus in patients with hypoxic ischemic encephalopathy was associated with a 100 % mortality. Although status epilepticus resolved in 66 % of the patients with aggressive treatment, this did not result in improved outcome.