Abstracts

Rationale: Seizures commonly occur in encephalitis. However, there is no consensus regarding the ideal duration of antiepileptic therapy after childhood encephalitis. We reviewed data from a cohort of children who had suspected encephalitis at Rady Children s Hospital from 2004-2011 and were referred to the California Encephalitis Project (CEP).Methods: Inclusion criteria for suspected encephalitis (CEP protocol) were: recent onset of encephalopathy >24 hours and at least one of the following: fever, seizure, focal neurologic signs, pleocytosis, EEG or neuroimaging findings concerning for encephalitis. From these children, we identified those who had seizures by the following criteria: seizures prior to ED arrival, seizures upon ED arrival, clinical seizures observed in the hospital, and seizures captured on EEG. We then excluded those with a prior seizure history. From this cohort, we evaluated those who were discharged on antiepileptic therapy. The number of children weaned off of antiepileptic therapy was quantified and duration of therapy was analyzed. Factors determining discontinuation of medication was also evaluated.Results: We prospectively identified 217 consecutive patients with suspected encephalitis who had been referred to the CEP. 100/217 children were found to have seizures. 80/100 of these children survived their hospitalization and did not have a prior seizure history. 66/80 of these children were discharged on antiepileptic therapy. 2 children, not discharged on medication, had recurrent seizures and were restarted on antiepileptic drugs (AEDs). In total 29 children were eventually weaned off of medications. In this cohort, duration of antiepileptic therapy from discharge ranged from 1 month to 5 years. 9 were lost to follow up. The other 30 children remain on AEDs. 10/29 patients were weaned in 2-3 months. These 10 had normal EEGs. In total, 20/29 had normal EEGs. Abnormal EEG findings included 4 with focal discharges and 5 with either generalized or focal slowing. Conclusions: Very little information is available about the risk of recurrent seizure after encephalitis and even less information regarding the ideal duration of antiepileptic therapy after encephalitis. In our cohort, 42% (29/68) of children were safely weaned off of AEDs with only one child requiring re-initiation of AEDs due to recurrent seizures. 34% (10/29) of patients were safely weaned in a 2-3 month period without recurrent seizures. Two primary factors involved in deciding discontinuation of AEDs included followup EEG findings and clinical neurological assessment. We propose AEDs can be safely discontinued if a 3 month followup EEG after discharge is normal and clinical evaluation is reassuring.