Abstracts

Rationale: The incidence and response to first line therapy of status epilepticus (SE) is known from prospective population based studies but there have been no prospective studies to determine the incidence of benzodiazepine refractory SE using contemporary dosing. Its incidence may be obtainable from retrospective case review, similar to other aspects of SE that have been reported. Many studies have retrospectively identified SE based on ICD9 codes. Thus, we performed a retrospective database review to determine whether retrospective SE case identification based on ICD9 codes is accurate for identifying cases of acute generalized convulsive SE (GCSE) and determined the incidence of identifiable GCSE. Methods: We retrospectively reviewed the ICD9 coding database for visits to the University of Virginia Hospital, Charlottesville, Virginia from 1/1/2009-12/31/2009 for primary and secondary SE codes (345.2 petit mal status , 345.3 grand mal status , and 345.7 epilepsia partialis continua ) and reviewed the medical records of each case to determine if patients coded as SE met criteria of GCSE presenting to the University of Virginia Emergency Department (ED). SE was defined as seizing on ED arrival or greater than 3 seizures without return to baseline. We also reviewed the same database for visits with an epilepsy primary diagnosis code of 345.0-345.9, excluding SE codes; the medical record from every twentieth case was reviewed to determine if any visits for SE were miscoded using other seizure and epilepsy diagnosis codes. Results: 145 visits were coded 345.2, 345.3, or 345.7 as primary or secondary diagnosis codes. Of the 115 coded 345.3, only 21 (18%) visits met our criteria for acute GCSE. If the criteria are expanded to include presentation of GCSE to an outside hospital ED but with clinical stabilization by the time of transfer to the UVA ED, then 31 visits (27%) met our criteria for acute GCSE. Of the 30 coded 345.2, none met our criteria for acute GCSE. No visits to the ED were coded 345.7. Conclusions: Retrospective analysis of coding databases is not an accurate way to identify incidence of GCSE since a large majority of cases coded for status epilepticus do not meet criteria for a diagnosis of acute GCSE. Prospective studies or different methods of retrospective review are necessary to perform accurate case identification of SE in clinical research. This retrospective review also suggests that the incidence of SE is low and many centers must be included in a treatment trial of benzodiazepine refractory SE.