Abstracts

Rationale: Inadequate prenatal and obstetrical care, infection, and head trauma are risk factors for symptomatic childhood epilepsy worldwide. Low-income countries are most affected due to poverty, poor access to health care and social instability. Few studies have characterized recent incidence and outcome of preventable causes of childhood epilepsy in a resource-rich population. Our objective is to describe the incidence and types of preventable causes for childhood epilepsy in Olmsted County, Minnesota, a predominantly middle-class region with low unemployment and good access to high-quality medical care through either the Mayo Clinic, Olmsted Medical Center or a small number of private care practitioners. Methods: This retrospective incidence cohort study include all residents ?18 years newly diagnosed with epilepsy (n=356) while living in Olmsted County between 1980 and 2004. We assigned one primary preventable condition per case to avoid double-counting cases with multiple conditions. Preventable causes were determined by consensus and based on available prevention methods such as quality obstetrical and perinatal care, childhood immunizations, mandatory seatbelt and helmet legislation, and access to tertiary care. Preventable causes were classified as prenatal, perinatal, and postnatal. Medically refractory epilepsy was identified in patients with seizures every 6-12 months despite adequate trial of two or more anticonvulsants. Results: Overall, 56 of 356 patients had a preventable cause for their epilepsy (16% of all childhood epilepsy, male = 57%). Attributable etiologies were prenatal in 3 patients (5%), perinatal in 34 patients (61%), and postnatal in 19 patients (34%). The leading single preventable cause was premature birth ?37 weeks in 17 patients (30%), including 10 patients born between 33 and 37 weeks, who all had early abnormal neurologic examination or brain imaging. Other perinatal causes included hypoxic ischemic encephalopathy in 15 patients (27%), perinatal hypoglycemia in 1 patient, and neonatal stroke in 1 patient. Prenatal causes included congenital CMV (n=1), porencephalic cyst (n=1), and maternal respiratory failure due asthma (n=1). Epilepsy in previously healthy children occurred in 8 patients (14%) due to infectious etiologies (including 1 case of cerebral malaria), 4 patients (7%) after head trauma, 3 patients after hypoxic injury, 3 patients with childhood stroke, and 1 patient due to hypoglycemia. With an overall mean duration of follow-up 12.0 1.0 years, medically refractory epilepsy was seen in 9 patients (16%) at 1-year after epilepsy diagnosis, in 12 patients (21%) at 2-years after diagnosis, and 14 patients (25%) at last follow-up. Conclusions: Despite advances in obstetrics and neonatal care, perinatal etiologies account for nearly two thirds of preventable causes of childhood epilepsy in a resource-rich population. A quarter of these children are at risk for medically intractable epilepsy, warranting continued efforts in possible methods of primary prevention.