A Populationbased Study of Long term Outcome of Epilepsy
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A population-based study of long-term outcome of epilepsy in childhood with a focal or hemispheric lesion on neuroimaging Radhika Dhamija, Brian D. Moseley, Gregory D. Cascino, and Elaine C. Wirrell Department of Neurology, Mayo Clinic, Rochester, Minnesota, U.S.A. SUMMARY Purpose: To evaluate long-term seizure outcome in chil- dren with epilepsy and a focal or hemispheric neuroimag- ing abnormality. Methods: All children (<18 years and residing in Olmsted County, Minnesota) with new-onset epilepsy diagnosed between 1980 and 2004 and a single focal lesion on neuro- imaging were identified by review of the Rochester Epi- demiologic Project database. Outcomes were divided into three categories: (1) seizure freedom for 1 or more years at last follow-up, (2) ongoing seizures but not medi- cally intractable epilepsy, and (3) medically intractable epilepsy or undergoing epilepsy surgery. We also evalu- ated the proportion who achieved seizure control without surgical intervention and whether lesion type predicted intractability. Key Findings: Of the 359 children with newly diagnosed epilepsy, 37 (10%) had a focal or hemispheric lesion on neuroimaging. Median age of diagnosis was 89 months (25th percentile 26 months, 75th percentile 142 months) and at follow-up was 137 months (25th percentile 95 months, 75th percentile 211 months). Eighty-three percent of children with malformations of cortical development, 67% with mesial temporal sclerosis, 33% with encephalomalacia, and 50% with vascular malforma- tions had intractable epilepsy at follow-up or underwent resective surgery for medically intractable epilepsy. Among the different etiologies, presence of encephalo- malacia predicted the lowest likelihood of medical intrac- tability or undergoing surgery (p < 0.01). At final follow- up, 24 (65%) of our entire cohort was seizure free. Follow- ing surgery, seizure freedom was achieved in 80% with mesial temporal sclerosis, 67% with encephalomalacia, 67% with vascular malformation, and 50% with malforma- tions of cortical development. There was no statistically significant difference between the different etiologies on neuroimaging and seizure freedom after surgery. Twelve children (32%) achieved seizure freedom with medical management alone. Significance: Focal lesions on neuroimaging confer a high risk of medical intractability among children with new- onset epilepsy. However, 32% of this cohort achieved seizure remission with medical management alone, including 58% with encephalomalacia and 33% with mesial temporal sclerosis. KEY WORDS: Epilepsy, Focal lesion, Outcome, Popula- tion-based study. Epilepsy is one of the most frequent neurologic disorders affecting the pediatric population. Advances in neuroimag- ing have made a major impact in the evaluation and management of patients with focal-onset seizures, with high-resolution magnetic resonance imaging (MRI) show- ing a structural abnormality in a significant number of patients previously labeled as ‘‘cryptogenic’’ (Von Oertzen et al., 2002; Goyal et al., 2004). The most common poten- tially resectable lesions detected on neuroimaging in children with epilepsy include malformations of cortical development, focal encephalomalacia or gliosis, mesial temporal lobe sclerosis, tumors, and vascular malformations (Woermann & Vollmar, 2009). Although many children achieve seizure control with medication, approximately 10–40% have medically intrac- table epilepsy (Camfield et al., 1993; Hauser et al., 1998; Kwan & Brodie, 2000; Berg et al., 2001; Dlugos et al., 2001). Such patients may benefit from surgical resection, with seizure freedom in 60–80% with unilateral mesial temporal lobe epilepsy or tumors and in 40–70% with malformations of cortical development or dual pathology (Sisodiya, 2000; Dlugos et al., 2001; Wieser et al., 2003; Nakase et al., 2007; Spencer & Huh, 2008; Roper, 2009). Surgical series and hospital-based studies have reported that focal lesions on neuroimaging correlate with high rates of intractability. However, such studies are biased toward Accepted June 8, 2011; Early View publication July 18, 2011. Address correspondence to Elaine Wirrell, MD, Department of Pediatric Neurology, Mayo Building, 16 th floor, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, U.S.A. E-mail: [email protected]Wiley Periodicals, Inc. ª 2011 International League Against Epilepsy Epilepsia, 52(8):1522–1526, 2011 doi: 10.1111/j.1528-1167.2011.03192.x FULL-LENGTH ORIGINAL RESEARCH 1522
A Populationbased Study of Long term Outcome of Epilepsy
A population-based study of long-term outcome of epilepsy in childhood with a focal or hemispheric lesion on neuroimagin
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Apopulation-based study of long-termoutcomeof epilepsy in
childhood with a focal or hemisphericlesion on neuroimagingRadhika
Dhamija, Brian D. Moseley, Gregory D. Cascino, and Elaine C.
WirrellDepartment of Neurology, Mayo Clinic, Rochester, Minnesota,
U.S.A.SUMMARYPurpose:Toevaluatelong-termseizureoutcomeinchil-dren
with epilepsy and a focal or hemispheric neuroimag-ing
abnormality.Methods:All children (
