Abstracts

Rationale:
Malformations of cortical development are associated with the development of pharmacoresistant (PR) epilepsy. Focal cortical dysplasia (FCD) has been described in up to half of series from pediatric epilepsy surgery centers. Pathology appears to make a difference patients with cytoarchitectural abnormalities (FCD IIa or IIb) may experience epilepsy onset earlier than patients without cytoarchitectural abnormalities (FCD Type 1a). Although FCD is reported to be associated with medical refractoriness from onset in surgical series, the overall prevalence of epilepsy in FCD is not known. The percentage of children with FCD who develop PR epilepsy is unknown. Due to enhancements in resolution and imaging processing in MRI, FCDs are now often more clearly delineated and more readily identified by skilled clinicians. The purpose of this study is to describe the natural history of FCD, and to determine how many children with FCD developed PR epilepsy.
Method:
This was an IRB-approved retrospective cohort study of Children’s National Hospital (Washington, DC) patients and the electronic medical record. Children were identified from a centralized radiology database containing all imaging reports for the hospital system. Patients were included if found to have FCD on MRI performed between 1/2011-1/2019. Patients were excluded if < 3 months of documented follow-up, except if no history of seizure. We tracked identifying data, diagnosis, MRI data, number of antiseizure medications (ASM), seizure type, follow-up duration, and surgical information if applicable. Results137 children (42% female) met inclusion criteria with median age 11.5y (IQR 7.7-15.3y), median duration of f/u 31.2mo (IQR 14.2-58.4mo). 82% of the cohort developed epilepsy (66% of cases were PR): 68% of patients had focal unaware epilepsy (FUE); 4% had focal aware epilepsy (FAE); 9% had other epilepsies (4% genetic, 4% spasms, 1% developmental and epileptic encephalopathies); and 18% had no epilepsy (7% only provoked or 1 lifetime unprovoked seizure; 11% no history of seizure). Of the 112 children with epilepsy, 75% were seizure-free at the last visit. 36% were seizure-free without surgery but still on ASM; 4% were seizure-free without surgery and off ASM; 28% were seizure-free after surgery but still on ASM; 8% were seizure-free after surgery and off ASM. MRIs were performed for seizure in 89% of cases; FCD were incidental in the 11% with no seizures. 35% of the entire cohort had resective surgery with 83% Engel I outcome. Of the FUE subgroup, 43% had resective surgery with median age onset of seizures (MOS) 1.5y (IQR 0.5-4y) and 78% were Engel I at median 44.2mo (IQR 26.2-72.8mo) of f/u. Of the FAE subgroup, 66% had resective surgery (MOS 0.94y (IQR 0.5-2.3y)), 100% Engel I at median f/u 88mo (IQR 78-98mo). Of the other epilepsies group, 31% had resective surgery (MOS 0.8y (IQR 0.6-0.9y)), 100% Engel I at median f/u 29 mo (IQR 27-30 mo). 15 children had no history of any seizures with median follow-up of 25 mo (IQR 9-63mo).
Conclusion:
Children with FCD have a high risk of expressing epilepsy. Two thirds of those with epilepsy s become pharmacoresistant, but may achieve good outcomes after resection. Overall, 75% of our series was seizure-free at the last visit, indicating that the appropriate selection of ASM and early consideration of epilepsy surgery are likely to be beneficial for patients.
Funding:
:N/A