Abstracts

Rationale: Sturge-Weber Syndrome (SWS) typically presents with facial port wine stain and leptomeningeal angiomatosis, and is reported to be associated with somatic GNAQ mutations in the affected regions. Most patients develop intractable epilepsy at early ages, likely associated with lesions of the intracranial leptomeningeal angiomatosis. In this study, we investigated children with unilateral SWS who underwent video EEG monitoring for evaluation of intractable epilepsy, and found cases with prominent ictal EEG changes in the hemisphere contralateral to the leptomeningeal angiomatosis. Methods: The study was approved by the institutional review board at Boston Children's Hospital. We retrospectively reviewed medical records, EEG findings and neuroimaging of children with SWS and medically intractable epilepsy who had their medical care at Boston Children's Hospital in 2015-17, and identified four children with unilateral SWS on neuroimaging, who had prominent ictal EEG changes in the contralateral hemisphere. The four children underwent inpatient video EEG telemetry for evaluation of medically intractable epilepsy; the EEG studies were often obtained when seizures became more difficult to control. Ictal EEG changes appeared to involve the contralateral hemisphere at the time seizures became clinically more wide-spread, such as when they were having secondary generalized seizures or complex partial seizures with alteration in consciousness. Results: In the four children (3 boys and 1 girl, mean age 5.8±5.0 years of age), the age of seizure onset was 0.9±0.8 years. All of them had right sided facial port wine stains and right hemisphere brain lesions with leptomeningeal angiomatosis on neuroimaging (seen using MRI with gadolinium), and with no contralateral brain lesion seen. Two children had lesions extending to the frontal lobe, and clinically had mild hemiparesis; the other two without frontal involvement did not have obvious hemiparesis on examination. Three children had a history of status epilepticus. One child had secondary generalized seizures, while the other three had complex partial seizures without secondary generalization. On EEG, all patients had bilateral frontal or widespread EEG changes at seizure onset, with one child having much greater amplitude on the side contralateral to the brain lesion. All children had prominent semirhythmic slowing, building up on the side contralateral to the brain lesion, at times greater than the ipsilateral side, while faster frequency activity was typically seen on the side ipsilateral to the brain lesion (table 1). Conclusions: We identified four children with intractable epilepsy associated with SWS, who had prominent ictal EEG changes in the hemisphere contralateral to the leptomeningeal angiomatosis. EEG could show semirhythmic activity with higher amplitude compared to the ipsilateral side; such findings could impose challenges when pursuing surgical evaluation. They may suggest electrographic or perfusion related changes during the seizures in children with SWS. Further studies will be necessary to assess for reproducibility of the findings, and correlation with clinical outcome. Funding: None