Abstracts

Rationale: Seizure affects about 30% of pediatric patients with a brain tumor. Brain tumor patients with epilepsy have significant epilepsy-related comorbidities and long-term sequelae. Despite its critical importance, little is known about the natural history, risk factors or pathogenesis of pediatric brain-tumor related epilepsy. Thus, we set out to investigate whether tumor location and grade, MRI and EEG findings, and resection type predict seizure type or severity in pediatric patients with brain tumor. Methods: This is a retrospective chart review study of 553 patients seen at Rady Children’s Hospital San Diego for primary brain tumor from 2010-2016. Of these, 45 patients were identified as having been treated for seizures. Data collected on these patients included tumor grade (high or low), location, type of final resection (no resection, subtotal, near total or gross total), MRI and EEG data, and medication history. The number of anti-epileptic medication administered was used as a surrogate marker for seizure severity. Results: Eight percent (n=45) of the primary brain tumor patients had epilepsy. Of these patients, 38.6% (n=17) had seizure as the presenting symptom. Data showed near statistical significant in patients with cortical tumors (p=0.088) or lateralized tumors (p=0.077) as more likely to have seizure as the presenting symptom than patients with subcortical tumors or midline/bilateral tumors. Tumors involving the temporal lobe were most commonly associated with epilepsy (n=23; 51%), followed by tumors involving the frontal lobe (n=8; 17.8%). EEG abnormalities were significantly more likely to be seen in patients with frontal lobe tumors (p = 0.013). The most common seizure type was partial seizure (n=32; 74.4%). 38.6 % (n=17) of patients had epilepsy requiring more than 3 anti-epileptic medications for treatment. Levetiracetam (Keppra) was the most commonly utilized anti-epileptic medication (n= 28; 62%). Smaller tumors, tumors measuring smaller than 1.9cm in diameter was significantly more likely to be associated with spiking on EEG (p=0.01). In contrast, larger edema size (1-2.9cm) was significantly associated with generalized seizures (p=0.047). No significant correlation was found between seizure severity and seizure type, tumor size, tumor grade, a specific type of EEG abnormality, edema seen on MRI or the type of surgical resection (p>0.05). Conclusions: Our study on tumor-related epilepsy in pediatric patients showed a slightly increased incidence of seizure on presentation, nearly 40% as compared to 15-30% found in general reviews. Temporal and frontal lobe tumors were the most common locations for brain tumor epilepsy, but these locations were not associated with seizure severity. Tumor grade, a specific EEG abnormality, edema seen on MRI or the type of surgical resection did not significantly correlate with seizure severity. Summation of the results suggest that children with lateralized cortical tumors with a larger edema are more likely to be associated with an EEG abnormality or generalized seizures, and that Keppra is the most commonly used anti-epileptic medication. Funding: None