Epilepsy in patients with pediatric brain tumors: Etiology, treatment & management

Central nervous system (CNS) tumors are the most common solid tumor type seen in the pediatric population and may present with a variety of neurological presentations, with seizure being the second most common. Supratentorial tumors commonly associated with seizures include low-grade gliomas such as pilocytic astrocytoma, subependymal giant cell astrocytoma (SEGA), gangliogliomas, and dysembryoplastic neuroepithelial tumors (DNET).

The etiology of seizures in pediatric brain tumor patients is often multifactorial, often the result of multimodal therapy and possible contributions from surgery, radiation therapy, chemotherapy, and other metabolic disturbances. Seizures can also be secondary to mass effect, hydrocephalus, or metastases. Additionally, tumor characteristics including its location in the temporal lobe, the presence of mixed neuronal and glial components, and the tumor's size and growth rate influence the likelihood of seizures.

Pediatric patients with a first lifetime unprovoked seizure should undergo further testing including electroencephalogram (EEG). MRI imaging is not warranted in all cases but should be strongly considered for children with focal presentation or EEG finding to identify possibly secondary causes such as brain tumors. The EEG can identify background activity alterations, epileptiform activity, and/or seizure activity, but sensitivity and specificity are limited and therefore, should be used in conjunction with neuroimaging like an MRI for a comprehensive evaluation.

Anti-seizure medication (ASM) is not recommended to be started in patients with a brain tumor without seizures, but rather only in patients that were identified with brain tumor who presented with seizures. ASM choices are influenced by patient's co-morbidities, drug interactions with chemotherapy, and the patient's tolerance to potential adverse drug reactions. With its limited drug-drug interactions, the most commonly used ASM is levetiracetam. Ultimately, gross total resection of the tumor if feasible is often favored for both diagnostic and therapeutic benefits, as well as seizure control.