Seizures and epilepsy in cancer: etiologies, evaluation, and management

Seizure and epilepsy are common neurologic issues in cancer patients. Etiologies include structural abnormalities of the brain (eg, brain metastasis), cerebrovascular disease, reversible posterior leukoencephalopathy syndrome (RPLS), and radiation toxicity. Seizures associated with these etiologies often have focal features. Metabolic causes include hypoglycemia, electrolyte abnormalities, tumor lysis syndrome, thrombotic thrombocytopenic purpura (TTP), and medications used in cancer. A careful clinical evaluation can suggest the seizure etiology and guide subsequent work-up. Nonconvulsive status epilepticus should be suspected with persistent decreased level of consciousness following a seizure. Certain etiologies, such as RPLS and TTP, must be treated aggressively to minimize permanent neurologic injury. Routine prophylaxis with antiepileptic drugs (AEDs) is not recommended in patients with primary brain tumors or brain metastasis who have never had a seizure. Where indicated, the selection of AEDs should take into consideration side effects and interactions with chemotherapy. For this reason, non-enzyme-inducing AEDs are preferable in the cancer setting.