Periodic lateralized epileptiform discharges: an initial electrographic pattern in reversible posterior leukoencephalopathy syndrome.

Reversible posterior leukoencephalopathy (RPLE) is a unique clinicoradiological entity characterized by diverse neurological symptoms with bilateral posterior cerebral white matter edema. It is frequently associated with seizures but rarely with status epilepticus. Periodic lateralized epileptiform discharges (PLEDs) as an initial electrographic pattern in a patient with RPLE have never been reported. We discuss a 47-year-old woman with a newly diagnosed non-small cell carcinoma of the lung on etoposide who was admitted with encephalopathy. Initial EEG demonstrated PLEDs. She later developed nonconvulsive status epilepticus. Magnetic resonance imaging (MRI) revealed bilateral subcortical edema predominantly of the temporo-occipital lobes. Discontinuation of etoposide resulted in full clinical, electrical recovery within 10 days and significant radiological improvement within 15 days. Our case indicates the importance of identifying and addressing any modifiable etiologic factors of RPLE. We emphasize identification of the unique initial electrographic pattern of PLEDs, which may be a predisposing factor to status epilepticus or an indication of structural damage.