A healthy 17-year-old boy with a high-functioning pervasive developmental disorder presented to the emergency department after having a 4-minute episode of seizure-like activity in the setting of presumed viral gastroenteritis. Within an hour of emergency department arrival, he developed a forehead-sparing facial droop, right-sided ptosis, and expressive aphasia, prompting stroke team assessment and urgent neuroimaging. Laboratory results later revealed a serum sodium of 119 mmol/L. Neurologic deficits self-resolved, and a full physical examination revealed diffuse abdominal tenderness in the lower abdomen with rebound tenderness in the right-lower quadrant. The patient was admitted to the PICU for electrolyte management and monitoring. A computed tomography (CT) scan of the abdomen obtained the following morning revealed the patient’s final diagnosis.