A Case of Cyclic Vomiting Syndrome-Induced Hypertension Causing Posterior Reversible Encephalopathy Syndrome.

Cyclic vomiting syndrome (CVS) is characterized by repeated episodes of vomiting in a stereotyped pattern and is a known cause of hypertension. Our patient is a 10-year-old female who presented with nonbilious, nonbloody vomiting, and constipation concerning for a flare of her known CVS. During the hospital course, she developed intermittent severe hypertensive episodes, leading to an acute episode of altered mental status and a tonic-clonic seizure. Magnetic resonance imaging confirmed diagnosis of posterior reversible encephalopathy syndrome (PRES) after eliminating other organic etiologies. This is one of the first documented cases of CVS-induced hypertension causing PRES.