A sinister cause of nausea and vomiting

A 30-year-old intellectually challenged woman with recent travel history to Texas presented with intractable nausea and nonprojectile vomiting for 3 weeks. She had diffuse abdominal pain with no change in her bowel movements. Her family noted that she had recently become more withdrawn. On presentation, she was afebrile with a normal abdominal exam. Physical examination was remarkable for subtle bilateral end-gaze nystagmus. An extensive workup at an outside hospital over 2 weeks included upper endoscopy with small bowel follow-through, pelvic sonogram, and a head computed tomography (CT), all of which were reportedly unremarkable. No outside films were accessible at the time. At our facility, laboratory examination was obtained that ruled out an infectious etiology. Abdominal CT showed no gastrointestinal or hepatobiliary abnormalities. Because of reported personality changes and nystagmus on physical exam, magnetic resonance imaging (MRI) of the head was obtained to rule out cerebellar or vestibular pathology.