The patient with Marfan’s syndrome is at an increased risk for cerebral aneurysms. Projectile vomiting in this patient indicates a ruptured cerebral aneurysm, which is a life-threatening medical emergency. The patient will exsanguinate and experience irreparable brain damage without immediate treatment. The 4-day-old with abdominal distention and bilious emesis may have a bowel obstruction; this patient should be seen quickly. The elderly patient with increasing confusion and adequate oxygen saturation may have a urinary tract infection. This is not a medical emergency. The college student with an upper respiratory infection and nuchal rigidity likely has meningitis. This patient should be seen quickly and removed from the crowded ER, but this is less urgent than the patient with projectile vomiting indicative of increased intracranial pressure.