title: Reversible cerebral vasoconstriction syndrome at the emergency department.
abstract: OBJECTIVE
  Reversible cerebral vasoconstriction syndrome (RCVS) is an underestimated cause of thunderclap headache that shares many characteristics with subarachnoid hemorrhage (SAH). This fact makes the two easily confused by emergency physicians. This study evaluated the clinical manifestations, radiological features, and outcomes of patients with RCVS.
  
  
  METHODS
  The electronic medical records of 18 patients meeting the diagnostic criteria of RCVS at our emergency department between January 2013 and December 2014 were retrospectively reviewed.
  
  
  RESULTS
  The mean patient age was 50.7 years, and 80% were women. Patients with RCVS encountered physicians 4.7 times before receiving an accurate diagnosis. The mean duration of symptoms until diagnosis was 9.3 days. All but one patient experienced severe headache of 8 to 10 on a numerical rating scale. A total of 44% of patients had nausea, and 66% of patients experienced worsening of the headache while gagging, leaning forward, defecating, urinating, or having sexual intercourse. The most frequently affected vessels were the middle cerebral arteries, which demonstrated a characteristic diffuse "string of beads" appearance. Four cases were complicated by SAH.
  
  
  CONCLUSIONS
  Patients with RCVS have a unique set of clinical and imaging features. Emergency physicians should have a high index of suspicion for this clinical entity to improve its rate of detection in patients with thunderclap headache when there is no evidence of aneurysmal SAH.
authors.affiliation: Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
authors.forename: Taerim
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
authors.forename: Shin
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Sohn
authors.affiliation: Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Seo
authors.affiliation: Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
authors.forename: Won Young
authors.initials: WY
authors.lastname: Kim
keywords: Emergency service, hospital; Headache disorders, primary; Subarachnoid hemorrhage