Reversible cerebral vasoconstriction syndrome: the importance of follow‐up imaging within 2 weeks

AIM: In patients with thunderclap headaches, reversible cerebral vasoconstriction syndrome (RCVS) should be considered as a differential diagnosis. However, RCVS diagnosis in the emergency department (ED) remains challenging. This report describes the clinical features and factors related to RCVS diagnosis and suggests diagnostic strategies for its management. METHODS: We retrospectively reviewed the medical records of eight patients diagnosed with RCVS from January 2010 to March 2019 (aged 18–69 years, 5 women). RESULTS: The median duration from the ED visit to RCVS diagnosis was 6 days (range, 1–11 days). Of the eight patients, seven were middle‐aged, six had apparent triggers, six had subarachnoid hemorrhage (SAH), five had high systolic blood pressure, and none had any specific abnormality observed upon physical examination. At the initial visit, RCVS was diagnosed in only one patient who had a history of RCVS. Of the other patients, SAH was diagnosed in two, and primary headache was diagnosed in four patients with negative computed tomography (CT) findings. Based on follow‐up angiography (e.g., magnetic resonance angiography), seven of eight patients with convexal SAH were diagnosed with RCVS (as the cause of SAH). CONCLUSION: Reversible cerebral vasoconstriction syndrome with negative CT findings at the ED visit was likely to be misdiagnosed as a primary headache. In patients with thunderclap headache and negative CT findings, physicians should consider RCVS as a differential diagnosis, inform patients of the risk of RCVS, and undertake follow‐up imaging within 2 weeks.