Reversible cerebral vasoconstriction syndrome in psychiatric settings: Context‐dependent diagnostic bias and consultation‐liaison psychiatry practice

Background: Reversible cerebral vasoconstriction syndrome (RCVS) is a potentially life-threatening neurological condition characterized by thunderclap headaches and multifocal cerebral arterial vasoconstriction resolving within 3 months. Context-dependent diagnostic bias in psychiatric settings may delay recognition of life-threatening conditions including RCVS. Case Presentation: A 52-year-old Japanese woman with bipolar II disorder stable on lithium developed recurrent thunderclap headaches 9 days after mild COVID-19 infection. Headaches were consistently triggered by hot showers, reached maximal intensity within seconds, and were described as the worst headache of her life. Initial neurosurgical evaluation included non-contrast head CT but attributed symptoms to tension-type headache without vascular imaging. The patient, dissatisfied with this explanation, sought re-evaluation through our psychiatry outpatient clinic. Psychiatric consultation identified characteristic RCVS features, prompting urgent referral to a headache specialist. Magnetic resonance angiography on Day 31 revealed multifocal segmental vasoconstriction confirming RCVS. Calcium channel blocker treatment led to complete symptom resolution with radiological resolution confirmed at Day 100. Conclusion: This case illustrates how context-dependent diagnostic bias can dangerously delay RCVS recognition in psychiatric settings. Thunderclap headache warrants immediate neuroimaging regardless of psychiatric comorbidity. Psychiatric consultation enabled appropriate diagnosis through collaborative evaluation with specialist neurology, underscoring the essential role of consultation-liaison psychiatry at the medical-psychiatric interface.