Background: Reversible Cerebral Vasoconstriction Syndrome (RCVS) may present as thunderclap headache (TCH), accompanied by reversible cerebral vasospasm and focal neurological deficits, often without a clear precipitant. RCVS may be mistaken for Primary Angiitis of the Central Nervous System (PACNS) due to the presence of similar angiographic features of segmental narrowing of cerebral arteries. We discuss the clinical features of a young female migraine patient who developed TCH and was found to have RCVS following initial treatment with corticosteroids for PACNS, in the context of a systematic review of the available medical literature.
Methods: A Medline search was performed to identify all case reports since 1966 describing RCVS and PACNS that provide sufficient clinical detail to permit diagnostic classification according to published criteria. RCVS included case studies in which there was angiographic or transcranial Doppler ultrasound evidence of near-to-complete resolution of cerebral vasoconstriction in the absence of a well-recognized secondary cause. PACNS included reports of histologically confirmed PACNS either through biopsy or necropsy.
Results: Reversible Cerebral Vasoconstriction Syndrome occurs primarily in females and is characterized by sudden, severe headache at onset, normal CSF analysis, vasoconstriction involving the Circle of Willis and its immediate branches, and angiographic or TCD ultrasound evidence of near-to-complete vasospastic resolution within 1-4 weeks. It occurs typically in the context of vasoconstrictive drug use, the peripartum period, bathing, and physical exertion.
Conclusion: Initial and follow-up (within 4 weeks) non-invasive angiographic studies are indicated in patients who present with TCH or who have clinical presentations that could be consistent with RCVS or PACNS in the absence of a well-recognized secondary cause, such as subarachnoid haemorrhage. Early reversibility of cerebral vasospasm is the key neuroradiological feature that supports the clinical diagnosis of RCVS.