Reversible Cerebral Vasoconstriction Syndrome (RCVS) is characterized by the presence of segmental, multifocal and reversible vasoconstriction of intracranial arteries, with clinical presentation being recurrent thunderclap headaches. In patients with RCVS, angiographic studies may initially appear normal, posing a differential diagnosis challenge with clinically similar conditions.

We included hospitalized patients with suspected RCVS. Patients were divided into one group (1) with evidence of cerebral vasospasm and another group (2) without evidence of vasospasm. We analyzed and compared demographic, clinical, and post-hospitalization outcomes through a retrospective analysis of medical records and subsequent in-person and/or telephone follow-up. The Fisher exact test was used for categorical variables, and the Wilcoxon test for continuous variables. Differences were considered statistically significant at a p-value of 0.05.

We included 102 patients. 56 patients completed follow-up after their hospitalization. A trigger for the episodes was identified in 40 patients, with sexual activity being the most common. We found a significant association (p=0.042) between female gender and the presence of angiographic vasospasm. In the subgroup of patients with an identified trigger other than sexual intercourse or orgasm, we found a significant association (p=0.031) with the presence of vasospasm. We also found a significant association (p=0.043) with the presence of post-hospitalization headaches in the group without evidence of vasospasm.

In this study, female gender and a trigger history unrelated to sexual activity were associated with a higher risk of vasoconstriction in angiographic studies. 

 The absence of vasospasm in non-invasive studies during the initial evaluation of patients with recurrent thunderclap headaches would require, in addition to repeating studies or performing digital angiography, close follow-up aimed at identifying a primary headache.