Type of headache at onset and risk for complications in reversible cerebral vasoconstriction syndrome

Background In a recent Italian study, 30% of patients with reversible cerebral vasoconstriction syndrome (RCVS) presented without thunderclap headache (TCH), and tended to present more severe forms of RCVS than patients with TCH. We aimed to analyze the risk for complications of RCVS in patients with and without TCH at onset. Methods In a pooled cohort of 345 French patients with RCVS, we compared patients with and without TCH at onset regarding rates of neurological complications, and the functional outcome at 3 months. Results As compared to the 281 patients with TCH at onset, the 64 patients without TCH had a higher risk for any neurological complication (61% vs. 24%, OR 4.9, 95% CI 2.8-8.7, p < 0.001). The association was strongest for cervical artery dissections (28% vs. 5%, OR 8.1, 95% CI 3.7-17.6, p < 0.001), followed by posterior reversible encephalopathy syndrome (17% vs. 3%, OR 7.1, 95% CI 2.7-18.4, p < 0.001), seizures (9% vs. 2.5%, OR 4.1, 95% CI 1.3-12.5, p = 0.019), and subarachnoid hemorrhage (41% vs. 16%, OR 3.5, 95% CI 1.9-6.3, p < 0.001). In multivariable analysis, the risk for any neurological complication remained significantly elevated in the absence of TCH (OR 3.5, 95% CI 1.8-6.8, p < 0.001). The functional outcome was equal in both groups, with a modified Rankin scale score of 0-1 in >= 90% of patients. Conclusions Absence of TCH at onset might predict a higher risk of complications in RCVS. Our results warrant further multicentric studies to prove this finding.

Automated summary

Patients with reversible cerebral vasoconstriction syndrome (RCVS) who do not present with thunderclap headache (TCH) at onset have a higher risk for neurological complications, including cervical artery dissections, posterior reversible encephalopathy syndrome, seizures, and subarachnoid hemorrhage, compared to those with TCH. However, the functional outcome at 3 months is similar in both groups, with most patients having a good prognosis. Further multicentric studies are needed to confirm these findings.