Characterization of thunderclap headache in a reversible cerebral vasoconstriction syndrome case series

To empirically address how thunderclap headache (TCH) is described in a relevant real-world setting.

TCH refers to a highly recognizable description of a severe headache that reaches maximum severity within 1 minute and endures for at least 5 minutes. The use of a numerical rating scale (NRS) to appraise TCH severity, as well as assessment of TCH progression in patients with pre-existing headache at the time of TCH onset has not been previously evaluated.

This was a retrospective case series of adults with a diagnosis of reversible cerebral vasoconstriction syndrome (RCVS), identified through a search of the electronic health record. Individuals meeting International Classification of Headache Disorders, 3rd Edition criteria for acute headache attributed to RCVS were included. Attacks described using a verbal descriptor scale (VDS), NRS, or both were recorded to evaluate acute headache characteristics.

In all, 56 individuals with available descriptions of 120 acute headaches were included in the study analysis. Patients were female (35, 62.5%) with a median age of 46 (range: 19-67). The majority of patients reported a RCVS trigger (39, 69.6%). Acute headaches were characterized using a VDS (52, 43.3%), NRS (51, 42.5%), or both (17, 14.1%). Acute headaches were always described as severe when a VDS was utilized, and with a median NRS of 10 (range: 4-10). Four patients (7%) did not have a single headache characterized as either severe or with a NRS 8 or greater. In the 10 cases for which there was a pre-TCH baseline headache, it was either rated as mild or with a median NRS of 3 (range: 2-6).

TCH in RCVS can be recognized using either VDS or NRS, with a broader range of peak intensities than previously recognized. TCH remains recognizable despite pre-existing baseline headache.