Headache attributed to a past spontaneous intracranial hypotension: a new diagnostic entity

Spontaneous intracranial hypotension (SIH) is attributed to spinal cerebrospinal fluid (CSF) leaks and typically presents with orthostatic headache. Although persistent headache has been reported in some patients after radiologic resolution of CSF leaks, longitudinal studies evaluating chronic headache following SIH are limited. This study aimed to characterize post-SIH headache after complete remission of spinal CSF leak. This prospective cohort study included patients with imaging-confirmed SIH who achieved radiologic remission between March 2022 and July 2025. Remission was defined as the complete disappearance of spinal longitudinal epidural fluid collection on follow-up spine MRI and resolution of SIH-related brain MRI abnormalities. The remission date was defined as the date of the treatment that resulted in radiologic resolution. Headache status, phenotype, and monthly headache days were assessed at 1, 3, 6, 9, and 12 months post-remission. Headache frequency was classified as episodic (< 15 days/month), chronic (≥ 15 days/month), or headache-free at each follow-up visit. Logistic regression analyses were performed to identify risk factors for chronic post-SIH headache at 3 months. A total of 58 patients (median age, 38.5 years; 67.2% female) were included, with a median follow-up duration of 178.5 days (IQR 136.5–263.0 days) after remission. Post-SIH headache was reported in 72.4%, 72.0%, 70.8%, 64.3%, and 56.0% of patients at 1, 3, 6, 9, and 12 months post-remission, respectively. Post-SIH headache phenotypes were tension-type headache-like (61.0%), migraine-like (23.7%), and stabbing phenotype (15.3%). Chronic post-SIH headache was observed in 56.9%, 40.0%, 35.4%, 32.1%, and 20.0% of patients across follow-up time points, demonstrating a gradual decline. Orthostatic headache also decreased over time, occurring in 52.4%, 25.0%, 20.6%, 16.7%, and 14.3% of patients at each respective time point. Membership in the longest disease-duration tertile (350‒4321 days; adjusted OR 9.159; 95% CI 1.357–61.831; p = 0.023) and premorbid migraine (adjusted OR, 6.862; 95% CI, 1.201–39.205; p = 0.030) were independently associated with chronic post-SIH headache at 3 months. Post-SIH headache remains common despite successful radiologic resolution of spinal CSF leaks. These findings suggest that post-SIH headache may represent a distinct clinical entity characterized by high prevalence and a substantial risk of chronicity.