Frequency and characteristics of multi‐domain autonomic dysfunction in patients with spontaneous intracranial hypotension

OBJECTIVE: We aimed to evaluate multi-domain autonomic function in patients with spontaneous intracranial hypotension (SIH) and investigate its association with clinical and radiological features. BACKGROUND: SIH often presents with orthostatic symptoms that overlap with autonomic disorders; however, the prevalence and distribution of autonomic dysfunction in SIH remain poorly characterized. METHODS: In this cross-sectional study conducted at a tertiary care center in Seoul, Republic of Korea, 34 patients with imaging-confirmed SIH underwent a comprehensive autonomic function testing between October 2024 and February 2025. The autonomic function testing battery included heart rate response to deep breathing, Valsalva maneuver, head-up tilt test, and quantitative sudomotor axon reflex test. Hemodynamic responses during head-up tilt were monitored using both intermittent brachial and continuous beat-to-beat blood pressure measurements. Autonomic abnormalities were determined using age- and sex-matched Korean normative data. RESULTS: All enrolled patients presented with extradural fluid collection on spinal magnetic resonance imaging, indicating SIH due to dural tears. Autonomic dysfunction was identified in 18 of 34 (52.9%) of patients in the orthostatic domain, nine of 34 (26.5%) in the cardiovagal domain, and 10 of 34 (29.4%) in the sudomotor domain. Postural orthostatic tachycardia syndrome was the most frequent orthostatic abnormality, observed in 12 of 34 (35.3%) patients, followed by classical orthostatic hypotension in four of 34 (11.8%), syncope in one of 34 (2.9%), and delayed orthostatic hypotension in one of 34 (2.9%). No significant associations were identified between domains of autonomic dysfunction and the clinical or imaging features of SIH in false discovery rate-corrected analyses. CONCLUSION: In patients with SIH due to dural tears, orthostatic hemodynamic abnormalities were common, with postural orthostatic tachycardia syndrome being the most frequent phenotype.