Atypical presentations and long-term sequelae of spontaneous intracranial hypotension: illustrative cases

BACKGROUND: Spontaneous intracranial hypotension (SIH) is typically recognized by orthostatic headache and characteristic neuroimaging findings such as brain sagging and dural enhancement, but atypical manifestations and long-term sequelae remain underreported. OBSERVATIONS: The authors present 5 cases that illustrate uncommon SIH presentations and complications, including reversible cerebral vasoconstriction syndrome, sinus vein thrombosis, ventral spinal cord herniation, thoracic meningocele, secondary Arnold-Chiari malformation type I, and superficial siderosis. LESSONS: SIH may present with diverse complications beyond orthostatic headache; awareness and follow-up imaging are important for timely diagnosis and management. https://thejns.org/doi/10.3171/CASE26236.