Update on spontaneous intracranial hypotension

Abstract

Background Spontaneous intracranial hypotension (SIH) is a secondary headache disorder caused by spontaneous cerebrospinal fluid (CSF) leakage, typically from dural tears, meningeal diverticula, or CSF venous fistulas, in the absence of preceding trauma or procedures. Although increasingly recognized, SIH remains underdiagnosed and frequently mistaken for primary headache syndromes.

Methods This narrative review synthesizes current evidence on the epidemiology, pathophysiology, clinical manifestations, neuroimaging features, complications, and management of SIH. Recent literature and expert consensus were analyzed to integrate advances in imaging-based diagnosis and leak type specific therapeutic strategies.

Results SIH arises from low CSF volume rather than true hypotension, leading to brain descent, venous engorgement, and the characteristic MRI features summarized by the SEEPS mnemonic: subdural collections, pachymeningeal enhancement, venous engorgement, pituitary enlargement, and brain sagging. Orthostatic headache is the hallmark symptom, though up to 15% of patients lack clear positional features. Associated symptoms include vestibulocochlear disturbances, neck or interscapular pain, cranial nerve palsies, and cognitive or motor dysfunction. Brain and whole spine MRI are first line diagnostic tools. MR myelography distinguishes SLEC positive (types 1 and 2) from SLEC negative (type 3) leaks, guiding targeted myelography with dynamic CT or digital subtraction techniques for leak localization. Treatment should be tailored to leak type and site: epidural blood or fibrin patching for dural and diverticular leaks, and transvenous embolization for CSF venous fistulas. Surgical repair is reserved for refractory or anatomically complex cases. Reported complications include subdural hematoma, cerebral venous thrombosis, superficial siderosis, and bibrachial amyotrophy.

Conclusions SIH represents a heterogeneous spinal disorder with intracranial manifestations. Early recognition, standardized imaging algorithms, and multidisciplinary management are crucial to improving outcomes. Ongoing research into imaging biomarkers, predictors of response, and consensus based care pathways will help advance precision medicine in SIH.