Background and Objectives Spontaneous intracranial hypotension is a postural headache syndrome unrelated to dural puncture. Due to the apparent failure of epidural blood patch to relieve headache in spontaneous intracranial hypotension, we investigated the epidemiologic features and treatment outcomes of this condition.

Methods The clinical findings and management of 22 cases (21 published + 1 reported) of spontaneous intracranial hypotension were analyzed retrospectively. The study population was stratified by age and sex; continuous variables were compared for differences by t-tests; categorical variables were compared by Fisher exact tests. Significant differences were identified by P values of .05 or less.

Results The mean age of the study population was 43 [plusmn] 16 years, with a female:male ratio of 3.4:1.0. Females with spontaneous intracranial hypotension were younger (P = .050) than males. Men presented with tinnitus (P = .021) and visual field defects (P = .009) more often than women. Meningeal enhancement on contrast magnetic resonance imaging was the most consistent radiographic finding. Radionuclide cisternography showed thoracolumbar dural leaks in 7 of 9 patients. Cerebrospinal fluid opening pressure was low in all patients (33.13 [plusmn] 31.02 mm H₂O). Epidural blood patch was performed in 8 patients, repeated in 3 patients, failed in 3 patients, and offered only transient improvement in 5 patients.

Conclusions Spontaneous intracranial hypotension was more common in women than men, was not uniformly responsive to epidural blood patch, and had significant comorbidities. The management of postural headache in spontaneous intracranial hypotension by other techniques to restore cerebrospinal fluid dynamics and prevent its leakage should be investigated.