A 44-year-old man presented with 5 months of history of positional headaches, fatigue, decreased hearing, and occasional nausea and dizziness. He noted having to lie down for about 30 minutes to obtain relief when the headaches were severe. His physical and neurologic examination had normal results.
Contrast-enhanced magnetic resonance imaging (MRI) of the brain showed characteristic imaging findings of spontaneous intracranial hypotension (SIH) (Figure 1), including brain sagging and mild lateral ventricular hydrocephalus attributable to partial obstruction at the level of the cerebral aqueduct from downward descent of the third ventricle. A total spine MRI and a conventional computed tomography (CT) myelogram did not reveal a site of cerebrospinal fluid (CSF) leak. His CSF opening pressure was 11 cm H2O. He underwent a nontargeted, large-volume, CT-guided epidural blood patch, which resulted in partial headache improvement for 3 weeks. When symptoms recurred, he underwent a dynamic decubitus CT myelogram, which demonstrated the precise site and causative mechanism of his CSF leak: a CSF-venous fistula on the left side at the T10-T11 level (Figure 2).