Intracranial hypotension is an uncommon phenomenon that can be iatrogenic, secondary to trauma, or spontaneous (commonly in the setting of CSF leak or dural tear). One increasingly recognized cause of spontaneous intracranial hypotension (SIH) is a CSF-Venous fistula, where CSF is typically shunted into an adjacent paraspinal vein. We present an unusual case of persistent postural headache caused by thoraco-lumbar CSF-venous fistula confirmed on imaging.

A 43-year-old woman presented with paresthesias, presyncope, and daily orthostatic headaches. Neurological examination was normal and initial work up with brain/spinal MRI, spinal MRA, EEG, and lumbar puncture was unremarkable. A CT myelogram performed after dynamic fluoroscopic myelogram demonstrated a small curvilinear opacity in the right L1-L2 neural foramen directly contiguous with the thecal sac. Contrast was also seen in the renal collecting systems, confirming CSF-venous fistula. She underwent CT-targeted fibrin sealant injection of the fistula, followed by temporary resolution of symptoms for 6 months. Symptomatic return warranted further myelographic workup, followed by epidural venous plexus embolization using liquid embolic agents. On follow up, the patient reported complete resolution of symptoms and return to her baseline.

CSF-Venous fistulas are an exceptionally rare but established cause of SIH, described as recently as 2014. Clinical and radiologic diagnosis of this pathology proves challenging, requiring a systematic and patient approach for success. We hope to highlight this entity and encourage neurologists to maintain a high index of suspicion when investigating intracranial hypotension, especially when clinical picture and history is consistent despite negative initial work up.