Rapid Cognitive Decline Secondary to CSF Venous Fistula With Postoperative Rebound Intracranial Hypertension and a Hyperintense Paraspinal Vein Sign Seen Retrospectively

A 56-year-old female with 2 prior Chiari decompressions presented with rapidly progressive cognitive decline. Brain magnetic resonance imaging, computed tomography myelogram, and prone digital subtraction myelography revealed signs of brain sag and left T9 perineural cysts but no cerebrospinal fluid leaks. Symptoms improved after multilevel blood patches but recurred. Lateral decubitus digital subtraction myelography revealed a spinal cerebrospinal fluid venous fistula (SCVF), which resolved after neurosurgeons ligated the nerve root. Rebound headaches with papilledema occurred on postoperative day 9 and then resolved 2 months after acetazolamide was started. A hyperintense paraspinal vein was seen retrospectively on T2-weighted magnetic resonance imaging with Dixon fat suppression sequencing. This case is unique in the acuity of cognitive decline secondary to SCVF. Acetazolamide at the time of treatment may potentially be used as prophylaxis for rebound intracranial hypertension. The hyperintense paraspinal vein may have utility in future diagnosis of SCVF.