To showcase a rare condition with potential for significant disability if not identified in a timely manner.  

Spinal dural arteriovenous fistulas account for 80% of spinal vascular malformations with an incidence of 5-10 cases per million.  The abnormal vascular connection results in venous engorgement and spinal cord infarction.  This condition, predominantly affecting men in their sixties, is often misdiagnosed as degenerative disk disease, transverse myelitis, and Guillain-Barre Syndrome amongst others.  On average, diagnosis is delayed by 1-3 years after symptom onset. 

Case report

A 68-year-old, trans woman developed radicular pain with bilateral, lower-extremity paresthesia.  Within 2.5 months, she also developed 2/5 weakness of her legs, urinary incontinence, and fecal incontinence.  Initial T-spine MRI demonstrated spinal cord edema from T7-T11, with disc herniations at T7-T8 and T8-T9.  Additional neuroimaging and CSF analysis were normal.  She was started on IV methylprednisolone, with some symptomatic improvement.  Ten months after symptom onset, she underwent a spinal angiogram.  Tortuous spinal branches without a discreet nidus or fistulous connection were found.  These results were atypical for a spinal vascular malformation.  Repeat T-spine MRI noted persistent edema.  One year after symptom onset, she underwent a laminectomy and exploration for possible biopsy of the lesion.  During dissection, the dural arteriovenous fistula was exposed and embolized.  Subsequent MRI demonstrated an improvement of spinal cord edema.  After two years, the patient has noted slow improvement of her weakness and paresthesia.  She continues to be wheelchair bound.

Delayed diagnosis of spinal dural arteriovenous fistulas results in extensive myelopathy and irreversible symptoms, despite treatment.  In this case, clinical improvement with use of IV methylprednisolone and a nondiagnostic catheter angiogram posed a conundrum for the specialists involved.  Though rare, spinal dural arteriovenous fistulas should be considered in patients with spinal cord edema and nonspecific symptoms.