A 75-year-old man was referred for evaluation of treatment-resistant transverse myelitis. His medical history included hypertension, coronary artery disease, benign prostatic hyperplasia, and chronic kidney disease. Eight years earlier, the patient noted development of radiating pain down the left lower extremity during long drives, lower extremity weakness and pain, on the left greater than right. He received epidural lumbar corticosteroid injections. Nine months before the current evaluation, his symptoms became refractory, and he underwent surgical decompression with laminectomy at L3-L5. This provided substantial relief for the lower extremity pain. Review of outside magnetic resonance imaging indicated multilevel lumbar stenosis before his surgery and possible, faint, T2-hyperintense cord signal extending into the conus. At the time his symptoms worsened, magnetic resonance imaging of the thoracic spine showed longitudinally extensive T2 hyperintensity extending from the thoracic cord into the conus without contrast enhancement. Evaluation in our department included cerebrospinal fluid analysis, which showed an increased protein concentration of 92 mg/dL, 1 total nucleated cell/µL, normal immunoglobulin G index, and no supernumerary oligoclonal bands. Magnetic resonance angiography of the spinal canal showed mild prominence of vascularity at T10-T12 but no clear spinal dural arteriovenous fistula. However, given the strong suspicion for spinal dural arteriovenous fistula in an older man with progressive myelopathy worsening with corticosteroids, longitudinally extensive lesion extending into the conus, and no evidence of inflammation, spinal digital subtraction angiography was performed. The spinal digital subtraction angiography confirmed the diagnosis of left spinal dural arteriovenous fistula at T11. A T11-12 laminectomy and ligation of the spinal dural arteriovenous fistula was successfully performed without complication. The patient followed up with his local providers for rehabilitation. Spinal dural arteriovenous fistula is the most common spinal arteriovenous malformation, arising from an acquired abnormal connection between a radicular artery and radiculomedullary vein. Progressive congestion and cord edema lead to neurologic deficits over time. Cases are commonly seen in older men with a history of back surgery or trauma. A delay in diagnosis of 1 to 3 years is common.
Serious myelopathy due to magnetic resonance imaging-occult arteriovenous fistula: Case report of petrous ridge dural arteriovenous fistula
