History: Patient is a 58 year old male with 2 week history of progressive pain in the feet. He has received multiple injections in his feet for heel spurs. The night prior to admission, he noted weakness in his legs and this morning he noted an inability to walk or urinate. Neurological exam demonstrates significant lower extremity weakness and increased deep tendon reflexes. Neurologist initial impression is acute paraplegia most likely due to lumbar/conus tumor or atypical Guillain-Barre syndrome.
Radiology: A stat Thoracic and Lumbar Spine MRI with and without contrast was performed. Image 1 is a midline T2 image demonstrating abnormal signal through the mid and lower spinal cord centrally. Posterior to the cord and to a lesser degree anterior to the cord are numerous hypointense foci. Image 2 is an axial T2 image of the thoracic cord demonstrating the central hyperintensity or edema within the cord with small hypointense foci along the periphery. Sagittal Stir Image3 better demonstrates the extensive abnormal cord signal and the hypointensities along the periphery of the cord. Image 4 is a Post Contrast T1 Fat Sat Sagittal Image demonstrating enhancement of the hypointense extramedullary foci.
Impression: Spinal Dural Arteriovenous Fistula (SDAVF) or Type 1 AVM
Discussion: The SDAVF is the most common spinal vascular malformation, resulting from an abnormal connection between the arterial and venous systems within a nerve sleeve. There is then drainage into the low pressure spinal pial veins. Ultimately, a high pressure venous system develops leading to stasis of blood, cord edema, and eventually infarction of the cord termed Subacute Necrotizing Myelopathy. Rarely, hemorrhage may occur. Clinically, most patients present within the 5-6th decade and males are more often affected then females as in this case. Symptoms of lower extremity weakness, sensory abnormalities, and nonradiationg pain occur slowly and progress superiorly from the feet. Treatment is usually via embolization by a neurointerventionalist although sometimes open surgery may be needed.
Case provided by Dr. Carl Raboi