Abstract Number ‐ 221: Lower Thoracic Spinal Dural Arteriovenous Fistula Presenting With Progressive Paraplegia: A Case Report

Abstract

Introduction We present a 72‐year‐old male with osteoarthritis, lumbar stenosis, coronary artery disease with a 4‐vessel bypass graft in February 2020, hypertension, hyperlipidemia, and obesity who presented with subacute progressive lower extremity weakness. He began having lower back pain following his cardiac surgery in February 2020. He was evaluated by a rehabilitation doctor in September 2020 who diagnosed him with lumbar radiculopathy and treated him with one round of steroid injections that helped a bit. Six months later he returned for follow‐up with the aid of a wheelchair which he started using in the last two weeks due to progressive lower extremity weakness. He was sent to the ED for neurologic evaluation. He denied radicular pain, saddle anesthesia, and urinary or bowel incontinence. Methods On neurologic exam, he had 2/5 bilateral hip flexion strength, 4/5 bilateral distal lower extremity strength, intact sensation to all modalities, and diffuse bilateral hyporeflexia (1+) with flexor plantar responses. An MRI brain was unremarkable. An MRI cervical, thoracic and lumbar spine with contrast showed extensive confluent cord edema with enhancement from T9 to the conus medullaris. He was started on high‐dose IV methylprednisolone for concern of transverse myelitis. Serum metabolic, hematologic, autoimmune, and infectious workup were negative. Due to a lack of improvement, his spinal imaging was reviewed with neuroradiology who recognized previously unidentified posterior T2 flow voids in the subarachnoid space at T1. A spinal angiogram for suspicion of a spinal dural arteriovenous fistula (dAVF) was subsequently scheduled. Results Angiography confirmed a type I spinal dAVF which was treated with posterior laminectomy and surgical ligation. The patient’s lower extremity strength improved and he was discharged to acute rehab. At his 1‐month neurology follow‐up appointment, he was ambulating with minimal assistance from a cane with near full lower extremity strength. Conclusions With an initial presentation of subacute progressive lower extremity weakness and imaging findings concerning for longitudinally extensive transverse myelitis, our initial suspicion was highest for an underlying autoimmune or infectious disease. However, this case teaches us to not presume all transverse myelitis or enhancing spinal cord lesions must be from an inflammatory, neoplastic, or infectious condition. A wide differential for this presentation including spinal dAVF is necessary as this is one of the most commonly missed neurovascular diagnoses. T2 flow voids are highly suggestive of this condition, but a spinal angiogram is the gold standard for diagnosis.