Spinal Glomus Arteriovenous Malformation Manifesting with a Subarachnoid Hemorrhage

Background Spinal arteriovenous malformations (AVMs) are rare lesions that may cause serious neurologic morbidity. With developments in endovascular technology and embolic materials, endovascular management of spinal AVMs has gained popularity. Case Description A 61-year-old woman presented with the worst headache of her life and an acute onset of nausea and vomiting and was shown to have a grade 2 subarachnoid hemorrhage (SAH) on computed tomography scan. A 6-vessel cerebral angiogram was negative for any vascular abnormalities. Magnetic resonance imaging and magnetic resonance angiography of the neck showed a flow-related enhancement compatible with a vascular abnormality at the level of C2. Cervical spinal angiography showed a cervical spinal cord glomus (type II) AVM at the level of C2 draining into perimedullary venous plexus. Transarterial Onyx embolization was performed and resulted in complete occlusion of the AVM. The patient made a complete neurologic recovery. Conclusions Spinal AVMs manifesting as intracranial SAH are uncommon. These lesions are frequently overlooked on cerebral angiography and account for a small proportion of angiogram-negative SAHs. A negative angiogram in the setting of SAH should prompt a comprehensive evaluation of the cervical segmental arterial supply to exclude a cervical spinal AVM. Endovascular embolization may be effective in treating spinal glomus AVMs with good clinical outcomes and with complete angiographic obliteration. Onyx embolic agent should be considered as the agent of choice to manage spinal glomus AVMs.