Intracranial subarachnoid hemorrhage as part of spinal arteriovenous metameric syndrome.

Spinal Arteriovenous Metameric Syndrome is a rare and complex nonhereditary genetic vascular disorder, affecting multiple layers of tissues at the same metamere, including the spinal cord. We present a case of a 20-year-old man who presented to the emergency department with sudden headache and transient loss of consciousness. Cranial computed tomography scan revealed subarachnoid hemorrhage predominantly in the cerebellar cisterns, fourth ventricle, extending to the basal cisterns. Cerebral angiography showed no abnormalities. Cervical angiographic acquisitions demonstrated a spinal metameric arteriovenous malformation (AVM) at the C3 and C4 levels. Cervical magnetic resonance imaging also confirmed the metameric AVM, revealing both intradural intramedullary and extra-dural vascular lesions in the vertebrae and adjacent soft tissues. The patient was referred for endovascular treatment. Although quite rare, the association between cervical spinal arteriovenous shunt diseases and intracranial hemorrhage has been reported. The bleeding in this case may be attributed to venous reflux into intracranial veins.