A Case of Vertebral Dissecting Aneurysm Presenting as Occipitalgia Initially and Subarachnoid Hemorrhage Secondarily

A 56-year-old woman presented with a sudden occipitalgia that occurred while swimming. No obvious abnormality was detected on the first CT scan. Thirty-five hours after the onset of occipitalgia, a second CT scan demonstrated a diffuse subarachnoid hemorrhage. Cerebral angiography revealed a pearl string sign on the left vertebral artery, suggesting a dissecting aneurysm. Proximal clipping of the left vertebral artery was successfully performed. The relationship between occipitalgia and the subsequent subarachnoid hemorrhage is discussed.