Subarachnoid hemorrhage due to de novo dissecting vertebral artery aneurysm in a patient with Guillain‐Barré syndrome

A 51‐year‐old man with Guillain‐Barré syndrome developed a dissecting vertebral artery aneurysm. Initial magnetic resonance angiography showed no abnormality, including dissecting aneurysm of the bilateral vertebral arteries. He developed subarachnoid hemorrhage. Radiological examination revealed bilateral dissecting vertebral artery aneurysms. The left ruptured dissecting vertebral artery aneurysm was treated by stent‐assisted coil embolization with preservation of the affected vertebral artery. Although it is rare, there is a possibility that dissection of the intracranial artery might occur in a patient with Guillain‐Barré syndrome in a short period of time. The dissecting aneurysm might be formed by external force to the vertebral artery, and the aneurysm might subsequently rupture due to hypertension.