A Patient with Encephalopathy Following Coil Embolization of Cerebral Aneurysm and Extracranial Stent Placement

Objective: We report a patient in whom encephalopathy developed after coil embolization of an unruptured basilar artery aneurysm and stent placement for vertebral artery stenosis. Case Presentation: A 69-year-old female. When the unruptured basilar artery aneurysm was treated with coil embolization, a balloon-expandable stent was placed for left vertebral artery stenosis, and treatment was completed without complication. Loss of appetite and lightheadedness developed from 2 weeks after discharge, and multiple FLAIR highintensity areas, and nodular contrast enhancement in the left vertebral artery territory were observed on MRI. Steroid pulse therapy was performed suspecting metal allergy and foreign body granuloma, and symptoms improved. Conclusion: Encephalopathy associated with foreign body granuloma and metal allergy may be caused by coil and stent placement. Patients should be sufficiently interviewed, and when allergies are suspected, reconsideration of the treatment method may be necessary in advance.