A thyroid storm causing strokes and unmasking moyamoya

Moyamoya disease is a rare progressive cerebrovascular condition that affects the internal carotid arteries and their major branches. This leads to the formation of a networks of collateral moyamoya vessels and can cause ischemic or hemorrhagic complications. Moyamoya syndrome is a secondary condition that presents with moyamoya vessels and is associated with other underlying causes including Down syndrome, sickle cell anemia, intracranial atherosclerosis or thyroid disease. In this case report, we discuss a 29-year-old female with Grave's disease who presented with recurrent headaches, acute intermittent numbness and paresthesia. Radiologic evaluation showed multifocal intracranial infarcts and stenosis of the bilateral internal carotid arteries and decreased caliber of the distal anterior circulation. This case highlights the importance of considering MMD/MMS as a differential diagnosis in patients suffering from headaches and/or seizures, especially in the third or fourth decades of life. Prompt diagnosis and management leads to favorable outcomes in patients with moyamoya.