An aneurysm is an abnormal bulging of small sections of arteries, which increases the risk of artery rupture. Intracranial aneurysms are a leading cause of subarachnoid hemorrhage, or bleeding around the brain within the subarachnoid space. There are various hereditary disorders associated with intracranial aneurysms, such as Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, and familial hyperaldosteronism type I. However, individuals without these disorders may also obtain aneurysms. The American Heart Association and American Stroke Association recommend controlling modifiable risk factors including smoking and hypertension.