A brain aneurysm is an abnormal widening or ballooning of a section of a blood vessel in the brain. It may be present from birth or it may develop later in life. They can occur in any blood vessel that supplies the brain and are caused by injuries to the blood vessel wall.
Aneurysms usually cause no symptoms unless they rupture and cause bleeding into the brain; then the symptoms are severe, ranging from sudden, severe headaches with nausea or vomiting to speech impairment and vision changes. A ruptured cerebral aneurysm is an emergency condition. Genetic factors play a recognized but not yet fully known role. About one in every 10 patients with a subarachnoid hemorrhage has a family history of intracranial aneurysms, and those who have a family history are usually younger at the time of diagnosis and more commonly have multiple and large aneurysms.
Other risk factors are anomalous vessels, alcohol abuse, smoking, and high blood pressure. Ruptured cerebral aneurysms are often deadly. Neurosurgery is the main treatment for cerebral aneurysm.