What causes a cerebral aneurysm?
Charles E. Stout Jr., MD
Diagnostic Radiology
Genetic diseases and circulatory disorders are associated with a cerebral aneurysm. Charles Stout, MD, from Riverside Community Hospital touches on these and other possible causes in this video.
A cerebral or brain aneurysm is the result of thinning or weakening of artery walls. This degenerating in the vascular wall can result in a bulging or blood-filled sac. In rare cases, the aneurysm can rupture.

A person may inherit a propensity for aneurysms, or aneurysms may develop because of hardening of the arteries (atherosclerosis) and aging.

Risk factors include a family history of aneurysms, gender, race, hypertension (high blood pressure) and smoking.
In most cases, a cerebral aneurysm causes no or few symptoms. 
Piedmont Heart Institute
Cerebral aneurysms can be congenital, resulting from an inborn abnormality in an artery wall. They are more common in people with certain genetic diseases, such as connective tissue disorders, polycystic kidney disease, or circulatory disorders, such as arteriovenous malformations (snarled tangles of arteries and veins in the brain that disrupt blood flow).
Other causes include trauma or injury to the head, high blood pressure, infection, tumors, atherosclerosis (a blood vessel disease in which fats build up on the inside of artery walls) and other diseases of the vascular system, cigarette smoking, and drug abuse. Some investigators have speculated that oral contraceptives may increase the risk of aneurysms.
Aneurysms that result from an infection in the arterial wall are called mycotic aneurysms. Cancer-related aneurysms are often associated with primary or metastatic tumors of the head and neck. Drug abuse, particularly the habitual use of cocaine, can inflame blood vessels and lead to the development of aneurysms in the brain.
This answer from the National Institute of Neurological Disorders and Stroke has been reviewed and/or edited by Dr. William D. Knopf.

Continue Learning about Brain Aneurysms

Brain Aneurysms

The arteries in the brain occasionally develop a weak spot or bulge, which is called an aneurysm. The concern is that it can burst or rupture at that weak spot, causing blood to leak into the brain, a brain aneurysm hemorrhage. A ...

rupture is very serious, often fatal or leaving permanent paralysis and disability. Doctors detect aneurysms with various scans. There are two surgical treatments that reduce the risk of rupture. One is open brain surgery (craniotomy) the other, less invasive, is endovascular surgery. Which is appropriate depends on where the aneurysm is located. An aneurysm is a very serious medical condition and requires immediate attention.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.