An aneurysm is an abnormal bulge or ballooning in the wall of a blood vessel. An aneurysm can burst (rupture), causing internal bleeding and often leading to death. Aneurysms usually don't cause symptoms, so you might not know you have an aneurysm even if it's large.
Aneurysms can develop in several parts of your body, including:
Some small aneurysms have a low risk of rupture. Your doctor will assess the size, location and appearance of your aneurysm, and your medical and family history, to clarify the risk of rupture. Your doctor will then compare that risk to the risk of treatment and decide whether to manage or treat the aneurysm.