An aneurysm is a balloon-like swelling of an artery wall. It forms where the wall has become weak.How an aneurysm forms. Atherosclerosis damages and weakens the artery wall and makes it less elastic. The artery also narrows, so blood builds up behind the narrowed region and the pressure there increases. The pressure of the blood pushes the weakened wall outwards, and it bulges to form a blood-filled swelling. As the swelling grows, the wall becomes thinner and weaker still.
Why aneurysms are dangerous. Many aneurysms cause no symptoms, so a person may not know they have one. If an aneurysm bursts (ruptures), it causes severe internal bleeding. A large amount of blood is lost very quickly and blood pressure falls, so a ruptured aneurysm is often fatal.Where they form. Aneurysms can form in any artery, but two common sites are:• the aorta in the abdomen, called an abdominal aortic aneurysm
• arteries in the brain, where a rupture causes a type of strokeRisk and screening. Aneurysms are more common in older people, men and smokers. High blood pressure increases the risk of an aneurysm forming and of it rupturing, because it puts more strain on the weakened wall. In England, men are offered an ultrasound scan of the abdominal aorta in the year they turn 65. If a large aneurysm is found, it can be repaired by surgery before it bursts.
Why aneurysms are dangerous. Many aneurysms cause no symptoms, so a person may not know they have one. If an aneurysm bursts (ruptures), it causes severe internal bleeding. A large amount of blood is lost very quickly and blood pressure falls, so a ruptured aneurysm is often fatal.Where they form. Aneurysms can form in any artery, but two common sites are:• the aorta in the abdomen, called an abdominal aortic aneurysm• arteries in the brain, where a rupture causes a type of strokeRisk and screening. Aneurysms are more common in older people, men and smokers. High blood pressure increases the risk of an aneurysm forming and of it rupturing, because it puts more strain on the weakened wall. In England, men are offered an ultrasound scan of the abdominal aorta in the year they turn 65. If a large aneurysm is found, it can be repaired by surgery before it bursts.