In medicine, an arterial aneurysm is an outpouching, or bulge, that develops in the wall of an artery. Arterial aneurysms occur in the arteries, which are the blood vessels that carry blood away from the heart. These are much more common than venous aneurysms, similar bulges that occur in the veins, which carry blood towards the heart. The fact that arterial aneurysms are more common than venous aneurysms may be attributed to the significantly higher blood pressure that occurs in arteries than in veins.
An arterial aneurysm most commonly occurs in older people, especially men. High blood pressure correlates closely with an increased risk of aneurysms. The majority of aneurysms are small and asymptomatic, and do not result in any serious health problems.
The main threat posed by an arterial aneurysm is that the blood vessel may eventually rupture. If this occurs, then tissues that are supplied with blood by the affected artery will be starved of the nutrients and, critically, the oxygen that they need. Rupture usually only occurs when an aneurysm has become very large. Therefore, it is important that patients who possess an arterial aneurysm carefully manage their blood pressure, as high blood pressure increases the risk of an arterial aneurysm growing, and may ultimately lead to rupture.
Abdominal aortic aneurysms are common aneurisms that often occur in older patients. Aortic aneurysms may also occur in the chest region, and these are called thoracic aortic aneurysms. Any kind of aortic aneurysm has the potential to be very serious, as a rupture can lead to massive, sometimes fatal, bleeding.
A popliteal artery aneurysm is another common type of aneurysm. This type of aneurysm is located at the back of the knee. Such aneurysms rarely rupture and are not usually considered life threatening, although in some rare cases loss of blood flow to parts of the leg may result in the development of gangrene, which may occasionally necessitate amputation of the limb. Aneurysms may also develop at other locations in the leg. A femoral artery aneurysm occurs in the groin region. As is the case with most aneurysms that occur in the limbs, these rarely rupture.
If an arterial aneurysm occurs in the brain, rupture can result in very serious damage. This is not a common condition, and is normally detected in older patients, more commonly in women than in men. A brain aneurysm, such as a cerebral artery aneurysm or an intracranial aneurysm, may cause severe pain, loss of nervous sensation, blurred vision, vomiting, and strokes.