An aneurysm is a bulge (dilation) in the wall of an artery.
(See also Aortic Branch Aneurysms and Brain Aneurysms.)
Aneurysms may occur in any artery. Aneurysms are most common in the aorta, which is the main artery that carries blood from the heart to the body. The aorta is located in the torso. Aneurysms may also occur in arteries outside the torso, including those in the
Legs (femoral arteries in the thighs, popliteal arteries behind the knees)
Brain (cerebral arteries)
Heart (coronary arteries)
Neck (carotid arteries)
Aneurysms of the carotid arteries are rare. Older people are more likely to have aneurysms than are younger people.
Causes
Many aneurysms result from
A weakness in the artery wall that is present at birth (congenital)
Atherosclerosis (caused by buildup of plaque in the walls of blood arteries)
Other aneurysms result from
Injuries caused by stab or gunshot wounds
Bacterial or fungal infections in the wall of the artery that develop after use of illicit intravenous drugs such as heroin
Infections of an artery wall usually start elsewhere in the body, typically in a heart valve, before spreading to the wall of the artery.
Symptoms
Most aneurysms of the popliteal and femoral arteries do not cause symptoms and are discovered when imaging studies are done for other reasons. However, blood clots can form within the aneurysm. If these blood clots break loose, they are called emboli. Emboli can move with the blood flow until they block an artery. If they block an artery in the lower leg or foot, the blockage causes sudden onset of severe pain, numbness, and coolness of the foot, which may also appear pale.
Emboli from carotid aneurysms can block an artery in the brain and cause a stroke.
Emboli from aneurysms in the arteries of the heart (coronary arteries) can result in symptoms of a heart attack (such as chest pain and shortness of breath).
Unlike aneurysms in the aorta or cerebral arteries, aneurysms in the popliteal, femoral, coronary, and carotid arteries rarely rupture.
When aneurysms are infected, people may have fever, pain, and weight loss.
Diagnosis
Imaging
Doctors may diagnose aneurysms in the legs or arms by feeling a pulsating mass in the affected artery. Ultrasonography or computed tomography (CT) can confirm the diagnosis.
Aneurysms of arteries in the heart require other imaging studies, such as conventional angiography, CT angiography, or magnetic resonance angiography.
Infected aneurysms usually have distinctive features on imaging. Blood tests are done to look for increased numbers of white blood cells and increased levels of inflammatory proteins, and cultures are done to identify the organism infecting the aneurysm.
Treatment
Surgery or stent-graft repair
Doctors repair aneurysms in the lower part of the body when the aneurysm is twice the size of the normal blood vessel or when the person with a known aneurysm but no previous symptoms develops new symptoms. Aneurysms in the arms are usually repaired right away even if the person has no symptoms because there is a higher chance that a blood clot will form in these blood vessels.
For popliteal aneurysms larger than 1 inch (2.5 centimeters) in diameter, open surgery or placement of a stent-graft within the aneurysm is usually done. A stent-graft is a hollow tube of synthetic material with a springy mesh in its wall. The mesh wall, like a collapsible straw, allows the stent to be compressed small enough to be inserted into an artery over a long thin wire. Doctors pass the stent through the artery to the aneurysm. Then the stent-graft is opened, forming a stable channel for blood flow. Stent-grafts can also be used for coronary artery aneurysms, although these sometimes require coronary artery bypass surgery.
Femoral and carotid aneurysms can also be surgically repaired.
Infected aneurysms typically require treatment with antibiotics or antifungal medications and may require open surgery or stent-graft repair, depending on where the aneurysm is located, how big it is, and how much it has been damaged by the infection.
