By Dr Ananya Mandal, MD
An aneurysm is a term used to define a bulge or ballooning in a blood vessel caused by a weakness in the blood vessel wall. With continued pressure on the vessel walls due to the flow blood and its pressure, the bulge increases.
Abdominal aorta aneurysm epidemiology
Abdominal aortic aneurysms commonly affect men over 65, with around in 1 in 25 men being affected. The rates of rupture are, however, rare with only around 1 in 10,000 people having a ruptured aortic aneurysm in any year in England.
Causes of aneurysms
The exact cause of the weakening of the vessel walls is unknown. Several risk factors that raise the possibility of such weakness however have been identified. Some of these include hardening of the arteries due to atherosclerosis. Other risk factors are smoking and high blood pressure that may raise the possibility of getting an aneurysm.
Location and types
The abdominal aorta is the largest blood vessel in the body. It transports clean and oxygen-filled blood from the heart to the rest of the body. The aorta comes down in a straight line from the heart, through the chest and abdomen and breaks off into two branches at the pelvis or hips to supply the genitals and both lower limbs. As it runs down it gives off vital branches of blood vessels that supply the intestines and the kidneys.
Aneurysms can occur anywhere in the body. However, one of the commonest sites for aneurysms is in the abdominal aorta and the brain.
Symptoms of abdominal aorta aneurysm
In most of the cases an abdominal aortic aneurysm causes no noticeable symptoms and may go unnoticed for long years. However, large aneurysms carry a risk of rupture. A ruptured abdominal aortic aneurysm can cause massive internal bleeding that may almost certainly lead to death if not contained immediately. The commonest symptom of a ruptured aortic aneurysm is sudden and severe pain in the abdomen.
Diagnosis and screening
Abdominal aorta aneurysm often goes unnoticed at early stages because of the lack of symptoms. However, a ruptured aneurysm may lead to almost certain death.
In March 2009, the NHS launched a screening service to assess males over 65 years for abdominal aortic aneurysms. Diagnosis can be made by non-invasive tests like imaging studies – ultrasonography, CT scan and MRI. MR angiography chalks out the clearly defined size and structure of the aneurysm and helps in planning surgery.
Treatment of abdominal aortic aneurysm
The aim of treatment is to prevent the rupture of the aneurysm. Smaller aneurysms may be treated with a watchful waiting and repeat imaging studies to assess rate of growth. Medications that lower cholesterol – statins, stopping smoking completely and maintaining a healthy body weight are important measures to prevent further growth of the aneurysm.
Larger aneurysms may require surgery to replace the weakened section of the blood vessel with a section of synthetic tubing. This surgery, however, itself carries a risk of causing serious complications. Preventative surgery is often recommended for an abdominal aortic aneurysm that is larger than 5.5cm.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)