Dear Dr. Gott: I am a 79-year-old female. I had a CT scan and ultrasound screening in September 2008. At that time, they found an abdominal aortic aneurysm. One doctor said it was 4.8 centimetres, but another said it was 4.2. Both told me that nothing would be done until it reached five or six, and, at that point, surgery would be recommended. What do I do now?

Reply: Abdominal aortic aneurysms are potentially fatal areas of ballooning of the large blood vessel that supplies the abdomen, pelvis and legs. They can occur in anyone, but are most common in males over 60 with one or more risk factors.

Those factors include emphysema, smoking, high blood pressure, obesity, high cholesterol, being male and certain genetic factors. There is no known cause.

In most cases, the aneurysm is found during routine screening tests or imaging studies for other conditions. Most aneurysms do not cause symptoms. They usually develop slowly over time but occasionally expand rapidly, leading to rupture, dissection (bleeding from the inner wall into the outer wall of the vessel) or other symptoms. All aneurysms carry risks, but small ones generally go unnoticed. Large aneurysms are more serious and more likely to rupture spontaneously and cause symptoms.

Symptoms are usually the result of rupture or dissection and include nausea, vomiting, back or abdominal pain, anxiety, clammy skin, an abdominal mass, abdominal rigidity, rapid heart rate upon standing, a pulsating sensation in the abdomen and shock.

Rupture is a medical emergency, and immediate attention is necessary.

Treatment is available. Small, non-symptomatic aneurysms should be monitored on a yearly basis to check for expansion.

If the aneurysm causes symptoms, expands rapidly or is larger than 5.5 centimetres, surgery is often done to prevent complications, such as leaks or rupture.

To provide related information, I am sending you copies of my Health Reports "An Informed Approach to Surgery" and "Blood – Donations and Disorders".