Abdominal Aortic Aneurysm: Internal Medicine Screening Guideline of the Week
To most people, the acronym AAA stands for the association that helps replace a flat tire or fill your car with gas when the tank goes empty. For doctors, it spells danger: a potentially lethal localized ballooning of the largest blood vessel in the body as it transverses the abdomen.
Of all demographics, elderly men with a smoking history—even distant history—are at an increased risk of having AAA. In fact, 5% of them develop AAA. Women (even those who smoke) are at a lower risk of developing AAA.
From the U.S. Preventive Services Task Force (USPSTF), all men between the ages of 65 and 75 years should have a one-time screening by ultrasonography. No recommendation from the USPSTF exists for non-smokers and it discourages testing in women.
The American College of Cardiology/American Heart Association, on the other hand, has issued an additional guideline: Men 60 years or older with a first-degree relative with AAA should undergo physical exam and ultrasonographic evaluation.
Most cases of AAA are asymptomatic. However, in patients who develop acute back pain, abdominal pain or a painful abdominal mass, the threat of rupture increases.
Eight of 10 patients who experience a rupture of the aneurysm die from this diagnosis. Size matters. It helps stratify the risk of rupture. Aneurysms with a transverse diameter smaller than 5cm have an annual rate of rupture 5% or less. With each 1cm increase in diameter, the annual rupture rate increases roughly 10%. Below are the appropriate follow up recommendations based on transverse diameter size.
<4cm: No further management is required
4-5.5cm: Risk factor reduction such as blood pressure control and ultrasound every six months is adequate management
≥5.5cm: Consider for surgical intervention
Symptomatic individuals: Must be treated surgically
Perhaps the most famous person with AAA was Albert Einstein, who suffered bouts of abdominal pain for years before being diagnosed. At age 70, the pipe-smoking physicist was operated on by the famous Dr. Rudolf Nissen (of Nissen fundoplication fame). Einstein lived for an additional five years post-operatively but died in 1955…due to a ruptured aneurysm.
You can see all the previous ABIM Exam Review Screening Guidelines at the Knowmedge Blog. You can find also additional topics and questions directly from the Knowmedge Internal Medicine ABIM Board Exam Review Questions QVault.