To narrow the differential diagnosis in this case, an ultrasound of the abdomen was conducted. The results showed that the distal aorta was dilated to 4.4 cm, which is about 1.4 cm above the reference range. The Doppler effect was added to the ultrasound scan, which revealed impeded blood flow within the vessel, indicating the presence of a thrombotic clot or plaque buildup in the aneurysm. The results of the ultrasound scan were pathognomonic for an AAA.
In addition to ultrasonography, the use of CT angiography was considered, owing to its superior ability to determine the size and dimensions of an aneurysm. However, the ultrasound scan showed that the aneurysm was smaller than 5.5 cm and thus was at lower risk for rupture. As a result, it was decided that CT angiography was not necessary for this patient.
An AAA is a dilation in the circumference of the aorta compared with the rest of the vessel. Risk factors for AAA include age, hypertension, and White ethnicity; however, the key factor in the disease is a history of smoking. Most AAAs are asymptomatic and are found incidentally on routine imaging studies. In fact, a study showed that 30% of AAAs in asymptomatic individuals are detected as pulsatile masses during physical examination.
Untreated AAAs are at risk for rupture when dilation of the vessel increases beyond 5.5 cm. The risk for rupture increases progressively with continued heavy smoking, poor control of blood pressure and cholesterol levels, and age. The Joint Council of the American Association for Vascular Surgery and the Society for Vascular Surgery have established guidelines on the risk for rupture in AAAs as follows:
< 4 cm in diameter: 0% risk
4-4.9 cm in diameter: 0.5%-5% risk
5-5.9 cm in diameter: 3%-15% risk
6-6.9 cm in diameter: 10%-20% risk
7-7.9 cm in diameter: 20%-40% risk
> 8 cm in diameter: 30%-50% risk
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Cite this: Muthunivas Muthuraj, Rahul R. Borra, Panagiotis Iakovidis. A Noncompliant Construction Worker With a Pulsating Abdomen - Medscape - Nov 22, 2021.