Ultrasound Case 059

Image 1: Transverse view of the abdominal aorta. There is a large abdominal aortic aneurysm. Retroperitoneal blood had dissected retroperitoneally on the left and was not obvious on ultrasound, however CT was expedited and confirmed AAA rupture as the cause of the left sided “renal colic”.

Image 2: Longitudinal view of the abdominal aorta. Two still images spliced for the purpose of this case demonstrating a very large fusiform aneurysm.

Abdominal aortic aneurysm.

The aim of POCUS level abdominal aortic ultrasound is to measure the aorta’s diameter, to integrate this with clinical suspicion, and then determine the most appropriate course of action.

Normal caliber aorta (≤ 2cm diameter) throughout the abdomen excludes abdominal aortic aneurysm – but does not exclude dissection or thrombosis or other pathology.

Aortic aneurysm (>3cm diameter) with consistent clinical findings make abdominal aortic aneurysm rupture very likely and further imaging (CT scan) and / or definitive management should be expedited.

Retroperitoneal haematoma with a AAA makes the diagnosis of ruptured AAA almost certain.

AAA without sonographically detected retroperitoneal haematoma is not sufficient to exclude the diagnosis of AAA rupture; abdominal CT angiogram is required to exclude leak or rupture in the presence of a known of newly discovered AAA.