MULTIPLE SACCULAR ANEURYSMS OF THE ABDOMINAL AORTA: A CASE REPORT AND SHORT REVIEW OF RISK FACTORS FOR RUPTURE ON CT SCAN

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M.S. Durojaye¹, T.O. Adeniyi ², and O.A. Alagbe²

1. Department of Radiology, Union Diagnostics & Clinical Services Plc, Lagos, Nigeria.
2. Departments of Radiology, LAUTECH Teaching Hospital, Osogbo, Nigeria.

Abstract

Introduction: Saccular abdominal aortic aneurysms (SAAA) are rare types of abdominal aortic aneurysm. It has a higher risk of rupture, hence must be repaired at smaller diameter. Mortality from rupture of an abdominal aortic aneurysm is high and has been reported to be about 90%.

Case presentation: This is the case of a 37-year-old woman with chronic waist pain and abdominal discomfort. Clinical examinations revealed a pulsating abdominal mass. Doppler ultrasound and abdominopelvic contrast enhanced CT scan showed multiple saccular aneurysms of the infrarenal abdominal aorta. This patient had no identified predisposing factor. She was being worked up for surgery, but eventually died of rupture, the most dreaded complication 3 days prior to surgical repair.

Conclusion: The risk factors for rupture found in this patient were the size and type (saccular) of the aneurysm, intraluminal thrombus in addition to the multiplicity of the aneurysm as well as their adjacent positions; that probably led
to arterial wall stress.

Keywords: Saccular abdominal aortic aneurysm, Rupture, Risk factor

Introduction

Abdominal aortic aneurysms are focal dilatation of the abdominal aorta greater than 3cm in maximum diameter¹. Aneurysms can be further categorized into fusiform and saccular types. The fusiform and the commoner type often arises in the setting of wall degeneration secondary to atherosclerotic disease. Saccular aneurysms, which are rarely encountered, have a more varied etiology, including aortic infection, degeneration of a penetrating atherosclerotic ulcer, trauma and previous aortic surgery^2,3. Generally, risk factors like male gender, advanced age, hypertension, smoking, peripheral artery disease and hypercholesterolemia have been associated with abdominal aortic aneurysms^4,5.

Case Report
A 37-year-old woman presented on account of a chronic waist and back pain and abdominal discomfort, which persisted despite the use of analgesics. There was no previous history of trauma or aortic surgery. She is not a known diabetic or
hypertensive and has never smoked cigarette. There is no family history of aortic aneurysms. Clinical examination revealed a pulsating mass at the left lumbar region. The lipid profile of the patient (total cholesterol, triglycerides, HDL, and LDL) was within normal limits.

Abdominal ultrasound was the first radiological investigation done for the patient being a cost-effective initial imaging modality. This showed multiple aneurysmal pouches that communicated with the lumen of the abdominal aorta below the origin of the renal arteries. Blood flow was demonstrated within the normal lumen and turbulent flow within the aneurysmal lumen on Doppler interrogation (Fig. 1).

Abdominopelvic contrast enhanced CT scan revealed multiple saccular aneurysms of the infrarenal abdominal aorta. Three aneurysms were identified, the largest measuring 66.3mm in diameter, is seen as an out pouch from the anterior wall 2.9cm below the origin of the renal artery and thrombus with a thickness of 22.5mm eccentrically located within the lumen. Two other adjacent but smaller saccular aneurysms measuring 22.4mm and 29.4mm in diameter are on the posterior wall. The IVC is compressed by the aneurysm (Fig. 2).

The patient was being worked up for surgery. But, 3 days prior surgery, patient had worsening abdominal pain with episodes of fainting attacks. Unfortunately, patient eventually had a rupture of the aneurysm and died.