CASE 3696 Published on 13.12.2005

Ruptured Abdominal Aortic aneurysm

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Dr Omar Bashir, Mr M Duxbury, Mr N Keeling. Department of Surgery West Suffolk Hospitals NHS Trust Bury St Edmunds UK

Patient

70 years, male

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Clinical History

A 70 year old man presented with a history of abdominal pain and a tender mass on examination. Computed tomography of the abdomen confirmed leaking abdominal aortic aneurysm. We report the radiological findings.

Imaging Findings

A 70 year old man presented with severe central abdominal pain radiating to left iliac fossa. On examination he was haemodynamically stable with a tender mass in the left lower quadrant of the abdomen. Following plain abdominal radiography, contrast-enhanced computed tomography (CT) of the abdomen with multiplanar reconstruction was carried out. The plain abdominal radiograph showed calcifications in right lateral wall of the abdominal aorta and the obliteration of the left psoas margin. Incidental calcification of the mesenteric lymph nodes was also noted. Contrast CT revealed a large infrarenal abdominal aortic aneurysm (AAA) with active retroperitoneal leakage. An intraluminal thrombus was also seen. The patient subsequently underwent successful repair of the aneurysm.

Discussion

The vast majority of abdominal aortic aneurysms (AAA) are infrarenal and frequently involve the common iliac arteries. Atherosclerosis is the major cause AAAs whilst the inflammatory aneurysms, charcterized by extensive periaortic inflammation, account for a minority of the cases. AAAs tend to develop after the age of 50 and are more common in men. They are usually asymptomatic and are found incidentally on physical examination or during radiological procedures for other indications. Rupture is the most feared complication of AAAs and presents as severe back or abdominal pain with varying degrees of shock. It tends occur either anteriorly (20%) or posteriorly (80%) into the retroperitoneal space. Anterior rupture results in free bleeding into the peritoneal cavity and is usually immediately fatal. Patients with posterior rupture have a 50% chance of survival if operated. Haemodynamically unstable patients are managed with immediate operation whilst stable patients may undergo emergency imaging investigations to confirm the diagnosis. Contrast-enhanced CT is the investigation of choice for such patients. It also helps in defining the anatomy of the aneurysm (size, relationship to renal arteries and aortic bifurcation, intraluminal thrombus etc) as well as depicting associated complications. With ruptured AAAs the haematoma is apparent as a periaortic soft tissue mass with extravasation of contrast material indicating active leakage. Contrast-enhanced sonography (not performed in our case) can also reveal features specific for ruptured aortic aneurysm and is reported to be a rapid, noninvasive diagnositic modality. Plain abdominal radiography, a commonly performed preliminary imaging investigation for acute abdomen, may reveal signs suggestive of AAA such as a soft tissue mass and curvilinear calcifications (in the wall of the aneurysm). Other signs like obliteration of psoas margins and renal outline, renal displacement and properitoneal flank stripe changes indicate a rupture into the retroperitoneal space.

Differential Diagnosis List

Ruptured infrarenal abdominal aortic aneurysm

Final Diagnosis

Ruptured infrarenal abdominal aortic aneurysm

References

[1] Prevalence and associations of abdominal aortic aneurysm detected through screening. Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Group. Lederle FA, Johnson GR, Wilson SE, Chute EP, Littooy FN, Bandyk D, Krupski WC, Barone GW, Acher CW, Ballard DJ. Ann Intern Med. 1997 Mar 15;126(6):441-9. (PMID: 9072929)

[2] Autopsy study of unoperated abdominal aortic aneurysms. The case for early resection. Darling RC, Messina CR, Brewster DC, Ottinger LW. Circulation. 1977 Sep;56(3 Suppl):II161-4. (PMID: 884821)

[3] The value of computed tomography in the management of symptomatic abdominal aortic aneurysms. Kvilekval KH, Best IM, Mason RA, Newton GB, Giron F. J Vasc Surg. 1990 Jul;12(1):28-33. (PMID: 2374251)

[4] Contrast-enhanced sonography for diagnosis of ruptured abdominal aortic aneurysm. Catalano O, Lobianco R, Cusati B, Siani A. AJR Am J Roentgenol. 2005 Feb;184(2):423-7. (PMID: 15671357)

[5] A review of the plain abdominal radiograph in acute rupture of abdominal aortic aneurysms. Loughran CF.
Clin Radiol. 1986 Jul;37(4):383-7. (PMID: 3731704)

[6] Abdominal and thoracoabdominal aortic aneurysm. Sternbergh WC 3rd, Gonze MD, Garrard CL, Money SR.
Surg Clin North Am. 1998 Oct;78(5):827-43, ix. (PMID: 9891579)

Case information

URL:	https://www.eurorad.org/case/3696
DOI:	10.1594/EURORAD/CASE.3696
ISSN:	1563-4086

Figure 1

Plain abdominal radiograph

Plain abdominal radiograph shows calcification in the right lateral wall of the aneurysm (black arrowhead), whilst the right psoas margin (black arrow) is preserved the left psoas margin is obliterated. Calcification in the mesenteric lymph nodes is also noted (white arrow)

Figure 2

Axial CT abdomen

Axial CT reveals a large abdominal aortic aneurysm with an intraluminal thrombus (arrowhead). Detection of the soft tissue mass indicates a haematoma whereas extravasation of contrast material (arrow) shows active leakage.

Figure 3

CT abdomen coronal reconstruction