eMedicine Specialties > Emergency Medicine > Cardiovascular
Aneurysm, Abdominal: Differential Diagnoses & Workup
Updated: Sep 8, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
| Appendicitis, Acute | Obstruction, Large Bowel |
| Cholelithiasis | Obstruction, Small Bowel |
| Diverticular Disease | Pancreatitis |
| Gastritis and Peptic Ulcer Disease | Urinary Tract Infection, Female |
| Myocardial Infarction |
Other Problems to Be Considered
Gastrointestinal bleed
Ischemic bowel
Nephrolithiasis
Musculoskeletal pain
Perforated gastrointestinal ulcer
Pyelonephritis
Pancreatitis
Workup
Laboratory Studies
No specific laboratory studies exists that can be used to make the diagnosis of abdominal aortic aneurysm (AAA). Laboratory testing may be used to aid in diagnosis of other pathology or diagnose associated medical disorders.
Imaging Studies
More than 80% of patients with ruptured abdominal aortic aneurysm (AAA) present without previous diagnosis of AAA, which contributes to an initial misdiagnosis rate of 24-42%. A rational approach to diagnostic evaluation is predicated on a high degree of suspicion. Options for radiologic evaluation of AAA include plain radiography, ultrasonography, CT scan, MRI, and angiography.
- Ultrasonography
- Ultrasonography is the standard imaging tool; if performed by trained personnel, it has a sensitivity and specificity approaching 100% and 96%, respectively, for the detection of infrarenal AAA.
- Bedside emergency ultrasonography should be performed without delay if AAA is suspected. Elderly patients with abdominal pain are prime candidates for bedside ultrasonography screening.
- Ultrasonography is noninvasive and may be performed at the bedside. Ultrasonography can be used to detect free peritoneal blood.
- Limitations of the study are few but do include inability to detect leakage, rupture, branch artery involvement, and suprarenal involvement. Also, ability to image the aorta is reduced in the presence of bowel gas or obesity.
- The primary role of ultrasonography is to screen patients at risk for AAA, to determine the size of the aneurysm, and to observe the aneurysm over time.
- Significant portions of abdominal aorta (at least one third of its length) are not visualized on bedside emergency ultrasonography in 8% of nonfasted patients.2 This rate is higher than reported for fasted patients receiving elective ultrasonography for evaluation of their aortas.
Ultrasonogram of a patient with an abdominal aortic aneurysm. This aneurysm was best visualized on a transverse or axial image. This patient underwent a conventional abdominal aortic aneurysm repair.
- Plain radiography
- Plain radiographs often are obtained on patients with abdominal complaints before the diagnosis of AAA has been entertained. Using this method to evaluate patients with AAA is difficult because the only marginally specific finding, aortic wall calcification, is seen less than half of the time. Aortic wall calcification may appear without aneurysm rim calcification, which leads to a high false-negative rate.
- Do not order plain radiography for the sole purpose of evaluating suspected AAA because it wastes time, delays care, and places the patient at risk for aortic rupture and death because of its low diagnostic yield.
Radiograph shows calcification of the abdominal aorta. The left wall is clearly depicted and appears aneurysmal; however, the right wall overlies the spine.
- CT
- CT scan sensitivity for detecting AAA is nearly 100%, and the study offers certain advantages over ultrasonography in defining aortic size, rostral-caudal extent, involvement of visceral arteries, and extension into the suprarenal aorta. CT scanning permits visualization of the retroperitoneum, is not limited by obesity or bowel gas, detects leakage, and permits concomitant evaluation of the kidneys.
- Spiral CT scan allows 3-dimensional imaging of abdominal contents, enhancing the ability to detect branch vessel and adjacent organ involvement.
- Major disadvantages of CT scanning include technician availability, cost, longer study time, exposure to contrast, and the need to send patients out of the department for an extended time.
CT demonstrates an abdominal aortic aneurysm. The aneurysm was noted during workup for back pain, and CT was ordered after the abdominal aortic aneurysm was identified on radiographs. No evidence of rupture is seen (same patient as in Media file 2).
- MRI
- MRI permits aorta imaging comparable to CT scanning and ultrasonography without subjecting the patient to dye load or ionizing radiation. The technique may offer superior imaging of branch vessels compared to CT scan or ultrasonography, but it is less valuable in assessing suprarenal extension and is not suitable in patients who are unstable. MRI may have a role in very stable patients with a severe dye allergy.
- Lack of widespread availability, need for a stable patient, incompatibility with monitoring equipment, and high cost limit its applicability.
MRI of a 77-year-old man with leg pain believed to be secondary to degenerative disk disease. During evaluation, an abdominal aortic aneurysm was discovered.
- Angiography
- Angiography is useful in determining aortic anatomy and has been advocated for preoperative use if suspicion of suprarenal or thoracic aneurysm, femoral or popliteal aneurysm, renal artery stenosis, unexplained impairment of renal function, occlusive iliofemoral disease, or visceral ischemia exists.
- The test is limited by its invasiveness, cost, lack of operator availability, time involved, and risk of complications (eg, bleeding, perforation, embolization). Routine use of angiography in evaluation of AAA is not recommended.
- Digital subtraction angiography (DSA) requires less time, uses less contrast material, and is less invasive than conventional angiography. The technique is not widely available and offers no real advantage over conventional CT scanning.
More on Aneurysm, Abdominal |
| Overview: Aneurysm, Abdominal |
 Differential Diagnoses & Workup: Aneurysm, Abdominal |
| Treatment & Medication: Aneurysm, Abdominal |
| Follow-up: Aneurysm, Abdominal |
| Multimedia: Aneurysm, Abdominal |
| References |
| « Previous Page | Next Page » |
References
[Guideline] U.S. Preventive Services Task Force. Screening for abdominal aortic aneurysm: recommendation statement. Ann Intern Med. Feb 1 2005;142(3):198-202. [Medline]. [Full Text].
Blaivas M, Theodoro D. Frequency of incomplete abdominal aorta visualization by emergency department bedside ultrasound. Acad Emerg Med. Jan 2004;11(1):103-5. [Medline].
Daly KJ, Torella F, Ashleigh R, McCollum CN. Screening, diagnosis and advances in aortic aneurysm surgery. Gerontology. Nov-Dec 2004;50(6):349-59. [Medline].
Reichart M, Geelkerken RH, Huisman AB, et al. Ruptured abdominal aortic aneurysm: endovascular repair is feasible in 40% of patients. Eur J Vasc Endovasc Surg. Nov 2003;26(5):479-86. [Medline].
AbuRahma AF, Woodruff BA, Lucente FC, et al. Factors affecting survival of patients with ruptured abdominal aortic aneurysm in a West Virginia community. Surg Gynecol Obstet. May 1991;172(5):377-82. [Medline].
Adamson AS, Darke SG. Aneurysm repair in patients presenting with distal embolization. Am J Surg. Feb 1992;163(2):273. [Medline].
Banerjee A. Atypical manifestations of ruptured abdominal aortic aneurysms. Postgrad Med J. Jan 1993;69(807):6-11. [Medline].
Bengtsson H, Bergqvist D, Ekberg O, et al. Expansion pattern and risk of rupture of abdominal aortic aneurysms that were not operated on. Eur J Surg. Sep 1993;159(9):461-7. [Medline].
Blanchard JF, Armenian HK, Friesen PP. Risk factors for abdominal aortic aneurysm: results of a case-control study. Am J Epidemiol. Mar 15 2000;151(6):575-83. [Medline].
Bower TC, Cherry KJ Jr, Pairolero PC. Unusual manifestations of abdominal aortic aneurysms. Surg Clin North Am. Aug 1989;69(4):745-54. [Medline].
Durham JR, Hackworth CA, Tober JC, et al. Magnetic resonance angiography in the preoperative evaluation of abdominal aortic aneurysms. Am J Surg. Aug 1993;166(2):173-7; discussion 177-8. [Medline].
Ernst CB. Abdominal aortic aneurysm. N Engl J Med. Apr 22 1993;328(16):1167-72. [Medline].
Frauenfelder T, Wildermuth S, Marincek B, Boehm T. Nontraumatic emergent abdominal vascular conditions: advantages of multi-detector row CT and three-dimensional imaging. Radiographics. Mar-Apr 2004;24(2):481-96. [Medline].
Kiell CS, Ernst CB. Advances in management of abdominal aortic aneurysm. Adv Surg. 1993;26:73-98. [Medline].
LaRoy LL, Cormier PJ, Matalon TA, et al. Imaging of abdominal aortic aneurysms. AJR Am J Roentgenol. Apr 1989;152(4):785-92. [Medline].
Lee WA, Carter JW, Upchurch G, Seeger JM, Huber TS. Perioperative outcomes after open and endovascular repair of intact abdominal aortic aneurysms in the United States during 2001. J Vasc Surg. Mar 2004;39(3):491-6. [Medline].
Loughran CF. A review of the plain abdominal radiograph in acute rupture of abdominal aortic aneurysms. Clin Radiol. Jul 1986;37(4):383-7. [Medline].
Lyon M, Brannam L, Ciamillo L, Blaivas M. False positive abdominal aortic aneurysm on bedside emergency ultrasound. J Emerg Med. Feb 2004;26(2):193-6. [Medline].
Marston WA, Ahlquist R, Johnson G Jr, et al. Misdiagnosis of ruptured abdominal aortic aneurysms. J Vasc Surg. Jul 1992;16(1):17-22. [Medline].
National Center for Health Statistics. Vital statistics of the United States. 1991. [Full Text].
Pavone P, Di Cesare E, Di Renzi P, et al. Abdominal aortic aneurysm evaluation: comparison of US, CT, MRI, and angiography. Magn Reson Imaging. 1990;8(3):199-204. [Medline].
Peppelenbosch N, Yilmaz N, van Marrewijk C, et al. Emergency treatment of acute symptomatic or ruptured abdominal aortic aneurysm. Outcome of a prospective intent-to-treat by EVAR protocol. Eur J Vasc Endovasc Surg. Sep 2003;26(3):303-10. [Medline].
Raghavan ML, Vorp DA, Federle MP, et al. Wall stress distribution on three-dimensionally reconstructed models of human abdominal aortic aneurysm. J Vasc Surg. Apr 2000;31(4):760-9. [Medline].
Reddy DJ, Shepard AD, Evans JR, et al. Management of infected aortoiliac aneurysms. Arch Surg. Jul 1991;126(7):873-8; discussion 878-9. [Medline].
Salen P, Melanson S, Buro D. ED screening to identify abdominal aortic aneurysms in asymptomatic geriatric patients. Am J Emerg Med. Mar 2003;21(2):133-5. [Medline].
Stanford W, Rooholamini SA, Galvin JR. Ultrafast computed tomography in the diagnosis of aortic aneurysms and dissections. J Thorac Imaging. Oct 1990;5(4):32-9. [Medline].
Tefera G, Carr SC, Turnipseed WD. Endovascular aortic repair or minimal incision aortic surgery: Which procedure to choose for treatment of high-risk aneurysms?. Surgery. Oct 2004;136(4):748-53. [Medline].
Vohra R, Reid D, Groome J, et al. Long-term survival in patients undergoing resection of abdominal aortic aneurysm. Ann Vasc Surg. Sep 1990;4(5):460-5. [Medline].
Further Reading
Keywords
abdominal aneurysm, abdominal aortic aneurysm, AAA, mycotic aneurysm, abscess formation, atherosclerosis, smoking, chronic obstructive pulmonary disease, COPD, hypertension, syncope, shock, cyanosis, sudden cardiovascular collapse, peripheral atherosclerotic vascular disease, Marfan syndrome, Ehlers-Danlos syndrome, collagen vascular diseases, mycotic aneurysm, claudication, pulsatile abdominal mass, abdominal bruit, aortic rupture
