History

Fact Explanation
None Around 75% of aortic aneurysms are asymptomatic and are discovered incidentally. [1] Suprarenal aneurysms usually occur with no symptoms.
Ureteric obstruction and hydronephrosis This is one of the pressure effects of the enlarging abdominal aortic aneurysm (AAA). Once it compresses the Ureters the back pressure on the kidney causes hydronephrosis.
Features of Inferior Vena Cava (IVC) obstruction. Eg: Edema of the lower extremities, Caput medusae. The enlarging AAA compresses the IVC resulting inferior vena cava syndrome (IVCS). Poor venous drainage of the lower limb vessels causes edema of the lower limbs. The dilatation of the co-lateral veins around the umbilicus makes the engorged veins visible known as Caput Medusae.
A classic triad of lower back pain, weight loss, and raised Erythrocyte Sedimentation Rate (ESR). This triad is characteristic of inflammatory AAA, which represent the most extreme end of the spectrum of chronic inflammatory change seen in degenerative aneurysms, and account for 10% of AAAs. [1]
A characteristic triad of abdominal or back pain, hypovolaemic shock, and a pulsatile abdominal mass. [2] Although characteristic, these symptoms are present only in a few patients, in those the aneurysm has ruptured. For this triad to be present it should be a retro peritoneal rupture of the AAA. The contained retro peritoneal haematoma acts as a tamponade and results in a temporary haemodynamic instability. [1] Patients might also develop cyanosis, mottling, altered mental status, tachycardia, along with hypotension due to rupture of the AAA.
Back pain, paralysis [3], groin pain and leg pain. Expanding AAA erosion of the lumbar vertebrae and later the spinal cord resulting in back pain and paralysis respectively. Local compression of the lumbar plexus of nerves causes groin pain and leg pain. Transient paralysis is seen in ruptured AAA. [3]
Acute ischemia of the foot and toes. According to the Virchow's triad the relative stasis of blood predisposes to the formation of in-situ thrombus and those may dislodge and embolise in the femoral and popliteal arteries causing acute ischemia of the foot and toes.
Symptoms due to arterio-venous fistula (AVF). Eg: tachycardia, congestive heart failure, leg swelling, abdominal bruit, renal failure and pheripheral ischemia. Small number of AAAs rupture in to the adjacent structures. Once it ruptures in to the IVC it causes an AVF. [4] It cause shunt of blood from the aorta to the IVC and relative hypovolaemia induces tachycardia, and renal failure. The large venous return to the heart causes congestive heart failure.
Massive upper gastro-intestinal bleeding. The AAA may rupture in to the fourth part of the duodenum and this results in massive upper gastro-intestinal bleeding causing hematemesis and even passage of fresh blood per-rectum. [5,6]
References
  1. ANDREW L TAMBYRAJA, RODERICK T.A CHALMERS. Aortic aneurysms. Surgery. 2004. 22, 294-6.
  2. RUTHERFORD RB, MCCROSKEY BL. Ruptured abdominal aortic aneurysms. Special considerations. Surg Clin North Am 1989;69:859–68
  3. WHITWELL GS, VOWDEN P. An unusual presentation of a ruptured abdominal aortic aneurysm. Eur J Vasc Endovasc Surg 2002;23:465–6.
  4. DAVIS PM, GLOVICZKI P, CHERRY KJ, et al. Aorto-caval and ilio-iliac arteriovenous fistulae. Am J Surg 1998;176:115–8.
  5. KASHYAP VS, O’HARA PJ. Aortoenteric fistulae. In: Rutherford R B, ed. Vascular surgery . 6th ed. Philadelphia: WB Saunders, 2005:902–14.
  6. LEMOS DW, RAFFETTO JD, MOORE TC, et al.. Primary aortoduodenal fistula: a case report and review of the literature. J Vasc Surg 2003;37:686–9

Examination

Fact Explanation
Pulsatile abdominal mass The enlarged abdominal aorta can be palpated abdominally especially in thin subjects. A pulsatile mass may not be palpable in obese patients. [1,2]
Flank ecchymosis (Grey Turner sign) This represents retroperitoneal hemorrhage.
Features due to the Arterio-Venous Fistula (AVF). Eg: abdominal bruit, tachycardia, congestive heart failure, leg swelling, abdominal bruit, renal failure and peripheral ischemia Due to the turbulent flow of blood across the AVF a bruit can be auscultated. The relative hypovolaemia due to the shunt of blood from the aorta to the IVC induces tachycardia and causes hypovolaemic renal failure. The overloaded IVC causes leg swelling.
Dilated superficial veins around the umbilicus Due to the obstruction of the IVC the co laterals connecting the IVC and Superior Vena Cava ) dilate. These dilated veins are visible around the umbilicus and called Caput Medusae.
Palpable enlarged kidneys The pressure exerted by the AAA over the ureter causes hydronephrosis. Then the kidneys become palpable as ballotable flank masses.
Palpable femoral and popliteal artery aneurysms. The association of peripheral aneurysms with aortic aneurysms has been proven. So it is better to examine for femoral and popliteal artery aneurysms in the presence of an AAA and vice versa. [3,4]
Features suggestive of Marfan and Ehlers-Danlos syndromes. People with Marfan syndrome and Ehlers-Danlos syndrome are at risk of development of AAA.
Features of hypovolaemic shock This occurs with the rupture of the AAA. Patients may have cyanosis, mottling, tachycardia and hypotension. Although the patient might be haemodynamically stable there is a possibility of a retroperitoneal rupture of the AAA. So exclusion of ruptured AAA should be done with great caution in patients with back pain and a pulsatile abdominal mass. [1,5]
References
  1. RUTHERFORD RB, MCCROSKEY BL. Ruptured abdominal aortic aneurysms. Special considerations. Surg Clin North Am 1989;69:859–68.
  2. BREWSTER DC, CRONENWETT JL, HALLETT JW, et al. Guidelines for the treatment of abdominal aortic aneurysms. Report of a subcommittee of the Joint Council of the American Association for Vascular Surgery and Society for Vascular Surgery. J Vasc Surg 2003;37:1106–17.
  3. ES Crawford, ME. DeBakey. Popliteal artery arteriosclerotic aneurysm. Circulation, 32 (1965), pp. 515–516
  4. TL DENT, SM LINDENAUER, CB Ernst, WJ. Fry. Multiple arteriosclerotic arterial aneurysms. Arch Surg, 105 (1972), pp. 338–344
  5. SAKALIHASAN N, LIMET R, DEFAWE OD. Abdominal aortic aneurysm. Lancet 2005;365:1577–89.

Differential Diagnoses

Fact Explanation
Pancreatitis Cullen's sign and or Grey Turner's sign can be present even in hemorrhagic pancreatitis due to retro peritoneal hematoma. Patient might present in shock so low volume pulse, cyanosis and tachycardia can also be present. The pain is frequently severe, constant and refractory to the usual doses of analgesics. Pain is usually experienced first in the epigastrium but may be localised to either upper quadrant or felt diffusely throughout the abdomen. There is radiation to the back in about 50% of patients, and some patients may gain relief by sitting or leaning forwards. [1] There might be a identifiable cause of pancreatitis. Eg: Alcohol consumption, Trauma, Gall stones.
Diverticulitis Dull aching type of pain. Diverticulitis occurs mostly in elderly patients with a long history of constipation.
Nephrolithiasis Acute waves of sharp constricting pain. Radiated from the loin to groin. There can be macroscopic hematuria even with aorta-left renal vein fistula. [2,3]
Disease affecting the lumbar vertebrae. Aching type of lower back pain, which may manifest with neurological symptoms like shooting pain along the back of the thigh radiating to the foot.
Gastrointestinal bleeding With aorto-duodenal fistula there can be massive gastrointestinal bleeding. So the causes of massive gastrointestinal bleeding like angiodysplasia, posteriorly perforated duodenal ulcer and Mekel's diverticulum should also be considered.
Musculoskeletal pain Pain due to musculoskeletal problem is worsened by the body movements.
Gastritis and Peptic Ulcer Disease There is a history of peptic ulcer disease or dyspeptic symptoms. Pain is mainly localized to the epigastrium.
Myocardial infarction (MI) Anterior myocardial infarction can present with hypo tension and bradycardia. A patient with known cardiovascular risk factors might present with severe chest pain which radiates to the left arm and neck. Electrocardiogram will help in differentiating the two. (There can be coexisting MI with the ruptured AAA due to severe bleeding. )
Biliary colic Acute waves of sharp constricting pain that is mainly localized to the epigastric region later radiating to the right upper quadrant of the abdomen.
Cholecystitis Epigastric pain later radiates to the right upper quadrant of the abdomen. Murphy's sign (When a firm pressure is applied over the tip of the right ninth costal cartilage the patient catches the breath during inspiration) is positive. AAA can have right hypochondrial pain. [4]
Urinary Tract Infection in Women This is associated with dull supra pubic pain, increased frequency of micturition, and dysuria.
References
  1. BAILEY, LOVE. ed. Norman S. Williams, Christopher J.K. Bulstrode, P. Ronan O’connell. Bailey & Love’s SHORT PRACTICE of SURGERY. 25th ed. London. Hodder Arnold. 2008.
  2. DEBAKEY ME, COOLEY DA, MORRIS GC, et al. Arteriovenous fistula involving the abdominal aorta: report of four cases with successful repair. Ann Surg 1958;147:646–58.
  3. BARRIER P, OTAL P, GARCIA O, et al. Aorta-left renal vein fistula complicating an aortic aneurysm: preoperative and postoperative multislice CT findings. Cardiovasc Intervent Radiol 2007;30:485–7.
  4. CIARDO LF, AGRESTA F, BEDIN N. The misdiagnosis of ruptured abdominal aortic aneurysm: an ancient problem always present. Report of an atypical case. G Chir 2007;28:213–5.

Investigations - for Diagnosis

Fact Explanation
Abdominal X Ray (AXR) An AAA may be visible in AXR if the aneurysm wall is calcified. This finding is reported as being 50% sensitive, and intuition suggests that it is close to 100% specific. [1] An abnormal aortic silhouette is also in favor of AAA but one can not accurately differentiate an AAA from a dilatation of a vessel.[2] However this method lacks sensitivity and is unsatisfactory for routine use.
Ultrasound scan This is the first line investigation for the diagnosis of AAAs, providing accurate assessment of the aneurysm diameter and some information regarding the site. [3] Although Ultrasound scan is operator dependent, when performed by trained personnel, it has a sensitivity and specificity approaching 100% and 96%. This can be combined with color Doppler for better results.
Computer Tomography (CT) or CT is the first line investigation during preoperative assessment to delineate AAA morphology and the relationship to the visceral and renal arteries. [3] CT is somewhat more reproducible than ultrasound. [4]
Magnetic Resonance Imaging (MRI) Visualizes the AAA. Not routinely done.
Magnetic Resonance Angiography (MRA) Thrombus is readily identified by MRA. Although this information is not important for conventional AAA operations, assessment of intraluminal thrombus may become important in planning endoluminal stent graft placement as the technology is introduced into clinical practice. [5]
References
  1. GOMES MN. Diagnosis of abdominal aortic aneurysms. Am Fam Physician. 1982 Mar; 25(3):167-76.
  2. ERIC M. ISSELBACHER, MD. Thoracic and Abdominal Aortic Aneurysms. Contemporary Reviews in Cardiovascular Medicine. 2005; 111: 816-828
  3. ANDREW L TAMBYRAJA, RODERICK TA CHALMERS. Aortic aneurysms. Surgery. 1 November 2004. Volume 22, Pages 294-296,
  4. LEDERLE FA, WILSON SE, JOHNSON GR, REINKE DB, LITTOOY FN, ACHER CW, MESSINA LM, BALLARD DJ, ANSEL HJ. Variability in measurement of abdominal aortic aneurysms. Abdominal Aortic Aneurysm Detection and Management Veterans Administration Cooperative Study Group. J Vasc Surg. 1995 Jun; 21(6):945-52.
  5. PRINCE Martin R, NARASIMHAM Dasika L, STANLEY James C, WAKEFIELD Thomas W et al. Gadolinium-enhanced magnetic resonance angiography of abdominal aortic aneurysms. Journal of Vascular Surgery [Online] Volume 21, Issue 4 , Pages 656-669, April 1995. [viewed 25 April 2014] Available from: http://www.jvascsurg.org/article/S0741-5214(95)70197-4/fulltext

Investigations - Fitness for Management

Fact Explanation
Full blood count When surgery is to be done patient's hemoglobin level should be checked and optimized prior to the surgery if needed. Raised white blood cells may reflect an inflammatory changes which should be treated prior to the surgery. [1,2]
Electrocardiogram In patients with significiant risk of cardiovascular disease and in all male patients. [3]
Blood grouping and cross matching At least six pints of blood should be available prior to the surgery.
Renal function test Since the surgery is done under general anesthesia renal function should be checked. (Serum electrolytes, blood urea, serum creatinine.)
Chest X Ray (CXR) CXR should be done in all patients with known lung disease and if needed. [3]
References
  1. NELSON AH, FLEISHER LA, ROSENBAUM SH. Relationship between postoperative anemia and cardiac morbidity in high-risk vascular patients in the intensive care unit. Crit Care Med. 1993; 21: 860–6.
  2. WU WC, SCHIFFTNER TL, HENDERSON WG, et al. Preoperative hematocrit levels and postoperative outcomes in older patients undergoing noncardiac surgery. JAMA. 2007; 297: 2481–8.
  3. ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery. Circulation. 2007; 116: e418-e500. http://circ.ahajournals.org/content/116/17/e418.full

Investigations - Followup

Fact Explanation
USS USS is considered the best investigation for the followup of asymptomatic patients who are not eligible for surgery. Small AAAs between 3.0 and 4.0 cm in diameter have a low annual risk of rupture, and periodic surveillance with abdominal ultrasonography is appropriate. [1,2,]
References
  1. POWELL JT, GREENHALGH RM. Review Clinical practice. Small abdominal aortic aneurysms. N Engl J Med. 2003 May 8; 348(19):1895-901.
  2. ERNST CB. Review Abdominal aortic aneurysm. N Engl J Med. 1993 Apr 22; 328(16):1167-72.

Investigations - Screening/Staging

Fact Explanation
USS Among asymptomatic patients, ultrasound is a cost effective method which detects the presence of AAA accurately and it is highly reproducible and inexpensive. Sensitivity and specificity are both close to 100% when compared with operative findings. [2] This reduces the mortality from rupture. [1] In general, ultrasound is an ideal test for mass screening. [2]
References
  1. DALY KJ, TORELLA F, ASHLEIGH R, MCCOLLUM CN. Screening, diagnosis and advances in aortic aneurysm surgery. Gerontology. Nov-Dec 2004;50(6):349-59.
  2. WILMINK AB, FORSHAW M, QUICK CR, HUBBARD CS, DAY NE. Accuracy of serial screening for abdominal aortic aneurysms by ultrasound. J Med Screen. 2002; 9(3):125-7.

Management - General Measures

Fact Explanation
Routine USS and watchful waiting This is accepted for asymptomatic AAAs when the morbidity and mortality of surgery is considered significantly higher than the risk of rupture. The annual incidence of rupture rises from 1% or less in aneurysms that are < 55 mm in diameter to a significant level, perhaps as high as 20%, in those that are 70 mm in diameter. Assuming elective surgery carries a 5% mortality rate, the balance is in favor of elective operation once the diameter is > 55 mm, provided there is no major co morbidity. [1]
References
  1. BAILEY, LOVE. ed. Norman S. Williams, Christopher J.K. Bulstrode, P. Ronan O’connell. Bailey & Love’s SHORT PRACTICE of SURGERY. 25th ed. London. Hodder Arnold. 2008.

Management - Specific Treatments

Fact Explanation
Surgery (open or endovascular repair) Large AAAs ≥5.5 cm in diameter have a high annual risk of rupture, and surgical repair is indicated. [1] Suprarenal aneurysms > 5.5 cm should be corrected with surgery where as infrarenal AAA which are 5.5 cm or larger should undergo surgical correction. When compared to the open repair, endovascular repair has less operative morbidity, it has significant long-term morbidity and is much more expensive. [2,3,4]
References
  1. LEDERLE FA, JOHNSON GR, WILSON SE, BALLARD DJ, JORDAN WD JR, BLEBEA J, LITTOOY FN, FREISCHLAG JA, BANDYK D, RAPP JH, SALAM AA. Rupture rate of large abdominal aortic aneurysms in patients refusing or unfit for elective repair. JAMA. 2002 Jun 12; 287(22):2968-72
  2. GREENHALGH RM, BROWN LC, POWELL JT, THOMPSON SG, EPSTEIN D, SCULPHERMJ. Endovascular versus open repair of abdominal aortic aneurysm. N Engl J Med. May 20 2010;362(20):1863-71.
  3. GREENHALGH RM, BROWN LC, POWELL JT, THOMPSON SG, EPSTEIN D. Endovascular repair of aortic aneurysm in patients physically ineligible for open repair. N Engl J Med. May 20 2010;362(20):1872-80.
  4. DE BRUIN JL, BAAS AF, BUTH J, PRINSSEN M, VERHOEVEN EL, CUYPERS PW, et al. Long-term outcome of open or endovascular repair of abdominal aortic aneurysm. N Engl J Med. May 20 2010;362(20):1881-9