Signs and Symptoms of Abdominal Aortic Aneurysm (AAA)
Most abdominal aortic aneurysms remain completely asymptomatic until rupture occurs, with approximately two-thirds being discovered incidentally on imaging performed for unrelated reasons. 1, 2
Asymptomatic Presentation (Most Common)
- The majority of AAAs produce no symptoms whatsoever and are detected as incidental findings on ultrasound, CT, or other abdominal imaging studies performed for unrelated medical issues 1, 3
- Asymptomatic AAAs are not detectable on physical examination in most cases and remain silent until discovered radiologically 3
- This asymptomatic nature is why screening programs target high-risk populations (men aged 65-75 who have ever smoked) 4
Symptomatic AAA (Indicates Impending or Actual Rupture)
Classic Triad of Ruptured AAA
- Acute back pain with a pulsatile abdominal mass, often associated with retroperitoneal hemorrhage represents the classic presentation 5, 1
- However, this classic triad has poor sensitivity and is frequently absent even in confirmed rupture cases 6
Pain Presentations
- Abdominal pain occurs in only 61.7% of ruptured AAA cases (low sensitivity) 6
- Back pain is present in only 53.6% of cases and may be the sole presenting symptom for months in chronic contained ruptures 6, 7
- Lower back pain can be misdiagnosed as lumbar radiculopathy or musculoskeletal pain, particularly in chronic contained ruptures 7
- Pain may also radiate to the flank, buttock, groin, testicles, or legs 3
- Pain quality is described as "sharp" or "stabbing" rather than the classic "tearing" or "ripping" quality seen in aortic dissection 1
Physical Examination Findings (Poor Sensitivity)
- Hypotension is present in only 30.9% of ruptured AAA cases 6
- Pulsatile abdominal mass is palpable in only 47.1% of cases 6
- Syncope occurs in 27.8% of presentations 6
- Cool and mottled skin may be present, particularly with thrombosis 8
- Absent femoral pulses and neurologic deficits below the level of occlusion can occur with thrombosed AAAs 8
Rare Symptomatic Presentations
Thrombosis of AAA
- Sudden thrombosis presents as a surgical emergency with severe pain from umbilicus to lower extremities 8
- Symptoms include impotence, abdominal pain, lower extremity pain, coolness, and weakness 8
- Femoral pulses are rarely present, and neurologic deficits are common 8
Chronic Contained Rupture
- Back pain and/or neurologic lower limb motor or sensory deficits may be the only symptoms, making diagnosis challenging 5
- Symptoms related to aortic disease may be subtle in chronic contained ruptures 5
- Patients remain hemodynamically stable despite ongoing rupture 5
Other Complications
- Thromboembolization or atheroembolization to distal vessels 2
- Development of arteriovenous or aortoenteric fistula 2
Critical Clinical Pitfall
The absence of classic symptoms (abdominal pain, back pain, hypotension, pulsatile mass) does NOT rule out ruptured AAA, as these findings have poor sensitivity ranging from 27.8% to 61.7%. 6 Any patient with risk factors (age >60, smoking history, male gender, hypertension) presenting with unexplained abdominal or back pain warrants imaging evaluation, as 25% of acute presentations occur in aneurysms <5.5 cm in diameter 1.