What are the symptoms of an abdominal aortic aneurysm (AAA)?

Symptoms of Abdominal Aortic Aneurysm (AAA)

Most abdominal aortic aneurysms are asymptomatic until they rupture, with classic rupture symptoms including sudden-onset abdominal or back pain, pulsatile abdominal mass, and hypotension. 1

Asymptomatic AAAs

• Approximately two-thirds of AAAs are asymptomatic and represent incidental findings on imaging studies performed for other reasons 1
• Most patients with AAA have no symptoms until rupture occurs 2
• Due to the asymptomatic nature, screening is recommended for high-risk populations:
  • Men ages 65-75 who have ever smoked should have one-time screening 2
  • Selective screening for men ages 65-75 who have never smoked 2

Symptomatic Presentation

When symptoms do occur, they may include:

Pain-Related Symptoms

• Back, abdominal, or flank pain, sometimes radiating to the groin 1
• Tenderness to palpation overlying the AAA 1
• Chest discomfort (particularly with large thoracic aneurysms) 2

Contained Rupture Symptoms

• Acute onset of chest and/or back pain 2
• Abdominal pain (in thoracoabdominal aneurysms) 2
• Atypical low flank or abdominal pain 1
• Recurrent or refractory pain 2
• Pleural or peritoneal effusions (particularly if increasing) 2

Overt Rupture Symptoms

• Sudden severe abdominal or back pain 1
• Hypotension and shock 1
• Pulsatile abdominal mass 1
• Acute respiratory failure (if rupture into left hemithorax) 2

Compression-Related Symptoms

• Dysphagia (rare, usually related to congenital distal arch lesions) 2
• Dyspnea (rare) 2
• Obstructive uropathy 1

Embolism-Related Symptoms

• Signs of embolism (e.g., blue toe syndrome) 1
• Thromboembolization 3
• Atheroembolization 3

Rare Complications

• Hemoptysis from aortobronchial fistula 2
• Hematemesis from aorto-esophageal fistula 2
• Jaundice (with chronic dissection and leaking aneurysms) 2
• Fever (may be related to inflammatory disease or mycotic aneurysms) 2

Clinical Pitfalls

• Relying solely on physical examination can lead to missed diagnoses, especially in obese patients 1
• Women may experience rupture at smaller aneurysm diameters than men 1
• Assuming thrombus reduces rupture risk is incorrect - evidence shows it does not reduce pressure on the aneurysm wall 1
• Delaying intervention for symptomatic aneurysms can lead to increased mortality 1
• Contained ruptures may present with atypical symptoms but still represent a medical emergency requiring urgent treatment 2

Diagnostic Approach

When AAA is suspected based on symptoms:

• Ultrasound is the preferred initial screening method 1
• CT/CTA is the gold standard for diagnosis and pre-intervention planning 1
• For suspected rupture, CT with non-contrast phase followed by contrast injection is indicated to detect intramural hematoma and contrast leaks 2

Any symptomatic AAA, regardless of size, warrants urgent evaluation and consideration for intervention due to the high mortality associated with rupture (75-90%) 1, 3.

High-Risk Features for Rupture

• Rapid aneurysm growth (≥10 mm/year or ≥5 mm/6 months) 2
• Saccular aneurysm morphology 2
• Uncontrolled resistant hypertension 2
• Female gender 3
• Persistent tobacco use 3
• Chronic pulmonary disease 3

Early recognition of symptoms and prompt imaging are critical, as mortality for ruptured AAA reaches 65-85% 4, with 54% mortality at 6 hours and 76% at 24 hours after the initial event 2.