What are the signs that an abdominal aortic aneurysm (AAA) is leaking?

Signs of a Leaking Abdominal Aortic Aneurysm

Any patient with a known AAA presenting with acute abdominal, back, or flank pain should be presumed to have impending rupture and requires immediate ICU admission with urgent repair within 24-48 hours. 1

Cardinal Clinical Symptoms

Acute onset pain is the hallmark of AAA rupture or impending rupture:

• Pain location: Lower back (65-90% of cases), abdomen, and flank are the typical sites due to the infrarenal location of most AAAs 1, 2
• Pain character: Sudden, severe onset distinguishes rupture from stable AAA 2
• Recurrent or refractory pain: Identifies patients at highest risk of progression to complete rupture 1
• Pain presence warrants ICU admission regardless of aneurysm size 1

Hemodynamic Signs

Blood pressure changes are critical prognostic indicators:

• Hypotension or shock: Scores 2 points on the AORTAs pretest probability assessment and indicates high rupture risk 2
• Fluctuating blood pressure: Can change dramatically as rupture transitions from contained to free rupture 2
• Hemodynamic instability with decreasing blood volume or hematocrit: Dictates immediate operation 3

Associated Physical Findings

• Fever: Present in ≥70% of ruptured AAA cases due to inflammatory response to retroperitoneal blood 2
• Pulsatile abdominal mass: May be palpable on examination, though this finding is neither sensitive nor specific for rupture 4

Critical Imaging Findings

When hemodynamically stable patients can undergo CT imaging:

• Intramural hematoma: Visible on non-contrast CT phase, critical sign of impending rupture 1
• Perivascular hematoma: Sealed off by retroperitoneal structures indicates contained rupture 1
• Periaortic stranding or soft tissue changes: Indicative of rupture 1
• Pleural or peritoneal effusions: Particularly if increasing on serial imaging, indicate contained or complete rupture 1
• Contrast extravasation: Indicates active bleeding and complete rupture 1
• Preserved aortic wall integrity despite acute pain: Significant finding suggesting impending rather than complete rupture 1

Clinical Context and Pitfalls

Contained vs. free rupture distinction:

• Contained ruptures maintain temporary hemodynamic stability because perivascular hematoma is sealed by pleura, pericardium, retroperitoneal space, and surrounding organs 2
• This temporary stability can be misleading—mortality may reach 54% at 6 hours and 76% at 24 hours after initial rupture 2

Common pitfall: Waiting for hemodynamic collapse before acting. The presence of pain attributable to AAA is sufficient indication for urgent intervention, as CT angiography has only 91.4% sensitivity and misses some rupture cases 1

Immediate Management Priorities

Once leaking AAA is suspected:

• Immediate ICU admission 1, 2
• Permissive hypotension (target systolic 70-90 mmHg) 2
• Urgent vascular surgery consultation for repair within 24-48 hours 1, 2
• Endovascular repair preferred over open repair when anatomically suitable (reduces perioperative mortality from 29-33% to 19-23%) 1, 2