Symptoms of Dissecting Abdominal Aortic Aneurysm
The classic presentation of a dissecting abdominal aortic aneurysm includes abrupt onset of severe abdominal and/or back pain, often described as sharp, ripping, or tearing, which is maximal at onset, accompanied by a pulsatile abdominal mass and hypotension or shock in cases of rupture. 1
Clinical Presentation
Cardinal Symptoms
Pain characteristics:
- Sudden onset with maximum intensity at the beginning
- Sharp, ripping, tearing, or stabbing quality
- Typically located in the abdomen and/or back
- May radiate to the groin or lower extremities
- Pain may change location as the dissection progresses 1
Associated symptoms:
- Syncope (in up to 20% of cases) 1
- Nausea and vomiting
- Diaphoresis
- Anxiety and sense of impending doom
Physical Examination Findings
- Pulsatile abdominal mass
- Pulse deficits (present in <20% of patients) 1
- Hypotension (in cases of rupture)
- Difference in blood pressure between arms
- Abdominal tenderness
- Signs of peripheral ischemia (cold, pale extremities)
Less Common Presentations
- Neurological deficits (loss of consciousness, ischemic paresis) in up to 40% of patients 1
- Paraplegia (due to involvement of intercostal arteries)
- Mesenteric ischemia (persistent abdominal pain, elevated acute phase proteins)
- Renal involvement (oliguria or anuria)
- Horner's syndrome
- Vocal cord paralysis
- Hemoptysis or hematemesis (rare)
Complications and High-Risk Features
Rupture
- Complete cardiovascular collapse
- Profound shock
- Mortality rate of 54% at 6 hours and 76% at 24 hours 2
- Less than half of patients with rupture arrive at the hospital alive
Malperfusion Syndromes
- Mesenteric ischemia (occurs in ~5% of patients) 1
- Renal ischemia
- Limb ischemia
- Spinal cord ischemia leading to paraplegia
- Cerebrovascular ischemia
Diagnostic Evaluation
Initial Assessment
- Measure blood pressure in both arms and legs to detect differences
- Auscultate for murmurs of aortic regurgitation
- Assess peripheral pulses
Imaging
- CT angiography: Gold standard for diagnosis, providing detailed anatomical information 1
- Transthoracic echocardiography: Initial screening tool, especially in unstable patients 1
- Transesophageal echocardiography: Reasonable alternative for initial diagnosis in unstable patients 1
- MRI: Alternative for stable patients, especially useful for follow-up in young patients to limit radiation exposure 1
Laboratory Tests
- D-dimer: Elevated in acute aortic syndromes, with highest diagnostic value during the first hour 1
- Complete blood count: May show anemia in cases of bleeding
- Renal function tests: To assess kidney involvement
- Cardiac biomarkers: To rule out myocardial infarction
Treatment Approach
Medical Management
- Blood pressure control: Immediate reduction of systolic blood pressure to 100-120 mmHg
- Heart rate control: Target heart rate <60 bpm
- Pain management: Adequate analgesia
- Fluid resuscitation: In cases of hypotension, with caution to avoid excessive fluid administration
Surgical Management
- Type A dissection (involving ascending aorta): Emergency surgical repair
- Type B dissection (distal to left subclavian artery): Medical management initially, with intervention for complications
- Ruptured AAA: Urgent intervention with either open repair or endovascular aortic repair (EVAR)
- EVAR shows lower 30-day mortality (19%) compared to open repair (33%) 2
Pitfalls and Caveats
Misdiagnosis: Abdominal aortic dissection can mimic other conditions such as myocardial infarction, pulmonary embolism, or acute abdomen. The key distinguishing feature is the abrupt onset of maximum pain intensity.
Atypical presentations: Up to 20% of patients may present without typical chest pain, and some may present solely with abdominal pain 1, 3.
Contained rupture: Patients may initially appear hemodynamically stable due to contained rupture, but remain at high risk for free rupture and death 1, 2.
Delayed diagnosis: The mortality rate increases significantly with delayed diagnosis and treatment. High clinical suspicion is crucial in at-risk patients.
Pulse deficits: These may be transient due to the changing position of the intimal flap, so their absence does not rule out dissection 1.
By recognizing these symptoms promptly and initiating appropriate diagnostic workup and treatment, mortality and morbidity from this life-threatening condition can be reduced.