Cardiology · Vascular Surgery
The facts most likely to be tested
One-time ultrasound screening is indicated for all men aged 65–75 who have ever smoked.
The most significant modifiable risk factor for the development and expansion of an abdominal aortic aneurysm (AAA) is tobacco use.
A pulsatile abdominal mass is the classic physical exam finding, but its sensitivity is low, especially in obese patients.
Symptomatic patients presenting with abdominal or back pain and hypotension must be managed as a ruptured AAA until proven otherwise.
Surgical repair is indicated for asymptomatic AAAs that are ≥5.5 cm in diameter or have expanded >0.5 cm in 6 months.
The most common complication following endovascular aneurysm repair (EVAR) is an endoleak, requiring lifelong surveillance.
Beta-blockers are the first-line medical therapy to reduce wall stress and slow the rate of aneurysm expansion.
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A 72-year-old male with a 40-pack-year smoking history presents to the emergency department with sudden-onset, severe tearing abdominal pain radiating to his back. On physical examination, he is diaphoretic and tachycardic with a blood pressure of 88/50 mmHg. Palpation of the abdomen reveals a pulsatile, tender mass located above the umbilicus. His medical history is significant for hypertension and hyperlipidemia.
What is the most appropriate next step in management?
Emergent surgical consultation
The patient presents with the classic triad of a ruptured AAA (abdominal/back pain, hypotension, and a pulsatile abdominal mass), which requires immediate surgical intervention rather than diagnostic imaging.
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High yield triage
Etiology / Epidemiology
Primarily affects elderly males with a history of smoking and atherosclerosis.
Clinical Manifestations
Often asymptomatic; classic triad of pulsatile abdominal mass, abdominal/back pain, and hypotension.
Diagnosis
Abdominal ultrasound is the screening gold standard; CT angiography is the diagnostic gold standard for symptomatic patients.
Treatment
Surgical repair for diameter ≥ 5.5 cm or rapid expansion; beta-blockers for medical management.
Prognosis
Rupture carries high mortality; hypotension and syncope are ominous signs.
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Epidemiology & Etiology
Strongest risk factor is smoking in males > 65 years old. Other major associations include hypertension, hyperlipidemia, and connective tissue disorders like Marfan syndrome. Prevalence increases significantly with age, particularly in patients with a family history.
Pertinent Anatomy
Most aneurysms occur infrarenally due to decreased vasa vasorum in the distal aorta. This location is critical for surgical planning to avoid renal artery compromise.
Pathophysiology
Chronic inflammation and degradation of the tunica media lead to loss of elastin and collagen. This structural weakening causes progressive aortic dilation under systemic pressure. The process is often exacerbated by matrix metalloproteinase activity.
Clinical Manifestations
Most are found incidentally. Symptomatic patients present with tearing abdominal or back pain. Rupture manifests as the classic triad: pulsatile abdominal mass, flank pain, and hypotension. Syncope or sudden collapse indicates impending or active rupture.
Diagnosis
Abdominal ultrasound is the screening tool of choice for asymptomatic patients. CT angiography is the gold standard for surgical planning and symptomatic evaluation. A diameter ≥ 3.0 cm defines an aneurysm; ≥ 5.5 cm is the threshold for intervention.
Treatment
Medical management includes beta-blockers to reduce wall stress. Surgical repair (EVAR or open) is indicated for diameter ≥ 5.5 cm or growth > 0.5 cm in 6 months. Do not delay surgery for imaging in hemodynamically unstable patients with a known mass.
Prognosis
Risk of rupture correlates directly with diameter. Aortoenteric fistula is a rare but lethal complication. Patients with small aneurysms require serial ultrasound surveillance to monitor expansion rates.
Differential Diagnosis
Renal colic: presence of hematuria and lack of pulsatile mass
Diverticulitis: fever, leukocytosis, and LLQ localization
Peptic ulcer disease: history of NSAID use and epigastric burning
Pancreatitis: elevated lipase and history of alcohol/gallstones
Myocardial infarction: EKG changes and cardiac enzyme elevation