Abdominal Aortic Aneurysm

Question 1

What is an abdominal aortic aneurysm (AAA)?

Answer 1

An AAA is a permanent, abnormal dilation of the abdominal aorta, typically defined as a diameter greater than 3 cm.

Question 2

Where is an abdominal aortic aneurysm typically located?

Answer 2

It is most commonly located below the level of the renal arteries (infrarenal).

Question 3

What are the risk factors for developing an AAA?

Answer 3

Risk factors include male sex, advanced age, smoking, hypertension, family history, and connective tissue disorders like Marfan syndrome.

Question 4

What are the common symptoms of an unruptured AAA?

Answer 4

Most unruptured AAAs are asymptomatic, but some may cause abdominal, back, or flank pain, or a pulsatile abdominal mass.

Question 5

What are the symptoms of a ruptured AAA?

Answer 5

Symptoms include sudden onset of severe abdominal or back pain, hypotension, syncope, and signs of shock.

Question 6

What is the aetiology of an AAA?

Answer 6

AAAs are commonly caused by atherosclerosis, which weakens the aortic wall. Other causes include connective tissue disorders, trauma, and infections.

Question 7

What is the pathophysiology of an AAA?

Answer 7

Degeneration of the aortic wall leads to thinning and weakening, which can result in progressive dilation. Factors such as inflammation and elastin degradation contribute to the process.

Question 8

What is the prevalence of AAA?

Answer 8

AAA is more common in older males, with a prevalence of around 4-8% in men over 65 years, but it is less common in women.

Question 9

What are the risk factors for rupture of an AAA?

Answer 9

Risk factors include large aneurysm size (>5.5 cm), rapid aneurysm growth, smoking, and hypertension.

Question 10

How is AAA typically detected in asymptomatic individuals?

Answer 10

It is often detected incidentally during imaging for other conditions or through screening programmes using ultrasound.

Question 11

What is the clinical examination finding most associated with AAA?

Answer 11

A pulsatile, expansile abdominal mass may be palpated in some cases.

Question 12

What imaging modality is the gold standard for diagnosing AAA?

Answer 12

Ultrasound is the gold standard for diagnosing AAA due to its accuracy, non-invasive nature, and cost-effectiveness.

Question 13

What other imaging studies can be used to evaluate AAA?

Answer 13

CT angiography is used to assess aneurysm size and morphology, especially when planning surgical intervention.

Question 14

What are the criteria for diagnosing an AAA on imaging?

Answer 14

An aortic diameter greater than 3 cm on imaging is diagnostic of an AAA.

Question 15

What are the indications for elective repair of an AAA?

Answer 15

Indications include an aneurysm diameter >5.5 cm, rapid growth (>1 cm per year), or symptomatic aneurysms.

Question 16

What are the surgical management options for AAA?

Answer 16

Surgical options include open surgical repair and endovascular aneurysm repair (EVAR).

Question 17

What are the advantages of EVAR compared to open surgical repair?

Answer 17

EVAR is less invasive, has a shorter recovery time, and lower perioperative morbidity and mortality, but requires regular follow-up for complications.

Question 18

What are the conservative management strategies for AAA?

Answer 18

Conservative management includes regular surveillance with imaging, smoking cessation, and optimisation of cardiovascular risk factors such as hypertension and hyperlipidaemia.

Question 19

What are the possible complications of an untreated AAA?

Answer 19

Complications include rupture, thromboembolism, compression of adjacent structures, and secondary infections.

Question 20

What is the mortality rate associated with a ruptured AAA?

Answer 20

The mortality rate is very high, with up to 80% of patients dying before reaching hospital or during emergency surgery.

Question 21

What are the common differential diagnoses for AAA?

Answer 21

Differential diagnoses include renal colic, pancreatitis, diverticulitis, and gastrointestinal perforation.

Question 22

How does smoking contribute to AAA development and rupture?

Answer 22

Smoking damages the vascular endothelium, promotes inflammation, and increases the rate of aneurysm growth and rupture.

Question 23

What is the role of screening programmes in AAA?

Answer 23

Screening programmes, such as ultrasound for men aged 65, reduce mortality by enabling early detection and management of asymptomatic AAAs.

Question 24

What are the key clinical features differentiating a ruptured AAA from other acute abdominal conditions?

Answer 24

Features include a history of AAA, sudden severe abdominal or back pain, haemodynamic instability, and the presence of a pulsatile abdominal mass.

Question 25

What medications may be used in the conservative management of AAA?

Answer 25

Medications include antihypertensives (e.g., beta-blockers) and statins to reduce cardiovascular risk.