Abdominal aortic aneurysm

Question 1

Who does it affect?

Answer 1

More common in males

Question 2

What is classified as an AAA?

Answer 2

Normal diameter of the abdominal aorta is approx 2cm = it increases with age.
An abdominal aneurysm is diameter of 3cm or greater.
Most arise from below the level of the renal arteries.

Question 3

What is the cause?

Answer 3

Degradation of the elastic lamellae, a leukocytic infiltrate, enhanced proteolysis and smooth muscle cell loss.

The dilation affects all three layers of the arterial wall.

Question 4

Difference between false aneurysm and true aneurysm.

Answer 4

False (pseudoaneurysm) is caused by blood leaking through the arterial wall but contained

Question 5

Types of AAA

Answer 5

• Congenital: while medial degeneration occurs naturally with age, it is accelerated in patients with bicuspid aortic valves and Marfan syndrome.
• Infectious: infection of the aortic wall (mycotic aneurysm) is rare. Staphylococcus and salmonella.
• inflammatory.

Question 6

Risk factors

Answer 6

• CIGARETTE SMOKING
• Hereditary/family history
• increased age
• Male sex (prevalence)
• Congenital/ connective tissue disorders.
• Hypertension
• Hyperlipidemia.
• COPD
• Obesity

DIABETES decrease risk.

Question 7

Symptoms?

Answer 7

Un-ruptured AAA:

1. Most patients have no symptoms.
   2) Usually incidental finding on scan
   3) May have back pain, loin pain due to pressure increase on nearby structures.
   4) Severe lumbar pain of recent onset may indicate impending rupture.

Ruptured AAA:

1) Hypotension
2) Atypical abdominal symptoms - not an easy diagnosis! So always consider AAA.
3) Pain in the abdomen, back or loin - the pain may be sudden and severe.
4) Syncope/ shock - the degree of shock varies according to the site of rupture and whether it is contained.

Question 8

Signs on examination?

Answer 8

• Palpation of the aorta can detect 61% of aneurysms over 3cm. nad 82% of those 5 cm.
• Pulsating AAA
• Abdominal swelling
• Abdominal bruit
• Grey Turner’s sign (because retroperitoneal haemorrhage).

Question 9

Investigations

Answer 9

FBC, clotting screen, renal and liver function.
ESR, cross- match if surgery is planned.
ECG, CXR

1st line investigations to order:

• Abdominal ultrasound.
• CT

Question 10

Treatment for acute ruptured AAA

Answer 10

1 st line:
Standard resuscitation measures:
- Central venous catheter
-Fluid replacement.

PLUS: Urgent surgical repair.