Abdominal aortic aneurysm

Question 1

Define AAA

Answer 1

localised enlargement of the abdominal aorta such that the diameter is > 3 cm or >50% larger than normal diameter

NOTE: normal diameter of the aorta = 2 cm

Question 2

Explain the aetiology/risk factors for AAA

Answer 2

There are NO specific identifiable causes

Risk Factors
Severe atherosclerotic damage to aortic wall
Family history
Smoking
Male
Age
Hypertension
Hyperlipidaemia

Connective tissue disorders: Marfan’s syndrome, Ehlers
-Danlos syndrome

Inflammatory disorders: Behcet’s disease, Takayasu’s arteritis

Question 3

Recognise the presenting symptoms of AAA

Answer 3

Unruptured
NO SYMPTOMS
Usually an incidental finding
May have pain in the back, abdomen, loin or groin

RUPTURED
Pain in the abdomen, back or loin
Pain may be sudden or severe
Syncope
Shock

NOTE: degree of shock depends on site of rupture and whether it is contained (Posterior is retroperitoneal and will tamponade)

Question 4

Recognise the signs of AAA on physical examination

Answer 4

Pulsatile and laterally expansile mass on bimanual palpation of the abdominal aorta

Abdominal bruit

Retroperitoneal haemorrhage can cause Grey-Turner’s sign

Question 5

Identify appropriate investigations for AAA

Answer 5

Bloods
FBC, clotting screen, renal function and liver function
Cross-match if surgery is planned

Scans
Ultrasound -can detect aneurysm but CANNOT tell whether it is leaking or not

CT with contrast - can show whether an aneurysm has ruptured

MRI angiography