Abdominal Aortic Aneurysm

Question 1

Definition of AAA

Answer 1

DEFINITION: a 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

Answer 2

There are NO specific identifiable causes

Question 3

Risk factors for AAA

Answer 3

• 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 4

Recognise the presenting symptoms of AAA

Answer 4

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- hypoperfusion of the brain

Shock

NOTE: degree of shock depends on site of rupture and whether it is contained

Question 5

Recognise the signs of AAA on physical examination

Answer 5

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

Abdominal bruit- like heart murmur

Retroperitoneal haemorrhage can cause Grey-Turner’s sign- bruising on the belly button and around the flanks

Question 6

Identify appropriate investigations for AAA

Answer 6

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- emphasises blood vessles

MRI angiography