Abdominal Aortic Aneurysm

Question 1

def

Answer 1

abnormal localised dilatation of the abdominal aorta >3cm (or >50% over normal diameter)

Question 2

where do AAA most commonly occur

Answer 2

infrarenal aorta (95%)

Question 3

aetiology

Answer 3

collagen + elastin degeneration in the arterial wall
associated with
1 atherosclerosis
2 arteritis
3 CTD (marfans, ehlers-danlos)

Question 4

associations/risk factors

Answer 4

1 smoking
2 family history (10x risk if first-degree relative affected)
3 HTN
4 CAD
5 popliteal artery aneurysms

Question 5

what is the risk of rupture of a AAA related to

Answer 5

diameter

Question 6

what is the risk of rupture of a 5-5.9cm AAA

Answer 6

3.3%PA

Question 7

what is the risk of rupture of a 6-6.9cm AAA

Answer 7

9.4%PA

Question 8

what is the risk of rupture of a 7-7.9cm AAA

Answer 8

24%PA

Question 9

epi

Answer 9

increases with age

males>females

Question 10

history

Answer 10

commonly asymptomatic
symptomatic
-rupture of undiagnosed AAA
1 epigastric/back pain
2 collapse

Question 11

DDx for rupture of AAA

Answer 11

1 renal colic
2 musculoskeletal
3 diverticulitis

Question 12

why might an intact AAA cause back pain

Answer 12

due to vertebral erosion

Question 13

why might an intact AAA cause lower limb ischaemia

Answer 13

distal embolisation

Question 14

examination of AAA

Answer 14

expansile mass above the umbilicus

Question 15

examination of ruptured AAA

Answer 15

1 abdominal/back tenderness
2 pallor
3 tachycardia
4 hypotension + hypovolaemic shock

Question 16

investigations

Answer 16

1 acute presentation
-bloods (FBC, UEs, clotting, urgent cross-matching of blood)
-ECG
-CXR
2 bedside USS
-to confirm presence + size of aneurysm