Abdominal aortic aneurysm

Question 1

Definition

Answer 1

Permanent pathologic dilitation of the aortic aneurysm 1.5 X size expected for age and gender

Question 2

Epidemiology

Answer 2

+With age

+in men

Question 3

Etiology

Answer 3

Most commonly associated with atherosclerosis

Aortic elastic medial degeneration and mild cystic necrosis= aortic dilation and aneurysm formation

Question 4

Pathopysiology

Answer 4

Reduction of collagen and elastin in media, adventitia and smooth muscle cell loss, tapering of medial wall, infiltration with lymphocytes, macrophages and neovascularisation

1. Proteolytic degradation
2. Transmural inflammation
3. Biochemical wall stress
4. Molecular genetics

Question 5

Risk factors

Answer 5

Smoking
Family
Age
Male
CT disorder
\+Lipids, HTN, obesity, DM

Question 6

Investigations

Answer 6

Abdominal USS
Elevated ESR and CRP support a diagnosis of possible inflammatory AAA. Leukocytosis and a relative anaemia on FBC with positive blood cultures are indicative of infectious AAA.

Question 7

Important history

Answer 7

Abdominal, back and groin pain

1. Development (lipids, DM, HTN, COPD, CTD)
2. Expansion (cardiac/renal transplant, previous stroke, +age, severe cardiac disease)
3. Rupture (female, cardiac/renal transplant, HTN)

Question 8

Management of symptomatic but not ruptured

Answer 8

Semi-urgent surgical repair
B-Blocker started one day prior to surgery
Perioperative antibiotic therapy

Question 9

Management when incidental finding

Answer 9

Small:

1. Surveillance-> older male, with significant comorbidities. USS for AAA BP, lipids, DM, smoking, obesity

Question 10

When is surgical repair indicated

Answer 10

with a diameter exceeding 5.5 cm in men or 5.0 cm in women in the US

Question 11

Mortality associated with rupture and surgery, rate of rupture / year

Answer 11

75% death rupture AA
50% if surgery
>5cm 25% rupture/year
>7cm 75% rupture

Question 12

What to look for on physical examination

Answer 12

Evidence of popliteal/other aneurysms

Question 13

What is involved in open surgical repair

Answer 13

Open surgical repair-->
can involve clamp and
sewing prosthetic arterial
graft, or ligating circulatoin
and creating a bypass

Question 14

Complications of open surgical repair

Answer 14

Renal dysfunction
Paraplegia
Ischemic colitis
Infection

Question 15

Management of AAA rupture

Answer 15

ABC
Oxygen, ETT
CV catheter, urinary catheter
Monitor and maintain BP 50-70 and withold fluids
Urgent surgical consultation, consenting
Peri-operative antibiotics
Monitor-BP, vitals, urine output, 02 sats