Aortic Dissection

Question 1

Define Aortic Dissection

Answer 1

Separation of the aortic wall intima, resulting in blood flow into a false lumen composed of the inner and outer layers of the tunica media

Question 2

What are the types of Aortic Dissection

Answer 2

Type A: ascending aorta

Type B: Descending aorta (after left subclavian branch)

Question 3

Aetiology of Aortic Dissection

Answer 3

Elastin, collagen and smooth muscle breakdown:
Marfan's, Ehlers-Danlos (Inherited)
Bicuspid aortic valve
Aortic atherosclerosis or coarctation
Inflammation/Trauma/Infection
Iatrogenic

Chronic HTN -> stress, increased blood volume, coarctation

Question 4

Epidemiology of Aortic Dissection

Answer 4

Men predominant

>50

Question 5

Presenting symptoms of Aortic Dissection

Answer 5

Sudden onset chest pain (tearing, radiates to back/interscapular)

Syncope 
Dyspnoea 
Altered mental status 
Paraplegia 
Hemiparesis/parasthaesiae
Abdominal pain 
Limb pain

Question 6

Signs of Aortic Dissection on examination

Answer 6

Different BP in arms (>20mmHg discrepancy) + wide PP

Collapsing pulse
Early diastolic murmur (aortic regurg)
HTN 
Hypotension (shock, tamponade)
Altered mental status 
Pallor 
Pleural effusion: Reduced breath sounds, dull percussion 
Horner's (compression from aorta)

Question 7

Investigations for Aortic Dissection

Answer 7

CT angiography - false lumen and intimal flap

ECG - ST depression (check for ischaemia)

FBC - possible anaemia
U+Es - elevated Cr and BUN 
Trops - -ve
X-match - for surgery 
D-dimer - +ve

TTE - intimal flap
MRI/Intravascular USS - intimal flap

Question 8

What are the features for the following positions of compression by Aortic Dissection: carotid, coronary, renal, coeliac trunk

Answer 8

Carotid: blackouts, hemiparesis
Coronary: MI, angina
Renal: AKI, renal failure
Coeliac trunk: abdo pain