Aneurysms Flashcards
Describe the common sites of atherosclerotic aneurysms
The more common sites are in descending, strong-flow vessels (and in descending order of incidence)
- the abdominal aorta
- iliac
- popliteal
- femoral arteries
- thoracic aorta.
What is the relative incidence of abdominal aortic aneurysms?
AAA is the most common atherosclerotic arterial aneurysm
- Present in 5% of males over 60
- They are 5x more common in males and are mainly asymptomatic
What is an aneurysm?
How can it present?
Aneurysm = a focal dilation of an artery >150% of its normal diameter.
They can present in different ways:
- Mass effects: pressuring adjacent structures
- Embolic events: due to development of mural thrombi
- Haemorrhage: due to rupture
Describe the pathophysiology of arterial dissection.
What are possible outcomes of arterial dissection?
- A tear in the intima leads to blood tracking into the arterial media
- The arterial media spilts, forming a false channel
- This most commonly occurs in the aorta
- There are two patterns:
- Type A (70%): involves the ascending aorta
- Type B (30%): do not involve the ascending aorta
- Possible outcomes:
- External rupture: massive fatal haemorrhage
- Internal rupture: Rare, blood tracks back into the lumen to produce a double-channelled aorta
- Cardiac tamponade: retrograde spread into the pericardial cavity
What are causes of arterial dissection?
Hypertension
Atheroma
Congential disease (Marfan’s/Ehlers-Danlos)
What are complications of arterial dissection as the dissection spreads?
- Retrograde spread can lead to cardiac tamponade
- If the dissection spreads distally then the origins of the main arterial branches become blocked; leading to symptms on the arteries involved:
- Coronary arteries - MI
- Brachiocephalic trunk - unequal arm pulses and central neurological symptoms
- Renal arteries - haematuria, anuria, AKI
- Iliac arteries - acute lower limb ischaemia
What is the presentation of a patient with a thoracic aortic dissection?
- Severe, very sudden onset central chest pain, describing as ‘tearing’
- It may radiate down the arm/to the back (mimicking MI)
- The patient is shocked
- There may be signs of blockage of distal arterial trunks
What are the signs and symptoms of a ruptured abdominal aortic aneurysm?
Until rupture most AAAs are asymptomatic
Rupture presentation:
- Severe epigastic pain radiating to the the back
- Pulsatile, expansile abdominal mass
- Signs of shock:
- Hypotension
- Tachycardia
- Rapid breathing ect.
What are differential diagnosis for signs of an abdominal aortic aneurysm?
- renal colic
- diverticulitis
- pancreatitis
- gastric/duodenal ulcer perforation
- MI
What is the management for an unruptured AAA?
Depends on size
- AAAs that measure <5.5cm
- Monitor by regular USS/CT
- Modification of risk factors: e.g. control of hypertension
- 75% of monitored aneurysms will eventually require surgery
- Indications for surgery:
- AAAs >6cm - risk of rupture increases from 1% to 25% at 6cm
- AAAs expanding at >1cm per year
- Symptomatic aneurysms
