Abdominal aortic examination Flashcards
what is the role of the abdominal aorta?
direct continuation of the descending aorta-> provides blood to much of abdominal cavity
define an abdominal aortic aneurysm?
a localised enlargement of the abdominal aorta such that the diameter is more than 3cm or more than 50% larger than normal diameter ( normal diameter is 2cm)
what are the differences between a true aneurysm and a false aneurysm?
true aneurysm- abnormal dilatation involving all layers of the arterial wall
- these can be fusiform or sac- like ( outpocketing)
False aneurysm ( pseudoaneurysms) involves a collection of blood in the outer layer ( adventitia) which communicates with lumen eg after iatrogenic trauma ( usually fusiform)
What are the risk factors for abdominal aorta aneurysm?
severe atherosclerotic damage to aortic wall
atheroma
family history
smoking
age
Hypertension
Hyperlipidaemia
Connective tissue disorders: Marfan’s syndrome, Ehlers-Danlos syndrome
Inflammatory disorders: Behcet’s disease, Takayasu’s arteritis
outline the aetiology of AAA?
There are NO specific identifiable causes
May be due to atherosclerosis and inflammatory changes
Unruptured aneurysms occur due to degeneration of elastic lamellae and smooth muscle loss.
In established aneurysmal disease there is dilation of all layers of the arterial wall and loss of both elastin and collagen. The primary event is loss of elastic fibres with subsequent degradation of collagen fibres.
summarise the epidemiology of AAA?
Ruptured AAA:125 deaths per million in ages 55-59
AAA screening programme being introduced in UK – all males >65 – ultrasound scan
Unruptured AAA: 3% of >50 yrs, male: female ratio 8:1
Female risk of rupture is higher and at smaller diameters
Where can ruptures AAA leak into?
retroperitoneal space ( relatively haemodynamically stable) or intraperitoneal space ( likely to result in shock)
also check for popliteal aneurysm
what are the presenting symptoms of an unruptures AAA?
NO SYMPTOMS
Usually an incidental finding
May have pain in the back, abdomen, loin or groin
What are the presenting symptoms of a ruptured aortic aneurysm?
Pain in the abdomen – intermittent or continuous; radiates to back, iliac fossae or groin
Pain may be sudden or severe
Syncope – low blood pressure
Shock-> NOTE: degree of shock depends on site of rupture and whether it is contained
what are the signs of AAA on physical examination?
mass on bimanual palpation of the abdominal aorta
Abdominal bruit
Retroperitoneal haemorrhage can cause Grey-Turner’s sign
Hypotension, tachycardia
What are the appropriate investigations for AAA?
Bloods
FBC, clotting screen, renal function and liver function
Cross-match if surgery is planned
Scans
Doppler Ultrasound - can detect aneurysm but CANNOT tell whether it is leaking or not – FIRST INVESTIGATION TO ORDER!
Close surveillance after (every 6 months)
CT with contrast - can show whether an aneurysm has ruptured/ more useful in localising the lesion and its relationship to renal vasculature - MOST COMMON MODALITY
MRI angiography - May be misleading as mural thrombus May mimic arterial wall and underestimate diameter
Usually with a suspected rupture, no imaging modality is needed, go straight to immediate resus
outline the management for AAA?
Management done in women if 5cm and in men if 5.5cm and you basics put a graft in to take the pressure off the AAA so it don’t rupture. Risk of aneurysm is sharply increased if 6cm+
Screening program:
Abdominal ultrasound for all men in their 65th year
3cm to 4.4 cm – yearly scan
4.5cm to 5.4 cm – 3 monthly scan
>5.5cm – seen by a vascular surgeon within 2 weeks
>6.5cm requires notification to the DVLA and can’t drive until aneurysm repaired
Management:
3cm to 5cm – smoking cessation, BP control, statin and aspirin therapy and weight loss
Consider surgery if AAA >5.5cm, expanding at >1cm/year or symptomatic
Surgical Options include EVAR or Open Repair
