Aortic aneurysm Flashcards
What is an abdominal aortic aneurysm?
An abdominal aortic aneurysm (AAA) is a condition where an area of the abdominal aorta bulges out. This is usually asymptomatic, however, it has the potential to rupture, leading to haemorrhage and rapid death.
What is the epidemiology of AAA?
AAA affects more males than females, with a prevalence of 1.3% in men > 65 years in the UK.
Why is it considered that atherosclerosis may be a contributing factor to AAAs?
Atherosclerotic plaques are thought to compress the aortic media, leading to ischaemia and wall weakening
Where does the abdominal aorta begin and end?
The abdominal aorta begins at T12 and ends at L4, dividing into the right and left common iliac arteries.
What is the normal diameter of the aorta?
<2cm
What is the pathophysiology of AAAs?
- Atherosclerosis causes inflammation, which leads to infiltration by macrophages and deposition of immune complexes in the aortic wall.
- There is elastin depletion, collagen degradation and smooth muscle loss
- this results in dilation in all layers of the wall
Define ‘aneurysm’:
the permanent dilation of the artery to twice the normal diameter
What is a true aneurysm?
in true aneurysms, the arterial wall forms the wall of the aneurysm while in false aneurysms, surrounding tissue forms the wall of the aneurysm
Where do abdominal aortic aneurysms most commonly occur?
Below the renal arteries
Give 4 broad causes of aneurysms:
1) atherosclerosis
2) infection
3) trauma
4) genetic conditions (Marfan’s, Ehlers-Danlos)
What 3 locations can AAAs be?
- Juxta-renal (Located within 1 cm of the renal arteries)
- Supra-renal (starting above the renal arteries)
- Infra-renal (starting below the renal arteries)
What is a saccular AAA?
A spherical outpouching
What is a fusiform AAA?
A diffuse and circumferential dilation
Name 10 risk factors for AAA?
- Smoking
- Family history
- Increased age
- Hyperlipidaemia
- History of atherosclerosis
- History of other aneurysms
- Hypertension
- COPD
- History of connective tissue disorders
- European ancestry
Give 3 infections that can cause aneurysms:
1) syphilis
2) E. coli
3) Salmonella
In which demographic group is AAA screening offered?
men aged 65-74
Name 10 differential diagnoses for AAA?
Diverticulitis
Renal colic
Biliary colic
Cauda equina syndrome
Spinal disc prolapse
Appendicitis
Ovarian torsion
Gastrointestinal haemorrhage
Bowel obstruction
Mesenteric artery occlusion
What type of screening is used for AAAs?
Ultrasound
What is the screening plan for AAA’s less than 5.5cm?
they should continue surveillance by the screening programme
What is the referral scheme for AAA more than 5.5cm?
they should be seen by a vascular specialist within 2 weeks