abdominal aortic aneurysm Flashcards
what is an aneurysm
the permanent dilation of the artery to twice its normal diameter
what is the measurement for diagnosis of an AAA
> 3cm
describe the aetiology of an AAA
older
men
first degree relative with AAA
may occur secondary to atheroma, infection or trauma
genetic component - Marfan’s or EDS
who can be screened for AAA by the NHS
men over 65
where do AAAs usually occur
infrarenally (below renal arteries) - 80%
describe the pathophysiology of AAA
degeneration of the media of the arterial wall
this occurs most commonly due to atheroma
describe the link between atheroma and AAA
during the formation of the plaque macrophages release enzymes
enzymes break down collagen and elastin of the media
media expands and eventually degenerates
what happens during rupture of an AAA
the wall of the aorta fails
blood escapes into the abdominal cavity
75% are fatal
survival is most likely if retroperitoneal (blood is contained). Intraperitoneal ruptures are quickly fatal
what proportion of AAA is asymptomatic
75%
what are the symptoms of a ruptured AAA
sudden onset abdo pain radiating to the back
expansile abdominal mass
what are the symptoms of an AAA
pt can have epigastric or umbilical pain with no rupture
75% asymptomatic
signs of AAA
‘trash feet’ - hypoxia of digits
collapse (due to hypotension)
tachycardia
investigations for a ruptured AAA
diagnosis is usually clinical - needs to be made quickly
CT is the only imaging that can identify a ruptured AAA - no time
vascular surgery needs to be contacted ASAP
what are the investigations used in AAA
over 65 male screening
USS - shows whether AAA is present, its diameter and whether there is iliac involvement
outline the medical management of AAA
control risk factors:
antihypertensives
smoking cessation
lipid lowering meds
