Abdominal Aortic Aneurysm Flashcards
what is an aneurysm?
dilatation of a vessel by more than 50% of its normal diameter
what is normal aortic diameter?
1.2-2 cm
what is a true aneurysm?
the vessel wall is intact
what is a false aneurysm?
there is a breach in vessel wall (surrounding structures act as vessel wall)
what are the 3 shapes of aneurysm?
saccular
fusiform
mycotic
when do mycotic aneurysms arise?
secondary to a infectious process, involving all 3 layers of the artery
what is the medical degeneration in an AAA?
regulation of elastin/collagen in aortic wall
aneurysmal dilatation
increase in aortic wall stress
progressive dilatation
what are the risk factors for an AAA?
age gender smoking hypertension atherosclerosis
how are asymptomatic AAAs identified?
imaging for other pathology
surveillance
how are symptomatic AAAs identified?
pain- may mimic renal colic
‘trashing’
rupture
describe the progression of a rupture of an AAA
sudden onset epigastric/central pain
may radiate through to back
may mimic renal colic pain
collapse
describe the exam of somebody with a symptomatic ruptured AAA
may look 'well' hypo/hypertensive pulsatile, expansile mass +/- tender transmitted pulse peripheral pulses
what are the types of rupture?
most retroperitoneal, contained rupture
free intra-peritoneal rupture is rapidly fatal
when to intervene with a symptomatic AAA?
pain
‘trashing’
rupture
when to intervene with an asymptomatic AAA?
size- >5.5 cm
expansion- 0.5cm/6 months
what is used for surveillance of AAAs?
duplex ultrasound
when is a CT scan used?
when contrast is in arterial system
what is a duplex ultrasound used for?
- AP diameter
- involvement of iliac arteries
what is a CT scan used for?
shape, size, iliac involvement
allows for management planning
only imaging method to identify ruptured AAA
how is an AA managed?
open repair
- laparotomy
- clamp aorta + iliacs
- dacron graft
- tube vs bifurcated graft
describe endovascular aneurysm repair
exclude AAA from ‘inside’ the vessel
inserted via peripheral artery
x ray guided
modular components
what is acute limb ischaemia?
sudden loss of blood supply to a limb due to occlusion of native artery or bypass graft
what are the causes of a sudden occlusion?
embolism atheroembolism arterial dissection trauma extrinsic compression
what are the clinical features of acute limb iscahemia
6 Ps pain pallor pulseless perishingly cold paraesthesia paralysis
no prior history of claudication
known cause for embolism
full complement of contra-lateral pulses
describe the pain of acute limb iscahemia
severe, sudden onset, resistant to analgesis
calf muscle tendereness with tight compartment indicates muscle necrosis- often irreversible
describe the pallor of acute limb iscahemia
limb initially white with empty veins
later, capillaires fill with atgnated de-oxygenated blood giving a mottled appearance
arteries distal to occlusion fill with propaganted thrombus with rupture of capillaries
describe blanching mottling
salvageable if prompt revascularisation
describe non blanching mottling
irreversible ischaemia
describe the paraesthesia/paralysis of acute limb ischaemia
sensorimotor deficit are indicative of muscle and nerve ischaemia
salvageable if prompt revascularisation
describe 0-4 hours
white foot
painful
sensorimotor deficit
salvageable
describe 4-12 hours
mottled
blanches on pressure
partly reversible
describe >12 hours
fixed mottling non blanching compartments tender/red paralysis non salvageable
describe the management of acute limb ischaemia
ABC FBC, U/Es, CK, coag +/- troponin ECG- MI, dysrhythmia CXR- underlying malignancy anticoagulate
what are diabetic foot problems?
diabetic neuropathy
peripheral vascular disease
infection
all of which lead to tissue ulceration, necrosis and gangrene
why would diabetic foot sepsis occur?
simple puncture wound
infection from the nail plate or inter-digital space
from a neuro-ischaemic ulcer
why is foot infection a problem?
infection tracts in the soft tissue into this rigid compartment
if the build up of pus cannot escape, the pressure builds up in this rigid compartment rapidly leading to impairment of capillary blood flow and further iscahemia and further tissue damage
what are the clinical systemic findings of diabetic foot sepsis?
Pyrexia Tachycardic Tachypnoeic Confused Kussmauls breathing
what are the local clinical findings of diabetic foot sepsis?
Swollen affected digit (‘sausage’ like)
Swollen forefoot (‘boggy’ feeling to swelling)
Tenderness
Ulcer with pus extruding
Erythema, may track up the limb
Patches of rapidly developing necrosis
Crepitus in the soft tissues of the foot (Gas from gas forming organisms)
what is the management of diabetic foot sepsis?
treated as vascular surgical emergency
Appropriate antibiotic should be administered at the earliest opportunity
Rapid surgical debridement of infected tissue
Remove all infected tissue
Wound open to encourage drainage
what is the aftercare of diabetic foot problems?
further problems can be prevented with adequate education, foot assessment (diabetic foot clinic, podiatrist) and pressure offloading footwear
