Acute Limb Ischaemia

Question 1

define acute limb ischaemia

Answer 1

sudden decrease in limb perfusion causing a potential threat to limb viability

Question 2

causes of acute limb ischaemia

Answer 2

1. embolism/ thrombosis
2. arterial dissection
3. trauma
4. extrinsic compression

Question 3

embolic/ thrombus causes of acute limb ischaemia

Answer 3

AF
MI
valvular disease
acute thrombosis of popliteal aneurysm
thrombus on atherosclerotic plaques

Question 4

how can arterial dissection cause occlusion?

Answer 4

tear in the initima/media of the artery wall can lead to a flap forming which may occlude the artery

Question 5

extrinsic compression causes of acute limb ischaemia

Answer 5

cervical rib

Question 6

presentation of limb ischaemia (6 P’s) critical/ acute

Answer 6

pain
pallor
pulseless
perishingly cold
paraesthesia
paralysis

Question 7

pain in acute/ critical limb ischaemia

Answer 7

severe
sudden onset
resistant to analgesia
calf/ muscle tenderness with woody compartment indicating muscle necrosis (irreversible ischaemia)

Question 8

pallor in acute/ critical limb ischaemia

Answer 8

empty veins that re-fill with stagnated de-oxygenated blood giving a mottled appearance

Question 9

features 0-4 hours in acute limb ischaemia

Answer 9

white foot
painful
sensorimotor deficit

salvageable

Question 10

features 4-12 hours in acute limb ischaemia

Answer 10

mottled
blanches on pressure

partly reversible

Question 11

features >12 hours in acute limb ischaemia

Answer 11

fixed mottling
non-blanching
compartments tender/ red
paralysis

non-salvageable

Question 12

diagnosis of acute limb ischaemia/ critical event

Answer 12

ABC
FBC, U&Es, CK, coag +/- troponin
ECG - MI, arrhythmias
CXR - underlying malignancy

Question 13

management of salvageable limb in acute event

Answer 13

embolectomy
fasciotomies
thrombolysis

Question 14

management in unsalvageable limb

Answer 14

palliation

amputation

Question 15

once patient is anticoagulated what can they not have?

Answer 15

regional anaesthesia

Question 16

what is an embolectomy?

Answer 16

surgical removal of embolus from inside an artery using an inflatable balloon (Fogarty balloon) to pull clot back

Question 17

what is a fasciotomy?

Answer 17

when limb is successfully re-perfused, reperfusion injury can take place causing massive oedema in the muscle/ tissue within fascial compartments leading to compartment syndrome.

Question 18

define reperfusion injury

Answer 18

reperfusion of suddenly blocked arteries leads to oedema (compartment syndrome) and release of toxins

Question 19

toxins released in reperfusion injury

Answer 19

myoglobin
potassium ions
hydrogen ions

Question 20

what will myoglobin affect?

Answer 20

renal function

Question 21

clinical definition of critical limb ischaemia

Answer 21

• ischaemic rest pain >2 weeks
• presence of ischaemic lesions or gangrene
• ABPI <0.5

Question 22

what is critical limb ischaemia?

Answer 22

advanced chronic limb ischaemia

Question 23

what is acute-on chronic?

Answer 23

embolic event in patient with history of PAD