acute limb ischaemia Flashcards Preview

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Flashcards in acute limb ischaemia Deck (12)
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1
Q

what is acute limb ischaemia?

A

the sudden decrease in limb perfusion that threatens the viability of the limb

complete or even partial occlusion of the arterial supply of a limb can lead to rapid ischaemia and poor functional outcomes within hours

2
Q

what are the causes of acute limb ischaemia?

A
  • embolisation e.g from sites as a result of AF, post MI mural thrombus, AAA or prosthetic heart valves
  • thrombus in situ where atheroma ruptures in artery and thrombus forms on plaques cap (can present as acute or acute on chronic)
  • trauma, less common. includes compartment syndrome
3
Q

what are the signs and symptoms of acute limb ischaemia?

A

6 P’s

  • pain
  • pallor
  • pulselessness
  • paraesthesia
  • perishing cold
  • paralysis

top 3 are the most common initial features.

  • sudden onset
  • normal contralateral limb suggests embolic occlusion
  • causes of potential embolisation should be considered
4
Q

what are the differentials for acute limb ischaemia?

A

critical chronic limb ischaemia

acute DVT

spinal cord or peripheral nerve compression

5
Q

what investigations should be done into acute limb ischaemia?

A
  • routine bloods including serum lactate to asses ischaemia level
  • thrombophilia screen if <50 without known risk factors
  • asses with bedside doppler USS of both limbs, followed by CT angiography
  • if limb is salvageable, CT arteriography can provide more info on the anatomical location of the occlusion and help with surgical approach
6
Q

how is an acute ischaemic limb initially managed?

A

surgical emergency
can get irreversible tissue damage within 6 hours

start on

  • high flow oxygen
  • IV access
  • therapeutic heparin dose or bolus dose, then heparin infusion
7
Q

how is acute limb ischaemia managed conservatively?

A

can consider with those with no or minimal sensory loss and audible arterial and/or venous doppler

  • prolonged corse of heparin
  • asses regularly
  • APTT (activated partial thromboplastin time) test should be done with clinical reviews
8
Q

what surgical intervention options are there for embolic causes of acute limb ischaemia?

A
  • embolectomy via Fogarty catheter
  • local intra arterial thrombolysis
  • bypass surgery if there is insufficient flow back

NB: Most post-operative cases require a high level of care, typically at a high dependency unit, due to the ischaemia reperfusion syndrome.

9
Q

what surgical intervention options are there for thrombotic causes of acute limb ischaemia?

A
  • local intra arterial thrombolysis
  • angioplasty
  • bypass surgery

NB: Most post-operative cases require a high level of care, typically at a high dependency unit, due to the ischaemia reperfusion syndrome.

10
Q

when will a limb need amputation and what aftercare is needed?

A

when there is irreversible limb ischaemia

(mottled, non blanching appearance with hard woody muscles)

after, need

  • occupational therapy
  • physiotherapy
  • long term rehabilitation plan
11
Q

how is acute limb ischaemia managed in the long term?

A
  • reduce CV mortality risk by lifestyle changes
  • start on anti platelet agent egg aspirin/clopidogrel, or even anticoagulation with warfarin or DOAC
  • treat underlying conditions
12
Q

what is reperfusion injury?

A

a complication of acute limb ischaemia

sudden increase in capillary permeability can result in

  • compartment syndrome
  • release of substances from damaged muscle cells e.g

K ions = hyperkalaemia
H ions = acidosis
Myoglobin = AKI

need to monitor patients at risk of compartment syndrome carefully and treat rapidly

electrolyte imbalance due to RI requires close monitoring and potential haemofiltration