limb_ischaemia
acute limb ischaemia
introduction
acute limb ischaemia is a time critical condition which requires rapid recognition, assessment and management to save the limb and perhaps the patient's life.
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it is characterized by a rapid decrease in limb perfusion which usually produces new or worsening symptoms or signs, and often threatens limb viability.
aetiology
acute - usually presentation within hours
acute on chronic - usually delayed presentation over days
clinical assessment
history
2 main aims:
determine presence, time of onset and severity of the ischaemia
determine risk factors, past relevant interventions and to exclude possible differentials to limb ischaemia
examination
remember the 5 P's
Pain - time of onset, variation over time, location, intensity
Pulselessness - absence of pedal pulses suggests acute limb ischaemia which can be confirmed on Doppler USS, and measurement of
ankle-brachial index (ABI)
Pallor (may be absent if collaterals present, and instead may have ischaemic rubor)
Paraesthesiae - if more than just in the toes, suggests limb viability is becoming critical
Paralysis - if present suggests probable non-viable limb
Prostration is Pratt's 6th P - hypotension and shock
assessing severity - Rutherford's categories of severity
category I: no sensory loss and no muscle weakness
category IIa: paraesthesiae confined to toes or not present suggests limb is viable and potentially salvageable
category IIb: more extensive paraethesiae with rest pain and only mild-moderate muscle weakness, but perhaps tender muscles and pain on passive movement suggests advanced acute limb ischaemia which may still be salvageable with immediate revascularisation
category III: profound anaesthesia and paralysis indicate major tissue loss and nerve damage which is probably irreversible and require amputation
is it really arterial ischaemia?
conditions mimicking acute limb ischaemia
other causes of arterial ischaemia
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arteritis with thrombosis (eg. giant cell arteritis)
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hypercoagulable states causing thrombosis
thrombosis of popliteal artery due to adventitial cyst or entrapment
compartment syndrome
initial Mx in ED
iv access, FBE, U&E, glucose, clotting profile, CK
ECG
early vascular surgical consult is imperative
early anticoagulation with iv
heparin is usually indicated to prevent extension of thrombosis
rapid confirmation with Doppler USS and/or CT angiography may be indicated
category I and IIa patients can usually have angiography to decide further Mx such as:
catheter directed thrombolytic Rx
percutaneous aspiration thrombectomy (PAT) +/- thrombolysis
percutaneous mechanical thrombectomy (PMT) +/- thrombolysis
category IIb patients will usually need immediate assessment for revascularisation procedure
category III patients will generally require amputation or palliation depending upon pre-existing co-morbidities and likelihood of survival from surgery if presentation is severely delayed.
references
limb_ischaemia.txt · Last modified: 2019/08/28 15:31 (external edit)