Synopsis
Identify a suddenly threatened limb, grade viability and start time-critical anticoagulation and vascular treatment without avoidable imaging delay.
- ALI is a sudden fall in limb perfusion, usually within 14 days, that threatens tissue viability.
- The six Ps—pain, pallor, pulselessness, perishing cold, paraesthesia and paralysis—describe the syndrome, but an incomplete set does not exclude it.
- Neurological deficit drives urgency: paraesthesia and especially motor weakness indicate a threatened limb.
Key red flags
Minimal sensory loss, usually toes, with no motor deficit; salvageable if treated promptly.
Investigation priorities
Grade limb viability and detect deterioration.
Management branches
Sudden limb pain/coldness, pulse loss, sensory change or weakness.
- First: assess ABCs, note exact onset, examine both limbs and document Doppler, sensation and motor power; give analgesia and keep the patient nil by mouth.
- Next: contact the on-call vascular specialist immediately and arrange transfer to a centre offering open and endovascular treatment.
Key medicines
Unfractionated heparin5,000 units IV bolus, or 70–100 units/kg IV, followed by an IV infusion adjusted to APTT or ACT response.
MorphineOne licensed injection regimen uses 2.5–10 mg IV, injected slowly over 4–5 minutes; select the lowest effective dose and titrate any further dosing to response in a monitored setting.