Sudden Leg Pain on a Medical Ward With Missed Anticoagulation
Mr. Haddad, 70, calls the ward 6 hours after the onset of sudden severe pain in his right leg. He is an inpatient being treated for pneumonia and takes apixaban for atrial fibrillation, though he missed two doses during admission because of a swallow study. Examination: right foot pale with mottled toes, cool to mid-calf, capillary refill 5 seconds, no palpable dorsalis pedis or posterior tibial pulse, and he cannot dorsiflex the foot. Sensation is reduced over the dorsum but present. Hand-held Doppler shows no arterial signal at the ankle; a venous signal is audible. BP 150/86, HR 104 irregularly irregular, creatinine 1.6 mg/dL. The surgical registrar is in theatre for four hours; the intern suggests elevating the leg and starting a heparin infusion while awaiting review.
1. Classify the threat to his limb and explain why the intern's plan is partly right and partly wrong.
Read the worked answer
Classification Sudden onset, pale mottled foot, cool to mid-calf, absent arterial Doppler signals with a preserved venous signal, reduced sensation and a motor deficit (cannot dorsiflex) place this in the threatened, immediately endangered category - sensory loss plus motor weakness means the limb is at imminent risk and revascularisation is needed within hours, not after a theatre list clears.
What is right Heparinisation is a reasonable adjunct to limit clot propagation while definitive treatment is arranged.
What is wrong
- Elevation is harmful. In acute arterial ischaemia the limb needs perfusion pressure; elevation lowers it further. Keep the leg flat or slightly dependent, protect it from pressure and from heating pads (burn risk with impaired sensation).
- Waiting four hours is not acceptable. The warm ischaemia time is already 6 hours; add 4 more and the limb may be unsalvageable. Escalate now to the on-call vascular surgeon, and if none is available, arrange transfer.
Additional actions: nil by mouth, IV access, analgesia, group and crossmatch, creatine kinase, potassium, renal function, coagulation screen, continuous ECG, and hourly neurovascular observations with documented warm-ischaemia time.
2. What will you monitor for in the first 24 hours after revascularisation, and why does each risk matter here?
Read the worked answer
Reperfusion injury - potassium, acidosis and myoglobin surge into the circulation when flow is restored. He has 6 or more hours of ischaemia, so anticipate hyperkalaemia and arrhythmia: continuous ECG, serial potassium and creatine kinase, and adequate IV hydration as prescribed. Rhabdomyolysis and acute kidney injury - his creatinine is already 1.6. Monitor urine output and colour, maintain hydration, and track creatine kinase trends. Compartment syndrome - pain out of proportion, pain on passive stretch, tense calf, worsening neurology. Hourly neurovascular checks; loosen constricting dressings; report immediately because fasciotomy is time-critical. Re-occlusion - loss of a restored pulse, return of pain, pallor or sensory change. Mark and document pulses. Bleeding - at the operative or access site and systemically, especially with heparin and residual apixaban. Cardiac monitoring - he is in atrial fibrillation at 104 with a recent embolic event; watch for further emboli and for rate-related ischaemia.
3. How does his anticoagulation history change your immediate actions and communication?
Read the worked answer
It is both the cause and a current hazard.
- The missed apixaban doses during the swallow study are the most likely reason an atrial-fibrillation thrombus embolised. That is a system failure worth naming, not a patient failing.
- Residual apixaban, plus his creatinine of 1.6 affecting clearance, raises bleeding risk for embolectomy and constrains anaesthetic choices (for example, neuraxial techniques).
Immediate actions
- Establish the exact timing and dose of the last apixaban; check renal function and weight for dosing accuracy.
- Hand this information directly to the surgeon, anaesthetist and receiving team - do not rely on the chart alone.
- Do not add further anticoagulation empirically; heparin may be appropriate but must be coordinated with the operative plan.
- Once he is stable, restart anticoagulation with a documented plan and address the reason doses were missed: a swallow study should trigger an alternative route or a bridging decision, not silent omission.
- Educate him that apixaban omission is what put his leg at risk, using teach-back, and document the conversation and the corrective action taken on the ward.