Leg Pain

at the bedside

airway, breathing, circulation; full vitals, SpO₂: leg symptoms with unexplained hypoxia, tachycardia, dyspnea or syncope → assess urgently for PE → dyspnea
where exactly → calf, thigh, joint, diffuse muscle, or radiating from the back
the chart → post-op day, days immobile, prophylaxis given or missed, anticoagulant, cannula in that limb, a fall on the ward
feel and look → temperature, pulses, capillary refill, tense compartments, sensation and power; swelling level, color, erythema border, bullae, crepitus, cannula site, joint effusion
analgesia early, paracetamol 1 g PO/IV; do not wait for imaging

escalate now if

pale, pulseless, cold, numb or weak leg → acute limb ischemia, vascular surgery now; the clock is muscle
pain out of proportion, fast spread, bullae, crepitus, skin anesthesia, toxic → necrotizing infection, surgery now
tense compartment, pain on passive stretch, after trauma, reperfusion or a long lie → compartment syndrome; normal pulses and capillary refill do not exclude it
swollen leg with hypoxia, syncope or hypotension → high-risk PE → dyspnea
hot swollen joint → septic arthritis until the aspirate says otherwise; can be afebrile in the elderly or immunosuppressed
back pain with bilateral leg symptoms or bladder change → cauda equina → back pain

vascular → DVT (one swollen tender calf); acute limb ischemia (sudden, pale, pulseless, cold; AF); thrombophlebitis at a cannula
infectious or inflammatory → cellulitis (spreading erythema, a skin break); necrotizing infection (pain beyond the findings, bullae, crepitus); septic arthritis or gout (hot joint; fever and not bearing weight favor infection)
musculoskeletal or neurological → compartment syndrome; muscle tear or hematoma (a fall, anticoagulated); ruptured Baker cyst; sciatica → back pain
other → bilateral edema (heart, kidney or liver failure); chronic venous disease; statin myopathy

onset → sudden (arterial, DVT, tear) vs days (cellulitis, gout) vs chronic with a change
risk → VTE: immobility, surgery or cast, cancer, previous VTE, estrogen; arterial: AF, peripheral arterial disease, recent vascular procedure
infection → wound, ulcer or cannula, diabetes, IV drug use, immunosuppression
drug chart → missed anticoagulant doses, statins (myositis), diuretics (gout)
measure → calf circumference both sides, erythema border marked, joint range

DVT suspected → Wells first; unlikely and D-dimer negative excludes it; otherwise proximal compression ultrasound
PE suspected → ECG, VBG, CTPA by the pathway → dyspnea
ischemia suspected → vascular surgery chooses the imaging; a threatened limb waits for no scan or creatinine
cellulitis, well → CBC, CRP, glucose; cultures, CK and lactate only if systemically ill or deep infection is suspected
necrotizing infection suspected → CBC, CRP, CK, lactate, blood cultures, group and save; imaging never delays surgery
hot joint → aspirate before antibiotics unless sepsis or septic shock: cell count, Gram stain, culture, crystals
before anticoagulation → CBC, renal function, coagulation, weight

DVT: when you can rule out without a scan

Wells ≤ 1 (“unlikely”) with a negative high-sensitivity D-dimer excludes DVT, no ultrasound
Wells ≥ 2 or D-dimer positive → proximal ultrasound; not possible within 4 h → one interim anticoagulant dose, scan within 24 h (NICE NG158)
negative scan, positive D-dimer → stop interim anticoagulation, repeat ultrasound at 6 to 8 days (NICE NG158)
age-adjusted D-dimer over 50 → age × 10 µg/L (FEU); inpatients almost always test positive, which rules nothing in

limb-threatening: acute limb ischemia

vascular surgery now; systemic unfractionated heparin at once unless contraindicated (weight-based bolus then infusion, local protocol); limb dependent and warm; NPO
imaging as vascular surgery directs; an immediately threatened limb goes to revascularization, not to a scanner or a creatinine first; viability (motor, sensory, Doppler signals) is graded by vascular surgery, not from mottling or rigor alone

limb-threatening: necrotizing soft tissue infection

surgery now → exploration is the diagnostic test; no imaging or score (LRINEC misses a third) delays the call; fluids, ICU early → fever
from the first dose: vancomycin 25 mg/kg IV load then 15–20 mg/kg q8–12h + piperacillin–tazobactam 4.5 g IV q6h (or a carbapenem) + clindamycin 900 mg IV q8h for toxin suppression → empiric antibiotics

limb-threatening: compartment syndrome

orthopedics now for fasciotomy (vascular surgery if after reperfusion); remove casts and dressings, limb at heart level, not elevated; analgesia; a clinical diagnosis, pressures only if unclear

thromboembolic: DVT or PE, stable

first decision → anticoagulate now; recent surgery, bleeding risk or a procedure within 24 h → treating team before the first dose → coagulation profile
first dose → enoxaparin 1 mg/kg SC q12h; unfractionated heparin instead when CrCl is below 30, unstable, a procedure is likely or reperfusion may be needed
RV strain or raised troponin → telemetry, ICU aware; unstable PE → thrombolysis → dyspnea

oral regimens, a treating-team decision once stable and eating

apixaban 10 mg PO BD for 7 days then 5 mg BD; or rivaroxaban 15 mg PO BD for 21 days then 20 mg OD with food; edoxaban or dabigatran need 5–10 days of parenteral anticoagulation first
cancer-associated → apixaban or rivaroxaban; LMWH if a luminal GI or GU tumor

infectious or inflammatory: cellulitis

cefazolin 1 g IV q8h; β-lactam allergy → ask what happened: anaphylaxis or a severe cutaneous reaction → vancomycin; a remote mild rash does not forbid cefazolin; MRSA cover if purulent, prior MRSA or IV drug use → empiric antibiotics
mark the border and the time; elevate; take out a cannula at the site; bilateral red legs without fever are stasis dermatitis, not cellulitis

infectious or inflammatory: hot joint

aspirate first; sepsis or septic shock → cultures then antibiotics at once; Gram-stain led regimen, orthopedics for washout → empiric antibiotics; crystals do not exclude concurrent septic arthritis
gout → NSAID if kidneys allow → analgesia; else colchicine 1.2 mg then 0.6 mg after 1 h, or prednisolone 30–35 mg PO OD for 5 days; do not stop allopurinol

other causes

hematoma on anticoagulation → hold the next dose, tell the treating team, Hb and coagulation; tense or expanding → orthopedics or vascular surgery
musculoskeletal or neurological → once dangerous causes are excluded: analgesia, mobilize, missed prophylaxis back on the chart, review in the morning

hand over → diagnosis, anticoagulant or antibiotic given and time, vascular or orthopedic plan, level of care, what triggers the next call

source	type
ASH 2020 VTE treatment guideline	international guideline
CHEST 2021 antithrombotic therapy for VTE	international guideline
NICE NG158 venous thromboembolic diseases	national guideline
2024 AHA/ACC peripheral artery disease guideline	international guideline
2024 ESC peripheral arterial and aortic diseases guideline	international guideline
IDSA 2014 skin and soft tissue infection guideline	international guideline
ACR 2020 gout guideline	specialty-society guidance
ACR/NKF 2020 consensus on contrast media and kidney injury	specialty-society guidance

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

free the on-call checklist covers the whole shift on one printable page.

studying for the IM exam? the IM Rapid Review covers this in the same format. see the sample chapter.

reviewed Jul 2026updated Oct 2026file complaint/leg-pain