Leg Pain

at the bedside

vitals including SpO₂: leg pain with hypoxia or tachycardia → think PE, not just DVT
feel both legs: temperature, pulses, capillary refill, tenseness
analgesia early: paracetamol 1 g IV; do not wait for imaging

limb or life threatening

acute limb ischemia: pain, pallor, pulseless, perishingly cold, paraesthesia, paralysis → vascular now, the clock is muscle
necrotizing infection: pain out of proportion, rapid progression over hours, systemic toxicity, crepitus, bullae or skin anesthesia → surgery now
compartment syndrome: tense swollen compartment, pain on passive stretch, after trauma, reperfusion or a long lie
massive PE with leg swelling: hypotension, syncope, hypoxia → resuscitate and call ICU

history

onset: sudden (arterial, DVT) vs days (cellulitis, gout) vs chronic with acute change
VTE risk: immobility, recent surgery or plaster, cancer, previous VTE, estrogen, long travel, pregnancy
arterial risk: AF, known peripheral arterial disease, claudication, recent vascular procedure, smoking
infection: fever, break in the skin, diabetes, ulcer, IV drug use
other: trauma, gout history, back pain radiating down the leg
meds: current anticoagulant, missed doses

examination

compare both legs: circumference, color, temperature, swelling
vascular: femoral, popliteal, dorsalis pedis and posterior tibial pulses; capillary refill; sensory and motor function
skin: erythema and its border, warmth, ulcer, bullae, crepitus, necrosis
joints: effusion, focal joint tenderness (gout, septic arthritis)
compartments: tenseness, pain on passive stretch
chest: tachycardia, hypoxia, pleuritic pain → PE

suspected DVT: score probability first, then D-dimer or ultrasound
suspected PE: ECG, ABG or SpO₂, CTPA after risk assessment; bedside echo if unstable
suspected ischemia: urgent arterial imaging, do not wait for renal function
suspected infection: CBC, CRP, blood cultures, glucose; do not delay surgical review for imaging
bloods: renal function and coagulation before anticoagulating; urate unhelpful acutely in gout

DVT: when you can rule out without scanning

Wells score ≤ 1 (“DVT unlikely”) + negative high-sensitivity D-dimer excludes DVT without ultrasound
Wells ≥ 2 or positive D-dimer → proximal compression ultrasound
Age-adjusted D-dimer (>50 yr): cut-off = age × 10 µg/L (FEU), reduces unnecessary scans in older inpatients
D-dimer nearly always raised in inpatients (post-surgery, infection, malignancy): positive result rules nothing in

confirmed DVT or PE, stable

first-line (no cancer): DOAC without heparin lead-in
- apixaban 10 mg PO BD for 7 days, then 5 mg PO BD
- rivaroxaban 15 mg PO BD for 21 days, then 20 mg PO OD with food
edoxaban or dabigatran: need 5–10 days parenteral anticoagulation first
parenteral option: enoxaparin 1 mg/kg SC q12h (renally adjusted); use if NPO, unstable, or procedure likely
cancer-associated VTE: oral factor Xa inhibitor first-line; LMWH reasonable with luminal GI or GU tumors
check renal function, weight, bleeding risk before first dose

PE: who needs more than anticoagulation

High-risk (massive) PE: hemodynamic instability, cardiac arrest, obstructive shock, or systolic <90 mmHg (or drop ≥40 mmHg) for >15 min; the only group with a Class I indication for systemic thrombolysis
Intermediate-high risk (RV strain + raised troponin, stable BP): anticoagulate and monitor; reperfusion only as rescue if deteriorating (routine thrombolysis cuts decompensation but increases major and intracranial bleeding)
sPESI identifies low-risk PE (age >80, cancer, chronic cardiopulmonary disease, HR ≥110, systolic <100, SaO₂ <90%: score 0 = low risk).
Thrombolysis regimens vary: ICU or cardiology decision, per local protocol.

acute limb ischemia

call vascular immediately; limb dependent and warm, nil by mouth
start IV unfractionated heparin at once unless contraindicated (weight-based bolus then infusion, per local protocol)
do not delay imaging or revascularization for creatinine. Ischemic clock outranks contrast risk: hydrate, use minimum contrast volume
sensory loss beyond the toes with any motor weakness = immediately threatened limb: emergency revascularization
fixed mottling, rigor, complete anesthesia, no Doppler signals = irreversible: amputation discussion, not imaging

necrotizing soft tissue infection

surgical exploration is the diagnostic test: call surgery before imaging or scores
empiric: piperacillin-tazobactam 4.5 g IV q6h + vancomycin 15–20 mg/kg IV q8–12h (pharmacy sets the interval), or a carbapenem plus vancomycin
confirmed group A streptococcus: penicillin + clindamycin 600–900 mg IV q8h
LRINEC <6 does not exclude it: sensitivity as low as 36%, not endorsed by IDSA. Trust clinical picture

cellulitis

cefazolin 1 g IV q8h (or clindamycin 600 mg IV q8h); add MRSA cover if purulent, penetrating injury, known MRSA, or systemic upset. Mark border, re-examine

gout

NSAID if renal function allows, otherwise colchicine or steroid; aspirate if septic arthritis possible

sciatica

escalate

vascular now: any threatened limb
surgery now: suspected necrotizing infection or compartment syndrome
ICU / cardiology: PE with hypotension, hypoxia or RV strain
senior: before anticoagulation in anyone with bleeding risk, recent surgery, or poor renal function

source	type
ASH 2020 VTE treatment guideline	specialty-society guidance
CHEST 2021 antithrombotic therapy guideline	specialty-society guidance
ACR/NKF 2020 consensus statement on contrast media and AKI	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 Sep 2026file complaint/leg-pain