In a 21-year-old female runner who developed leg pain and progressively spreading bruising, what urgent evaluation and management are indicated?

Urgent Vascular Emergency: Immediate Evaluation Required

This 21-year-old female runner with leg pain and spreading bruising requires immediate vascular surgery consultation within 6 hours to rule out acute limb ischemia (ALI), as skeletal muscle tolerates ischemia for only 4-6 hours before irreversible damage occurs. 1, 2

Immediate Bedside Assessment (Within Minutes)

Evaluate the "6 P's" immediately to determine limb viability: 1, 2

• Pain intensity and location - ALI pain extends above the ankle and is severe 1
• Pallor - pale or mottled skin suggests arterial compromise 1, 2
• Pulselessness - use handheld continuous-wave Doppler immediately if pulses are not clearly palpable 1, 2
• Paresthesias - numbness or tingling indicates nerve ischemia 1, 2
• Paralysis - any motor weakness is a critical red flag requiring emergency revascularization 1, 2
• Poikilothermia - cold limb compared to contralateral side 2

Loss of arterial Doppler signal indicates a threatened limb requiring emergency intervention; absence of both arterial and venous signals suggests irreversible damage. 1, 2

Critical Time-Dependent Categorization

Classify the limb immediately using these categories: 1, 2

• Category I (Viable): No sensory/motor deficit, audible arterial Doppler - allows time for workup
• Category IIa (Marginally Threatened): Minimal sensory loss, no motor deficit - salvageable if promptly treated
• Category IIb (Immediately Threatened): Moderate sensory loss, mild-to-moderate motor deficit - requires revascularization within 4-6 hours 1, 2
• Category III (Irreversible): Profound sensory loss, paralysis, muscle rigor - primary amputation indicated 1, 2

Immediate Management Actions

Start unfractionated heparin IV immediately unless contraindicated to prevent thrombus propagation. 2

Obtain stat imaging based on clinical severity: 3, 2

• CTA of lower extremity if vascular injury suspected (95-100% sensitivity for arterial injury) 2
• Duplex ultrasound if CTA unavailable or to assess urgency when neurological deficit assessment is challenging 3
• Plain radiographs to exclude fracture or compartment syndrome 2

Check creatinine kinase (CK) and myoglobin levels, as elevation indicates rhabdomyolysis with increased amputation and mortality risk 3

Alternative Diagnoses to Consider

If pulses are present and no motor/sensory deficits exist, consider: 4, 5, 6

• Exercise-induced purpura - benign condition causing erythematous/purpuric plaques on lower legs after unusual muscular activity in otherwise healthy young females, showing leukocytoclastic vasculitis on biopsy 7
• Chronic exertional compartment syndrome - exertional pain with dull aching, absence of physical signs between episodes, requires compartment pressure measurement 5
• Medial tibial stress syndrome - persistent pain after activity, diffuse medial tibial tenderness, diagnosed clinically 5
• Stress fracture - localized bone tenderness, requires MRI or bone scan for confirmation 5

Definitive Management Pathway

For Category IIb limbs with motor deficit or progressive symptoms, immediate revascularization (endovascular or surgical) within 4-6 hours is mandatory to prevent amputation. 1, 2

Revascularization options include: 3

• Catheter-directed thrombolytic therapy
• Percutaneous mechanical thrombectomy
• Surgical thrombectomy or bypass
• Combined endovascular-surgical approach

For Category III limbs with profound paralysis and muscle rigor, primary amputation is indicated as salvage attempts increase mortality risk without improving limb outcome. 1, 2

Critical Pitfalls to Avoid

• Do not delay vascular surgery consultation to obtain imaging if Category IIb features are present - the 4-6 hour window is absolute 1, 2
• Do not assume benign etiology based on age alone - young athletes can develop popliteal artery entrapment syndrome or arterial endofibrosis 4, 6
• Do not rely on palpable pulses alone - use Doppler assessment as pulses may be difficult to assess with edema or anatomic variation 1, 2
• Do not attribute spreading bruising to simple contusion without excluding compartment syndrome or vascular injury 2