What is the normal workup for a patient presenting with upper leg pain?

Diagnostic Workup for Upper Leg Pain

Begin with a focused vascular assessment including resting ankle-brachial index (ABI) measurement to establish or exclude peripheral artery disease (PAD), as this represents the most critical life-threatening cause of leg pain that requires immediate identification. 1

Initial Clinical Characterization

Pain Pattern Assessment:

• Determine if pain occurs predictably with walking a certain distance and resolves within 10 minutes of rest, which indicates vascular claudication 2
• Assess for bilateral buttock and posterior thigh pain that worsens with standing or spinal extension and improves with sitting or lumbar flexion, suggesting spinal stenosis 3
• Evaluate for aching discomfort in lateral hip/thigh after variable exercise that is not quickly relieved by rest, indicating hip arthritis 2
• Document if pain is sharp and lancinating, radiating down the leg, worse with sitting, suggesting nerve root compression 2

Risk Factor Screening:

• Document age ≥65 years, or age 50-64 years with diabetes, smoking history, dyslipidemia, hypertension, chronic kidney disease, or family history of PAD 2
• Assess for known atherosclerotic disease in other vascular beds (coronary, carotid, renal) 2

Physical Examination

Vascular Examination (with shoes and socks removed):

• Palpate femoral, popliteal, dorsalis pedis, and posterior tibial pulses bilaterally, rating as 0 (absent), 1 (diminished), 2 (normal), or 3 (bounding) 2
• Auscultate for femoral bruits 2
• Inspect for nonhealing wounds, gangrene, asymmetric hair growth, nail bed changes, calf muscle atrophy, or elevation pallor/dependent rubor 2

Neurological Examination:

• Perform straight-leg-raise testing 3
• Assess knee strength and reflexes, great toe and foot dorsiflexion strength, foot plantarflexion and ankle reflexes 3
• Evaluate sensory distribution for specific nerve root patterns 3

Diagnostic Testing Algorithm

Step 1: Resting ABI (Initial Test for All Patients with Suspected PAD):

• Obtain resting ABI with or without segmental pressures and waveforms 2, 1
• Interpret results: ≤0.90 = Abnormal (PAD confirmed), 0.91-0.99 = Borderline, 1.00-1.40 = Normal, >1.40 = Noncompressible arteries 2, 1

Step 2: Additional Physiological Testing Based on ABI Results:

• If ABI >1.40 (noncompressible): Measure toe-brachial index (TBI) to diagnose PAD 2, 1
• If ABI normal or borderline (>0.90 and ≤1.40) with persistent exertional leg symptoms: Perform exercise treadmill ABI testing 2, 1
• If ABI abnormal (≤0.90) with claudication: Consider exercise treadmill ABI testing to objectively assess functional status 2, 1

Step 3: Imaging for Anatomic Assessment (Only if Revascularization Considered):

• For symptomatic PAD patients being considered for revascularization: Duplex ultrasound, CTA, or MRA to diagnose anatomic location and severity of stenosis 2, 1
• For critical limb ischemia patients being considered for revascularization: Invasive angiography 2, 1
• Do not obtain anatomic imaging for asymptomatic PAD patients 2

Step 4: If ABI Normal and Spinal Stenosis Suspected:

• Obtain anteroposterior pelvis and lateral radiographs initially 3
• Obtain MRI if symptoms persist beyond 1 month of conservative management or if surgical intervention is being considered 3

Critical Clinical Pitfalls

Diabetic Patients and Chronic Kidney Disease:

• Do not rely on ABI alone due to high incidence of noncompressible arteries; obtain TBI 1
• Patients with diabetes and critical limb ischemia may have no pain due to neuropathy but still have severe tissue loss requiring urgent evaluation 2, 1

Vascular Emergencies:

• Patients at risk for critical limb ischemia (ABI <0.4 in non-diabetic, or any diabetic with known PAD) who develop acute limb symptoms represent vascular emergencies and require immediate assessment by a vascular specialist 2, 1

Distinguishing Vascular from Neurogenic Claudication:

• Vascular claudication resolves within 10 minutes of simple rest 2
• Neurogenic claudication from spinal stenosis is relieved by lumbar flexion (sitting) rather than simple rest 3
• Bilateral leg symptoms can mimic PAD, but spinal stenosis improves with position change 3

Physical Examination Limitations:

• Absence of dorsalis pedis pulse can occur in healthy patients and is less accurate than absence of posterior tibial pulse 2
• Cool or discolored skin and delayed capillary refill are not reliable for PAD diagnosis 2
• Abnormal physical findings require confirmation with ABI testing 2