What are the differential diagnoses for bilateral ankle pain in an adult patient with no significant medical history?

Differential Diagnoses for Bilateral Ankle Pain

In an adult with bilateral ankle pain and no significant medical history, the primary differentials include inflammatory arthropathies, systemic conditions, overuse syndromes, and bilateral traumatic injuries, with inflammatory causes being the most critical to rule out given the bilateral presentation. 1

Key Distinguishing Feature: Bilateral vs. Unilateral Presentation

Bilateral ankle pain is inherently different from unilateral presentations and should raise suspicion for systemic etiologies rather than isolated traumatic or mechanical causes. 1, 2

Primary Differential Diagnoses

Inflammatory/Systemic Causes (Most Critical to Exclude)

• Inflammatory arthropathies (rheumatoid arthritis, psoriatic arthritis, reactive arthritis, ankylosing spondylitis) should be considered first in bilateral presentations, particularly if accompanied by morning stiffness, pain in other joints, or systemic symptoms 1
• Peripheral neuropathy from diabetes, vitamin B12 deficiency, alcohol abuse, heavy metal poisoning, neurotoxic medications, renal disease, or inherited neuropathies can present as bilateral ankle pain with burning or tingling sensations 3, 1
• Peripheral arterial disease (PAD) should be evaluated in patients ≥65 years, age 50-64 with atherosclerotic risk factors, or those with known atherosclerotic disease elsewhere, presenting with exertional leg symptoms or rest pain 3

Overuse/Mechanical Causes

• Bilateral Achilles tendinopathy from increased activity, particularly in patients reporting recent changes in walking surface or activity level 1, 2
• Bilateral plantar fasciitis with pain at the Achilles insertion or plantar heel, worse with first steps in morning 1
• Calcaneal stress fractures presenting with progressively worsening pain following increased activity, positive calcaneal squeeze test (compression from medial to lateral) 1
• Haglund's deformity with retrocalcaneal bursitis causing posterior and lateral heel pain bilaterally, with prominent posterior superior calcaneus 1

Traumatic Causes (Less Likely if Truly Bilateral Without Clear Trauma)

• Bilateral lateral ankle sprains are uncommon without clear bilateral inversion trauma history 3, 4, 5
• Syndesmotic (high ankle) sprains from dorsiflexion and eversion with internal tibial rotation 3, 5

Other Systemic Considerations

• Lymphedema presenting as bilateral non-pitting ankle edema with thickened skinfold, particularly if progressive over months to years 6
• Sever disease (calcaneal apophysitis) if the patient is an adolescent, as this is the most common cause of heel pain in children 1

Essential History Elements to Obtain

• Timing and onset: Acute vs. chronic, progressive vs. intermittent 1, 5
• Pain characteristics: Burning/tingling (neurologic), aching/cramping (vascular), sharp (mechanical) 3, 1
• Activity relationship: Pain with walking that improves with rest <10 minutes suggests claudication from PAD; pain worse with first steps suggests plantar fasciitis 3, 1
• Recent activity changes: Increased walking, new exercise regimen, change to harder walking surface 1
• Systemic symptoms: Morning stiffness, other joint pain, fever, weight loss, fatigue 1, 6
• Medical history: Diabetes, smoking, dyslipidemia, hypertension, known atherosclerotic disease, inflammatory conditions 3
• Medication history: Neurotoxic medications 3

Critical Physical Examination Findings

Vascular Assessment

• Pulse palpation of femoral, popliteal, dorsalis pedis, and posterior tibial arteries bilaterally 3
• Inspection for elevation pallor, dependent rubor, asymmetric hair growth, nail changes, calf atrophy 3
• Ankle-brachial index (ABI) if PAD suspected based on risk factors and symptoms 3

Musculoskeletal Assessment

• Point tenderness location: Achilles insertion, lateral malleoli, posterior superior calcaneus, lateral calcaneal wall, calcaneofibular ligament 1
• Calcaneal squeeze test: Compress calcaneus medially to laterally to assess for stress fracture 1
• Anterior drawer test: Best performed 4-5 days post-injury if trauma history present 4, 5
• Inspection for deformities: Haglund's deformity (prominent posterior superior calcaneus) 1

Neurologic Assessment

• Sensory examination: Loss of protective sensation, burning, tingling 3, 1
• Motor examination: Weakness, particularly in diabetic patients 3

Skin and Soft Tissue

• Edema type: Pitting vs. non-pitting, thickened skinfold 6
• Skin changes: Wounds, ulcers, gangrene, warmth, erythema 3

Diagnostic Algorithm

Initial Workup

1. Plain radiographs (AP, lateral, mortise views) of both ankles are the most appropriate initial imaging study for all ankle pain 3, 5
2. Laboratory testing should include:
   • Complete blood count, ESR, CRP (inflammatory markers) 6
   • Glucose, HbA1c (diabetes screening) 3
   • Vitamin B12, thyroid function 3, 6
   • Creatinine, urinalysis (renal function) 3, 6
   • Consider ANA, rheumatoid factor if inflammatory arthropathy suspected 6

If Radiographs Are Normal

• MRI without contrast for suspected osteochondral lesions, impingement syndromes, occult fractures, tendon pathology, or pain of uncertain etiology 3, 5
• Ultrasound for focal soft tissue abnormalities or peripheral nerve evaluation (higher resolution than MRI for nerves) 3, 5
• Technetium bone scan for suspected stress fracture with negative radiographs, as symptoms often precede radiographic findings 1

If Vascular Etiology Suspected

• ABI measurement as initial screening 3
• Vascular referral if significant claudication or positive ABI 3

Common Pitfalls to Avoid

• Do not dismiss bilateral presentation as simply "bilateral sprains" without clear bilateral trauma history; systemic causes are more likely 1, 2
• Do not examine only once within 48 hours of injury if trauma occurred; excessive swelling limits accuracy—reexamine at 4-5 days 4, 5
• Do not overlook stress fractures as radiographs may initially be negative; maintain high suspicion with appropriate activity history 1
• Do not use corticosteroid injections near the Achilles tendon due to rupture risk 5
• Do not miss PAD in at-risk patients (age ≥65, diabetes, smoking history); perform comprehensive vascular examination 3
• Do not attribute all bilateral ankle pain to mechanical causes in patients with other joint involvement or systemic symptoms; inflammatory arthropathies require prompt diagnosis 1

When to Refer

• Immediate subspecialist referral for suspected neurologic causes requiring EMG, nerve conduction studies, or advanced imaging 1
• Rheumatology referral if inflammatory arthropathy suspected based on bilateral symptoms, other joint pain, or positive inflammatory markers 1
• Vascular surgery referral for significant claudication, positive ABI, or clinical PAD 3
• Podiatric or orthopedic referral if no improvement after 6-8 weeks of conservative treatment, need for advanced imaging interpretation, or surgical consideration 1, 4