What is the initial workup for a patient presenting with ankle swelling?

Initial Workup for Ankle Swelling

Immediate Clinical Assessment

The initial workup for ankle swelling depends critically on whether the presentation is unilateral or bilateral, and whether trauma is involved. 1, 2

Step 1: Determine Unilateral vs. Bilateral Presentation

Unilateral ankle swelling suggests:

• Trauma/sprain
• Localized infection
• DVT
• Localized inflammatory process 1

Bilateral ankle swelling suggests:

• Heart failure
• Renal disease (nephrotic syndrome, glomerulonephritis, chronic kidney disease)
• Liver disease
• Medication-related edema (NSAIDs, calcium channel blockers)
• Venous insufficiency
• Systemic inflammatory conditions 1, 3

Step 2: History - Key Features to Elicit

For ALL presentations:

• Speed of onset (acute vs. chronic) 4
• Trauma history and mechanism of injury 4
• Medication review (calcium channel blockers, NSAIDs) 1
• Systemic symptoms (fever, weight loss, dyspnea, orthopnea) 3
• Diabetes status and presence of neuropathy 1

Critical red flags requiring different evaluation:

• Peripheral neuropathy or diabetic neuropathy 2
• High-energy trauma 2
• Suspected foreign body 2

Step 3: Physical Examination - Specific Findings to Document

For unilateral traumatic ankle swelling:

• Ability to bear weight immediately after injury and ambulate 4 steps 5, 2
• Point tenderness over posterior edge or inferior tip of medial malleolus 5, 2
• Point tenderness over posterior edge or inferior tip of lateral malleolus 5, 2
• Point tenderness over talus or calcaneus 5, 2
• Anterior drawer test for ligament rupture 5
• Presence of hematoma 5

For bilateral ankle swelling:

• Pitting vs. non-pitting edema 6
• Warmth (temperature difference ≥2°C between feet suggests active Charcot neuro-osteoarthropathy in diabetics) 1
• Bilateral warmth suggests inflammatory arthropathy, gout, or systemic inflammatory conditions 1
• Skin changes (thickened skinfold, venous stasis changes) 6
• Cardiovascular examination (JVD, S3 gallop, pulmonary rales) 3

Initial Laboratory Workup

For bilateral ankle swelling:

• Urinalysis with protein quantification (essential for suspected renal disease) 1
• Basic metabolic panel (creatinine, electrolytes) 3
• Complete blood count 3
• Albumin level 6, 3
• Brain natriuretic peptide (BNP) if heart failure suspected 3
• Liver function tests if hepatic disease suspected 3

For unilateral traumatic ankle swelling:

• Laboratory tests are generally not indicated unless systemic disease suspected 5

Initial Imaging Strategy

For Traumatic Unilateral Ankle Swelling (Age ≥5 years)

Apply Ottawa Ankle Rules immediately (sensitivity 92-100% for fractures): 5, 2

Order ankle radiographs (3 views) if ANY of the following:

1. Inability to bear weight immediately after injury OR
2. Point tenderness over posterior edge or inferior tip of medial or lateral malleolus OR
3. Point tenderness over talus or calcaneus OR
4. Inability to ambulate 4 steps 5, 2

Do NOT order radiographs if Ottawa Ankle Rules are negative (no point tenderness, able to walk) 5

Important caveat: Ottawa Ankle Rules should NOT be applied if patient has peripheral neuropathy, diabetic neuropathy, suspected foreign body, or high-energy trauma - these patients require radiographs regardless 2, 5

For Bilateral Ankle Swelling Without Trauma

Plain radiographs are NOT routinely indicated 1

Consider chest radiography if heart failure suspected 3

Consider echocardiogram if clinical suspicion for heart failure 1, 3

Common Pitfalls to Avoid

• Do NOT empirically prescribe diuretics for all bilateral ankle swelling - diuretics should only be used when systemic fluid overload is identified (heart failure, renal disease, liver disease), as inappropriate use in elderly patients can cause severe electrolyte imbalances, volume depletion, and falls 1, 3

• Do NOT examine the ankle within 48 hours of acute injury if initial assessment is limited by pain/swelling - re-examine at 3-5 days post-injury to better distinguish partial tears from complete ligament ruptures 5

• Do NOT overlook medication-related edema - calcium channel blockers and NSAIDs are common culprits 1

• Do NOT miss Charcot neuro-osteoarthropathy in diabetics - minimal pain with warmth and swelling should prompt immediate immobilization in a knee-high offloading device while completing diagnostic evaluation 1

• Do NOT order unnecessary imaging - if Ottawa Ankle Rules are negative in appropriate patients, radiographs correctly rule out fracture in 299 out of 300 patients 5