What is the best course of action for a 28-year-old female with a 4-day history of bilateral foot and ankle swelling and pain, accompanied by a 1-day history of fever, with progression to the distal leg and no calf tenderness or swelling?

Bilateral Foot and Ankle Swelling with Fever: Urgent Evaluation Required

This 28-year-old female requires immediate assessment for infection and deep vein thrombosis, with urgent surgical consultation if deep-space infection is suspected. The combination of bilateral swelling, pain, fever, and proximal progression to the distal leg represents a potentially serious condition that demands rapid diagnostic workup and treatment.

Immediate Life-Threatening Conditions to Exclude

Infection Assessment

• Obtain urgent surgical consultation immediately if there is clinical evidence of deep-space infection, compartment syndrome, or necrotizing soft tissue infection 1
• Look for severe pain disproportionate to physical findings, systemic toxicity, or rapid progression—these mandate immediate surgical evaluation 1
• Check for at least two of the following infection signs: local swelling/induration, erythema, local tenderness/pain, local warmth, or purulent discharge 2
• Do not be falsely reassured by absence of fever or elevated white blood cell count—these may be absent in up to half of patients with significant infections 3, 2, 1
• Initiate empiric broad-spectrum antibiotics immediately covering Gram-positive, Gram-negative, and anaerobic bacteria if infection is suspected 1

Deep Vein Thrombosis Evaluation

• Although bilateral presentation is less typical for DVT, perform proximal compression ultrasound or whole-leg ultrasound as the initial diagnostic test 1
• Consider iliac vein imaging if extensive unexplained leg swelling persists without DVT on standard ultrasound 1
• Initiate anticoagulation therapy immediately upon diagnosis of DVT 1

Diagnostic Workup Algorithm

Initial Imaging

• Obtain three-view radiographs (AP, oblique, lateral) of both feet immediately to evaluate for fractures, dislocations, bone destruction, or foreign bodies 2
• Plain radiographs are essential in all cases of unexplained foot swelling 2

Laboratory Studies

• Measure C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) 3
• If inflammatory markers are elevated, obtain: serum albumin, serum transaminase levels, complete blood cell count, and urinalysis 3
• Remember that elevated inflammatory markers predict worse clinical outcomes but their absence does not exclude serious infection 3

Advanced Imaging if Indicated

• For suspected osteomyelitis with negative X-rays, MRI is the preferred modality 2
• Ultrasound duplex Doppler for suspected DVT has diagnostic sensitivities and specificities above 80% 2

Critical Clinical Examination Points

Vascular Assessment

• Palpate femoral, popliteal, and pedal pulses bilaterally 3
• Calculate ankle-brachial index (ABI) if pedal pulses are absent or diminished: normal is 0.90-1.30, <0.40 indicates severe obstruction 3
• Assess for venous insufficiency which may cause edema and impede healing 3

Infection-Specific Findings

• Examine for proximal spread of infection to contiguous skin, lymphatic channels, or regional lymph nodes 3
• Look for plantar wound with dorsal erythema or fluctuance, which suggests infection through fascial compartments requiring surgical intervention 1
• Assess for foot deformities that may predispose to abnormal loading and subsequent swelling 2

Neuropathy Evaluation

• Test for loss of protective sensation using a 10-g nylon monofilament (Semmes-Weinstein 5.07) 3
• Never assume absence of pain rules out serious pathology in patients with potential neuropathy—pain may be minimal or absent due to sensory neuropathy 2

Common Pitfalls to Avoid

• Do not delay surgical consultation waiting for imaging results if necrotizing infection is suspected—clinical diagnosis takes precedence 1
• Do not rely solely on fever or leukocytosis to determine the need for surgical intervention 1
• Do not use D-dimer alone as a stand-alone test in high pretest probability DVT 1
• Meticulous examination of shoes and footwear is crucial, as ill-fitting shoes are a frequent cause of foot pathology 2

When to Refer Urgently

• Immediate surgical consultation for moderate-to-severe infections 1
• Vascular surgery referral if critical limb ischemia is suspected 2
• Suspected osteomyelitis requiring bone biopsy for definitive diagnosis or antibiotic sensitivity testing 2

Initial Treatment Considerations

If Infection is Confirmed

• Broad-spectrum antibiotics covering Gram-positive, Gram-negative, and anaerobic organisms 1
• NSAIDs may help reduce swelling and pain 3
• Pressure off-loading and appropriate wound care 3

Supportive Measures

• Elevate the affected limbs 4, 5
• Remove any constricting footwear or clothing 2
• Coordinate care among consulting specialists, preferably through a multidisciplinary approach 3