What is the appropriate management for a toddler presenting with bilateral foot pain?

Bilateral Foot Pain in a Toddler

Start with plain radiographs of both feet and lower extremities as the initial imaging study, while simultaneously ruling out septic arthritis or osteomyelitis through clinical assessment and laboratory markers, as infection is the most critical diagnosis not to miss in this age group. 1

Immediate Priority: Rule Out Infection

In toddlers under 5 years of age presenting with bilateral foot pain, septic arthritis and osteomyelitis are orthopedic emergencies that can rapidly destroy cartilage and bone if untreated. 1, 2

Red Flags Requiring Urgent Evaluation:

• Fever, refusal to bear weight, or inability to move the affected limbs 3, 4
• Systemic toxicity or irritability 1
• Concurrent osteomyelitis and septic arthritis occur frequently in children under 5 years, with 68% of septic arthritis cases having coexisting osteomyelitis 5

Laboratory Workup for Suspected Infection:

• ESR ≥40 mm/hour, WBC ≥12,000 cells/mm³, and CRP >2.0 mg/dL are predictive of septic arthritis 3
• Blood cultures should be obtained before starting antibiotics 2, 6
• Infants and toddlers often present with a limp but have difficulty localizing the site of involvement on physical examination, making imaging essential for site identification 1

Initial Imaging Algorithm

Step 1: Plain Radiographs

Obtain AP and lateral radiographs of both feet and the entire lower extremities (hip through foot) as the initial imaging study. 1

• Radiographs can identify fractures (including toddler's fractures), early osteomyelitis changes, or alternative diagnoses 1
• Toddler's fractures (nondisplaced oblique distal tibial fractures) are frequently missed on initial radiographs, with 41% showing evidence only on follow-up films 1
• Negative radiographs do not exclude fracture or early osteomyelitis 1

Step 2: MRI if Infection Suspected or Radiographs Negative

MRI of the area of interest (or entire lower extremity if site cannot be localized) is the next step when infection is suspected or radiographs are negative with persistent symptoms. 1

• MRI has 82-100% sensitivity and 75-96% specificity for acute osteomyelitis 1
• MRI should always include the nearest joint to evaluate for concurrent septic arthritis, as both conditions frequently coexist 5
• In children under 2 years old, septic arthritis is more common than isolated osteomyelitis 5

Step 3: Ultrasound for Joint Effusions

Ultrasound is sensitive for detecting joint effusions and can guide arthrocentesis if septic arthritis is suspected. 1

• Ultrasound has limited field of view but is useful when the hip is involved, as hip pathology can present as referred pain to the knee or foot 1

Non-Infectious Differential Diagnoses

Mechanical/Structural Causes:

Nonspecific lower leg and foot pains are frequently underreported in toddlers and may be associated with pes planovalgus (flat feet), benefiting from orthotics. 1

Metabolic Causes:

Cramping pain from hypocalcemia should be considered, particularly in children with underlying conditions 1

Traumatic Causes:

• Toddler's fractures present with refusal to bear weight following minor trauma or increased walking activity 1
• History of trauma should prompt focused radiographic evaluation 1

Management Based on Findings

If Infection Confirmed:

• Immediate orthopedic consultation for surgical drainage if pus or infected tissue is present 2
• Empiric IV antibiotics targeting Staphylococcus aureus (most common pathogen): anti-staphylococcal penicillin or cephalosporin for children over 3 months; add gentamicin for infants under 3 months 6
• Early diagnosis and adequate treatment give good outcomes; delayed treatment results in chronic osteomyelitis or irreversible joint destruction 2

If Toddler's Fracture or Mechanical Pain:

• Activity modification, NSAIDs for pain relief, and possible immobilization with casting or walking boot 1
• Orthotics for pes planovalgus-related pain 1
• Follow-up radiographs in 7-10 days if initial films negative but clinical suspicion remains high 1

If Radiographs and Initial Workup Negative:

• Consider whole-body bone scan to localize pathology when symptoms are nonlocalized and persist despite negative initial imaging 1
• MRI of the entire lower extremity may be performed when radiographs and clinical examination fail to localize symptoms 1

Critical Pitfalls to Avoid

• Never assume bilateral presentation excludes infection—multifocal osteomyelitis can occur, particularly in infants and toddlers 1, 7
• Do not delay imaging in children under 5 who refuse to bear weight, as they often cannot localize pain and infection must be ruled out urgently 1
• Always include adjacent joints in MRI evaluation, as 68% of septic arthritis cases have concurrent osteomyelitis 5
• Do not rely solely on radiographs to exclude toddler's fracture—clinical suspicion warrants immobilization and follow-up imaging 1