How should I evaluate and manage a 7-year-old with swelling of the great toe?

Evaluation and Management of Big Toe Swelling in a 7-Year-Old

In a 7-year-old with big toe swelling, immediately assess for musculoskeletal infection (osteomyelitis or septic arthritis), which requires urgent imaging and potential surgical intervention. 1

Immediate Clinical Assessment

Obtain a focused history targeting these specific red flags:

• Duration and onset: Acute onset (hours to 1-2 days) strongly suggests infection, while gradual onset may indicate trauma, inflammatory conditions, or developmental issues 1
• Fever, irritability, or refusal to bear weight: These are key features of musculoskeletal infection 1
• Recent trauma or minor injury: Frequently reported even in hematogenous osteomyelitis, so its presence does not exclude infection 1
• Systemic symptoms: Fever, malaise, or decreased oral intake suggest infection 1

On physical examination, specifically look for:

• Erythema, warmth, tenderness, or purulent discharge: Signs of infection requiring urgent intervention 2
• Pain with passive range of motion: Highly suggestive of septic arthritis 1
• Swelling characteristics: Sharp demarcation at ankle/wrist with painful swelling suggests Kawasaki disease in the appropriate clinical context 3

Diagnostic Workup

Order plain radiographs of the affected foot as the initial imaging study to evaluate for osteomyelitis, fractures, bony deformities, or foreign bodies. 1, 2

If infection is suspected based on clinical findings, proceed immediately with:

• Complete blood count with differential: Elevated WBC suggests infection 1
• Inflammatory markers (ESR and CRP): Elevated in osteomyelitis and septic arthritis 1
• Blood cultures: Positive in hematogenous osteomyelitis 1

If radiographs are negative but clinical suspicion for infection remains high, obtain MRI, which has 82-100% sensitivity and 75-96% specificity for acute osteomyelitis and is the gold standard imaging modality. 1

Critical Differential Diagnoses

Musculoskeletal Infection (Primary Concern)

This is the most important diagnosis to exclude given the potential for rapid progression and permanent sequelae. 1, 4

Kawasaki Disease

Consider if the child has:

• Fever >102.2°F (39°C) for ≥5 days 3
• Bilateral non-purulent conjunctival injection 3
• Swelling or erythema of hands/feet with sharp demarcation at ankles/wrists 3
• Oral mucosal changes, polymorphous rash, or cervical lymphadenopathy 3

If Kawasaki disease is suspected, obtain echocardiography and initiate treatment with IVIG 2 g/kg as a single infusion plus high-dose aspirin (80-100 mg/kg/day divided into four doses). 3

Trauma-Related Conditions

Fractures, contusions, or soft tissue injuries are common in children but should not be assumed without imaging. 5

Management Algorithm

If Infection is Confirmed or Highly Suspected:

1. Initiate empiric intravenous antibiotics immediately after obtaining cultures 1
2. Obtain urgent orthopedic consultation for potential surgical debridement 1
3. Surgical drainage is necessary if abscess or septic joint is identified 1

If Imaging and Labs are Reassuring:

• Consider conservative management with observation for minor trauma or developmental variants 5, 6
• Provide specific return precautions: worsening pain, fever, inability to bear weight, or spreading erythema 1

Common Pitfalls to Avoid

• Do not dismiss infection based on history of minor trauma alone, as recent trauma is frequently reported even in hematogenous osteomyelitis 1
• Do not delay imaging or antibiotics if clinical suspicion is high, as early intervention is critical to prevent complications 1, 4
• Do not assume a benign developmental variant without excluding infection first, particularly in children with fever, refusal to bear weight, or systemic symptoms 1, 4
• Do not overlook Kawasaki disease in a child with prolonged fever and extremity swelling, as delayed treatment increases risk of coronary artery aneurysms 3