Differential Diagnosis for a 2-year-old with Tibial Tenderness after a Fall and Normal X-rays

• Single most likely diagnosis:
  • Toddler's fracture: This is a common injury in young children, typically occurring after a minor fall. It's a small, non-displaced fracture of the tibia that may not be visible on initial X-rays due to the age of the child and the nature of the fracture.
• Other Likely diagnoses:
  • Bone bruise or contusion: A fall can cause a bruise or contusion of the bone, which would not be visible on X-rays but could cause tenderness over the tibia.
  • Soft tissue injury: Injuries to the muscles, ligaments, or tendons around the tibia could also cause tenderness in the area.
• Do Not Miss diagnoses:
  • Child abuse: It's crucial to consider non-accidental trauma, especially if the history provided does not match the injury or if there are other signs of abuse.
  • Osteomyelitis: Although less common, an infection of the bone could present with pain and tenderness over the tibia, and normal initial X-rays do not rule out this condition.
  • Pathologic fracture: A fracture through a pre-existing bone lesion, such as a cyst or tumor, which might not be apparent on initial X-rays.
• Rare diagnoses:
  • Stress fracture: Though more common in older children and adults, stress fractures can occur in young children, especially with repetitive stress rather than a single fall.
  • Bone cysts or tumors: These could cause pain and tenderness, especially if there's a pathologic fracture, but are less common in this age group and presentation.