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Periosteal Reaction

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Periosteal Reaction, Periosteal Bone Formation

  • Pathophysiology
  1. Periosteal Reactions are triggered by Cortical Bone injury or inflammation
    1. Region of injury/inflammation raises the periosteum from the Cortical Bone
  2. Children are more prone to Periosteal Reaction, with more exaggerated findings on imaging
    1. Periosteum most active in children
    2. Periosteum is less adherent to the Cortical Bone of children
  • Causes
  1. Infection (e.g. Osteomyelitis)
  2. Malignancy (e.g. Ewing Sarcoma, Osteosarcoma)
  3. Medications
  4. Arthritis
  5. Trauma (e.g. Fractures)
    1. Single bone Periosteal Reactions are typically due to Trauma
    2. Fractures lead to Periosteal Reactions at 5 days to 3 weeks in children
  • Types
  1. Nonaggressive (slow effects, contained by the periosteum, and healable in an organized process)
    1. Thin
    2. Thick irregular
    3. Solid
    4. Shell
  2. Aggressive (rapid effects outpace periosteum's ability to heal)
    1. Hair on end
    2. Sunburst
    3. Lamellated
    4. Codman triangle
  • Imaging
  1. XRay
  2. Ultrasound
  3. CT
  4. Bone Scintigraphy (Bone Scan)
  5. MRI
    1. Best visualization, extent and characterization of Periosteal Reaction and surrounding tissue findings
    2. Can identify subtle Periosteal Reactions that are not fully ossified
  • References
  1. Andriescu et al (2025) Crit Dec Emerg Med 39(7): 16-8