A child with suspected acute haematogenous osteomyelitis has a completely normal plain radiograph of the tibia on day 3 of symptoms. What is the correct interpretation?
- A Normal radiograph excludes osteomyelitis and MRI is unnecessary
- B Osteopenia should be visible by day 3 and its absence indicates fracture instead
- C Plain films typically require 10 to 14 days of infection before lytic change and periosteal reaction appear ✓
- D Sequestrum formation would be visible by now if infection were present
Correct answer: C. Plain films typically require 10 to 14 days of infection before lytic change and periosteal reaction appear
Explanation
At least 30 to 50 percent of bone mineral must be lost before a lytic lesion becomes visible on plain film, so radiographs remain normal for roughly the first 10 to 14 days of acute osteomyelitis. The earliest detectable changes are soft tissue swelling and deep fascial plane blurring. MRI demonstrates marrow oedema within 24 to 48 hours and is the investigation of choice for early disease.
Reference: Tachdjian's Pediatric Orthopedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.