Nocturnal bone pain revealing chronic nonbacterial osteomyelitis: a case report

Introduction: Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory disorder characterized by sterile bone inflammation, mainly affecting children. Diagnosis is challenging and delays may lead to permanent skeletal damage. Case report: An eight-year-old girl presented with a six-week history of right ankle pain, associated with nocturnal worsening, which initially improved with non-steroidal anti-inflammatory drugs but subsequently progressed to involve the left wrist. She had elevated inflammatory markers, X-rays revealed lytic bone lesions, and MRI showed a lesion suggestive of a Brodie abscess. Bone scintigraphy revealed increased uptake in the distal right tibia, left radius, and right costovertebral joint. Surgical exploration found no purulent material. Histopathology revealed subacute/chronic inflammation, and microbiological tests were negative. A diagnosis of CNO was established. Discussion: CNO should be considered in children presenting with insidious multifocal bone pain and characteristic imaging findings. Early recognition is essential to avoid unnecessary antibiotic treatments, invasive procedures, and potential long-term complications.