Chronic Non-Bacterial Osteitis: Imaging Review and Management Implications

Chronic Non-Bacterial Osteitis (CNO) was first described in 1972 by [1]. This condition consists of an Autoinflammatory bone disorder that results in bone lesions and is often seen in young children (approximately 7-12 years old) [2]. Patients may suffer from a single to multiple bone lesions that may selfresolve, persist, and/or reoccur [3]. When patients have the most severe manifestation of CNO with multiple, reoccurring lesions, this condition is also known as chronic recurrent multifocal osteomyelitis (CRMO) [2]. CNO is classified as an orphan disease (ORPHA: 324964, OMIM: 259680) with a study in Germany showing an incidence of 0.45/100,000 children [4]. Patients typically have a nonspecific initial presentation. Often, they present with localized pain +/swelling [2-5]. Since this presentation is common in other conditions like bacterial osteomyelitis, bone malignancies, fibrous dysplasia, and/or Langerhans cell histiocytosis, a delay in diagnosis and appropriate treatment may occur. One study showed a delay of diagnosis for 17.3 ± 24.8 months [5]. Therefore, initiating workup for CNO requires an astute clinical suspicion by general practitioners. Timely suspicion can lead to appropriate workup that can improve the management, reduce unnecessary biopsies, reduce unnecessary imaging studies and reduce unnecessary antibiotic use. Pathophysiology