Chronic recurrent multifocal osteomyelitis in pediatric patients: A Chinese single center observational study and literature review

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disorder that commonly poses diagnostic challenges due to its atypical symptomatology. This observational study aimed to investigate the clinical features, laboratory test results, imaging features, and treatment strategies for pediatric patients with CRMO. We retrospectively analyzed 7 pediatric patients with CRMO treated at the Department of Pediatric Orthopedics, First Affiliated Hospital of Guangzhou University of Chinese Medicine between January 2018 and February 2022. This study aimed to enhance current understanding of CRMO by exploring in-depth clinical data. The study cohort comprised 5 males and 2 females, aged 3 to 13 years. All patients experienced symptoms for a median duration of 6 months prior to hospitalization, at which point they presented with recurrent pain and various accompanying signs including hypothermia (14.28%), swelling (42.85%), localized skin warmth (42.85%), and plantar pustules (14.28%). The femurs (71.42%) and tibia (71.42%) were frequently affected. Radiographic and computed tomography scans revealed osteosclerosis and osteolytic lesions, while magnetic resonance imaging revealed bone marrow edema. Histological examination of bone biopsies from 4 patients revealed fibrous tissue hyperplasia and lymphocytic and neutrophilic infiltration, despite negative bacterial cultures. Laboratory test results were either normal or slightly elevated. Symptomatic improvement was observed in 6 patients (85.72%) treated with nonsteroidal anti-inflammatory drugs, while 1 patient (14.28%) resistant to nonsteroidal anti-inflammatory drugs responded well to tumor necrosis factor inhibitors. The clinical presentation of CRMO lacks specificity, with unexplained bone pain being the most common symptom. Precise diagnosis and timely intervention depend on a thorough magnetic resonance imaging evaluation for lesion detection, which facilitates CRMO diagnosis. This study offers valuable insights into the clinical manifestations, laboratory findings, imaging features, and treatment strategies of CRMO in pediatric patients.