Chronic Recurrent Multifocal Osteomyelitis in pediatric patients: a case series of 7 patients

Abstract Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare auto-inflammatory disorder that often eludes accurate diagnosis due to its atypical symptomatology. This retrospective study aims to investigate the clinical manifestations, laboratory parameters, imaging characteristics, and therapeutic approaches employed in the management of CRMO among pediatric patients. Methods: A retrospective analysis was conducted on the medical records of seven pediatric patients diagnosed with CRMO, who sought treatment at the Department of Pediatric Orthopedics, First Affiliated Hospital of Guangzhou University of Chinese Medicine, between January 2018 and February 2022. The objective was to enhance clinicians' comprehension of CRMO through an in-depth exploration of pertinent clinical data. Results: The study cohort consisted of five males and two females, with a median age of 12 years (range: 3-13 years). The median duration from symptom onset to hospital admission was 6 months (range: 1.5-24 months). All patients presented with recurrent pain, accompanied by manifestations such as hypothermia (14.28%), swelling (42.85%), localized elevated skin temperature (42.85%), and plantar pustules (14.28%). The femur (71.42%) and tibia (71.42%) were the most frequently affected bones. Radiographic and computed tomography (CT) imaging unveiled osteosclerosis and osteolytic lesions, while magnetic resonance imaging (MRI) revealed evidence of bone marrow edema. Histological examination of bone biopsies from four patients demonstrated conspicuous fibrous tissue hyperplasia, along with lymphocytic and neutrophilic infiltration, despite negative bacterial culture results. Laboratory assessments unveiled predominantly normal or slightly elevated indices. Symptomatic remission was achieved in six patients (85.72%) following nonsteroidal anti-inflammatory drug (NSAID) therapy, whereas one patient (14.28%) exhibited resistance to NSAID treatment but exhibited a favorable response to tumor necrosis factor (TNF) inhibitor therapy. Conclusions: The clinical presentation of CRMO lacks specificity, with unexplained bone pain emerging as the most prevalent symptom. Accurate diagnosis and timely intervention heavily rely on meticulous MRI evaluation, facilitating lesion detection and bolstering the diagnostic yield of CRMO. The findings of this study provide valuable insights into the clinical manifestations, laboratory parameters, imaging characteristics, and therapeutic strategies employed in the management of CRMO among pediatric patients.