Osteoarticular Infection in Immunocompromised Children and Neonates: A Retrospective Case Series Emphasising Diagnostic Challenges and Multimodal Management

BACKGROUND: Osteoarticular infections (OAIs) in neonates and immunocompromised children present distinct diagnostic and therapeutic challenges. Atypical clinical presentations, attenuated inflammatory responses, and a broader spectrum of pathogens complicate early recognition and management. This study characterizes the clinical presentation, microbiology, management, and outcomes of OAIs in this highly vulnerable population. METHODS: We conducted a retrospective case series of patients younger than 16 years with osteomyelitis and/or septic arthritis managed at a tertiary pediatric center between February 2017 and February 2024. The cohort comprised neonates and children with primary or secondary immunodeficiency. Clinical presentation, inflammatory markers, microbiology, antimicrobial and surgical treatment, immune-directed therapy, and outcomes were analyzed descriptively. Ethical approval was obtained from the SingHealth Centralized Institutional Review Board (CIRB Ref: 2023-2559). RESULTS: Eighteen patients were included; 6 (33.3%) were neonates. All patients had reduced active limb mobility, and 14 (77.8%) had localized swelling. Twelve patients (66.7%) had fever, whereas 6 (33.3%), predominantly neonates, remained afebrile. CRP was elevated in all patients despite variable white blood cell responses. Staphylococcus aureus was the most frequently identified pathogen [6/18 (33.3%)]; other organisms included Streptococci, Mycobacteria, Candida tropicalis, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Bacillus spp. Fifteen patients (83.3%) underwent surgical intervention, and 6 (33.3%) received immune-directed therapy. At last follow-up, 14 patients (77.8%) had complete resolution, 2 died from causes unrelated to the OAI, 1 was lost to follow-up, and 1 had persistent or recurrent infection. Two patients developed chronic musculoskeletal sequelae. CONCLUSION: OIAs in this heterogeneous cohort were frequently accompanied by attenuated systemic features and diverse microbiology. Fever and leucocytosis were not invariably present, whereas CRP was elevated in all cases and provided supplementary information alongside clinical assessment. Favorable outcomes were observed in the context of multidisciplinary, multimodal management, but the retrospective design, small sample, and population heterogeneity preclude causal or subgroup-specific conclusions. These findings are descriptive and hypothesis-generating and require prospective validation. LEVEL OF EVIDENCE: Level IV-retrospective case series.