Etiology of septic arthritis in children of Qatar

Septic arthritis is an orthopedic emergency and if not evaluated and treated appropriately, it can lead to poor clinical outcomes. Previously several studies have been performed to identify the etiology of septic arthritis in the pediatric population in developed countries. The main objective of our study was to identify the etiology of septic arthritis in children in Qatar in previously healthy and fully vaccinated children.

We performed retrospective chart analysis of children presenting to our emergency department between July 2018 and June 2024, who were diagnosed and treated with septic arthritis. The study was conducted at a level 1 pediatric trauma center and the only children's hospital in the country. We used ICD 9 and ICD 10 codes to identify such cases. After using predefined exclusion criteria, children with positive blood cultures, blood titers for Brucella and/or synovial cultures were included in the analysis. Clinical symptoms and signs, ultrasound findings, and culture results were tabulated using descriptive statistics.

A total of 45 patients were included. The median age of children was 5 years (interquartile range [IQR] 2-10 years). Majority (60%) were male. The most common clinical findings were limping/limitation of joint movement (100%), fever (80%), and swelling of joints (58%). The median C-reactive protein and erythrocyte sedimentation rate were 94 mg/L and 47 mm/h. The knee and hip were the most common joints affected. The most common causative organisms were Staphylococcus aureus (56%), Streptococcus pyogenes (13%), and Brucella (11%). Pre-intervention imaging, such as ultrasound and/or magnetic resonance imaging, was performed in 95% of patients. All patients recovered without any complications. One of the limitations of our study is that cases of Kingella kingae septic arthritis may be underreported as polymerase chain reaction (PCR) analysis of synovial fluid was not performed on all patients.

Gram-positive cocci, especially S. aureus, remains the most common cause of septic arthritis in vaccinated children. We also identified Gram-negative bacilli as causative organisms in our study. We suggest including empiric coverage for both Gram- and Gram-negative bacilli when treating children with suspected septic arthritis till culture results are available.