Mustafa Çiftçi1, Bilgehan Çatal2, Fırat Erdoğan1

1Department of Child Health and Diseases, Istanbul Medipol University, Istanbul, Turkey
2Department of Orthopedics and Traumatology, Istanbul Medipol University, Istanbul, Turkey

Keywords: Atypical localization, atypical pathogen, pediatric, septic arthritis

Abstract

Septic arthritis generally affects the lower extremities in children. Shoulders involvement is rare. Although Staphylococcus aureus (S. aureus) is the most common pathogen causing septic arthritis in children, methicillin-resistant strains are rarely isolated from healthy children. An eight-year-old boy presented to the emergency outpatient clinic with a complaint of shoulder pain lasting for two days. Leukocytosis and an elevated C-reactive protein level and sedimentation rate were found in the examinations performed with the suspicion of arthritis, and a widening of the joint space was observed in the shoulder X-ray of the patient, who had no history of trauma. The magnetic resonance imaging, performed for the differential diagnosis of the patient, showed increased intra-articular fluid and bone marrow edema, and there was no sign of periarticular osteomyelitis. The patient’s joint fluid was taken for diagnosis. The joint fluid was purulent, a high number of leukocytes was present in the microscopic evaluation and bacteria could not be isolated. The patient was scheduled for arthroscopy. Intra-articular washing was performed, septic vegetations were observed and debrided during the arthroscopy. After the arthroscopy, the patient was given teicoplanin and ceftriaxone parenterally as empiric antibiotic therapy. On the second day of treatment, the patient's fever and shoulder pain decreased. Methicillin-resistant S. aureus (MRSA) growth was observed in the joint fluid culture of the patient at the 36th h, and there was no growth in the blood culture. The course of parenteral antibiotherapy was continued for 21 days until the patient's laboratory results returned to normal values, and then oral clindamycin therapy was started. The patient's clinical and laboratory findings returned to normal after three weeks of oral antibiotic therapy, and the treatment was discontinued. The range of motion of the joint was evaluated to be full at the six-month postoperative follow-up. In conclusion, in this case of septic arthritis the shoulder joint was affected which is a rare occurrence in children, and MRSA, a pathogen rarely found in healthy children, grew in the joint fluid. Since the most important prognostic factor for septic arthritis is the duration of initiation of the treatment, the fact that the complaint is in an uncommon joint and the pathogen has a high antibiotic resistance may delay the initiation of appropriate treatment, which may negatively affect the prognosis.