Pathology
Septic arthritis of the shoulder is a bacterial infection that involves the synovial membrane, articular cartilage, and subchondral bone of the glenohumeral joint. The causative organisms are usually bacteria, with Staphylococcus aureus being the most common pathogen in children. Other causative organisms include Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae. Septic arthritis of the shoulder can occur as a primary infection or secondary to hematogenous spread from a distant focus of infection.
The clinical presentation of pediatric septic arthritis of the shoulder
can vary, but typically includes fever, pain, swelling, and limited range of motion of the affected shoulder. The child may hold the arm in a fixed position close to the body, with the elbow flexed and the forearm pronated. Infants and young children may present with nonspecific symptoms, such as irritability, poor feeding, or lethargy, and may not localize the site of pain or swelling to the shoulder joint.
Diagnosis of septic arthritis of the shoulder
is based on a combination of clinical examination, laboratory tests, and imaging studies. Physical examination may reveal warmth, swelling, and tenderness over the affected joint, as well as limited range of motion. Laboratory tests can help confirm the diagnosis, with an elevated white blood cell count and erythrocyte sedimentation rate (ESR) being common findings. Synovial fluid analysis is essential for establishing the diagnosis and identifying the causative organism. Gram staining and culture of synovial fluid can help identify the causative organism in up to 90% of cases. Imaging studies, such as radiographs, ultrasonography, or magnetic resonance imaging (MRI), can be helpful in identifying joint effusion and associated bone or soft tissue changes.
Treatment of pediatric septic arthritis of the shoulder
involves a combination of antimicrobial therapy and drainage of the affected joint. Antibiotic therapy should be initiated promptly, ideally after obtaining synovial fluid for culture and sensitivity testing. Empiric antibiotic therapy should cover the most likely pathogens, such as Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. In patients with a suspected or confirmed Neisseria gonorrhoeae infection, ceftriaxone is the recommended therapy. The duration of antibiotic therapy varies depending on the severity of infection and response to treatment, but typically lasts for 2-4 weeks.
Joint drainage is an essential component of treatment, as it allows for the removal of infected synovial fluid and debris, and improves joint function and healing. Joint aspiration can be performed under local anesthesia, with ultrasound guidance to ensure accurate needle placement. In patients with a large joint effusion or multiple loculations, surgical drainage may be necessary. Open joint lavage and debridement can also be considered in patients with severe joint destruction or abscess formation.
Complications of pediatric septic arthritis of the shoulder
can include joint destruction, osteomyelitis, and recurrent infection. Long-term follow-up is necessary to monitor for these complications and assess for functional impairment. Physical therapy and rehabilitation are important components of management, as they can help improve range of motion, strength, and function of the affected shoulder.