Osteomyelitis with a twist: Streptococcus pneumoniae causing sternoclavicular septic arthritis

CASE PRESENTATION An 80-year-old woman of Caribbean descent with a history of type 2 diabetes mellitus, gout, osteoarthritis, gastrointestinal reflux and atrial fibrillation, presented with a 12 h history of left-sided shoulder, neck and back pain. Her temperature was 38.0°C and her white blood cell count was 15×109 cells/L. She experienced tenderness in the left sternoclavicular and sternomanubrial regions associated with warmth and erythema, but without an effusion. Her neck range of motion was restricted by pain on the left side, including neck deviation to the right, which was compatible with torticollis. She could not abduct her shoulder beyond 60 degrees. She had a III/VI systolic ejection murmur at the left upper sternal border, but no stigmata of infectious endocarditis. Her gastrointestinal, dermatological and respiratory examinations were within normal limits. On admission, she was empirically started on ceftriaxone for suspected shoulder joint septic arthritis. An unsuccessful attempt was made to aspirate the left shoulder joint. The pain progressed toward her anterior chest wall and within 72 h C-reactive protein levels had increased from 11 mg/L to 240 mg/L. Blood cultures were positive in three of three sets for penicillin-susceptible Streptococcus pneumoniae. Aspiration of the sternoclavicular joint (SCJ) was unsuccessful. Transesophageal echocardiography did not reveal evidence of endocarditis. The chest radiograph did not reveal evidence of pneumonia. Despite prolonged antibiotic therapy, the patient never experienced full recovery of function, primarily with respect to arm adduction, which was limited by pain at the SCJ. Repeat computed tomography (CT) scan after therapy revealed arthritic changes related to her treated infection. Avoidance of pain led to the patient’s torticollis, which was the most distressing clinical feature for her. This persisted for months despite regular physiotherapy sessions.