A 62–year–old male, previously healthy, not immunocompromised, presented with low grade fever, chills, and worsening redness, pain and swelling of the right shoulder, strenoclavicular area and neck. He was recently hospitalized and treated for cough and fever with azithromycin; he had a close contact with grandchildren with strep throat. At that time, no source of infection was isolated; blood and throat cultures were negative. Shortly afterwards, he presented with right shoulder pain, treated as rotator cuff tear. Worsening symptoms prompted reevaluation; ultrasound/CT scan showed an inflammatory process at the right sternoclavicular joint (SCJ) area. The Sternoclavicular joint was aspirated. Incision, irrigation, and drainage of the pus were performed. Group A Streptococcus (GAS) was identified in the joint fluid and clavicle specimen. Blood cultures remained negative. Echocardiography did not show vegetations. He was treated with cefazolin initially, followed by penicillin G continuous infusion at home for a total of 5.5 weeks. One week after he finished the antibiotics, a swelling, tenderness and redness of the left pacemaker area developed. Ultrasound showed a pacemaker pocket infection. Again, transthoracic echocardiography was negative for vegetations. The pacemaker was removed, and the pus from the pacemaker pocket grew GAS. The patient was placed on another 4 weeks course of continuous penicillin G infusion. Further follow up showed full recovery.
The source of infection in our patient was probably the pharynx. He had exposure to GAS at home. Throat and blood cultures were negative, likely because he was receiving antibiotic. He did not have any risk factors for the infection, such as intravenous drug use, trauma, distant infection, diabetes, infected central line, however, no risk factor is found in 23% of patients. The course of the disease was complicated by pacemaker infection. This case might be the first report of GAS–Sternoclavicular Arthritis in an adult.
This uncommon localization and etiology of septic arthritis can delay diagnosis and treatment, with possible negative effect on outcome. Differential of shoulder/lateral neck pain should include Sternoclavicular Arthritis. GAS could be the causative organism in the appropriate clinical setting.