Sternoclavicular Joint Infection Caused by Staphylococcus capitis.

A 74-year-old female patient presented with "palpitations and chest tightness for half a day." The symptoms developed suddenly while riding an elevator, accompanied by shortness of breath, but without dizziness or chest pain. The patient had a 5-year history of diabetes, managed with metformin. She had undergone a right mastectomy 20 years ago for breast cancer. On admission, her vital signs were stable. Physical examination revealed a tender, swollen mass in the right side of the neck, soft in texture, with purulent drainage. Blood tests showed an elevated C-reactive protein (CRP) level (51.47 mg/L). Imaging studies (computed tomography [CT], ultrasound, magnetic resonance imaging [MRI]) revealed a soft tissue mass in the right clavicular region, with possible osteomyelitis. The patient was diagnosed with a right-sided sternoclavicular joint skin infection complicated by osteomyelitis. Surgical debridement and drainage were performed, and pathological examination confirmed a Staphylococcus capitis infection. The patient was treated with a 10-week course of antibiotics, initially with intravenous ertapenem, later switched to oral linezolid. Throughout the treatment, no adverse drug reactions were observed. One month later, follow-up observations indicate that the patient's surgical wound is healing well. The patient's symptoms significantly improved, with complete resolution of palpitations, chest tightness, and shortness of breath. The treatment was well-tolerated. This case report aims to raise clinicians' awareness of sternoclavicular joint infections caused by Staphylococcus capitis and to highlight the importance of early diagnosis and individualized treatment strategies.