Case Presentation: A 69 years old farmer presented to the hospital with right shoulder pain, fever and chills. Past medical history was significant for coronary artery disease, a remote history of neck tumor status post resection and radiation, bilateral shoulder arthritis, and left shoulder replacement. The pain worsened in severity and radiated to the right chest wall and right side of the neck. Right shoulder radiograph showed degenerative changes. ESR and CRP were elevated at 109 mm/hr and 335 mg/L respectively. Physical exam was remarkable for reproducible tenderness in right chest wall and neck, tenderness and decreased range of motion in right shoulder, superficial cuts in right hand, and erythema of the right sternoclavicular joint (SCJ). Due to concern for septic arthritis, joint aspiration of right glenohumeral joint was performed which yielded minimal clear fluid. Synovial fluid culture from the shoulder showed no growth. Blood cultures grew Methicillin Sensitive Staphylococcus Aureus. Broad spectrum antibiotics were begun but then narrowed to intravenous Cefazolin based on sensitivities. As the source of bacteremia was not evident, MRI of the right shoulder and clavicle was performed. There was septic arthritis and osteomyelitis of the right SCJ associated with edema within the anterior mediastinum and myositis of the R pectoralis muscle. Severe osteoarthritis with rotator cuff tear was seen in the right shoulder joint. In par with the negative investigation studies there was no evidence of septic process involving the right shoulder. Thoracic surgery and infectious disease specialists were consulted to guide management. Due to proximity of SCJ to major vascular structures, decision was made to treat the septic arthritis conservatively with long term intravenous antibiotics for 6-8 weeks. Surgical resection of SCJ would have been necessary if medical treatment failed or complications like abscess or mediastinitis developed. Fortunately, our patient’s Sternoclavicular joint Septic Arthritis improved with antibiotics alone.

Discussion: Sternoclavicular joint septic arthritis and osteomyelitis is a rare condition with just over 200 cases reported in the past 45 years. This accounts for ~1% of septic arthritis infections. Risk factors for SCJ septic arthritis include long term indwelling catheter (especially subclavian catheterization), intravenous drug use, chronic kidney disease, alcoholism, chronic steroid use, rheumatoid arthritis, cirrhosis and malignancy. Due to the rarity of the condition, there is no standardized mode of treatment; however, treatment with antibiotics certainly affords a less invasive treatment course. Delay in presentation or diagnosis leads to more severe cases complicated with abscess formation and even mediastinitis; these advanced presentations often fail antibiotic therapy and require surgical intervention with debridement and resection of the affected joint

Conclusions: Our case highlights the importance of timely risk factor identification coupled with a thorough examination to allow for a less morbid treatment course of this rare condition. Our patient’s presentation of shoulder pain was also unique.