Shouldering the Pain: Septic Sternoclavicular Arthritis Following Pericardiostomy in a Systemic Lupus Erythematosus Patient

The sternoclavicular joint (SCJ) is a rather uncommon site of septic arthritis (SA), which usually develops in patients with predisposing factors, such as intravenous drug use or diabetes mellitus. Up until now, there has been no description of SCJ SA associated with a pericardiostomy procedure. A young African Brazilian woman presented with a two-month history of shoulder pain and elevated inflammatory markers. She had been diagnosed with systemic lupus erythematosus (SLE) eight months earlier, at which time she required a pericardiostomy for a large pericardial effusion due to lupus pericarditis and nephrotic syndrome. Four months before the current presentation, she treated a soft tissue abscess on the previous site of the pericardiostomy caused by a Pseudomonas aeruginosa. After extensive evaluation, the cause of her shoulder pain was concluded to be due to septic arthritis of the SCJ with adjacent osteomyelitis. Computed tomography-guided bone biopsy and aspiration of synovial fluid yielded a Pseudomonas aeruginosa, which may have spread from the pericardiostomy orifice into the bloodstream, colonized the joint, and later developed a full-blown infection manifesting as referred pain to the shoulder. We present a highly unusual case of SCJ SA with adjacent osteomyelitis of the sternum manifesting as shoulder pain in an immunosuppressed patient with SLE.