Septic arthritis is a medical emergency that requires immediate action to prevent significant morbidity and mortality. The sternoclavicular joint may have a more insidious onset than septic arthritis at other sites. A high index of suspicion and judicious use of laboratory and radiologic evaluation can help solidify this diagnosis. The sternoclavicular joint is likely to become infected in the immunocompromised patient or the patient who uses intravenous drugs, but sternoclavicular joint arthritis in the former is uncommon. This case series describes the course of 2 immunocompetent patients who were treated conservatively for septic arthritis of the sternoclavicular joint.
Case 1A 50-year-old man presented to his primary care physician with a 1-week history of nausea, vomiting, and diarrhea. His medical history was significant for 1 episode of pseudo-gout. He had no chronic medical illnesses. He was noted to have a heart rate of 60 beats per minute and a blood pressure of 94/58 mm Hg. His heart rate increased to 72 beats per minute while seated. He had presumed gastroenteritis. He was given 2 L intravenous 0.9% normal saline in the outpatient setting, with an increase in blood pressure to 100/68 mm Hg. He was seen 2 days later and was beginning to feel better but had a new complaint of tenderness at the left sternum. The patient began a 5-day course of prednisone. Blood was collected at this time. The next day, blood analysis revealed a critical laboratory value for creatine phosphokinase level of 9005 U/L and an erythrocyte sedimentation rate of 120 mm/hour. The patient was asked to go to the hospital to receive further evaluation. At the time of admission, he continued to complain of left clavicular pain, and the course of prednisone failed to provide any pain relief. The patient denied any current fevers or chills. He was afebrile, and examination revealed a swollen and tender left sternoclavicular (SC) joint. The prostate was normal in size and texture and was not tender during palpation. Laboratory analysis showed a white blood cell count of 19.3 thousand/microliter, with 92% segmented neutrophils and no bands (Table 1). Urinalysis was significant for blood and leukocyte esterase. Blood and urine cultures were obtained. A radiograph of the clavicle was normal. The patient was started on intravenous fluids for the elevated creatine phosphokinase level. Ceftriaxone (1 g intravenous daily) was started for the leukocytosis, pyuria, and history of fever. On hospital day 1, blood and urine cultures yielded Gram-negative bacilli that were later identified as Escherichia coli. It was believed that the E. coli bacteremia seeded the SC joint, leading to septic arthritis. A computed tomography (CT) scan of the sternum was performed to assist with diagnosis and showed no fluid in the SC joint and no sign of bony erosion or sclerosis at the manubrium or medial end of the clavicle. The antibiotic was changed to intravenous ciprofloxacin for better tissue penetration of the urinary tract because the prostate was a concer...