Bemoan My Collarbone: A Case of Costocondral Junction Syndrome Complicated by Methicillin Sensitive Staphylococcus aureus Sternoclavicular Osteomyelitis and Septic Arthritis

A 35-year-old female with a past medical history of untreated Hepatitis-C, and a history of intravenous (IV) drug use initially presented to the emergency department with chief complaints of gradual worsening sharp, constant left-sided chest pain with no radiation starting three weeks before presentation. In the emergency department (ED), she was afebrile, normotensive, and tachycardia with 99% oxygen saturation on room air. A physical exam revealed a well-developed Caucasian female, alert and oriented with moderate distress. Respiratory exam with symmetrical bilateral excursions without wheezes, crackles, or rhonchi. On cardiovascular exam, she was tachycardic with a regular rhythm without murmurs, rubs, or gallops. There was a 2 x 2 cm tender erythematous swelling on the left sternal border inferior to the clavicle. The neck was supple and negative for Jugular Venous Distension (JVD). Neurologically grossly intact. Abnormal laboratory findings included leukocytosis with neutrophilic predominance. The patient received intravenous (IV) antibiotics with broad-spectrum vancomycin, cefepime, and azithromycin and underwent computed tomography angiography (CTA) chest, revealing a 26.8 mm x 26.5 mm left anterior subapical pleural-based pulmonary mass-like lesion with central hypoattenuation in surrounding ground-glass changes. Biopsy of the left subapical pulmonary lesion results showed chronic inflammatory infiltrate. Unfortunately, the patient left the hospital against medical advice after supportive care and pain control. Our patient's history of intravenous drug use and active Hepatitis-C infection were typical risk factors associated with invasive infections. In the clinical context, leukocytosis with hypo-attenuated pulmonary lesion should raise suspicion for septic emboli, localized abscess pocket, infection by atypical organisms, infective endocarditis, and malignancy which was considered upon initial assessment.