PRIMARY STERNAL OSTEOMYELITIS CAUSED BY NOCARDIA NOVA

Abstract

A 51-year-old Caucasian woman was admitted to the Rheumatology Department of our hospital due to a 3-week history of diffuse neck, shoulder and upper torso pain, exacerbated by movements. An outpatient trial of non-steroidal anti-inflammatory medications had been unsuccessful. A few days later, the pain was localised above the manubrium, the left clavicle and sternomastoid muscle and fever up to 39.5°C was reported. The patient had no significant past medical history and lived in a suburban area. She did not work and liked to do gardening in her spare time. There was no history of local trauma or any medications. On examination, there was intense redness, tenderness and swelling of the manubrium and the left sternoclavicular joint. Chest CT revealed osteolytic changes of the manubrium and presence of inflammatory tissue surrounding the manubrium and extending posteriorly. The lung parenchyma was unaffected. Brain and abdominal CT were unremarkable. A triple-phase bone scan was indicative of sternal osteomyelitis without other bone involvement. Blood and urine cultures remained negative. The patient was empirically treated with high-dose intravenous vancomycin and ciprofloxacin with no response. Antibody testing to human immunodeficiency virus and hepatitis viruses was negative. An open biopsy was performed 1 week later, revealing persistent inflammatory tissue around the sternum and fluid collection posteriorly. Multiple bone specimens were sent for histological examination and cultures. Histology showed acute and chronic granulomatous inflammation, while both cultures of the bone marrow and the fluid revealed Nocardia nova. No other pathogen was identified. The patient responded to high-dose intravenous trimethoprim-sulfamethoxazole, which was continued on an outpatient basis for 1 year without further sequelae.

This is the first reported case of primary sternal osteomyelitis due to Nocardia species. The possibility of nocardiosis needs to be included in the differential diagnosis of sternal osteomyelitis, even for apparently immunocompetent adults.