Primary sternal osteomyelitis: A case report

Abstract

Introduction: Primary sternal osteomyelitis is a rare condition that is frequently caused by Staphylococcus aureus. It is often confused with other cardiac and pulmonary conditions. Early antimicrobial treatment and surgical debridement is the cornerstone of treatment.

Case presentation: A 51-year-old male adult came to the emergency room (ER) with a 2-week history of chest pain, fever, and malaise. His past medical history was unremarkable. Examination revealed a tender anterior chest wall swelling. White Blood Cells (WBCs) (21.6 × 10⁴)/mm³) and C-reactive protein (CRP) (294.10 mg/L) were elevated. Pus from the swelling and blood samples were sent for culture and sensitivity. Electrocardiogram (ECG) was normal and a computed tomography (CT) scan of the chest showed a large dense anterior chest wall abscess extending deep in the chest and to both axillae which caused bony erosion of the sternum. Incision and drainage of the abscess were performed, followed by surgical debridement of the wound. Cultures along the course showed both Staphylococcus aureus and Enterococcus. The patient improved gradually and 2 months after his initial presentation, he became free of symptoms, and CT has shown complete resolution.

Discussion: Osteomyelitis usually happens after an external bacterium seeds the bone where it begins to grow and thrive, leading to the destruction and pus accumulation under the periosteum. For the treatment, identifying the causative agent is critical in giving intravenous (IV) antibiotic. Thereafter, incision and drainage of an abscess can be performed, similar to what was done with the patient mentioned. Radiography, specifically a CT scan, is crucial as it clearly reveals bony margins and can differentiate between a sequestrum and an involucrum. It also identifies cortical erosion, intraosseous gases and periosteal reactions.

Conclusion: Sternal osteomyelitis can have a nonspecific clinical presentation. Laboratory investigations and radiological findings are crucial for a prompt diagnosis. To prevent the progression of the disease and complications, early intervention is vital to ensure a good prognosis.

Keywords: Case report; Debridement; Osteomyelitis; Staphylococcus aureus; Sternum.

Fig. 1

Left infraclavicular abscess following sternal osteomyelitis is shown.

Fig. 2

Sternal bone shows destruction, cortical erosion, and inhomogeneous density. Retrosternal space is showing fluid collection, fat stranding, and inflammatory changes. Subcutaneous air loculi along the incisional line (arrow).