Another cause of chest pain: Staphylococcus aureus sternal osteomyelitis in an otherwise healthy adult

Abstract

Chest pain requires a detailed differential diagnosis with good history-taking skills to differentiate between cardiogenic and noncardiogenic causes. Moreover, when other symptoms such as fever and elevated white blood cell count are involved, it may be necessary to consider causes that include infectious sources. A 53-year-old female with no significant past medical history returned to the hospital with recurrent complaints of chest pain that was constant, substernal, reproducible, and exacerbated with inspiration and expiration. The chest pain was thought to be noncardiogenic, as electrocardiography did not demonstrate changes, and cardiac enzymes were found to be negative for signs of ischemia. The patient's blood cultures were analyzed from a previous admission and were shown to be positive for Staphylococcus aureus. The patient was started empirically on vancomycin, which was later switched to ceftriaxone as the bacteria were more sensitive to this antibiotic. A transthoracic echocardiogram did not demonstrate any vegetation or signs of endocarditis. There was a small right pleural effusion discovered on X-ray. Therefore, computed tomography as well as magnetic resonance imaging of the chest were performed, and showed osteomyelitis of the chest. The patient was continued on intravenous ceftriaxone for a total of 6 weeks. Tests for HIV, hepatitis A, B, and C were all found to be negative. The patient had no history of childhood illness, recurrent infections, or previous trauma to the chest, and had had no recent respiratory infections, pneumonia, or any underlying lung condition. Hence, her condition was thought to be a case of primary sternal osteomyelitis without known cause.

Keywords: differential; myocardial infarction; pleuritic; substernal.

Figure 1

Electrocardiogram. Note: This was a normal electrocardiogram with no changes. Abbreviations: a, augmented; V, vector; L, left; R, right; F, foot.

Figure 2

Chest X-rays. Note: Chest X-rays show an interval development of a right pleural effusion that is best seen on the lateral view (arrow). Abbreviation: L, left.

Figure 3

Magnetic resonance imaging of the chest. Notes: Increased signal is seen on T2-weighted images in subcutaneous fat in the anterior abdominal wall at the midline. Increased signal is also noted in anterior mediastinum fat posterior to the sternum. There is periosteum enhancement of the sternum manubrium and at the upper part of the body of the sternum after contrast administration. There is also increased signal in the bone marrow noted on T2-weighted images in the sternum manubrium and in the upper part of the body of the sternum, suggesting bone marrow edema. No evidence of fracture is noted. Findings are consistent with osteomyelitis involving the manubrium and the upper part of the sternum body. Arrows indicate the area of osteomyelitis.