Staphylococcus aureus mediastinitis following a skin infection in a non-immunocompromised patient: A case report

Abstract

Mediastinitis is a severe inflammation of the structures located in the mid-chest cavity. Three main causes of infective mediastinitis are traditionally recognized: Deep infection of a sternal wound following cardiothoracic surgery, perforation of the esophagus, and the descending necrotizing mediastinitis as a result of odontogenic, pharyngeal or cervical infections. Mediastinitis, as a complication of skin infection with hematogenous spread is infrequent. Methicillin-resistant Staphylococcus aureus (MRSA) is a gram-positive bacteria, and is responsible for numerous severe infections. MRSA mediastinitis is a rare infection and is typically associated with complications of sternotomy and retropharyngeal abscesses. Here, the second known case of mediastinitis of a hematogenous origin in a non-immunocompromised 41-year-old patient following primary skin infection, accompanied by sternal osteomyelitis, lung consolidation and pleural effusion is described; MRSA was the responsible pathogen. The clinical course was favorable after 6 weeks of antibiotics administration without drainage or surgical intervention.

Keywords: mediastinitis; methicillin-resistant Staphylococcus aureus; osteomyelitis; staphylococcal skin infection.

Figure 1

The skin lesion and chest X-ray on admission. (A) Pus-filled, 1 cm in greatest dimension, skin lesion on the patient’s forehead. The skin over the infected area is red and swollen. (B) Chest X-ray shows consolidation in the left lower lobe with blunting of the left costophrenic angle.

Figure 2

Chest computed tomography (mediastinal window) shows edema of the soft tissue adjacent to the first sternocostal joint and retrosternal fat heterogeneity/invasion. A, anterior; P, posterior.

Figure 3

Lung window: Consolidation in the left lower lobe with left pleural effusion. A, anterior; P, posterior.

Figure 4

Magnetic Resonance Imaging of the chest shows a large abnormal soft tissue containing cystic lesions, adjacent to the first sternocostal joint. A, anterior; P, posterior.

Figure 5

Chest computed tomography after 6 weeks of treatment (A) Chest computed tomography (mediastinal window). (B) Chest computed tomography (lung window). Complete remission of the lesions can be seen in both the panels.