PMC7481557_01
Chest X-ray (CXR) findings. (A) On admission, CXR revealed ground-glass opacities in bilateral lower lung fields. (B) After initial methylprednisolone pulse therapy, C-reactive protein (CRP) level decreased (data not shown) and lung involvement remarkably improved. (C) Ten days after admission, following second steroid pulse therapy, CRP became elevated again (data not shown) and progressive bilateral diffuse extensive infiltrates appeared.
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C-reactive protein (CRP) (16.63 mg/dL; normal,  0.3 mg/dL) were increased and marked hypoxemia (partial pressure of oxygen and carbon dioxide in arterial blood were 57.5 mmHg and 32.9 mmHg under 10 L/min oxygen supplementation, respectively). Chest X-ray revealed ground-glass opacities (GGO) in bilateral lower lung fields (Fig. 1A) and chest computed tomography showed extensive consolidation with GGO in bilateral lung fields (Fig. 2). After methylprednisolone pulse therapy (1000 mg/day for 3 days), CRP level decreased (2.62 mg/dL) and lung involvement remarkably improved (Fig. 1B). However, 10 days after admission, following second steroid pulse therapy, CRP levels became elevated again (15.09 mg/dL) and progressive bilateral diffuse extensive infiltrates appeared (Fig. 1C).
Autopsy findings of the lung (A, hematoxylin-eosin staining, 30x). During intensive treatment, Corynebacterium spp. was detected in tracheal sputum culture, and histologic findings of the autopsy revealed diffuse alveolar damage (DAD) with hyaline membrane (B, black arrow) and extensive fibrosis with no evidence of bacterial pneumonia. Dense fibrotic lesions reflect inappropriate repair of DAD after initial steroid pulse therapy.
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During treatment, Corynebacterium spp. had been detected in tracheal sputum culture, and histologic findings of autopsy revealed DAD and extensive fibrosis with no evidence of bacterial pneumonia (Fig. 3).
Autopsy findings of the trachea. Neutrophilic infiltration (A, black arrows) was observed in the tracheal epithelium with mucosal hemorrhage (B, hematoxylin-eosin staining, 20x). Considering the finding of diffuse alveolar damage with no evidence of bacterial pneumonia, we concluded that the diagnosis of this case was acute respiratory distress syndrome related to ventilator-associated tracheitis caused by Corynebacterium spp. infection.
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Additionally, neutrophilic infiltration was observed in the tracheal epithelium with mucosal hemorrhage (Fig. 4).