Bloody Bronchial Cast Formation Due to Alveolar Hemorrhage Associated with H1N1 Influenza Infection

Abstract

A previously healthy 55-year-old man with H1N1 influenza A presented with severe respiratory failure and cardiac arrest. Following the return of spontaneous circulation, venovenous extracorporeal membrane oxygenation was required to maintain oxygenation. On day 2, bronchoscopy revealed a bloody bronchial cast obstructing the right main bronchus. A pathological examination revealed that it was composed of intrabronchial and intra-alveolar hemorrhagic tissue. Unfortunately, the patient died due to severe brain ischemia; a subsequent autopsy revealed marked alveolar hemorrhage. It is possible that anticoagulant therapy, alveolar collapse, and neuromuscular blocking agents provoked cast development in this case.

Keywords: ECMO; alveolar collapse; anticoagulation; complication; plastic bronchitis; white out.

Figure 1.

A: Bilateral patchy infiltration was observed on chest computed tomography at admission. B: Severe consolidation in both lungs on chest radiography, known as whiteout, after the initiation of venovenous extracorporeal membrane oxygenation.

Figure 2.

A: Bronchoscopy on day 1 showing alveolar hemorrhage without a cast. B: Bronchoscopy on day 2 showing a bloody bronchial cast totally obstructing the right main bronchus.

Figure 3.

A: A macroscopic image of the bloody bronchial cast that was removed from the right main bronchus. B: The microscopic pathological findings of the cast extracted from the right bronchus. The extracted cast was mainly composed of red blood cells, together with fibrin, neutrophils, and necrotic debris (Hematoxylin and Eosin staining, 100×).

Figure 4.

Microscopic pathological findings at autopsy (Left lung, upper lobe). Edema, intra-alveolar hemorrhage, and fibrinous exudation can be seen (Hematoxylin and Eosin staining, 2.5×, 20×).