A 7-year-old boy with a history of allergies was admitted to the pediatric ICU of Shenzhen Children’s Hospital with acute respiratory failure. The day before admission, he had cough, fever to 38.5°C, wheezing, and dyspnea. In the ED, he received aerosolized albuterol, supplemental oxygen, and IV ceftriaxone without improvement. In the pediatric ICU he was febrile, his WBC count was 21.9 ×109/L, and his C-reactive protein level was 39 mg/L. Chest radiography showed left pulmonary infiltrate, and a chest CT scan showed bilateral patchy consolidation. Breathing 70% oxygen, arterial pH was 7.17, Paco2 was 75 mm Hg, and Pao2 was 60 mm Hg. He was intubated and mechanically ventilated. Flexible bronchoscopy identified gelatinous secretions in the large bronchi bilaterally. After bronchial aspiration and bronchial lavage, an airway plug was partially removed, and this had characteristics of a bronchial cast. On histologic examination, the casts were composed of fibrinous and necrotic material, but there were no inflammatory cells (Fig 3). A second flexible bronchial aspiration was performed the following day with further removal of the bronchial cast. After this, the oxygen saturation increased. He received a 7-day course of oral oseltamivir. He was extubated in 72 h and discharged from the hospital after 2 weeks. A month after discharge, the chest CT scan returned to normal.