[Coronary artery bypass grafting in a patient with chronic bird fancier's lung].

Acute exacerbation is a devastating and fatal event of hypersensitivity pneumonitis. We report an 80-year-old man with chronic bird fancier's lung which acutely exacerbated after off-pump coronary artery bypass grafting. Our perioperative management included avoidance of inhalation of high concentration oxygen, administration of neutrophil elastase inhibitor, and long-term administration of antibiotics. Nevertheless, the patient experienced severe respiratory failure after influenza infection. High-resolution computed tomography (CT) showed new ground-glass opacities overlying fibrosis and traction bronchiectasis. We diagnosed acute exacerbation of hypersensitivity pneumonitis. Immediate steroid pulse therapy with empirical antibiotic administration was effective, and he recovered from critical respiratory failure. High-resolution CT was very helpful in the early detection of acute exacerbation of pneumonitis.