[A case of hypersensitivity pneumonitis presenting with copious sputum and marked obstructive impairment of lung...

A 44-year-old male was hospitalized due to dyspnea and persistent cough with copious sputum (about 100 ml/day). Chest radiograph on admission showed hyperinflation and fine nodular shadows throughout both lungs, as well as a tram line appearance in the right lower lung field which suggested thickening of bronchial walls. Pulmonary function tests demonstrated moderate to severe reduction of %VC, FEV1.0 and PaO2. Fiberoptic bronchoscopy revealed inflammatory change in the walls of proximal bronchi. Although his dyspnea resolved rapidly, productive cough and impaired lung function were persistent and improved very slowly over the one-month-period following admission. After resolution, similar symptoms were provoked again 5 to 6 hours after returning to his home, suggesting the recurrence of hypersensitivity pneumonitis. Open lung biopsy was performed for the differential diagnosis of hypersensitivity, diffuse panbronchiolitis, and bronchial asthma, because neither transbronchial lung biopsy nor broncho-alveolar lavage was diagnostic. Histopathology of the open lung biopsy specimens revealed marked desquamation of bronchiolar epithelium in addition to bronchiolo-alveolitis with epithelial granulomas, consistent with hypersensitivity pneumonitis. Copious sputum is a very uncommon clinical feature in hypersensitivity pneumonitis. We consider that the large volume of airway fluid was caused by epithelial ulceration of bronchioles and catarrhal bronchitis associated with hypersensitivity pneumonitis.