A 68-year-old woman was admitted to our hospital with a persistent dry cough in 2010. A previous chest X-ray performed at another hospital showed interstitial densities in 2005. She had never smoked, and she used duvets stuffed with pheasant feathers. Oxygen saturation on room air while she was lying was 96%, which dropped to 88% after 6 min of walking. A physical examination revealed fine crackles in both lower lung fields. The serum levels of sialylated carbohydrate antigen KL-6 (KL-6) and pulmonary surfactant protein D (SP-D) were elevated (1111 U/mL, normal, <500 U/mL and 294 ng/mL, normal, <110 ng/mL, respectively; Table 1). A chest X-ray showed reticular shadows in both lung fields (Fig. 1). Chest computed tomography (CT) images revealed diffuse reticulation admixed with ground glass opacity without honeycombing, as well as prominent traction bronchiectasis in the right upper lobe (Fig. 2). The cell fractionation of bronchoalveolar lavage was normal. Transbronchial lung biopsy (TBLB) revealed an infiltration of inflammatory cells, predominantly lymphocytes as well as moderate alveolar septal fibrosis.
Based on the above findings, video-assisted thoracoscopic surgery (VATS) was performed, with chronic HP and idiopathic interstitial pneumonia considered as a differential diagnosis. Histologic sections of right upper lobe showed the peripheral and subpleural distribution of the fibrosis, architectural distortion with a microscopic honeycombing, and fibroblastic foci. Granuloma was not observed. These findings indicated the diagnosis of a usual interstitial pneumonia. (Fig. 3A and B). BRCHP was suspected from her environmental history. Serum antibodies to pigeon dropping extract (PDE) were detected (PDE IgG, 0.425 mug/mL, cut-off, 0.36 mug/mL; PDE IgA, 0.583 mug/mL, cut-off, 0.15 mug/mL), while Trichosporon asahii antibodies were not detected; she was diagnosed with BRCHP. Following our recommendation to move to another house and to stop using feather-filled duvets for antigen avoidance, she moved to her daughter's house intermittently. Her symptoms of worsening dry cough, general malaise, and anorexia, which she experienced when at her house, gradually improved when staying at her daughter's house.
In August 2011, she was readmitted to our hospital due to exertional dyspnea with the deterioration of ground glass opacity in bilateral lung fields and desaturation. She was diagnosed with acute exacerbation of BRCHP and administered 10 mg/day prednisolone and 150 mg/day cyclosporine A and discharged on home oxygen therapy.
In December 2011, she was again readmitted to our hospital with acute exacerbation (Fig. 4) and died following intensive care treatment with steroid pulse therapy and invasive positive pressure ventilation. An autopsy was performed and the microscopic examination demonstrated a diffuse alveolar damage (DAD) with hyaline membrane superimposed on diffuse interstitial fibrosis (Fig. 5).