An asthmatic patient with progressive lung dysfunction: a case of misdiagnosis.

摘要

In May, 2005, a 40-year-old installer of thermohydraulic systems, who was a heavy smoker and had asthma, was referred to our hospital for progressive lung dysfunction of mixed type (Tiffeneau index 57%; forced expiratory volume in 1 s 1-73 L, 43% predicted; total lung capacity 5-75 L, 80% predicted; vital capacity 3-26 L, 64% predicted). He had a history of an acute episode of pneumonitis with asthma exacerbation and pleural effusion in March, 2005. High-resolution CT showed wandering bilateral nodular shadows, more obvious in the lower right apical lobe. Blood tests showed mild eosinophilia (11-7%; normal range 1-0-6 0), increased IgE (567 kU/L; 0-91), ESR (59 mm/h; 1-12), and C-reactive protein (31-1 mg/L; 0-5-0). All other laboratory results, including immunological markers, were within normal range. From the clinical (asthmatic and rhinitic symptoms), serological (eosinophilia), and CT (wandering bilateral nodular shadow) findings, a working diagnosis of Churg-Strauss syndrome was made. However, because of persistent eosinophilia, worsening dyspnoea, and persistent opacities on CT, the patient underwent bronchoscopy, bronchoalveolar lavage (BAL), and transbronchial biopsy (TBB). Brown fluid (300 mL) was collected and cytofluorirnetry showed an increased cell count (250000/mL; normal range 120000-190000) with recruitment of eosinophils (5%; 0-3). No informative diagnostic features were apparent from TBB. Microbiological investigations (viral, bacterial, fungal, mycobacterial) done on the BAL specimens and blood were all negative. Parasitic infestations were investigated and excluded. A lung biopsy was then taken by surgery, and histology showed a variegated appearance characterised by necrotising granulomas, with a bronchocentric distribution associated with mild eosinophilic interstitial infiltration and foci of organising pneumonia (figure). Staining for microorganism detection was negative.