Abstract

A 48-year-old man presented to the pulmonary clinic with a 2-year history of a persistent dry cough, dyspnea, and an abnormal chest x-ray. The patient smoked 20 cigarettes daily for 20 years. He worked in an animal research laboratory for 12 years. He was exposed to primates, mice, dogs, pigs, rats and sheep. Physical examination on presentation showed a temperature of 98.6°F, blood pressure of 142/82 mm Hg, heart rate of 76/min and a respiratory rate of 16/min. Chest auscultation revealed bilateral diffuse crackles. Cardiac, abdominal, and neurologic examinations were unremarkable. Bilateral clubbing of both hands was noted. Pulmonary function testing revealed a total lung capacity (TLC) of 4.77 L (69%), a forced expiratory volume (FEV1) of 1.77 L (69%) and a diffusion capacity (DLCO) of 10.8 mL/mm Hg/min (38%). A computed tomography (CT) scan of the chest showed diffuse bilateral interstitial fibrosis with honeycombing, especially in the right upper lobe and small mediastinal lymph nodes (Fig.). A complete blood count, serum chemistry, liver function tests, serum angiotensin converting enzyme (ACE) level, anti-Scl-70 antibody, serum complement levels, rheumatoid factor, and erythrocyte sedimentation rate were normal. The antinuclear antibody (ANA), anticentromere antibody, and antineutrophil cytoplasm antibodies were negative. An interesting finding was an elevated serum IgE of 6501 mg/dL (1-180 mg/dL) with normal serum IgG, IgA, and IgM levels. The serum antibody precipitants to Aspergillus niger, A fumigatus, and A flavus were negative.