Development of Bird Fancier's Lung After Withdrawal of Secondhand Smoke

Abstract

Bird fancier's lung (BFL) is a form of hypersensitivity pneumonitis (HP) caused by an exaggerated immune response to avian antigen. BFL is much less common in smokers. In this case, development of BFL occurred in a previously asymptomatic patient with long-standing exposure to avian antigen after withdrawal of secondhand smoke. CASE PRESENTATION: A 71-year-old female presented with worsening exertional dyspnea and non-productive cough for 3 months. She denied fever or weight loss. She denied occupational exposure or new pets but has owned a cockatoo for 29 years. She is a lifetime non-smoker. Her husband smoked 1.5 packs per day for 50 years but quit 3 months prior to onset of her symptoms. Lung auscultation revealed diffuse, fine crackles. Nail clubbing was not present. On 6-minute walk test, her O2 saturation decreased from 96% to 88% and she required supplemental O2. Pulmonary function testing revealed a non-obstructive FEV1/ FVC of 87%. DLCO was moderately decreased at 8.8 mL/min/mmHg, VC was 73% of predicted. Chest CT revealed diffuse ground-glass opacification. Autoimmune assays were unremarkable. Serologic studies revealed antibodies against cockatiel droppings and parrot serum antigens. BFL was suspected as the underlying etiology. Steroid therapy resulted in rapid symptom improvement. Five weeks after re-homing her bird and deep cleaning her home, she experienced complete resolution of her symptoms.