Pulmonary Function Abnormalities in Regard to Age at the Time of Diagnosis of Hypersensitivity Pneumonitis.

Abstract

Hypersensitivity pneumonitis (HP) is a complex syndrome caused by exaggerated immune response to inhalation of a variety of organic particles in susceptible individuals. In this study we assessed the relationship between age at the time of diagnosis and the degree of functional and radiological changes in HP. The diagnosis of HP was made on the basis of a combination of clinical symptoms, medical history, serological tests, radiologic evidence of diffuse lung disease, and absence of other identifiable causes of lung disease. We reviewed the records of 111 patients (68 women) diagnosed with HP over a period of 18years (1995-2013). The patients were stratified into 3 age-groups: <30, 30-49, and ≥50years old. The commonest cause of HP was avian antigens (56.8%). Dyspnea was present in 97.3% of patients, weight loss in 54.7% of patients, and respiratory insufficiency in 24.3% of patients. Lung fibrosis in chest computed tomography was found in 35.1% of patients. Lung function was impaired more seriously in the youngest age-group, with lung diffusing capacity for carbon monoxide (DLCO) <40% in 69.2% of these patients. Restrictive pattern was present in 92.3% of patients in this group, as compared with the 41.0% in the whole cohort. In this group, desaturation in the six minute walk test also was most notable, amounting to a median of 11%. In conclusion, diagnosis of HP at young age is predictive of a more severe clinical course of disease, with lung fibrosis and higher disturbances in pulmonary function.