Diagnostic Approach to Hypersensitivity Pneumonitis: A Report of Two Cases.

Hypersensitivity pneumonitis (HP) is a bronchopulmonary granulomatosis of immunological mechanism, caused by an aberrant response to an inhaled exposure, which results in mostly T cell-mediated inflammation, granuloma formation, and fibrosis in some cases. The most common forms are bird breeder's disease and farmer's lung disease. The diagnosis of HP is based on the presence of compatible symptoms, the notion of exposure to antigens known to be pathogenic, and the existence of interstitial and bronchiolar images on the thoracic scan, lymphocytosis in the alveolar lavage, and precipitins. Chronic forms, in case of insidious exposure, especially in poultry, may evolve into pulmonary fibrosis with a poor prognosis. Through this work, we want to underline the frequency of this disease in our country, its heterogeneity as well as the difficult early diagnosis. Finally, we will investigate the therapeutic effect of corticosteroids in the early stages and the antifibrotic treatment in fibrotic forms.