Hypersensitivity pneumonitis: clinical, radiological and pathological profile of 103 patients from North India

Hypersensitivity pneumonitis (HP) is an interstitial lung disease, commonly occurring due to exposure to various inciting agent related to occupation. Few studies have shown that it can also occur without any occupation exposure. In this study we are presenting clinical, radiological and bronchoscopic finding of 103 HP patients. We retrospective analysis of 5½ years HP patient's data from a chest institute of India. The diagnosis of HP was considered with following criteria: i) known exposure to an inciting antigen; ii) presence of respiratory symptoms; iii) radiologic evidence of diffuse lung disease; iv) no other identifiable cause; v) lung biopsy specimen that demonstrated features of HP; and vi) bronchoalveolar lavage lymphocytosis (≥30%). The mean ±SD age was 47±12.8 years; 67% were female. The common symptoms were cough (97%) and dyspnea (91%). History of exposure to inciting agent was present in 61% with pigeon exposure being the most common (56%). Majority of patients (86%) were having chronic symptoms for >6 months. On 6MWT oxygen desaturation >4% was seen in 57% patients. Centrilobular nodules (61%) and ground glass opacity (47.5%) were common finding on HRCT chest. Bronchoalveolar lavage (BAL) lymphocytosis >30% was present in 48.5% and histopathological diagnosis HP on transbronchial lung biopsy (TBLB) and/or endobronchial lung biopsy (EBLB) was in 50% patients. HP is exposure related environmental disease, as it can occur without any occupational history. Bronchoscopy with BAL and lung biopsy should do in all suspected cases to confirm diagnosis in our country as it is less invasive, day care procedure with less complication.