Hypersentivity pneumonitis in an Interstitial Lung Disease Unit, 5 years’ experience

Introduction: Hypersensitivity pneumonitis (HP) in a prevalent disease in the ILD Units, and often a diagnostic challenge. The objective is to analyze the prevalence and main epidemiological characteristics of HP patients attended at our hospital in the last 5 years. Material & Methods: Observational and descriptive study in which all ILD patients were included, from Jan 2014 - Oct 2019. We have collected epidemiological, clinical and functional data. Results: 63 HP patients from 485 ILD patients 12.9%, 3rd cause after IPF and secondary to CTD. 54% males, mean age 68.11 y/o. 23.8% are acute/subacute, 76.2% chronic. At diagnosis, 28.6% presented dyspnea 0, 1 30.2%, 2 39.7%, 3 1.6%, nobody grade 4. Mean functional tests at diagnosis: FVC 80.8%, FEV1 84.7%, DCO 58; 6MWT distance 499 meters, initial satO2 95%, final satO2 88%. 68.3% live in urban environment, 31.7% in rural one. Exposure was clinically identified in half of the cases: birds 24.2%, farmhouse environment 9.7%, humidity at home 6.4%, occupational exposure 4.8%, pillow, drugs and sculpture material; unknown in 31 cases. Radiological pattern was predominantly fibrotic in 18 patients 28.6% and inflammatory in 45 71.4%. Anatomopathological sample was obtained in 26 patients 41.3%, 4 by surgical biopsy 6.3%, 22 cryobiopsy 34.9%; no biopsy in 58.7%. BAL was performed in 61.9% with an average lymphocyte count of 16.34% (> 20% in 9 patients 25%). Five patients died 7.9% and two patients have been transplanted in these 5 years. Conclusions: HP is the 3rd cause of ILD in our population, 13% of all ILDs. 3/4 of the patients present chronic forms. Only 41% have been biopsied. In half of the cases the exposure could not be identified