Hypersensitivity Pneumonitis Medical Slides

Present the two-category system: non-fibrotic HP (ground-glass, mosaic attenuation, centrilobular nodules without honeycombing/traction bronchiectasis — generally good prognosis with antigen avoidance) and fibrotic HP (features of fibrosis present — traction bronchiectasis, honeycombing, reticulation — poor prognosis similar to IPF). Diagnostic confidence levels: definite, high, or low confidence based on exposure identification, HRCT pattern, BAL lymphocytosis, and biopsy findings.

Present a systematic exposure questionnaire covering: home environment (birds, feather bedding, hot tub, visible mold, humidifier, basement moisture), occupation (farming, metalworking fluids, paint spraying, mushroom growing), hobbies (bird keeping, hot tub use, woodworking). Emphasize that repeat visits may be needed — patients often do not initially disclose relevant exposures. IgG precipitins/specific IgG testing confirms sensitization but not disease (30% of exposed asymptomatic individuals are positive).

Present the management framework: Non-fibrotic HP — strict antigen avoidance (may be curative), short-course corticosteroids if symptomatic (prednisone 0.5 mg/kg tapered over 4-8 weeks), excellent prognosis. Fibrotic HP — antigen avoidance still essential but fibrosis may progress regardless; immunosuppression (mycophenolate or azathioprine) for inflammatory component; antifibrotic therapy (nintedanib per INBUILD trial subgroup analysis) for progressive fibrosis. Median survival: non-fibrotic >15 years vs fibrotic 7-9 years.