Thoughts on hypersensitivity pneumonitis
Thoughts on pathology hypersensitivity pneumonitis from the newish ATS, ACCP consensus statement, and a review article by Andrew Churg https://pubmed.ncbi.nlm.nih.gov/34531525 https://pubmed.ncbi.nlm.nih.gov/35738345 https://pubmed.ncbi.nlm.nih.gov/32706311 These criteria are designed primarily to provide a uniform language for clinical trials. Nonetheless, they provide a platform to air general problems with current approaches. Both ATS and ACCP emphasize that HP should be thought of as non-fibrotic vs fibrotic rather than acute, subacute or chronic. This seems like a good thing but is basically relabeling how I (and presumably others) always thought of them with a more logical label. A precedent would be acute (cellular only) vs chronic/fibrotic interstitial nephritis. No attempt though is made to define how much fibrosis is needed to be labeled fibrotic e.g. is one reticulation on HRCT enough? Lack of quantitation for all criteria is a problem throughout...