ATS guideline addresses challenges in diagnosing hypersensitivity pneumonitis
The American Thoracic Society issued a new clinical practice guideline to aid clinicians in diagnosing hypersensitivity pneumonitis in patients with newly diagnosed interstitial lung disease — the first new guidance in 3 decades.
The guideline was developed in collaboration with the Asociación Latinoamericana de Tórax and the Japanese Respiratory Society.
“The clinician is often unable to distinguish features of fibrotic hypersensitivity pneumonitis from those of idiopathic pulmonary fibrosis and some patients meeting the criteria for the diagnosis of IPF may in face have fibrotic hypersensitivity pneumonitis with pulmonary fibrosis,” Ganesh Raghu, MD, professor of medicine at the University of Washington and director of the Center for Interstitial Lung Disease at the University of Washington Medical Center, said in a press release issued by ATS. “The high rate of screen failures in patients participating in IPF clinical trials highlights this diagnostic challenge, as pulmonologists may be misdiagnosing patients with fibrotic hypersensitivity pneumonitis as having IPF, overlooking environmental factors that can contribute to the disease.”
Aiding clinicians in diagnosis
The new guideline, published in the American Journal of Respiratory and Critical Care Medicine, lists recommendations to aid clinicians in making a confident and accurate diagnosis of hypersensitivity pneumonitis in patients with newly diagnosed ILD.
The guideline committee included a multidisciplinary panel of experts to identify clinically important concerns about diagnostic testing for hypersensitivity pneumonitis among patients with newly diagnosed ILD. The panel categorized hypersensitivity pneumonitis as nonfibrotic or fibrotic, and made recommendations for each clinical phenotype.
“It should be emphasized that clinicians should apply the recommendations within this clinical practice guideline in the clinical context of each individual patient, considering the patient’s values and preferences and should not consider any recommendations as mandates,” the authors wrote.
Recommendations for clinicians
The recommendations for clinicians to overcome the challenges in diagnosing nonfibrotic or fibrotic hypersensitivity pneumonitis in patients with newly diagnosed ILD include the following:
- Develop and validate a questionnaire to identify potential inciting agents for patients whose differential diagnosis includes nonfibrotic or fibrotic hypersensitivity pneumonitis. The guideline committee does not make a recommendation or suggestion for or against the use of a specific questionnaire. Pending availability of such a questionnaire, the guideline committee recommends taking a thorough history to identify potential exposures and sources in a patient’s environment.
- Perform serum immunoglobulin G testing to target potential antigens linked to hypersensitivity pneumonitis.
- Obtain bronchoalveolar lavage fluid for lymphocyte cellular analysis.
- Perform transbronchial forceps lung biopsy for nonfibrotic hypersensitivity pneumonitis; the guideline committee does not recommend for or against transbronchial forceps lung biopsy for fibrotic hypersensitivity pneumonitis.
- There is no recommendation for or against transbronchial lung cryobiopsy for nonfibrotic hypersensitivity pneumonitis; however, transbronchial lung cryobiopsy is suggested for fibrotic hypersensitivity pneumonitis.
- Perform surgical lung biopsy when all other alternative diagnostic options have not provided a diagnosis for nonfibrotic or fibrotic hypersensitivity pneumonitis.
The full list of recommendations and related details are published in the American Journal of Respiratory and Critical Care Medicine.
“These guidelines create a framework that we hope will standardize clinical care and facilitate research,” Kevin C. Wilson, MD, professor of medicine at Boston University School of Medicine, said in the press release.