The American College of Chest Physicians^® (CHEST) recently released new clinical guidelines on the Diagnosis and Evaluation of Hypersensitivity Pneumonitis (HP). The guidelines contain 14 evidence-based recommendations to improve individual diagnostic decision-making and to decrease diagnostic practice variability.

Occurring at any age, HP is an immunologically mediated form of lung disease resulting from inhalational exposure to a large variety of environmental and/or occupational inciting antigens (typically fungal, bacterial, avian). Over the years, the categorization of HP based on clinical features and disease duration coupled with traditional diagnostic criteria has been unhelpful, even when accurate, when separated from a probabilistic diagnostic reasoning approach and multidisciplinary consensus.

By outlining a patient-centered and interdisciplinary diagnostic approach to a confident or working HP diagnosis, these guidelines will serve as a central source to help optimize diagnostic consistency and decision-making in HP across multidisciplinary teams and among clinicians.

"Guidelines for medical diagnoses are fundamental to better align diagnostic approaches across practicing institutions," says Evans Fernández, MD, MS, a pulmonologist at National Jewish Health. "Along with streamlining the approach to diagnosing HP, the guidelines also provide a diagnostic algorithm incorporating the evidence and informed by expert consensus, to aid physicians in gauging the probability of HP."

Several of the guidelines presented in the report include the following recommendations:

• In patients with suspected HP, the panel suggests:
  • Classifying patients based on the likelihood of occupational or environmental inciting antigen exposure and as fibrotic or nonfibrotic based on the presence or absence of fibrosis on high-resolution CT of the chest.
  • Against performing bronchoalveolar lavage fluid analysis in patients who have a compelling exposure history within the appropriate clinical context and a pattern typical for HP on high-resolution CT of the chest.
  • Considering histological lung biopsy for additional diagnostic evaluation when all available data such as clinical, laboratory and radiologic findings (along with bronchoscopic results) do not yield a confident diagnosis, and results may help guide management.

The full list of recommendations and an explanation of the methodology applied is available on the journal CHEST^® website.

"Along with the physician's diagnosis, it is important for patients to understand their disease," says Dr. Fernández. "To assist those diagnosed with an interstitial lung disease, like HP, there are resources available on the CHEST Foundation website."

In addition to the updated CHEST guidelines for clinicians, providing patients with resources that explain their lung disease can improve understanding and response to treatment. The CHEST Foundation, through the support of the Erin Popovich Endowment, created a comprehensive guide on interstitial lung diseases (ILDs). Clinicians may access these resources or provide the links to the information to their patients at chestfoundation.org.