American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias
ADOPTED BY THE
THIS JOINT STATEMENT OF THE AMERICAN THORACIC SOCIETY (ATS), AND THE EUROPEAN RESPIRATORY SOCIETY (ERS) WAS ATS BOARD OF DIRECTORS, JUNE 2001 AND BY THE ERS EXECUTIVE COMMITTEE, JUNE 2001
CONTENTSExecutive Summary Objectives Participants Evidence Validation Key Messages Introduction Rationale for a Change in the Approach to Classification of Idiopathic Interstitial Pneumonias Development of a New Classification of Idiopathic Interstitial Pneumonia Current Classification of IIP New ATS/ERS Classification Principles Guiding the Assessment of Patients with Idiopathic Interstitial PneumoniasThe Diagnostic Process Is Dynamic Clinical Evaluation Radiological Evaluation Role of Surgical Lung Biopsy Unclassifiable Interstitial Pneumonia Bronchoalveolar Lavage Fluid Evaluation Idiopathic Pulmonary Fibrosis Clinical Features Radiologic Features Histologic Features IPF: Areas of Uncertainty Nonspecific Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features NSIP:Areas of Uncertainty Cryptogenic Organizing Pneumonia Clinical Features Radiologic Features Histologic Features COP: Areas of Uncertainty Acute Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features AIP: Areas of Uncertainty Respiratory Bronchiolitis-Associated Interstitial Lung Disease Clinical Features Radiologic Features Histologic Features RB-ILD: Areas of UncertaintyDesquamative Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features DIP: Areas of Uncertainty Lymphoid Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features LIP: Areas of Uncertainty References Appendix
Despite the considerable progress in the classification of the idiopathic interstitial pneumonias (IIPs), the lack of an international standardhas resulted in variable and confusing diagnostic criteria and terminology. The advent of high-resolution computerized tomography, the narrowed pathologic definition of usual interstitial pneumonia (UIP) and recognition of the prognostic importance of separating UIP from other IIP patterns have profoundly changed the approach to the IIPs. This is an international Consensus Statement defining theclinical manifestations, pathology, and radiologic features of patients with IIP. The major objectives of this statement are to standardize the classification of the idiopathic interstitial pneumonias (IIPs) and to establish a uniform set of definitions and criteria for the diagnosis of IIPs. The targeted specialties are pulmonologists, radiologists, and pathologists. A multidisciplinary core panelwas responsible for review of background articles and writing of the document. In addition, this group reviewed the clinical, radiologic, and pathologic aspects of a wide spectrum of cases of diffuse parenchymal interstitial lung diseases to establish a uniform and consistent approach to these diseases and to clarify the terminology, definitions, and descriptions used in routine clinical practice.The final statement was drafted after a series of meetings of the entire committee. The level of evidence for the recommendations made in this statement is largely that of expert opinion developed by consensus. This classification of IIPs includes seven clinico–radiologic–pathologic entities: idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia, cryptogenic organizingpneumonia, acute interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia, and lymphoid interstitial pneumonia. The need for dynamic interaction between pathologists, radiologists, and pulmonologists to accurately diagnose these disorders is emphasized. The level of evidence for the recommendations made in this Statement is largely that...