Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases

Interstitial lung disease (ILD) comprises a heterogeneous group of disorders characterized by interstitial compartment proliferation, inflammatory infiltration, and potential fibrosis with abnormal collagen deposition. Diagnosis requires a multidisciplinary consensus integrating clinical, radiological, and pathological findings. Idiopathic interstitial pneumonia (IIP) includes idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia, desquamative interstitial pneumonia, acute interstitial pneumonia, and respiratory bronchiolitis-ILD, each exhibiting distinct prognostic and therapeutic implications. Some non-IPF ILDs progress despite standard treatment, classified as progressive fibrosing-ILD or progressive pulmonary fibrosis (PPF), diagnosed by worsening symptoms, physiological decline, and radiological progression. Nintedanib is conditionally recommended for refractory PPF cases. Combined pulmonary fibrosis and emphysema is characterized by upper-lobe predominant emphysema and lower-lobe fibrosis, frequently complicated by pulmonary hypertension and lung cancer. Interstitial lung abnormality, observed in both smokers and the general population, is associated with increased mortality and disease risk, warranting further research. Despite advancements, refinement in classification, diagnostic criteria, and therapeutic strategies remains crucial for improving patient outcomes.