<unk>  affects gas flow in the alveoli The alveoli Micrograph of usual interstitial pneumonia (UIP). UIP is the most common pattern of idiopathic interstitial pneumonia (a type of<unk>  and usually represents idiopathic pulmonary fibrosis. H&E stain. Autopsy specimen. An<unk>  may be classified as to whether its cause is not known (idiopathic) or known (secondary). Idiopathic Idiopathic interstitial pneumonia is the term given to<unk> s with an unknown cause. They represent the majority of cases of<unk> s (up to two-thirds of cases). They were subclassified by the American Thoracic Society in 2002 into 7 subgroups: * Idiopathic pulmonary fibrosis (IPF): the most common subgroup * Desquamative interstitial pneumonia (DIP) * Acute interstitial pneumonia (AIP): also known as Hamman-Rich syndrome * Nonspecific interstitial pneumonia (NSIP) * Respiratory bronchiolitis-associated<unk>  (RB-ILD) * Cryptogenic organizing pneumonia (COP): also known by the older name bronchiolitis obliterans organizing pneumonia (BOOP) * Lymphoid interstitial pneumonia (LIP) Secondary Secondary<unk> s are those<unk> s with a known etiology, including: * Connective tissue and Autoimmune<unk> s * Sarcoidosis * Rheumatoid arthritis * Systemic lupus erythematosus * Systemic sclerosis * Polymyositis * Dermatomyositis * Antisynthetase syndrome * Inhaled substances (Pneumoconiosis) * Inorganic * Silicosis * Asbestosis * Berylliosis * Industrial printing chemicals (e.g. carbon black, ink mist) * Organic * Hypersensitivity pneumonitis (extrinisic allergic alveolitis) * Drug-induced * Antibiotics * Chemotherapeutic drugs * Antiarrhythmic agents * Infection * Coronavirus<unk>  2019 * Atypical pneumonia * Pneumocystis pneumonia (PCP) * Tuberculosis * Chlamydia trachomatis * Respiratory Syncytial Virus * Malignancy * Lymphangitic carcinomatosis * Predominately in children * Diffuse developmental disorders * Growth abnormalities deficient alveolarisation * Infant conditions of undefined cause *<unk>  related to alveolar surfactant region
Interstitial lung disease
Idiopathic pulmonary fibrosis
Alveolar lung disease
Alcoholic lung disease
Pulmonary interstitial emphysema
Pulmonary alveolar proteinosis
Pulmonary fibrosis
Emphysema