<unk>  may be classified into several subtypes based on duration of symptoms, severity and origin of the bleeding. Based on the duration of symptoms,<unk>  may be classified as either acute or chronic.<unk>  may be classified according to severity into 3 groups of mild, moderate, and massive bleeding. Based on the origin of bleeding,<unk>  may be classified into two groups of pulmonary versus extrapulmonary bleeding.
Hemoptysis classification
Lung abscess classification
Hemothorax classification
Non small cell lung cancer classification
Pleural effusion classification
Emphysema classification
Pneumothorax classification
Pneumomediastinum classification