| Cardiovascular | |
| Pulmonary oedema | |
| Pulmonary embolism | |
| Neoplastic | |
| Lung cancer | |
| Endobronchial metastases | |
| Lymphoma | |
| Immunological disorders | |
| Vasculitic diffuse alveolar haemorrhage | |
| Wegener’s granulomatosis | |
| Cryptogenic organising pneumonia | |
| Acute interstitial pneumonia | |
| Sarcoidosis | |
| Pulmonary alveolar proteinosis | |
| Systemic lupus erythematosus | |
| Polymyositis and dermatomyositis | |
| Acute and chronic eosinophilic pneumonia | |
| Drug toxicity | |
| Radiation pneumonitis |