Differential Diagnosis of Suspected Pneumonia
| Disorder | Comment |
|---|---|
| Cardiovascular disorders | |
| Pulmonary embolism | Risk factor(s) for venous thromboembolism Sudden-onset shortness of breath See Chapter 57. |
| Tricuspid valve endocarditis | IVDU or indwelling venous cannula e.g. for haemodialysis in blood cultures. |
| Neoplastic disorders | |
| Bronchial carcinoma | Weight loss, chronic cough, abnormal CXR (nodule or mass, mediastinal lymphadenopathy) |
| Alveolar cell carcinoma | Similar CXR appearance to pneumonia. If there is no leucocytosis or fever or if the patient doesn't respond to antibiotics. |
| Immune-mediated disorders | |
| Wegener granulomatosis | Haematuria, haemoptysis, epistaxis, scleritis, uveitis |
| Diffuse alveolar haemorrhage in pulmonary-renal syndromes | Haematuria, haemoptysis, positive anti-GBM, ANCA antibodies |
| Systemic lupus erythematosus | Skin rash, sensitivity to sunlight, positive ANA |
| Acute interstitial pneumonia | Ground glass changes and traction bronchiectasis on HRCT |
| Eosinophilic pneumonia syndromes | Peripheral blood eosinophilia, peripheral infiltrate within the outer two-thirds of the lung fields on X-ray, responds to steroids |
| Bronchiolitis obliterans – organizing pneumonia | Acute to subacute onset of symptoms, migratory patchy infiltrates on X-ray, responds to steroids |
| Other disorders | |
| Drug toxicity (e.g. amiodarone pneumonitis) | Restrictive spirometry, decreased gas transfer, responds to steroids and stopping offending drug(s) |
| Radiation pneumonitis | History of recent radiotherapy, responds to steroids |