Table 1.

Differential diagnosis of various radiological patterns in HAPE (only common causes enumerated with most important differentials listed first)

Bilateral symmetrical perihilar opacities	Bilateral symmetrical diffuse opacities	Unilateral diffuse opacities	Bilateral asymmetrical focal opacities	Lobar consolidation
Cardiogenic pulmonary edema Diffuse alveolar hemorrhage ARDS Viral pneumonia PJP Acute interstitial pneumonia Acute eosinophilic pneumonia	ARDS Diffuse alveolar hemorrhage Viral pneumonia PJP Cardiogenic edema Acute hypersensitivity pneumonitis Acute interstitial pneumonia Acute eosinophilic pneumonia	Unilateral pulmonary edema (as in some cases of mitral regurgitation) Re-expansion pulmonary edema Aspiration pneumonitis Postobstructive pneumonia Bronchogenic carcinoma Pulmonary embolism (oligemia on the affected side may be misinterpreted as diffuse opacity on the unaffected side)	Bronchopneumonia Tuberculosis Bronchogenic carcinoma with metastasis Pneumoconiosis Septic emboli Allergic bronchopulmonary aspergillosis Sarcoidosis Organizing pneumonia Vasculitis Aspiration pneumonitis	Pneumonia Bronchogenic carcinoma Aspiration pneumonia Pulmonary embolism Zonal predilection: Upper-tuberculosis, pneumoconiosis, right upper lobe edema in acute mitral regurgitation Lower-aspiration pneumonia, asbestosis

ARDS, acute respiratory distress syndrome;

PJP, Pneumocystis jirovecii pneumonia