Most frequent (in advanced stages) |
Destruction of pulmonary capillary bed by parenchymal fibrosis |
Others |
Extrinsic compression of large pulmonary arteries |
By enlarged hilar or mediastinal lymph nodes |
By fibrosing mediastinitis |
Vascular infiltration by noncaseating granulomas and/or perivascular fibrosis |
Of pulmonary arteries |
Of pulmonary veins (with pulmonary veno-occlusive disease) |
Myocardial infiltration by noncaseating granulomas |
Pulmonary vasoconstriction |
By hypoxaemia |
By other vasoactive factors |
Liver sarcoidosis (with portal pulmonary arterial hypertension) |
Of note: multiple aetiologies can co-exist.