Signs evocative of venous and capillary (pulmonary veno-occlusive disease/pulmonary capillary haemangiomatosis) involvement

Pulmonary function testsDecreased DLCO (frequently <50%)
Severe hypoxaemia
Chest HRCTSeptal lines
Centrilobular ground-glass opacities/nodules
Mediastinal lymph node enlargement
Response to PAH therapyPossible pulmonary oedema
Genetic backgroundBiallelic EIF2AK4 mutations
Occupational exposureOrganic solvent (trichloroethylene)

DLCO: diffusing capacity of the lung for carbon monoxide; HRCT: high-resolution computed tomography; PAH: pulmonary arterial hypertension.