Can be divided into two main categories, hydrostatic and non-hydrostatic.
- Normal pulmonary capillary wedge pressure 6-12 mm Hg
- Redistribution of the pulmonary blood flow 16-19 mm Hg
- Interstitial edema 20-25 mm Hg
- Alveolar edema 25-30 mm Hg
- Kerley A lines centrally radiating from hila
- Kerley B lines peripherally
Secondary to increased venous pressure.
Edema will spare a lobe with pulmonary embolus or emphysema. Mitral valve regurgitation may cause right upper lobe edema mimicing pneumonia.
Secondary to increased capillary permeability.