Upper-lobe diversion, then interstitial oedema (Kerley B lines, peribronchial cuffing, fissural thickening), then alveolar oedema in a bat-wing distribution with effusions — graded in order.
Orient first
- Pulmonary venous pressure rise produces a predictable sequence; the stage roughly tracks the pressure.
- Cardiomegaly, a widened vascular pedicle and bilateral effusions favour cardiogenic over non-cardiogenic oedema.
- Asymmetric oedema occurs with mitral regurgitation (right upper lobe), emphysema and position.
Acquire the study
- Erect PA chest radiograph where possible (AP portable in the unwell), same projection for follow-up.
The manoeuvre
- Heart size (cardiothoracic ratio on PA) and vascular pedicle width in cm.
- Upper lobe vessels as large as or larger than lower lobe vessels at equal distance from the hilum (diversion — erect films only).
- Interstitial: Kerley B lines at the costophrenic angles, peribronchial cuffing, fissural thickening.
- Alveolar: perihilar bat-wing opacities; air bronchograms.
- Effusions: blunted costophrenic angles, subpulmonic fluid.
What confirms it
- Cardiomegaly with interstitial or alveolar oedema and effusions that respond to diuresis on the next radiograph.
What licenses you to exclude it
- Normal heart size, no septal lines and no effusions make cardiogenic oedema unlikely.
The classic misread
- Judging diversion on a supine film, where upper-lobe vessels are normally prominent.
- Calling lymphangitic carcinomatosis oedema — nodular septa and nodes argue against it.