Pulmonary Edema and Lung Infiltrates

Radiographic Manifestations

The American Thoracic Society notes that hydrostatic pulmonary edema presents with hazy opacities, Kerley B lines, and a classic "batwing" appearance on chest radiographs 1
Pleural effusions are more frequently observed in hydrostatic edema compared to permeability edema, as reported by the European Respiratory Society 1
The infiltrates reflect expansion of connective tissue space around conducting airways, accompanying vessels, and interlobular septa, according to the American College of Chest Physicians 1
Ground-glass opacities and consolidation develop as fluid accumulates in alveolar spaces and interstitium, as described by the Society of Critical Care Medicine 1
Permeability pulmonary edema manifests as patchy and widespread areas of parenchymal opacities with evolutional changes over time, as noted by the European Society of Intensive Care Medicine 1
In ARDS/ALI, bilateral infiltrates appear without overt evidence of fluid overload, as reported by the American Thoracic Society 2

The European Society of Intensive Care Medicine explains that pulmonary edema creates infiltrates through fluid accumulation in the pulmonary interstitium and alveoli, which appears as increased density on imaging 3
Fluid flux across the alveolar-capillary membrane follows Starling forces, with edema occurring when fluid deposition exceeds lymphatic clearance capacity, as described by the American Physiological Society 3
In sepsis and ARDS, variable degrees of capillary permeability increase the effect of hydrostatic pressure gradients, allowing plasma proteins to cross into alveolar spaces, according to the Society of Critical Care Medicine 3

The Infectious Diseases Society of America notes that asymmetric pulmonary infiltrates consistent with pulmonary edema can be caused by numerous noninfectious disorders, making radiographic specificity only 27-35% 4
Differential diagnosis includes atelectasis, chemical pneumonitis, asymmetric cardiac pulmonary edema, pulmonary embolism, cryptogenic organizing pneumonia, pulmonary contusion, pulmonary hemorrhage, and drug reactions, as reported by the American College of Chest Physicians 4
In ARDS settings, detecting new radiographic infiltrates becomes especially challenging, with false-negative rates up to 46% for clinical diagnosis, according to the European Society of Intensive Care Medicine 4

The European Respiratory Society describes that in pulmonary veno-occlusive disease (PVOD), chest radiographs reveal Kerley B lines and peripheral interstitial infiltrates, with high-resolution CT showing subpleural thickened septal lines and centrilobular ground-glass opacities 5, 6
These findings reflect chronic interstitial pulmonary edema typical of PVOD, as noted by the American Thoracic Society 5, 6

The Society of Critical Care Medicine explains that the timing and evolution of infiltrates provides diagnostic clues, with most alveolar edema resolving after approximately 1 week in ARDS 2
Mononuclear cells replace the neutrophilic infiltrate as fibroblasts proliferate within the interstitium, according to the European Society of Intensive Care Medicine 2