Crazy paving refers to the appearance of ground-glass opacities with superimposed interlobular septal thickening and intralobular septal thickening, seen on chest HRCT or standard CT chest. It is a non-specific finding that can be seen in a number of conditions.
Pathology
Etiology
Common causes:
- acute respiratory distress syndrome (ARDS)
- bacterial pneumonia
- acute interstitial pneumonia: ARDS of unknown etiology
- pulmonary alveolar proteinosis (PAP): the great majority of patients with PAP demonstrate crazy paving
Less common causes:
- drug-induced pneumonitis
- radiation pneumonitis
- pulmonary hemorrhage / diffuse pulmonary hemorrhage
- chronic eosinophilic pneumonia
- usual interstitial pneumonia (UIP) with superimposed diffuse alveolar damage
- pulmonary edema
- pulmonary infections
- cryptogenic organizing pneumonia (COP, formerly BOOP)
- invasive mucinous adenocarcinoma of the lung (formerly mucinous bronchoalveolar carcinoma
- sarcoidosis, especially alveolar sarcoidosis
- lipoid pneumonia
- pulmonary veno-occlusive disease