A Pediatric Radiology textbook and Pediatric Radiology digital library
Lung Abscess
Etiology: gram positive cocci predominate, consider gram negative bacilli + anaerobes in patient with aspiration
Imaging: spherical in shape, destroys lung, thick walled cavity with air fluid levels after necrotic pneumonia
US: moves with respiration which distinguishes it from empyema
DDX: pleural empyema — Abscess – spherical in shape, destroys lung — Empyema – nonspherical in shape, displaces lung, split pleura sign, enhancing rim sign of pleura, obtuse angles to chest wall, thickened pleura
DDX: pneumatocele — Abscess appears earlier in infection, has thick irregular walls, lasts long time — Pneumatocoele occurs later in infection, has thin wall, usually no air fluid level
DDX: infected congenital pulmonary airway malformation / bronchopulmonary foregut malformation which often present with recurrent lung infections — Repeat imaging after infection resolves to look for residual lesion
Cases of Lung Abscess
CXR shows a round cavitary lesion with an air-fluid level in the left upper lobe.CXR and axial and coronal CT without contrast of the chest shows a cavitary mass in the densely consolidated left lower lobe and a moderate left pleural effusion.