Chest Imaging

Lobar pneumonia

the result of alveolar wall injury with severe haemorrhagic oedema induced by inhaled infectious organisms that reach the subpleural zone of the lung. This injury is followed by a rapid multiplication of organisms and invasion of the infected oedematous fluid by polynuclear leukocytes. The process spreads rapidly through the pores of Kohn leading to a consolidation of an entire lobe or segment. The most common causes are streptococcus pneumonia, klebsiella pneumonial infection, legionella infection and mycoplasma pneumonia infection.

The typical radiological pattern is air space consolidation involving an entire lobe containing air bronchograms. Because of the use of antibiotics, the pneumonia is limited to one or more segments within a lobe. Sometimes, particularly in the case of klebsiella pneumonial infection, voluminous oedema may result in expansion of the lobe recognized radiographically by bulging of the fissures. Necrosis and cavitation represent the potential complication of lobar pneumonia. Pulmonary gangrene may occur rarely.

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