What are the four stages of lobar pneumonia?
Lobar pneumonia is a form of pneumonia in which inflammatory exudate appears within intra-alveolar space. It belongs to one of the two anatomic classifications of pneumonia.
There are four stages of lobar pneumonia: congestion, red hepatization or consolidation, grey hepatization and resolution.
In the first 24 hours after the onset, congestion appears. Histologically, congestion is characterized by vascular engorgement, intra-alveolar fluid, small numbers of neutrophils. The lung is hyperemic and heavy now.
Vascular congestion persists, with extravasation of red cells into alveolar spaces, red hepatization appears.
Red cells disintegrate, the color is paler and the cut surface is drier, thus grey hepatization appears.
The last stage is resolution, which means complete recovery, in which the exudate is digested by enzymatic activity, cleared by macrophages or cough mechanism.
Keyword: lobar pneumonia four stages