The Four Stages Of Pneumonia are congestion, red hepatization, gray hepatization, and resolution. Each stage represents a different phase of the infection and inflammation within the lungs.
What Are The Four Stages Of Pneumonia?
Table of Contents
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Congestion
This initial stage, occurring within the first 24 hours, sees the lungs become heavy, boggy, and red due to increased blood flow and fluid accumulation. Microscopically, there’s vascular engorgement and intra-alveolar edema, with a few neutrophils and many bacteria present. Symptoms may include coughing and fatigue.
Red Hepatization
Starting around 2-3 days after congestion and lasting for 2-4 days, the affected lung area becomes firm, red-pink, and dry due to fibrin strands replacing the edema fluid. This stage is characterized by a firm, liver-like consistency, hence the term “hepatization”. Symptoms may worsen, with more severe cough and fatigue.
Gray Hepatization
Occurring 2-3 days after red hepatization, this stage sees the lung appear gray due to the presence of fibrinopurulent exudate and the breakdown of red blood cells. Macrophages start to appear, and the lung maintains a firm, liver-like consistency. Symptoms are often persistent.
Resolution
Beginning around the 8th day, this stage involves enzymatic action that liquefies the previous solid fibrinous content and restores aeration in the lungs. Macrophages are the predominant cells, and the lungs begin to return to their normal state. Symptoms typically improve as the body fights off the infection, and patients begin to feel better.
