Which of the following correctly lists the four classical stages of lobar pneumonia in order?

• A. Initiation, Proliferation, Maturation, Recovery
• B. Incubation, Invasion, Multiplication, Decline
• C. Exposure, Infection, Inflammation, Healing
• D. Congestion, Red hepatization, Gray hepatization, Resolution

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the classical stages of lobar pneumonia. Lobar pneumonia is a type of bacterial pneumonia that progresses through distinct pathological stages.
2. Step 2: The first stage is 'Congestion,' which occurs due to the accumulation of fluid and bacteria in the alveoli, leading to inflammation and vascular engorgement.
3. Step 3: The second stage is 'Red hepatization,' characterized by the presence of red blood cells, fibrin, and neutrophils in the alveoli, giving the lung tissue a liver-like appearance.
4. Step 4: The third stage is 'Gray hepatization,' where the red blood cells break down, and the lung tissue appears gray due to the accumulation of fibrin and macrophages.
5. Step 5: The final stage is 'Resolution,' during which the immune system clears the infection, and the lung tissue gradually returns to its normal state.