Respiratory Medicine MCQ Answer 011

The Correct answer is D.

Lobar Pneumonia: There is involvement of the entire lobe basically at one stage of disease. There is fairly uniform involvement of the alveoli. We can barely make out the alveolar septa in the background and the alveoli are quite filled with degenerated cells. There is a series of stages in the evolution of this infection. First we see the red hepatization stage with congestion, acute inflammation and neutrophils. Then there is grey hepatization as the acute inflammation subsides. The macrophages move in to clean up the debris. So in this stage, the neutrophils are being replaced by macrophages. Some of the macrophages accumulate hemosiderin pigments in them because there is small amount of hemorrhage and diapedesis of red cells out of the capillary network into the alveolar space. So in association with acute inflammation as these cells degenerate, the iron is taken up by the macrophages.

The thing that helps us in diagnosis of pneumonia is that at the site of lesion, there is most dramatic pathology. The interstitial areas are little bit filled and there is some increase in cellularity, they are very much overwhelmed by the involvement of alveoli.

Category: Respiratory Medicine MCQs