Q.Why is pneumonia considered a dangerous disease?

Pneumonia inflames and fills the alveoli with fluid, severely reducing the lungs' gas-exchange surface, so oxygen uptake fails and the condition can become life-threatening.

Pneumonia is an infection of the lung tissue, most often caused by bacteria (e.g., Streptococcus pneumoniae), viruses, or fungi, that inflames the alveoli (the tiny air sacs where gas exchange occurs).

During pneumonia, the alveoli become inflamed and fill up with fluid, mucus and pus instead of air. This has several serious consequences:

• The surface area available for oxygen and carbon dioxide exchange is drastically reduced, since fluid-filled alveoli cannot exchange gases efficiently.
• The diffusion distance for oxygen across the alveolar wall increases (thickened, fluid-laden membrane), further slowing gas exchange.
• The patient experiences difficulty breathing, low blood oxygen levels (hypoxia), fever, chest pain and cough. …