The cough reflex is further subdued by sedative use and neurologic disease, which are common in the elderly. Once our initial defense mechanism of mucus has been penetrated, we rely upon our immune system to eliminate foreign bodies. Quick Quiz Return to top of Page. As indicated above, the major underlying cause of the increased risk with age is a decline in the immune system s ability to fight-off infection. The elderly are also more prone to aspirating food, which can introduce infection, and they are more likely to be institutionalized, which increases the likelihood for spreading infectious lung diseases.
Pneumonia is the most common infectious disease of the lung leading to death.
The mortality rate from pneumonia increased 10 fold for each decade of life after the age of 20. Pneumonia can be caused by viral and bacterial infections of the lungs. Some of the more common bacterial infections include pneumococci, gram-negative bacteria and anaerobic bacteria. The major viral infections leading to pneumonia comes from influenza strains. The most important tool in establishing a pneumonia is the chest X-ray, which can detect the lung infection.