Merck Manual

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Spotlight on Aging: Pneumonia

Spotlight on Aging: Pneumonia

Pneumonia occurs more commonly in older than in younger people, and it also tends to be more serious. In many older people, the infection spreads beyond the lungs.

Older people have weakened defenses against infection. The mechanisms that clear microorganisms from the airways are not as effective in older people as they are in younger people. Weakness may make coughing less vigorous. Aging also weakens the immune system. Older people at greater risk of developing pneumonia include those

  • Whose lungs have been damaged by smoking (smoking irritates the lining of the lungs and paralyzes the cells that normally sweep and cleanse the airways) or chronic obstructive pulmonary disease

  • Whose lungs have recently been irritated by a mild infection, such as a cold or, especially, influenza

  • Who have a poor cough reflex, for example, resulting from a previous stroke, or who are too weak (or who are in pain from recent surgery or an accident) to cough vigorously

  • Who are less able to fight off infections, including people who are undernourished

  • Who are taking certain drugs that weaken the immune system, such as corticosteroids

  • Who have certain diseases, such as heart failure or diabetes

  • Who have cancer in or near the airways of the lungs (the cancer may block the airways and trap any microorganisms that have reached the air sacs)

  • Who are paralyzed (for example, because of a spinal injury or stroke)

  • Who are not fully conscious (in part because they are unable to cough)

Most older people who get pneumonia are treated in the hospital with intravenous antibiotics. Pneumonia can cause older people to get very sick very quickly, and older people tend to respond less well to oral antibiotics.