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What Is Pneumonia?

Pneumonia is when the lungs get inflamed, usually due to infection. Breathing in certain chemical fumes can also cause pneumonia. It's a more common problem than most people think. Usually it's a mild disease, but some forms are very dangerous. In all cases you'll need a doctor's advice.
Pneumonia can affect just one section of the lung or many sections of the lung. When both lungs are affected, it's called double pneumonia.

About 30 different kinds of germs infect the lungs and cause pneumonia. Infected lungs leak fluids and shed dead cells. This material clogs up air sacs and makes it hard for the lungs to do their job of getting oxygen into the blood. Without enough oxygen, none of the cells in your body work as they should.

Pneumonia generally lasts about two weeks. Even healthy people may feel tired or weak for a month or more after the lungs clear up.

What Causes It?

Viruses cause about half of all cases of pneumonia. Bacteria are the most common cause of pneumonia in adults over the age of 30. Fungi can also cause pneumonia.

Many of these germs are all around us. They usually can't get past a healthy person's natural defenses. That's why pneumonia is most common in elderly people, in cigarette smokers, in alcoholics, and in people suffering from other diseases such as the flu.