Pneumonia is an infection and inflammation of the lungs.
Pneumonia occurs when the lungs are exposed to germs not usually present in the lungs. You have an underlying illness, such as diabetes, chronic bronchitis, or cancer, which makes it easier for you to get all kinds of infections. It is for this reason that so many older adults develop pneumonia. Also, an underlying illness may make it difficult to survive a bout of pneumonia. Aspiration pneumonia occurs when gastrointestinal problems cause stomach contents to back up into the esophagus and trachea.