Pneumonia is an inflammation of one or both lungs caused by an infection. Often, the lungs' air sacs fill with fluid or pus or other liquid, making it difficult to breathe. The inflammation also makes it difficult for oxygen to reach your blood.
Lobar pneumonia affects one or more large sections (lobes) of the lungs. Bronchial pneumonia (also known as bronchopneumonia) affects small patches throughout both lungs.
“In the United States, pneumonia is the sixth leading cause of death, and the number one cause of death from infection,” says infectious disease doctor Luther Rhodes III, MD, with Lehigh Valley Health Network. “Half of all pneumonia cases are adults over age 65, and often they are hospitalized.” Older adults are three to five times more likely to die from pneumonia.
Pneumonia can have more than 30 causes, but these are the three main culprits:
According to the American Lung Association, about half of all pneumonias are believed to be caused by viruses, including influenza (flu). Most of these pneumonias are not serious and last a short time. Viral pneumonias also may make a person susceptible to bacterial pneumonia.
The bacteria Streptococcus pneumonia (pneumococcal bacteria) is the most common cause of bacterial pneumonia acquired outside of hospitals. The pneumococcal bacteria are found in many healthy people and are spread from person-to-person through coughing, sneezing or close contact. Bacterial pneumonia usually occurs when the body is weakened in some way, such as by flu or other illness, malnutrition, old age or impaired immunity, and the bacteria are able to work their way into the lungs.
Bacterial pneumonia also can be considered hospital-acquired pneumonia. Hospital-acquired pneumonia develops at least 48 hours after hospitalization. The most common causes are bacteria such as Staphylococcus aureus.
The pneumococcal vaccine (Pneumovax) and the flu vaccine both help prevent pneumococcal pneumonia and its complications in people at risk. Many bacteria are resistant to antibiotics now, so vaccines are very important.
Lehigh Valley Health Network physicians encourage all adults over age 50 to receive the flu vaccine every year in the fall, as well as health care workers and people in the risk categories listed above, along with people caring for people at increased risk. The pneumococcal vaccine should be given just once to all adults over age 65, or younger if they have the types of chronic illnesses listed above. Sometimes boosters are needed for the pneumococcal vaccine, so ask your doctor about that. Both vaccines can be given at the same time.
This type of pneumonia is referred to as “atypical pneumonia” or “walking pneumonia,” and accounts for approximately 3 percent of all cases of pneumonia. It is caused by Mycoplasma pneumoniae – the smallest disease-causing agents known to man – which have characteristics of both bacteria and viruses. They generally cause a mild pneumonia that affects all age groups.
Other pneumonias are less common and may be caused by the inhaling of food, liquid, gases, dust or fungi.
There are things you can do to prevent pneumonia. Wash your hands frequently. Avoid contact with others who have colds. Don't smoke. Take good care of yourself, and make sure you see your doctor regularly.