Pneumonia is a term used to describe infections of the lungs that can be caused by a variety of bacteria, viruses, and fungi. There are over 30 potential causes of pneumonia, though 30% of all cases are caused by respiratory viruses. In children and young adults, respiratory viruses are the most common cause of pneumonia. In adults, pneumonia is more commonly caused by the flu virus. Pneumonia causes the inflammation of the alveoli, the air sacs in your lungs. When the alveoli become inflamed, breathing becomes difficult and less oxygen is delivered to the body.
Pneumonia can be classified by the location of the infection:
- Lobar pneumonia only affects an isolated area of the lungs.
- Bronchial pneumonia is widespread throughout both lungs.
Pneumonia can also be classified by the environment in which it was contracted:
- Community-acquired pneumonia (CAP) is contracted outside of a hospital through exposure to a virus or bacteria.
- Hospital-acquired pneumonia is contracted during a hospital stay. Cases of hospital-acquired pneumonia can be especially serious given the weakened immune systems of hospital patients and the high populations of bacteria and other infectious materials in hospitals.
- Nursing-home acquired pneumonia is contracted in a nursing home or hospice care facility. Pneumonia is a fairly common infectious disease in nursing homes, prompting many nursing homes to do regular screenings for the disease.
- Ventilator-associated pneumonia is contracted during the use of a ventilator.
With proper treatment, most cases of pneumonia clear up relatively quickly, lasting only about 2 weeks. For elderly patients, young children, and those with a compromised immune system, the risk of complication or death from the disease is higher. Risks of pneumonia are also much higher for individuals in hospitals and nursing home facilities.