Pneumonia
Pneumonia, including community acquired pneumonia (CAP), is an inflammation or swelling in the lungs, affecting the small bronchioles and alveoli. Most cases are caused by infection, usually with bacteria or viruses, but in some cases fungi or parasites. Pneumonia can also be caused by a chemical or physical injury to the lungs.
Pneumonia develops when the alveoli become inflamed because of the infection or the injury and fill with fluid, making it difficult to breathe.
What happens if I have pneumonia?
For most people, breathing in bacteria, viruses or other germs will not cause pneumonia because the germs become trapped in the mucus that is naturally present in your airways and killed by your immune system. Sometimes, however, these germs multiply and cause infection. The infection causes symptoms, such as coughing, which makes the inflammation in the lungs worse.
Figure 1 Anatomy of the respiratory tract
The information provided on this website does not replace a consultation with a medical professional. If you have any concern about your condition please contact a medical professional.
Types of pneumonia
- Community acquired pneumonia (CAP): this refers to patients having acquired pneumonia outside a hospital or long-term nursing home as they go about their daily lives
- Pneumonia developed more than 2-3 days after hospital admission is called hospital acquired pneumonia (or institution acquired pneumonia). This may happen after major surgery or when a ventilator has been used to assist breathing
- Aspiration pneumonia: caused when someone inhales particles (usually vomit, food, liquids or fluids from the mouth) into their lungs. An altered mental status and cerebrovascular accidents (CVA) add to the risks of getting pneumonia.
