Pneumonia is a bacterial, viral, or fungal infection of one or both sides of the lungs that causes the air sacs, or alveoli, of the lungs to fill up with fluid or pus. Symptoms can be mild or severe and may include a cough with phlegm (a slimy substance), fever, chills, and trouble breathing. Many factors affect how serious pneumonia is, such as the type of germ causing the lung infection, your age, and your overall health. Pneumonia tends to be more serious for children under the age of five, adults over the age of 65, people with certain conditions such as heart failure, diabetes, or COPD (chronic obstructive pulmonary disease), or people who have weak immune systems due to HIV/AIDS, chemotherapy (a treatment for cancer), or organ or blood and marrow stem cell transplant procedures.
To diagnose pneumonia, your doctor will review your medical history, perform a physical exam, and order diagnostic tests. This information can help your doctor determine what type of pneumonia you have. If your doctor suspects you got your infection while in a hospital, you may be diagnosed with hospital-acquired pneumonia. If you have been on a ventilator to help you breathe, you may have ventilator-associated pneumonia. The most common form of pneumonia is community-acquired pneumonia, which is when you get an infection outside of a hospital.
Treatment depends on whether bacteria, viruses, or fungi are causing your pneumonia. If bacteria are causing your pneumonia, you usually are treated at home with oral antibiotics. Most people respond quickly to treatment. If your symptoms worsen you should see a doctor right away. If you have severe symptoms or underlying health problems, you may need to be treated in a hospital. It may take several weeks to recover from pneumonia.
Explore this Health Topic to learn more about pneumonia, our role in research and clinical trials to improve health, and where to find more information.