Pneumonia: Know the Facts For Infection Prevention

Pneumonia: Know the Facts For Infection Prevention

Pneumonia: Explained

What Is Pneumonia?

Pneumonia is an infection in one or both of the lungs. Many small germs, such as bacteria, viruses, and fungi, can cause pneumonia.

The infection causes your lungs’ air sacs, called alveoli, to become inflamed. The air sacs may fill up with fluid or pus, causing symptoms such as a cough (with phlegm), fever, chills, and trouble breathing.

Pneumonia and its symptoms can vary from mild to severe. Many factors affect how serious pneumonia is, such as the type of germ causing the infection and your age and overall health.

Pneumonia tends to be more serious for:

  • Infants and young children.
  • Older adults (people 65 years or older).
  • People who have other health problems like heart failure, diabetes, or COPD (chronic obstructive pulmonary disease).
  • People who have weak immune systems as a result of diseases or other factors. These may include HIV/AIDS, chemotherapy (a treatment for cancer), or an organ or bone marrow transplant.
Pneumonia Facts and Figures

Pneumonia is common in the United States. Treatment for pneumonia depends on its cause, how severe your symptoms are, and your age and overall health. Many people can be treated at home, often with oral antibiotics.

Children usually start to feel better in 1 to 2 days. For adults, it usually takes 2 to 3 days. Anyone whose symptoms get worse should be checked by a doctor.

People who have more severe symptoms or underlying health problems may need treatment in a hospital. It may take 3 weeks or more before they can go back to their normal routines.

Fatigue (tiredness) from pneumonia can last for a month or more.

Types of Pneumonia

Pneumonia is named for the way in which a person gets the infection or for the germ that causes it.

Lobar Pneumonia
  • Figure A shows the location of the lungs and airways in the body. It also shows pneumonia that’s affecting the lower lobe of the left lung.
  • Figure B shows normal alveoli.
  • Figure C shows infected alveoli.
Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) occurs outside of hospitals and other health care settings. Most people get CAP by breathing in germs (especially while sleeping) that live in the mouth, nose, or throat.

CAP is the most common type of pneumonia. Most cases occur during the winter. About 4 million people get this form of pneumonia each year. About 1 out of every 5 people who has CAP needs to be treated in a hospital.

Hospital-Acquired Pneumonia

Some people catch pneumonia during a hospital stay for another illness. This is called hospital-acquired pneumonia (HAP). You’re at higher risk for getting HAP if you’re on a mechanical ventilator (a machine that helps you breathe).

HAP tends to be more serious than CAP. This is because you’re already sick. Also, hospitals tend to have more germs that are resistant to antibiotics (antibiotics are a treatment for pneumonia).

Health Care-Associated Pneumonia

Patients also may get pneumonia in other health care settings, such as nursing homes, dialysis centers, and outpatient clinics. This is called health care-associated pneumonia.

Aspiration Pneumonia

Another common type of pneumonia occurs when you accidentally inhale food, drink, vomit, or saliva from your mouth into your lungs. This usually happens when something disturbs your normal gag reflex, such as a brain injury, swallowing problem, or excessive use of alcohol or drugs.

Aspiration pneumonia can cause pus to form in a cavity in the lung. This is called a lung abscess.

Atypical Pneumonia

Several types of bacteria (Legionella Pneumophila, Mycoplasma Pneumonia, and Chlamydophila Pneumoniae) cause this type of CAP. Atypical pneumonia is passed from person to person.

Other Names for Pneumonia

  • Pneumonitis (nu-mo-NI-tis).
  • Bronchopneumonia (BRONG-ko-nu-MO-ne-ah).
  • Nosocomial (nos-o-KO-me-al) pneumonia. This is another name for hospital-acquired pneumonia.
  • Walking pneumonia. This refers to pneumonia that’s mild enough that you’re not bedridden.
  • Double pneumonia. This refers to pneumonia that affects both lobes of the lungs.

Content Created/Medically Reviewed by our Expert Doctors