Pneumonia is an infection deep in the small airways and air sacs of the lungs. The infection will make the air sacs swell and fill with fluid or pus. This causes intense coughing and can make it difficult to breathe.

Development of Pneumonia in the Air Sacs of the Lungs

pneumonia lung fluid
Copyright © Nucleus Medical Media, Inc.

Types of pneumonia include:

  • Community-acquired—infection is picked up outside of a medical setting; most common type
  • Hospital-acquired pneumonia—infection is picked up while in a hospital
  • Aspiration—happens when something, such as food, liquid, saliva, or vomit is inhaled into the lungs

This article will focus on community-acquired pneumonia.


Pneumonia is caused by a germ in the air that you breathe. Germs that most often cause community-acquired pneumonia include:

  • Viruses—such as flu or cold viruses
  • Bacteria
  • Fungus—more likely to happen in people with other health issues or immune system problems

Risk Factors

Pneumonia is more common in older adults. Other factors that may increase the chances of pneumonia:

  • Living in crowded living conditions such as dormitories or nursing homes
  • Smoking
  • Being underweight
  • Regular contact with children
  • Frequent visits to doctor's office
  • Alcohol use disorder or drug abuse

Health conditions that may increase the risk of community-acquired pneumonia include:

Other environmental factors include:

  • Coming in contact with droppings or dust from:
    • Bats or birds
    • Rabbits
    • Farm animals
  • Recent stay in cruise or hotel
  • Flu is present in your community


Pneumonia may cause:

  • Cough
  • Shortness of breath
  • Chest pain
  • Increased mucus production
  • Fever and chills
  • Weakness


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your doctor may suspect pneumonia based on your symptoms and lung sounds.

Pictures of the lungs can show that pneumonia is present. Pictures may be taken with:

Your doctor may need to know the exact germ that is causing the problem. This step may be needed if there is a severe infection. The germ can be tested through:

  • Blood tests and/or cultures
  • Sputum (fluid you cough up) culture
  • Urine tests


Treatment will be based on what may have caused the pneumonia and your overall health. More support may be needed if there is a severe infection. A hospital stay may be needed if it becomes difficult to breathe.

Your doctor may advise:

  • Antibiotics—for pneumonia caused by bacteria
  • Antifungal medications—for pneumonia caused by a fungus
  • Antiviral medications—for pneumonia caused viruses such as the flu
  • Over-the-counter medications to reduce fever and discomfort
  • Vitamin C may be advised if you do not get enough in your diet

Oxygen may need to be given for severe infections. This will help to increase the level of oxygen that passes to the blood.


Vaccines may help to prevent certain pneumonia:

  • Flu vaccine—pneumonia may be a complication of the flu, especially people aged 50 years and older
  • Pneumococcal vaccine—protects against pneumonia caused by specific bacteria; recommended for:
    • All adults who are aged 65 years or older
    • Adults of any age who are at high risk of infection or have a suppressed immune system

Steps that may decrease the risk for any respiratory infection include:

  • If you smoke, talk to your doctor about how you can successfully quit. Smoke weakens the lungs' resistance to infection and increases recovery time.
  • Avoid close contact with people who have the cold or flu.
  • Wash your hands often, especially after coming into contact with someone who is sick.
  • Protect yourself on jobs that have risk factors above.
  • Follow your plan for control of any chronic diseases such as asthma and diabetes.