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What is pneumonia?

Pneumonia is a general term for a variety of diseases that cause an inflammation of the lungs. Pneumonia is most often caused by a bacterial infection (bacterial pneumonia) or a viral infection (viral pneumonia). Typical symptoms of pneumonia include fever, shortness of breath, and a wet cough that produces thick white, yellow, green or brownish phlegm.

Pneumonia is a common disease that can occur at any time of the year. It can occur in almost any population but is most common in smokers and people who have chronic infections and diseases, such as:

In generally healthy adults, pneumonia can be a relatively moderate condition and not require hospitalization. However, pneumonia is a common complication of a variety of diseases and can lead to life-threatening complications, such as sepsis and respiratory failure. Pneumonia is a frequent cause of death, especially in infants and older adults with chronic diseases, or people who have immune systems that are weakened as a result of such conditions as HIV/AIDS.

Seek prompt medical care if you have symptoms of pneumonia, such as fever and a wet cough that produces white, yellow, green or brownish phlegm. Seek immediate medical care (call 911) if you, or someone you are with, have moderate to severe shortness of breath, bluish coloration of the lips or fingernails, or a change in level of consciousness or alertness.


What are the symptoms of pneumonia?

The symptoms of pneumonia are caused by inflammation of the lungs due to infection or irritation. In response, the lungs produce excessive amounts of thick phlegm, which must be coughed up in order to keep the airways open for effective breathing.

The types and severity of symptoms of pneumonia vary depending on a variety of factors, such as a person’s age, general health, and medical history. In generally healthy adults, symptoms of pneumonia can be relatively moderate. Symptoms are often more severe in people who have chronic illnesses, such as COPD or congestive heart failure, or in the very young or very old.

Symptoms of pneumonia include:

Serious symptoms that might indicate a life-threatening condition

In some cases, pneumonia can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, are experiencing any of the following life-threatening symptoms:

  • Bluish coloration of the lips or fingernails (cyanosis)

  • Change in level of consciousness

  • Confusion or disorientation

  • Gurgling sound in the throat

  • High fever (higher than 101 degrees Fahrenheit)

  • Lethargy

  • Moderate to severe shortness of breath

  • Rapid, labored breathing

  • Rapid pulse

  • Wheezing, a whistling sound made with breathing


What causes pneumonia?

Pneumonia is usually caused by a bacterial infection (bacterial pneumonia) or a viral infection (viral pneumonia). Pneumonia caused by an infection (infectious pneumonia) usually spreads from person to person when someone with the disease coughs, talks or sneezes. This shoots contaminated droplets into the air where they can be breathed in by others.

Pneumonia can also be caused by:

  • Choking or aspiration of food or liquid into the lungs

  • Fungal infection

  • Inflammation of the lungs due to exposure to toxic gases or lung irritants

  • Near drowning

  • Trauma

  • Yeast infection

What are the risk factors for catching pneumonia?

Pneumonia can occur in any age group or population. A number of factors increase the risk of catching or developing pneumonia. Risk factors include:

  • Acute bronchitis

  • Being an infant, young child, or older adult

  • Being immobile or bedridden for a long period of time

  • Being too ill or weak to effectively cough up mucus from the respiratory tract

  • Chronic diseases, such as congestive heart failure, COPD, asthma, and lung cancer

  • Diseases that result in an impaired or weakened immune system, such as HIV/AIDS

  • Drugs that suppress the immune system, such as corticosteroids and chemotherapy

  • Inhaling toxic gases or other lung irritants, such as heavy smoke

  • Living in a long-term care facility

  • Near drowning

  • Not being vaccinated against pneumonia

  • Problems with chewing or swallowing and choking on foods or liquids

  • Smoking

  • Trauma, such as rib fractures or injuries that cause prolonged immobility

Reducing your risk of pneumonia

Not all people with risk factors will get pneumonia, but you can lower your risk of catching or spreading pneumonia by:

  • Avoiding contact with a person who has pneumonia, a cold, or the flu

  • Avoiding exposure to air pollutants, toxic gases, and lung irritants, such as heavy smoke

  • Avoiding long periods of immobility

  • Covering your mouth and nose with your elbow (not your hand) or a tissue when sneezing or coughing

  • Following your health care provider’s advice for exercise and deep breathing exercises, and following your treatment plan for chronic illnesses and injuries

  • Getting vaccinated for pneumonia as recommended by your health care provider

  • Not smoking

  • Washing hands frequently with soap and water for at least 15 seconds


How is pneumonia treated?

The goals of pneumonia treatment include minimizing the risk of serious complications and controlling symptoms to allow you to rest and recover. Mild to moderate cases of pneumonia that occur in generally healthy adults may be treated at home. More severe cases of pneumonia or cases in infants, older adults, or people with chronic diseases often require hospitalization.

Treatment of bacterial pneumonia includes antibiotic medications. Antibiotics are not effective for treating viral pneumonia. A serious type of bacterial pneumonia called methicillin-resistant Staphylococcus aureus (MRSA) pneumonia can be very difficult to treat because the bacteria that cause MRSA are resistant to the effects of antibiotics.

Treatment of pneumonia generally includes:

  • Antibiotic medications for bacterial pneumonia. Antibiotics may need to be administered intravenously in moderate to severe cases or for infants and people with chronic diseases.

  • Bronchodilators may be prescribed to help ease breathing and relieve shortness of breath. Bronchodilators relax and open up the lower airways in the lungs and are inhaled using a device called an inhaler.

  • Cool-mist vaporizer

  • Drinking plenty of fluids to prevent dehydration. Fluids may need to be administered intravenously to prevent or treat dehydration.

  • Intubation of the airway with a breathing tube and mechanical ventilation may be required in severe cases in which hypoxia, respiratory failure, and shock occur or are likely to occur.

  • Medications to relieve fever and body aches

  • Oxygen therapy delivers extra oxygen through nasal prongs or a mask. Supplemental oxygen can help relieve shortness of breath and ensure that vital organs, such as the heart and brain, get enough oxygen. Concentrations of oxygen and the types of devices used vary depending on the severity of an individual’s condition.

  • Rest

  • Thick phlegm may need to be medically suctioned.

What are the possible complications of pneumonia?

In some people, especially infants, older adults, and people with chronic diseases, complications of pneumonia can be severe, even life threatening. Complications can include:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Jan 5
  1. Pneumonia – adults (community acquired). Medline Plus, a service of the National Library of Medicine National Institutes of Health.   
  2. Pneumonia can be prevented – vaccines can help. Centers for Disease Control and Prevention.
  3. Johansson N, Kalin M, Tiveljung-Lindell A, et al. Etiology of community-acquired pneumonia: increased microbiological yield with new diagnostic methods. Clin Infect Dis 2010; 50:202.
  4. Cesario TC. Viruses associated with pneumonia in adults. Clin Infect Dis 2012; 55:107.
  5. Bope ET, Kellerman RD (Eds.) Conn’s Current Therapy. Philadelphia: Saunders, 2013.
  6. Domino FJ (Ed.) Five Minute Clinical Consult. Philadelphia: Lippincott Williams & Wilkins, 2013.
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