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Pneumonia

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

PubMed Health Glossary
(Source: NIH - National Heart, Lung, and Blood Institute)

Pneumonia

Pneumonia (nu-MO-ne-ah) is an infection in one or both of the lungs. Many germs—such as bacteria, viruses, and fungi—can cause pneumonia.

The infection inflames your lungs' air sacs, which are called alveoli (al-VEE-uhl-eye). The air sacs may fill up with fluid or pus, causing symptoms such as a cough with phlegm (a slimy substance), fever, chills, and trouble breathing.

Overview

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, such as heart failure, diabetes, or COPD (chronic obstructive pulmonary disease).
  • People who have weak immune systems as a result of diseases or other factors. Examples of these diseases and...

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What works? Research summarized

Evidence reviews

Pneumonia: Diagnosis and Management of Community- and Hospital-Acquired Pneumonia in Adults

The microbial causes of pneumonia vary according to its origin and the immune constitution of the patient. Pneumonia is classified into community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and pneumonia in the immunocompromised. The guideline development process is guided by its scope - published after stakeholder consultation. This guideline does not cover all aspects of pneumonia, but focuses on areas of uncertainty or variable practice and those considered of greatest clinical importance. Best practice guidance on the diagnosis and management of CAP and HAP is offered, based on systematic analysis of clinical and economic evidence with the aim of reducing mortality and morbidity from pneumonia and maximising resources.

Surfactant for bacterial pneumonia in term and late preterm infants

Bacterial pneumonia in preterm and term newborn babies can cause problems with the functioning of pulmonary surfactant, a complex combination of fats and proteins that lines the lung and causes the lung to work effectively. Disrupting surfactant function makes breathing very difficult for these infants. In this review, we did not find any suitable clinical trials to assess the benefits or harms of surfactant treatment in addition to standard intensive care in the treatment of babies with bacterial pneumonia. More research is needed to answer the question of whether surfactant treatment is beneficial for near‐term and term infants with bacterial pneumonia.

Pneumonia (pneumococcal) vaccine for children and adults with asthma

Pneumonia is a serious illness for people who have asthma and pneumococcal vaccine has been studied to see if it reduces illness or death in those people. A thorough search for randomised controlled trials of pneumococcal vaccine in asthma has found only one small study in children which was not of high quality. This showed a reduction in the rate of asthma attacks from ten per year to seven per year. Randomised trials to test pneumococcal vaccine in asthmatic children and adults are needed to assess how beneficial it is for asthmatics to receive this vaccination.

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Summaries for consumers

Surfactant for bacterial pneumonia in term and late preterm infants

Bacterial pneumonia in preterm and term newborn babies can cause problems with the functioning of pulmonary surfactant, a complex combination of fats and proteins that lines the lung and causes the lung to work effectively. Disrupting surfactant function makes breathing very difficult for these infants. In this review, we did not find any suitable clinical trials to assess the benefits or harms of surfactant treatment in addition to standard intensive care in the treatment of babies with bacterial pneumonia. More research is needed to answer the question of whether surfactant treatment is beneficial for near‐term and term infants with bacterial pneumonia.

Pneumonia (pneumococcal) vaccine for children and adults with asthma

Pneumonia is a serious illness for people who have asthma and pneumococcal vaccine has been studied to see if it reduces illness or death in those people. A thorough search for randomised controlled trials of pneumococcal vaccine in asthma has found only one small study in children which was not of high quality. This showed a reduction in the rate of asthma attacks from ten per year to seven per year. Randomised trials to test pneumococcal vaccine in asthmatic children and adults are needed to assess how beneficial it is for asthmatics to receive this vaccination.

Corticosteroids for pneumonia

Pneumonia is an acute respiratory disease that is usually caused by bacteria but it can also be caused by other infectious agents such as fungi, parasites and viruses. Corticosteroids can act as an anti‐inflammatory agent for patients with pneumonia but they can adversely suppress the immune system, which prevents the body from fighting the causative pathogens and results in a serious infection. The purpose of this review was to assess whether corticosteroids for pneumonia are beneficial.

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Terms to know

Alveoli
Tiny air sacs at the end of the bronchioles (tiny branches of air tubes) in the lungs. The alveoli are where the lungs and the bloodstream exchange carbon dioxide and oxygen. Carbon dioxide in the blood passes into the lungs through the alveoli. Oxygen in the lungs passes through the alveoli into the blood.
Bacteria
A large group of single-cell microorganisms. Some cause infections and disease in animals and humans. The singular of bacteria is bacterium.
Fungus
A plant-like organism that does not make chlorophyll. Mushrooms, yeasts, and molds are examples. The plural is fungi.
Infection
The invasion and growth of germs in the body. The germs may be bacteria, viruses, yeast, fungi, or other microorganisms.
Lungs
One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.
Viruses
In medicine, a very simple microorganism that infects cells and may cause disease. Because viruses can multiply only inside infected cells, they are not considered to be alive.

More about Pneumonia

Photo of an adult

See Also: Chronic Obstructive Pulmonary Disease, Cough: Symptom, Heart Failure

Other terms to know: See all 6
Alveoli, Bacteria, Fungus

Related articles:
How the Lungs Work

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