Suite101

Pneumonia Caused by Virus

Causes, Course, Symptoms & Treatment of Pulmonary Viral Infection

© Tami Port

Oct 13, 2007
Influenza Virua, NIH
Pneumonia is an inflammation of the lungs that can result from infection with a bacterial, fungal or viral pathogen.

What Is Pneumonia?

Pneumonia occurs when the air sacs and small airways in the lungs fill with liquid and cannot function properly. When gas exchange is impeded, the body cannot take in oxygen as it normally would. Oxygen is vital to the body’s cells, where it is needed for aerobic respiration; the breakdown of glucose to obtain energy for cellular work.

Causes of Pneumonia

Pneumonia can have many different causes: viral, bacterial, fungal or, in the case of aspiration pneumonia, may result from the inhalation of substances such as caustic chemicals, food or vomit.

Viral Pneumonia

Pneumonia that is caused by a viral infection causes irritation, swelling, and congestion in the lungs. Also called pneumonitis (nu-mo-NI-tis), this infectious disease occurs most often in the winter, afflicting 1 in 100 people. Viruses are the most common cause of pneumonia in children.

Cause

The viruses that most commonly cause pneumonia include:

  • Influenza virus
  • Respiratory syncytial virus (RSV)
  • Adenoviruses
  • Metapneumovirus

Course

Viral Invasion

Viruses cannot reproduce on their own, but are parasitic and must invade the cells of the host in order to reproduce. A virus typically reaches the lungs by traveling in droplets inhaled through the mouth or nose. Once in the lungs, the virus invades cells lining the airways and alveoli.

Cellular Destruction

Once invaded, cells of the lung can die due to direct killing by the virus or when the host’s immune system destroys its own infected cells. The lungs can be further damaged by the immune response to infection when white blood cells activate chemicals which cause the body’s fluid to leak into the alveoli.

This combination of cellular destruction and fluid in the lungs interferes with oxygen moving into the bloodstream.

Viral pneumonia also lowers the body's immunity, and additional illnesses, such as bacterial infection, may result leading to more serious forms of pneumonia.

Resolution of Illness

Most cases of viral pneumonia are mild and, in one to three weeks, will improve without treatment. More serious episodes may require hospitalization. Those at risk for serious viral pneumonia usually have impaired immune systems; and serious infections may result in respiratory failure, liver failure, and heart failure.

Signs & Symptoms

Symptoms are similar to those of bacterial pneumonia; the most common being headache, fever, chills, muscle aches, loss of appetite and a productive cough. Breathing may be difficult or painful. Upon physical examination, crackles may be heard when the patient’s chest is examined with a stethoscope.

Medical tests for viral pneumonia may include chest x-ray or CAT scan, arterial blood gases to check oxygen level, pleural fluid culture can be used to identify the pathogen if there is fluid in the space surrounding the lungs.

Treatment

Antibiotics, although sometimes prescribed in the treatment of viral pneumonia, are a type of medication that only kill bacteria and are not effective in treating viral pneumonia. Serious viral infections can be treated with antiviral medications.

Additional supportive care may include use of humidified air, increased fluids, and oxygen. Hospitalization may be required to prevent dehydration, assist breathing and supplement oxygen if the infection is serious.

Pneumonia Resources

For more information on types of pneumonia, see the Mayo Clinic: Infectious Diseases or Science Prof Online. For additional material on other types of pneumonia see the Suite101.com articles Gram Positive Bacterial Pneumonia, Gram Negative Bacterial Pneumonia, Primary Atypical Pneumonia, Opportunistic Fungal Pneumonia and Endemic Fungal Pneumonia.

This article is a summary of the causes, course, symptoms and treatment of viral pneumonia. It is not meant to be used for self-diagnosis or as a substitute for professional medical care.

Sources

Bauman, R. (2005) Microbiology.

Park Talaro, K. (2008) Foundations in Microbiology.


The copyright of the article Pneumonia Caused by Virus in Human Infections is owned by Tami Port. Permission to republish Pneumonia Caused by Virus in print or online must be granted by the author in writing.


Influenza Virua, NIH
       


Post this Article to facebook Add this Article to del.icio.us! Digg this Article furl this Article Add this Article to Reddit Add this Article to Technorati Add this Article to Newsvine Add this Article to Windows Live Add this Article to Yahoo Add this Article to StumbleUpon Add this Article to BlinkLists Add this Article to Spurl Add this Article to Google Add this Article to Ask Add this Article to Squidoo

Comments
Aug 17, 2008 12:04 AM
Guest :
hi there sounds right to me , i have been ill for 6 weeks now have taken a course of amoxollin 500mg and now my nose ios blocked and cant breath worse at nights my doc said i had a infection in my right lung feel really tired and listless dont know what to do but think should go bk to the docs.
Mar 24, 2009 10:02 AM
Guest :
my mom has been sick for a month now and i dont know what to do. we don't know if its a pneumonia or what? the doctors say that it might be a co vination of bronchitis, asthama, and something with nea on it please post more imfo as soon as posible

2 Comments