Health Encyclopedia

Viral pneumonia

Definition

Viral pneumonia is an inflammation (irritation and swelling) of the lungs caused by infection with a virus.

Alternative Names

Pneumonia - viral

Causes, incidence, and risk factors

Pneumonia is an infection of the lung that affects 1 out of 100 people annually. Viral pneumonia is caused by one of several viruses, including influenza, parainfluenza, adenovirus, rhinovirus, herpes simplex virus, respiratory syncytial virus, hantavirus, and cytomegalovirus.

People at risk for more serious viral pneumonia typically have weakened immune systems. This includes young children, especially those with heart defects, and the elderly. The following also weaken the immune system and raise the risk for pneumonia:

HIV
Medications that suppress the immune system
Organ transplant

Symptoms

Chills
Clammy skin
Cough
Fatigue
Fever
Headache
Joint stiffness
Muscle stiffness and aching
Nausea and vomiting
Sore throat
Shortness of breath
Sweating

Signs and tests

Persons with suspected pneumonia should have a complete medical evaluation, including a thorough physical exam and a chest x-ray -- especially since the physical exam may not always distinguish pneumonia from acute bronchitis or other respiratory infections.

Depending on the severity of illness, additional studies may be done, include:

Complete blood count (CBC)
Blood cultures
Blood tests for antibodies to specific viruses
Bronchoscopy
Open lung biopsy (only done in very serious illnesses when the diagnosis cannot be made from other sources)
Sputum culture

Treatment

Some of the more serious forms of viral pneumonia can be treated with antiviral medications. Antibiotics are not effective.

Treatment may also involve:

Increased fluids
Oxygen
Use of humidified air

A hospital stay may be necessary to prevent dehydration and to help with breathing if the infection is serious.

Expectations (prognosis)

Most cases of viral pneumonia are mild and get better without treatment within 1-3 weeks, but some cases are more serious and require hospitalization.

Complications

More serious infections can result in respiratory failure, liver failure, and heart failure. Sometimes, bacterial infections occur during or just after viral pneumonia, which may lead to more serious forms of pneumonia.

Calling your health care provider

Call your health care provider if symptoms of viral pneumonia develop.

Prevention

Vaccines against the flu and RSV are available for those at high risk for viral pneumonia.

References

Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007 Mar 1;44 Suppl 2:S27-72.

Limper AH. Overview of pneumonia. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 97.

Review Date:9/24/2008
Reviewed By:Benjamin Medoff, MD, Assistant Professor of Medicine, Harvard Medical School, Pulmonary and Critical Care Unit, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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