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

See also:

• Atypical pneumonia
• Influenza
• Mycoplasma pneumonia
• Respiratory syncytial virus

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

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

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

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.

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.

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.

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

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

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.