Viral pneumonia

Causes

Viral pneumonia is more likely to occur in young children and older adults, because their bodies have a harder time fighting off the virus.

Viral pneumonia is most often caused by one of several viruses:

• Adenovirus
• Influenza
• Parainfluenza
• Respiratory syncytial virus

Serious viral pneumonia is more likely to happen in those with a weakened immune system, such as:

• Babies who are born too early
• Children with heart and lung problems
• HIV infection
• People receiving chemotherapy for cancer, or other medications that weaken the immune system.
• Organ transplant recipients

Symptoms

Symptoms of viral pneumonia often begin slowly and may not be severe at first.

The most common symptoms of pneumonia are:

• Cough (with some pneumonias you may cough up mucus, or even bloody mucus)
• Fever, which may be mild or high
• Shaking chills
• Shortness of breath (may only occur when you climb stairs)

Other symptoms include:

• Confusion, especially in older people
• Excessive sweating and clammy skin
• Headache
• Loss of appetite, low energy, and fatigue
• Sharp or stabbing chest pain that gets worse when you breathe deeply or cough
• Fatigue

Exams and Tests

If your doctor or nurse thinks you have pneumonia, you will have a complete physical exam and a chest x-ray -- especially since the physical exam may not be able to tell pneumonia from acute bronchitis or other respiratory infections.

Depending on the severity of illness, other tests may be done, including:

• Complete blood count (CBC)
• CT scan of the chest
• Blood cultures
• Blood tests to diagnose specific viruses
• Bronchoscopy (rarely needed)
• Nasal swab test to check for viruses such as the flu
• Open lung biopsy (only done in very serious illnesses when the diagnosis cannot be made from other sources)
• Sputum culture

Treatment

Antibiotics do not treat viral pneumonia. Antiviral medication only works against influenza pneumonia and some causes by the herpes family of viruses.

Treatment may also involve:

• Corticosteroid medicines
• 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.

You are more likely to be admitted to the hospital if you:

• Are older than 65 years or a young child
• Are unable to care for yourself at home, or are unable to eat or drink
• Have another serious medical problem, such as a heart or kidney problem
• Have been taking antibiotics at home and are not getting better
• Have severe symptoms

However, many people can be treated at home.

You can take these steps at home:

• Control your fever with aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen or naproxen), or acetaminophen. DO NOT give aspirin to children.
• Do not take cough medicines without first talking to your doctor. Cough medicines may make it harder for your body to cough up the extra sputum.
• Drink plenty of fluids to help loosen secretions and bring up phlegm.
• Get a lot of rest. Have someone else do household chores.

Outlook (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.

Possible 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.

When to Contact a Medical Professional

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

Prevention

Wash your hands often, especially after blowing your nose, going to the bathroom, diapering a baby, and before eating or preparing foods.

Don't smoke. Tobacco damages your lungs' ability to ward off infection.

Vaccines may help prevent pneumonia in children, the elderly, and people with diabetes, asthma, emphysema, HIV, cancer, or other chronic conditions.

• A drug called palivizumab (Synagis) is given to some children under 24 months old to prevent pneumonia caused by respiratory syncytial virus.
• Flu vaccine prevents pneumonia and other problems caused by the influenza virus. It must be given each year to protect against new virus strains.

If your immune system is weak, stay away from crowds. Ask visitors who have a cold to wear a mask.

Alternative Names

Pneumonia - viral; "Walking pneumonia" - viral

References

Lee FE, Treanor J. Viral infections. In: Mason RJ, VC Broaddus, Martin TR, et al, eds. Murray and Nadel’s Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 31.

Limper AH. Overview of pneumonia. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 97.

Update Date: 8/30/2012

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.