What is Legionnaires' pneumonia?

Legionnaires' pneumonia is inflammation and infection of the lungs caused by bacteria called Legionella pneumophila.

How does it occur?

Bacteria that cause Legionnaires' disease are found in soil and water. Legionnaires' pneumonia occurs most often in summer and fall. During these seasons, people are more exposed to contaminated construction sites, air conditioners, and whirlpools.

People at highest risk include:

• the elderly

• smokers

• anyone whose immune system doesn't function normally because of cancer therapy, use of steroid drugs in high doses, or AIDS.

What are the symptoms?

Symptoms of Legionnaires' pneumonia that appear first include:

• fever

• shaking chills

• cough that doesn't produce sputum

• headache

• general ill feeling

• muscle pain.

Symptoms that occur 1 to 2 days later may include:

• spiking fever (fever that goes high at times and then comes down)

• repeated chills

• chest pain

• confusion

• delirium

• stupor

• diarrhea

• abdominal pain

• blood in the urine.

How is it diagnosed?

To diagnose Legionnaires' pneumonia, the doctor will examine you and review your symptoms. In addition, the doctor may use the following lab tests:

• exam of sputum, lung tissue, and pleural fluid (fluid in the space between the lungs and the lining of the lungs, called pleura)

• sputum and tissue cultures (tests to identify the bacteria)

• urine test for Legionella antigen

• x-ray.

How is it treated?

When the doctor suspects Legionnaires' pneumonia, treatment begins at once. If you are very sick, the doctor will hospitalize you and usually give erythromycin into the veins every 6 hours for 10 to 14 days. Follow-up treatment may include erythromycin pills for 18 to 21 days. Oral antibiotics can be given to people who are less sick and do not need to be hospitalized.

Treatment also includes replacing body fluids lost because of high fever, rapid breathing, and sweating. You may need oxygen to help with breathing during the acute stage of the disease.

The person with Legionnaires' pneumonia usually isn't contagious. Recovery takes 1 or 2 weeks with treatment. Children, adults over age 60, and those with other illnesses may require a longer recovery time.

The doctor may take chest x-rays if:

• you fail to show improvement after 5 to 7 days of treatment

• you have a relapse

• you are over age 40

• you smoke.

If you are elderly, have emphysema, or suffer from alcoholism, the x-rays may not show that your lungs are clear for 2 to 6 weeks longer.

How long will the effects last?

Legionnaires' disease is a serious disease. The effects will gradually improve over 1 to 2 weeks of treatment.

How can I take care of myself?

To help take care of yourself at home after being discharged from the hospital, follow the treatment the doctor prescribes. In addition:

• Rest in bed until the fever disappears and pain and shortness of breath decrease.

• Increase the amount of water, tea, and fruit juice you drink each day. The extra fluid will help you cough up lung secretions more easily.

• Use a humidifier to increase air moisture. Avoid steam vaporizers because they can cause burns.

• Avoid taking cough medicine if the cough produces sputum or mucus.

• Cough up lung secretions as much as possible.

• Use over-the-counter pain relievers such as acetaminophen to relieve minor discomfort.

For fever:

• If you have a fever above 100 degrees F (37.8 degrees C), stay in bed. When your temperature falls below 100 degrees F (37.8 degrees C), you may become as active as you comfortably can.

• Take aspirin or acetaminophen to control your fever. Anyone under 21 with a viral illness should not take aspirin because of the increased risk of Reye's syndrome. (Although Legionnaires' pneumonia is not a viral illness, its symptoms may be similar to those of viral illnesses, so take aspirin only if your doctor agrees.)

• Keep a daily record of your temperature.

Call your doctor if:

• symptoms recur

• your temperature is higher than 102 degrees F (38 degrees C)

• chest pain isn't relieved by heat (such as from a heating pad) or prescribed medication

• shortness of breath increases

• skin, fingernails, or toenails turn blue

• you cough up blood

• nausea, vomiting, or diarrhea appear as new symptoms

• other new symptoms appear.

If you live in a nursing home and develop pneumonia, your doctor may decide to treat you in the nursing home if:

• Your vital signs are stable and you do not have lung, heart, or blood vessel problems.

• Labs for running tests are readily available.

• There are enough qualified medical providers to monitor and treat you.

What can be done to help prevent Legionnaires' pneumonia?

There is no known way to prevent Legionnaires' pneumonia.