Legionnaires' Disease
What is it?
Legionnaires' disease is a form of pneumonia
that is caused by the Legionella bacteria. This
bacteria was first identified in 1976 after an
unusual outbreak of respiratory illness among
people attending an American Legion convention in
Philadelphia, Pennsylvania. However, it is
believed that this bacteria existed, but was
unidentified, since 1947.
Who gets it?
People over the age of 50 are more likely to
develop Legionnaires' disease, which accounts for
one to eight percent of all pneumonias in the
United States. The populations at the highest risk
are the elderly, smokers, and people whose immune
system doesn't function normally. While it is less
likely to occur in children, it can occur in
newborns undergoing respiratory therapy, children
with immune system problems, and children who have
had recent operations.
What causes it?
The bacteria that cause Legionnaires' disease
are found in warm, stagnant water and the soil it
seeps into. People inhale the bacteria when it
becomes airborne, usually through air
conditioners, humidifiers, shower heads and
faucets, whirlpool spas, and even the water
misters found in grocery stores. The bacteria has
also been found in soil and groundwater at
construction sites. Some people can be exposed to
the Legionella bacteria, but not develop the
infection.
What are the symptoms?
When the bacteria enters the lungs, the body's
immune system sends out immune cells to destroy
them. However, the Legionella bacteria are
resistant to the immune cells. They continue to
grow and eventually kill the immune cells. Then,
even more Legionella bacteria enter the lungs and
the infection gets worse. Symptoms begin to appear
around 2 to 10 days after infection, and include
fever, chills, headache, muscle pain, low
appetite, and fatigue. This is followed by a dry
cough. Around one to two days later, symptoms
progress and can include a fever that goes up and
down, chest pain, confusion, delirium, diarrhea,
and stomach pain. The cough usually becomes
productive, meaning it brings up sputum (saliva
and mucus). There may be blood in the sputum and
the urine. A small percentage of patients may
experience kidney failure. Legionnaires' disease
is not contagious, which means it cannot be passed
from one person directly to another.
How is it diagnosed?
Your doctor will take a complete medical
history so he or she can assess your risk factors
for Legionnaires' disease. Your doctor will
perform a complete physical examination and will
order laboratory tests to check for the bacteria
that causes Legionnaires' disease. These include a
sputum sample, blood and urine tests, and a chest
x-ray. Early diagnosis is important to successful
treatment, but most patients who are otherwise
fully healthy recover from this disease.
What is the treatment?
Legionnaires' disease is treated with oral or
intravenous (IV) antibiotics, usually
erythromycin. The antibiotic your doctor
prescribes depends upon how severe your infection
is, whether you have any allergies, and any other
medications you are already taking. Severe cases
are treated in a hospital and may also require
oxygen to help with breathing. Kidney failure is
treated with dialysis. You will be told to drink
plenty of fluids to replace those lost through
fever and to get plenty of rest. Most people
recover within two weeks of receiving treatment.
However, small children and the elderly usually
take longer to recover.
Self-care tips
Because the bacteria that cause Legionnaires'
disease grow in warm, stagnant water, it is
important to regularly disinfect air conditioning
ducts, humidifiers, shower heads, and any piping
in which water can lay. If you have been diagnosed
with Legionnaires' disease, follow your doctor's
treatment advice. Notify your doctor immediately
if your symptoms get worse while under treatment.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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