Pneumonia
What is it?
Pneumonia is an infection of the lungs. It
involves the tiny air sacs, called alveoli, which
are located at the tips of the body’s smallest
breathing tubes, called the bronchi. The alveoli
are responsible for passing oxygen into the blood.
Who gets it?
While anyone who is exposed to the germs that
cause pneumonia can develop it, it is more likely
to occur in people whose immune system is weakened
by an existing illness, such as the flu, cancer,
or AIDS, and in people with chronic conditions,
such as sickle cell disease, heart disease,
diabetes, kidney disease, asthma, chronic
bronchitis, chronic obstructive pulmonary disease
(COPD), emphysema, or cystic fibrosis. People,
especially the elderly, who have recently had
surgery or suffered a traumatic injury are also
more likely to develop pneumonia because they are
less able to breathe deeply, cough, and get rid of
mucous. Frequent exposure to cigarette smoke can
affect the lungs in ways that make a person more
likely to develop pneumonia. People who have
seizures, strokes, abuse drugs or alcohol, or are
bedridden or paralyzed are also at greater risk of
developing pneumonia. Pneumonia is the sixth most
common disease that causes death in the United
States. It is the most common cause of death in
patients who are hospitalized for some other
reason. It is also a leading cause of death in
developing countries.
What causes it?
Pneumonia is caused by many different
microscopic organisms, including viruses,
bacteria, bacteria-like organisms, fungi, and
parasites. In adults, pneumonia is most often
caused by bacteria such as Streptococcus
pneumoniae, Staphylococcus aureus, Haemophilus
influenzae, and Legionella. The Legionella
bacteria was responsible for a well-known outbreak
of pneumonia called Legionnaires’ disease. Young
children are more likely to develop pneumonia from
exposure to a virus, such as the parainfluenza and
influenza viruses, respiratory syncytial virus,
and adenovirus. The chickenpox virus can cause
pneumonia in adults and children. Mycoplasma
pneumoniae is the cause of walking pneumonia, more
likely to occur in older children and younger
adults. Bird droppings, specifically poultry,
carry an organism called Chlamydia psittaci, which
can also cause pneumonia. Pneumocystis carinii,
which has been classified as a parasite and a
fungi, causes pneumonia in people with compromised
immune systems, such as those with AIDS or
undergoing cancer treatment. Healthy lungs are
free of any type of bacteria or virus because our
body has many safeguards that protect the lungs.
However, these safeguards can be overwhelmed by
exposure to a large number of the organisms that
cause pneumonia. People can develop pneumonia
after inhaling any of these organisms into the
lungs, when the organisms enter the lungs through
the bloodstream, or when a nearby infection
introduces the organisms into the lungs. Symptoms
are caused by the immune system producing so many
antibodies (infection-fighting cells) in the lungs
that they damage the lung tissue. The small blood
vessels in the lungs then leak fluid into the
alveoli, which are less able to provide oxygen to
the blood.
What are the symptoms?
The most common symptoms of pneumonia are
shortness of breath; chest pain, especially when
breathing in; coughing; shallow, rapid breathing;
and fever and chills. Coughs usually bring up
mucus, also called sputum. The sputum may even be
streaked with blood or pus. In serious cases, the
patient’s lips or nail bed will appear blue due to
lack of oxygen.
How is it diagnosed?
Your doctor will perform a thorough physical
examination, looking specifically for the telltale
symptoms of pneumonia. He or she will also look at
your medical history to check whether you have any
underlying condition that puts you at greater risk
for pneumonia. Your doctor will listen carefully
to your lungs, listening for the breath sounds
that indicate pneumonia. Pneumonia can be
diagnosed by a number of laboratory tests,
including chest x-rays, complete blood counts,
blood cultures, and sputum samples. These tests
can help determine what type of infection is
causing the pneumonia so your doctor can plan the
most effective course of treatment.
What is the treatment?
The elderly, people with underlying medical
conditions, and people who are having difficulty
breathing are usually treated for pneumonia in a
hospital. The most common treatment is
antibiotics, usually given intravenously, oxygen
therapy, and intravenous fluids. Others can be
treated with oral antibiotics at home. The type of
antibiotic you are given depends upon the type of
pneumonia you have. All patients with pneumonia
require complete bed rest and plenty of fluids.
Drinking warm fluids can help thin secretions in
the lungs so it is easier to cough them up. Your
doctor may also recommend using a humidifier to
keep the air you breathe moist. You can help
relieve fever and pain with acetaminophen or
ibuprofen. However, never give a child aspirin,
which can cause a serious condition called Reye’s
syndrome. Most people recover completely from
pneumonia. However, some people are more likely to
develop complications despite treatment. These
include those with an underlying illness, the very
young, and the very old.
Self-care tips
Those who are at a higher risk for developing
pneumonia can help lower their risk by getting a
yearly flu vaccine. Pneumonia is often a
complication of the flu in those who are high
risk. People with chronic illnesses can also be
vaccinated against certain types of infections
that cause pneumonia. If you are in the high risk
category, discuss ways to prevent pneumonia with
your doctor. If you have been diagnosed with
pneumonia, follow your doctor’s treatment plan to
avoid complications. You can help avoid exposure
to many illnesses by washing your hands
frequently, especially before eating.
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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