BACKGROUND REPORT MARCH 19, 2009
Lower respiratory tract infections
Cases of pneumonia make up the vast
majority of debilitating lower respiratory tract infections, which affect
the trachea, lungs and bronchi, according to the World Health Organization.
Bronchitis and bronchiolitis, which cause inflammation of the bronchi,
also fall into the same category.
Pneumonia, an inflammation of the lungs, can be deadly if that inflammation
fills the air sacs in the lungs and interferes with breathing. In some
cases, the infection can invade the bloodstream and spread quickly to
An estimated 4 million people died
in 2004 from lower respiratory infections. Worldwide, pneumonia is the
leading cause of death in children. About 20 percent of all deaths in
children under 5 years old are due to acute lower respiratory tract
infections and 90 percent of these deaths are due to pneumonia, according
to the World Health Organization.
In the United States, more
than 60,000 Americans die of pneumonia
each year, according to the Mayo
Foundation for Medical Education and Research.
Pneumonia can be caused by bacteria,
viruses or fungi, and can follow acute or chronic bouts of bronchitis.
It is also possible to get pneumonia by accidentally inhaling a liquid
Transmission of pneumonia from person-to-person through direct contact
with infectious secretions can occur, however most infections are not
caught from another person but are a product of a weakened immune system.
Hospital patients are at an especially high risk of pneumonia.
A bacterium is the most common cause
of pneumonia in adults and children over the age of three. Bacterial
pneumonias tend to be the most serious and among the elderly can be
brought on after influenza or the common cold.
Respiratory viruses are the most common
cause of pneumonia in young children, according to the National Institutes
Bronchitis, which is an inflammation
of the main air passages to the lungs, is generally caused by viral
respiratory infections. The main cause of chronic bronchitis is cigarette
smoke, or long-term exposure to secondhand smoke. The affliction usually
clears up on its own, but it can lead to pneumonia in some severe cases.
Pneumonia has similar symptoms to a
cold or the flu at its onset, with a cough and fever. The main signs
and symptoms are often shaking, chills, a high fever, sweating, shortness
of breath, chest pain, and coughing greenish or yellow phlegm.
Additional symptoms can include headache,
excessive sweating, loss of appetite, excessive fatigue and confusion,
especially in the elderly.
Vaccines can help prevent pneumonia
in children, the elderly and those with chronically debilitating conditions
or diseases such as HIV. The pneumococcal vaccine prevents the most
common form of bacterial pneumonia, Streptococcus pneumoniae. Getting
a flu vaccination can help prevent an illness that would develop into
pneumonia, while the Hib vaccine prevents pneumonia in children from
Haemophilus influenzae type b.
Smoking is discouraged because it damages
the lungs' natural defenses against disease. Not smoking, or quitting
smoking are recommended to prevent both pneumonia and bronchitis, as
well as limiting exposure to air pollutants and washing hands regularly
to avoid spreading infections and viruses.
Pneumonia treatments vary depending
on the cause and severity. Bacterial pneumonia is treated with antibiotics,
while most viral pneumonias are treated the same way as the flu, with
rest and fluids. Pneumonia caused by a fungus is usually treated with
Severe pneumonia leads to hospitalization
and treatment with intravenous antibiotics and oxygen.
Sources: National Library of Medicine,
National Institutes of Health, the Mayo Clinic, the New England Journal
of Medicine, University of Maryland Medical Center