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BACKGROUND REPORT MARCH 19, 2009
Chronic respiratory diseases
Chronic respiratory diseases affect the
airways and other structures of the lungs. Chronic obstructive pulmonary
disease and asthma are the two most prevalent. Both cause difficulties
breathing.
Chronic obstructive pulmonary disease,
or COPD, and asthma can be deadly, though COPD causes the majority of
chronic respiratory disease deaths.
Hundreds of millions of people suffer
from chronic respiratory diseases. According to 2007 WHO estimates,
300 million people have asthma, 210 million people have chronic obstructive
pulmonary disease and millions more have other under diagnosed chronic
respiratory diseases.
An estimated 3 million people died of
COPD in 2005, and it is predicted to become the third leading cause
of death worldwide by 2030. Asthma, which is under diagnosed and undertreated,
can also be deadly and nearly 290,000 people died of asthma in 2004.
Most asthma-related deaths occur in low- and lower-middle income countries.
In high and middle-income countries,
the primary cause of chronic obstructive pulmonary disease is tobacco
smoke, including second-hand or passive exposure. In low-income countries
that risk is surpassed by exposure to indoor air pollution, such as
the use of biomass fuels for cooking and heating.
Chronic obstructive pulmonary disease
is caused by an obstruction in the lungs, usually from chronic bronchitis
or emphysema, which hinders a person's ability to exhale. Chronic
bronchitis causes inflammation and narrowing of bronchial tubes, while
emphysema can cause the collapse of some of the small airways in the
lungs. COPD can also be characterized by a loss of elasticity in the
airways and air sacs of the lungs.
Asthma also causes difficulty breathing,
and is characterized by inflammation and constriction of the bronchial
tubes that act as air passageways to and from the lungs.
Asthma can be caused by environmental
or genetic factors, or can be caused by certain respiratory infections
during childhood. Triggers for asthma attacks can include airborne allergens
like pollen, respiratory infections, physical activity, air pollutants,
allergic reactions or stress.
Symptoms of COPD may not appear until
there's significant lung damage, but once symptoms are present they
may include persistent cough and increased mucus production. COPD and
asthmas both cause shortness of breath, wheezing and tightness in the
chest.
The best way to prevent COPD is to not
smoke or quit smoking.
Conditions like asthma can be prevented
by avoiding triggers, taking maintenance medications that reduce inflammation
in the airways, and acting quickly to prevent the early stages of an
asthma attack from growing more severe through use of an inhaler.
There is no cure for COPD and damage
to the lungs cannot be undone, but
stopping smoking can result in an improvement
in lung function. Medications can be prescribed to control some of the
symptoms of COPD, including bronchodilators, used through an inhaler,
that can relax the muscles of the airways and ease breathing. Inhaled
steroids can also reduce inflammation.
Bronchilators are also used to control
asthma. Oral or intravenous medications may be used for severe cases.
Allergy induced asthma can be treated through shots that desensitize
the body to the allergen or medications that reduce the immune system's
reaction to an allergen.
Other interventions for COPD are oxygen
therapy or surgery for some severe cases of emphysema. A single lung
transplant may be performed, or small sections of damaged lung tissue
may be removed.
Sources: National Heart, Lung and Blood
Institute, World Health Organization, Mayo Clinic
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