Chronic obstructive pulmonary
disease (COPD), also
called chronic obstructive lung disease,
is a term that is
used for two closely related diseases of
the respiratory
system: chronic bronchitis and
emphysema. In many
patients these diseases occur together,
although there
may be more symptoms of one than the
other.
Types of
COPD
Chronic bronchitis, one
of the
two major diseases of the lung grouped
under COPD, is
diagnosed when a patient has
excessive airway mucus
secretion leading to a persistent,
productive cough. An
individual is considered to have chronic
bronchitis if
cough and sputum are present on most
days for a
minimum of 3 months for at least 2
successive years or
for 6 months during 1 year. In chronic
bronchitis, there
also may be narrowing of the large and
small airways
making it more difficult to move air in
and out of the lungs.
In emphysema there is permanent
destruction of the
alveoli, the tiny elastic air sacs of the
lung, because of
irreversible destruction of a protein in
the lung called
elastin that is important for maintaining
the strength of
the alveolar walls. The loss of elastin
also causes
collapse or narrowing of the smallest
air passages,
called bronchioles, which in turn limits
airflow out of the
lung.
Causes
Cigarette
smoking is the most
important risk factor for COPD; it would
probably be a
minor health problem if people did not
smoke. Other risk
factors include age, heredity, exposure
to air pollution at
work and in the environment, and a
history of childhood
respiratory infections. Living in low
socioeconomic
conditions also seems to be a
contributing factor.
Symptoms
COPD
gets gradually
worse
over time. At first there may be only a
mild shortness of
breath and occasional coughing. Then
a chronic cough
develops with clear, colorless sputum.
As the disease
progresses, the cough becomes more
frequent and
more and more effort is needed to get
air into and out of
the lungs. In later stages of the
disease, the heart may be
affected. Eventually death occurs when
the function of the
lungs and heart is no longer adequate
to deliver oxygen
to the body's organs and tissues.
Last Updated: December 03, 2007
