Bronchitis is an
INFLAMMATION of the membrane that lines
the air passages, or, bronchial tubes, of the
LUNGS and results in the narrowing of these air
passages. This disorder may be of either an acute
or chronic type. Irritation of mucus-producing
glands within the membrane results in the
production of excess bronchial secretions. The
main symptoms of bronchitis are cough and
increased expectoration of sputum, with or without
associated wheezing and shortness of breath.
Acute bronchitis is usually caused by infection by
one of the many viruses that cause the common
COLD or INFLUENZA and is frequently
associated with MEASLES. The patient may
suffer from additional symptoms, such as chest
discomfort, fever, and aching, that are
characteristic of these diseases. WHOOPING
COUGH is a form of severe bronchitis caused by
the bacterium Hemophilus pertussis. Treatment of
a pure viral infection is directed toward the relief
of symptoms, but frequently secondary infections
by bacteria complicate the condition. In such a
case the patient\'s sputum may turn from white to
yellow (purulent, or pus containing), and treatment
with various antibiotics is recommended. Acute
chemical bronchitis may be caused by the
inhalation of irritating fumes, such as smoke,
chlorine, ammonia, and ozone. Chronic bronchitis
results from prolonged irritation of the bronchial
membrane, causing cough and the excessive
secretion of mucus for extended periods. By far
the most common cause of chronic bronchitis is
cigarette SMOKING, but air pollution and
industrial fume and dust inhalation are also
important irritants. Patients with chronic bronchitis
are subject to recurrent infections with H.
influenzae and pneumococci. Pulmonary
EMPHYSEMA often coexists, and over a long
period of time the patient may suffer from
increasing breathlessness, decreasing exercise
tolerance, and, finally, total disability. In the most
severe forms of the disease, the patient may have
a blue, bloated appearance, and a fatal heart
disease, known as COR PULMONALE.
HOWARD BUECHNER, M.D. Bibliography:
Burrows, B., Respiratory Disorders (1983);
Fletcher, C., et al., The Natural History of
Chronic Bronchitis and Emphysema (1976);
Pennington, J. E., ed., Respiratory Infections

Category: Science