smooth MUSCLE tissue with no cartilage. The
bronchi are susceptible to irritation, INFLAMMATION,
and INFECTION. When inflamed or irritated the
bronchi can cause difficulty breathing (DYSPNEA).
For further discussion of the bronchi within the
context of pulmonary structure and function
please see the overview section “The Pulmonary
System.”
See also ALVEOLUS; ASTHMA; BRONCHIECTASIS; BRON-
CHITIS.
byssinosis A lung disorder resulting from
extended exposure to the dust from cotton, flax,
or other textile fibers. Also called brown lung, cot-
ton worker’s lung, or cotton bract disease, byssi-
nosis is an occupational disease that causes
ASTHMA-like symptoms. When detected in its early
stages, byssinosis is reversible by eliminating expo-
sure to the responsible irritant. When exposure
continues the byssinosis can cause permanent
damage to the LUNGSwith symptoms similar to
those of CHRONIC OBSTRUCTIVE PULMONARY DISEASE
(COPD). In the United States people who work in
jobs where they handle unprocessed cotton have
the highest risk of developing byssinosis.
The symptoms of byssinosis tend to be worse at
the workplace and improve away from the work-
place and typically include wheezing and cough-
ing. The diagnostic path focuses on the work
history and includes X-rays of the chest and tests
to assess pulmonary capacity and function. The
most effective treatment is preventing continued
exposure, which may involve workplace improve-
ments or changing jobs. Medications to reduce the
HYPERSENSITIVITY REACTIONthe airways have to the
fiber dust, such as bronchodilators and sometimes
CORTICOSTEROID MEDICATIONS, can relieve or prevent
symptoms. Smoking significantly exacerbates
byssinosis, so SMOKING CESSATIONis crucial to other
treatment approaches.
See also ASTHMA; BERYLLIOSIS; OCCUPATIONAL
HEALTH AND SAFETY; SARCOIDOSIS; SILICOSIS.198 The Pulmonary System