BROCA'S AREA
BRONCHOCONSTRICTOR
B
are soft and have an increased tendency
both to become deformed and to frac-
ture. The inherited disorder
osteogenesis
imperfecta
is a rare cause of brittle
bones and frequent fractures and is
usually detected in infancy.
Broca's area
An area of the cerebral
cortex (the outer layer of the
brain
) that
is responsible for speech origination.
broken tooth
See
fracture, dental.
broken veins
See
telangiectasia
.
bromides
Substances formerly used as
sedative
drugs
or
as
anticonvulsant
drugs
in the treatment of
epilepsy
. They
are no longer prescribed because of
their side effects.
bromocriptine
A drug used to suppress
production of the hormone
prolactin
to
treat conditions such as noncancerous
pituitary tumours (see
prolactinomas
and
acromegaly
). Bromocriptine can be
used to suppress lactation after child-
birth. The drug may also be used as a
treatment for
Parkinson's disease.
Side
effects of bromocriptine include nausea
and vomiting. High doses may cause
drowsiness and confusion.
bronchiectasis
A lung disorder in which
1
or more bronchi (the air passages
leading from the trachea) are abnormally
widened, distorted, and have damaged
linings. Bronchiectasis most often deve-
lops during childhood and was once
commonly associated with infections
such as
m easles
and
pertussis
(whoop-
ing cough). The condition is also a
complication of
cystic fibrosis.
It results
in pockets of long-term infection within
the airways and the continuous produc-
tion of large volumes of green or yellow
sputum (phlegm). Extensive bronchi-
ectasis causes shortness of breath. The
symptoms are usually controlled with
antibiotic drugs
and
postural drainage
. If
the condition is confined to one area of
the lung, surgical removal of the dam-
aged area may be recommended.
bronchiole
One of many small airways
of the
lungs
. Bronchioles branch from
larger airways (bronchi) and subdivide
into progressively smaller tubes before
reaching the
alveoli
(see
alveolus
,
pul-
monary
), where gases are exchanged.
bronchiolitis
An acute viral infection of
the lungs, mainly affecting babies and
young children, in which the bronchi-
oles (the smaller airways branching off
from the bronchi in the lungs) become
inflamed. The most common cause is
the respiratory syncytial virus (RSV).
Symptoms include rapid breathing, a
cough, and fever. Sometimes no treat-
ment is necessary but, in more severe
cases, hospital admission is needed so
that
oxygen therapy
and
physiotherapy
(to clear the mucus) can be given. With
prompt treatment, sufferers usually re-
cover within a few days.
Antibiotic drugs
may be prescribed to prevent any sec-
ondary bacterial infection.
bronchitis
A disorder in which the bron-
chi, the airways connecting the trachea
(windpipe) to the lungs, are inflamed.
Bronchitis results in a cough that may
produce considerable quantities of spu-
tum (phlegm) and may be acute or
chronic. Both types are more common
in smokers and in areas with high atmo-
spheric pollution. (See also
bronchitis
,
acute; bronchitis, chronic.)
bronchitis, acute
A form of
bronchitis
that develops suddenly but usually clears
up within a few days. It is usually due to
a viral infection. Bacterial infection of
the airways may occur as a complica-
tion. Smokers, babies, elderly people,
and those with lung disease are particu-
larly susceptible. The main symptoms
are wheezing, shortness of breath, and
a cough that produces yellow or green
sputum. There may also be pain behind
the sternum (breastbone) and fever.
Symptoms may be relieved by drinking
plenty of fluids and inhaling steam or
using a humidifier. Most cases clear up
without further treatment, but acute
bronchitis may be serious in people
who already have lung damage.
bronchitis, chronic
Inflammation of
the airways, as a result of smoking, that
is always associated with emphysema.
The combination of chronic bronchitis
and emphysema are now known as chro-
nic obstructive pulmonary disease (see
pulmonary disease
,
chronic obstructive
).
bronchoconstrictor
A substance that
causes constriction (narrowing) of the
airways in the lungs. Bronchoconstric-
tors, such as
histamine
, are released
during an
allergic
reaction. They may
98
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