Definition
Chronic dilation of bronchi or bronchioles as a sequel of
inflammatory disease or obstruction.
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Radiographic Appearance
Standard chest x-rays may show increased bronchovascular
markings from peribronchial fibrosis and intrabronchial secretions,
crowding from an atelectatic lung, tram lines (parallel lines
outlining dilated bronchi due to peribronchial inflammation and
fibrosis), areas of honeycombing, or cystic areas with or without
fluid levels, but occasionally x-rays are normal. High-resolution CT
(HRCT) of the chest (1- to 2-mm cuts) has largely replaced
bronchography. With 10-mm collimation, dilation of small bronchi may
be missed, but the better resolution of HRCT provides results
comparable or preferable to bronchography. Its widespread use
indicates that bronchiectasis is probably more common than can be
diagnosed by clinical findings and standard x-rays alone.
Characteristic CT findings are dilated airways, indicated by tram
lines, by a signet ring appearance with a luminal diameter > 1.5
times that of the adjacent vessel in cross section, or by grapelike
clusters in more severely affected areas. These dilated medium-sized
bronchi may extend almost to the pleura because of the destruction
of lung parenchyma. Thickening of the bronchial walls, obstruction
of airways (evidenced by opacification--eg, from a mucus plug--or by
air trapping), and, sometimes, consolidation are other findings.
The CT signs of bronchiectasis include air/fluid levels in distended
bronchi, a linear array or cluster of cysts, dilated bronchi in the
periphery of the lung, and bronchial wall thickening due to
peribronchial fibrosis. Distended bronchi are easily distinguished
from bulla, which generally have no definable wall thickness and no
accompanying vessels.
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Pathology
Bronchiectasis is a relatively rare condition that affects the Iungs.
In this disorder the bronchial tubes become enlarged and distended
forming pockets where infection may gather. The walls themselves are
damaged which results in impairment to the lung’s complex cleaning
system. The tiny hairs, lled cilia - which line the bronchial tubes
and sweep them free of dust, germs and excess mucus - are destroyed.
When this cleaning system is not working effectively dust, mucus and
bacteria accumulate. Infection develops and is difficult to remove.
The Causes
Bronchiectasis is caused by various types of infections which
damage and weaken the bronchial walls and interfere with the action
of the cilia. Patients may be predisposed to get this condition with
various congenital or inherited deficiencies such as immunological
deficiency or cystic fibrosis. Rarely patients inherit a primary
abnormality of the hair cells or cilia which renders them more prone
to develop bronchiectasis.
Certain pneumonias which may be associated with measles and
whooping cough, usually occurring in childhood may predispose to
this condition by weakening the walls of the bronchial tubes and
causing pockets of infection to form.
An obstruction of some sort - anything that presses on the
bronchial tubes from the outside or blocks them from the inside -
may also cause bronchiectasis. In childhood this most commonly
results from choking on food such as a peanut which is small enough
to go down the windpipe and large enough to block off one of the air
tubes. When this happens the wall of the tube is injured and air is
prevented from passing beyond the obstruction. The bronchial tube,
below the obstruction, balloons out to form a perfect hiding place
for infection and pus.
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Treatment:
The treatment of bronchiectasis is designed to prevent
the complications of pneumonia and blood spitting and to allow
patients with this condition to live as normal a life as possible.
The most important aspect of the treatment is done at home by the
patient often with the help of family members. Because the usual
mechanism for cleaning the lung is not effective a helping hand is
necessary. As a result patients with bronchiectasis must learn to
position themselves so that the damaged areas of the lungs can drain
by gravity. This is usually done by hanging one’s head over the side
of the bed with the affected part of the Iung upper most. This is
usually necessary one to three times a day and can be taught to the
patient by a physician or physiotherapist. Clapping the chest to
help the mucus run out is also very helpful. This can be done by a
family member by hand or using a mechanical percussor. If the
patient practices this "postural drain- age" on a regular basis the
complications are often avoided and the patient can carry on
a relatively normal life.
The patient must learn to recognize an impending superimposed
infection from symptoms such as fever, chest pain and a change in
the quality and quantity of the phlegm. Early treatment of such
infections with antibiotics can also prevent complications.
If the patient has recurrent pneumonia or blood spitting and the
bronchiectasis is limited to a very small isolated part of the Iung,
this can be removed surgically leaving the patient with no further
problems. If the damage is widespread, surgery is usually not
advisable.
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Useful Link http://www.lung.ca/
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