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Interstitial Lung Disease
Definition
Interstitial lung disease (ILD) is an
umbrella term for a group of lung disorders characterized by inflammation
and eventual scarring of the deep lung tissues. Another term for
these disorders is Pulmonary Fibrosis.
Causes, incidence & risk
factors
ILDs
are a group of diseases that are caused by inflammation and scarring
of the air sacs (alveoli) in the lungs and their supporting structures
(the interstitium). The scarring leads to decreased oxygen transfer
from the lungs to the blood and an eventual decreased blood oxygen
level. There are numerous causes of ILD and there is no uniformly
accepted classification system; however, ILD can be broken down into
two large groups:
- Those that have no known cause (known as idiopathic ILD)
- Those
with identifiable causes – examples
include:
- Occupational exposure to things such as asbestos,
silica, certain fungal spores, certain dusts or chemicals,
etc.
- Connective
tissue disorders that can affect the lungs such as rheumatoid
arthritis, scleroderma, lupus and sarcoidosis
- Some medications can
cause ILD such as bleomycin, amiodarone and methotrexate
The risk factors, genetic predispositions, and
rate of ILD depend on the specific disease being considered. For
example, sarcoidosis is relatively common in African-Americans, but
idiopathic ILD is relatively rare in African-Americans.
Cigarette smoking has been shown to increase the risk of developing
some forms of ILD and to increase the severity of all forms of ILD.
Symptoms
- Shortness of breath
at rest or with exertion
- Decreased activity tolerance
- Cough
- Fatigue
Tests
- Chest X-ray
- High-resolution CT scan
- Pulmonary
function tests
- Arterial
blood gases
- Lab tests
to look for connective tissue diseases
- Bronchoscopy
- Lung
biopsy
Treatment
Treatment for ILD depends on the underlying
cause. Most often, anti-inflammatory drugs such as corticosteroids
or immune-suppressing drugs are used. If the underlying cause is
not able to be determined (idiopathic) or does not have a specific
treatment option available, then supportive treatment is indicated.
Oxygen therapy is prescribed for those with low blood oxygen levels.
For some people, pulmonary rehabilitation may be helpful.
For those who smoke, smoking cessation programs should be incorporated
into their treatment plan.
For those with severe ILD that is not responding
to treatment, lung transplantation may be an option.
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