The NLM has
indexes (MeSH) for the various lung diseases that result in lung scarring
(fibrosis):1
Pulmonary Fibrosis
A process in which normal lung
tissues are progressively replaced by FIBROBLASTS and COLLAGEN causing an
irreversible loss of the ability to transfer oxygen into the bloodstream via
PULMONARY ALVEOLI. Patients show progressive DYSPNEA finally resulting in
death.
Lung Diseases, Interstitial
A diverse group of lung diseases that
affect the lung parenchyma. They are characterized by an initial inflammation
of PULMONARY ALVEOLI that extends to the interstitium and beyond leading to
diffuse PULMONARY FIBROSIS. Interstitial lung diseases are classified by their
etiology (known or unknown causes), and radiological-pathological features.
Year introduced: 1994
Pneumoconiosis
A diffuse parenchymal lung disease
caused by inhalation of dust and by tissue reaction to their presence. These
inorganic, organic, particulate, or vaporized matters usually are inhaled by
workers in their occupational environment, leading to the various forms
(ASBESTOSIS; BYSSINOSIS; and others). Similar air pollution can also have
deleterious effects on the general population. Year introduced: 1966
Idiopathic
Pulmonary Fibrosis
A common interstitial lung disease of
unknown etiology, usually occurring between 50-70 years of age. Clinically, it
is characterized by an insidious onset of breathlessness with exertion and a
nonproductive cough, leading to progressive DYSPNEA. Pathological features
show scant interstitial inflammation, patchy collagen fibrosis, prominent
fibroblast proliferation foci, and microscopic honeycomb change. Year
introduced: 2009
So, "pulmonary fibrosis," "interstitial lung
disease," and "pneumoconiosis" are three terms that can refer
to the same disease process (scarring or fibrosis) at the same anatomical site (the
interstitium of the lung). The interstitium is the supporting lung tissue
adjacent to pulmonary airways and blood vessels. Idiopathic pulmonary fibrosis
is a subset of pulmonary fibrosis in which the cause is unknown after
extensive testing and the lung biopsy shows the presence of usual interstitial
pneumonia (UIP).2
The occupational
interstitial lung diseases in Haz-Map include:
§
Asbestosis
§
Chronic beryllium disease
§
Coal workers' pneumoconiosis
§
Coal workers’ pneumoconiosis (CWP), complicated
§
Hard metal disease
§
Hypersensitivity pneumonitis
§
Pneumoconiosis, benign
§
Pneumoconiosis, other
§
Silicosis, acute
§
Silicosis, complicated
§
Silicosis, simple.3
Byssinosis is
not classified as pneumoconiosis in Haz-Map, but as an "Airway
Disease."
As noted in
the chapter on "Pulmonary Fibrosis and Interstitial Lung Diseases"
by Carrie A. Redlich "The term pneumoconiosis has traditionally been
defined as the accumulation of dust in the lungs and the resulting tissue
reaction."4 In that chapter, she shows Table
1
that lists the occupational and non-occupational causes of interstitial lung
disease.
A similar
list can be found on the Mayo Clinic website5, and the author
brings up some excellent caveats.
·
Pulmonary fibrosis is the end stage of interstitial lung disease,
a large group of disorders that cause progressive lung scarring.
·
The list of substances and conditions that can lead to pulmonary
fibrosis is long. Even so, in most cases, the cause is never found.
Pulmonary fibrosis with no known cause is called idiopathic pulmonary
fibrosis.
·
Researchers have several theories about what might trigger
idiopathic pulmonary fibrosis, including viruses and exposure to tobacco
smoke. And because one type of idiopathic pulmonary fibrosis runs in
families, heredity also is thought to play a role, even in people who don't
directly inherit the disease.
·
Diagnosing pulmonary fibrosis can be extremely challenging. The
difference between idiopathic and nonidiopathic forms of the disease isn't
always clear, and the naming and classification systems for both have
historically been confusing and controversial.
·
In addition, many medical conditions, including chronic
obstructive pulmonary disease (COPD), asthma and even heart failure, can
mimic pulmonary fibrosis, so doctors must rule these out before making a
definitive diagnosis.
·
A complete medical history, physical exam and even a chest X-ray
aren't enough to diagnose pulmonary fibrosis. For that reason, you may have
tests such as a high-resolution computerized tomography (CT) scan, which
provides sharper and more detailed images than conventional CT scans do; an
exercise test on a treadmill or stationary bike to monitor your lung
function when you're active; and pulmonary function tests to measure how
well your lungs work overall.
·
Often, though, pulmonary fibrosis can be definitively diagnosed
only by examining a small amount of lung tissue (biopsy) in a laboratory.
The tissue sample may be obtained in one of these ways: [bronchoscopy,
bronchoalveolar lavage, and surgical biopsy]
References
1.
National
Library of Medicine. 2009. PubMed: MeSH. Available at https://www.ncbi.nlm.nih.gov/mesh/?term=pulmonary+fibrosis
2.
International
consensus statement on idiopathic pulmonary fibrosis. 2001. Full text
available at http://www.erj.ersjournals.com/cgi/content/full/17/2/163.
3.
National
Library of Medicine. 2009. Haz-Map: Interstitial Lung Disease. Available at https://hazmap.nlm.nih.gov/disease-category?level=1&disease_category_id=5.
4.
Redlich
CA. 1996. Pulmonary Fibrosis and Interstitial Lung Diseases. In: Harber P, Schenker MB,
Balmes JR (eds). Occupational and Environmental Respiratory Diseases. St. Louis: Mosby, p. 216-217.
5.
MayoClinic.com.
2019. Pulmonary Fibrosis. Available at https://www.mayoclinic.org/diseases-conditions/pulmonary-fibrosis/symptoms-causes/syc-20353690
[Redlich
CA. Pulmonary Fibrosis and Interstitial Lung Diseases. In: Harber,
p. 217]
More common
causes of occupational interstitial lung diseases
1.
Free silica
2.
Silicates
a.
Fibrous-asbestos
b.
Mixed dust
3.
Coal
4.
Metals
a.
Beryllium
b.
Hard metal-cobalt
Less common
causes of occupational interstitial lung diseases
1.
Silicates
a.
Talc
b.
Kaolin
c.
Diatomaceous earth
d.
Man-made vitreous fibers (MMVF)
e. Mica
2.
Hydrocarbon-containing sedimentary rocks
a.
Graphite
b.
Oil shale
3.
Metals
a.
Tin
b.
Aluminum
c.
Antimony
d.
Barium
e.
Iron
f.
Titanium
4.
Irritant gases, fumes, vapors
a.
Sequelae of toxic pneumonitis
5.
Plastics
a.
Polyvinylchloride
b.
Toluene diisocyanate
6.
Organic dusts
a.
Bacteria
b.
Fungi
c. Animal proteins
d.
Plant proteins
7.
Paraquat
Most common
causes of nonoccupational interstitial lung disease
1.
Unknown etiology
a. Idiopathic
b. Sarcoidosis
c. Bronchiolitis obliterans organizing pneumonia
(BOOP)
2.
Collagen vascular diseases
a. Rheumatoid arthritis;
b.
Progressive systemic sclerosis;
c.
Systemic lupus erythematosus;
d.
Mixed connective tissue disease
3.
Pulmonary granulomatoses: Wegener's granulomatosis; Bronchocentric
granulomatosis
4.
Vasculitides: Churg-Strauss syndrome
5.
Lymphoproliferative disorders: Lymphomatoid granulomatosis
6.
Inherited disorders: Tuberous sclerosis; Neurofibromatosis; Cystic
fibrosis
7.
Drugs and treatment (selected examples)
a. Antibiotics (nitrofurantoin, penicillins, and
sulfasalazine);
b. Cardiac drugs (hydralazine, procainamide, and
amiodarone);
c.
Antineoplastic agents (bleomycin, busulfan, methotrexate, cyclophosphamide,
nitrosureas);
d. Antiinflammatory agents (gold salts and
penicillamine);
e. Central nervous system drugs
(diphenylhydantoin);
f.
Radiation;
g. Oxygen;
h. Bone marrow transplantation;
i.
Miscellaneous: Intravenous use of illicit drugs; Mineral oil; Silicone;
Penicillamine
8.
Infections
a. Viruses; Mycobacteria; Fungi
9.
Other
a. Aspiration; Pulmonary edema; Pulmonary hemorrhage