Pneumoconiosis
Alternative names
Black lung disease; Pneumoconiosis
Definition
Coal worker's pneumoconiosis is
a respiratory disease caused by inhaling coal dust for
prolonged periods.
Causes, incidence, and risk factors
Coal worker's pneumoconiosis occurs
in two forms: simple and complicated (progressive massive
fibrosis). Inhalation of coal dust causes this disease.
The simple form is usually not disabling, but the complicated
form often is. Smoking does not increase the prevalence
of this disease but may have an additive detrimental
effect on lung function.
The risk of developing the disease is related to the
duration and extent of exposure to the coal dust. Most
affected workers are over the age of 50.
Symptoms
- shortness of breath
- chronic cough
Signs and tests
How the test is performed
In a spirometry test, a person breathes
into mouthpiece that is connected to an instrument called
a spirometer. The spirometer records the amount and
the rate of air that is breathed in and out over a specified
time. Some of the test measurements are obtained by
normal, quiet breathing, and other tests require forced
inhalation or exhalation after a deep breath.
Lung volume measurement can be performed in two ways.
The most accurate way is for a person to sit in a body
plethysmograph, a sealed, transparent box that resembles
a telephone booth, while breathing in and out against
into a mouthpiece. Changes in pressure inside the box
allow determination of the lung volume. Lung volume
can also be measured when a person breathes nitrogen
or helium gas through a tube for a specified period
of time. The concentration of the gas in a chamber attached
to the tube is measured, allowing estimation of the
lung volume.
The diffusion capacity is measured when a person breathes
carbon monoxide for a very short time, often one breath.
The concentration of carbon monoxide in exhaled air
is then measured. The difference in the amount of carbon
monoxide inhaled and the amount exhaled allows estimation
of how rapidly gas can travel from the lungs into the
blood.
Treatment
There is no specific treatment for
this disorder other than treatment of complications.
Avoidance of further exposure to coal dust is recommended.
Expectations (Prognosis)
The outcome for the simple form
is usually good. However, the complicated form may become
a disabling illness.
Complications
Cor Pulmonale failure of the right
side of the heart)
Failure of the right side of the heart caused by prolonged
high blood pressure in the pulmonary artery and right
ventricle of the heart.
Normally, the left side of the heart produces a higher
level of blood pressure in order to pump blood to the
body; the right side pumps blood through the lungs under
much lower pressure. Any condition that leads to prolonged
high blood pressure in the arteries or veins of the
lungs (called pulmonary hypertension) will be poorly
tolerated by the right ventricle of the heart. When
this right ventricle fails or is unable to properly
pump against these abnormally high pressures, this is
called cor pulmonale.
Pulmonary Tuberculosis
Pulmonary tuberculosis is a contagious
bacterial infection caused by Mycobacterium tuberculosis
(TB). The lungs are primarily involved, but the infection
can spread to other organs.
Causes, Incidence, and Risk Factors
Tuberculosis can develop after
inhaling droplets sprayed into the air from a cough or
sneeze by someone infected with Mycobacterium tuberculosis.
The disease is characterized by the development of granulomas
(granular tumours) in the infected tissues.
The usual site of the disease is the lungs, but other
organs may be involved. The primary stage of the infection
is usually asymptomatic
Asymptomatic means there are no symptoms. A person is
asymptomatic if an illness or condition is present without
recognizable symptoms.
Pulmonary TB develops in the minority of people whose
immune systems do not successfully contain the primary
infection. The disease may occur within weeks after the
primary infection, or it may lie dormant for years before
causing disease.
The risk of contracting TB increases with the frequency
of contact with people who have the disease, and with
crowded or unsanitary living conditions and poor nutrition.
An increased incidence of TB has been seen recently in
the United States. Factors that may contribute to the
increase in tuberculosis infection are:- Incomplete treatment
of TB infections (such as failure to take medications
for the prescribed length of time) can contribute to the
emergence of drug-resistant strains of bacteria. |
