Pneumoconiosis is an occupational lung disease caused by inhaling dust particles like coal, asbestos, silica, and others. It is classified based on the type of dust inhaled, like silicosis from silica dust. The pathology requires exposure to dust particles of a certain size for a sufficient duration. Silicosis specifically results from inhaling crystalline silica dust and shows characteristic lesions and calcifications on chest x-rays. It is a major global health problem resulting in thousands of deaths annually.

1. PNEUMOCONIOSIS
By-Anubhav Agrawal,514

2. CONTENTS
• Introduction
• Pathogenesis
• Classification
• Silicosis
• Diagnosis

3. INTRODUCTION
• Pneumoconiosis is an occupational lung disease and a restrictive lung
disease caused by the inhalation of dust, often in mines and from
agriculture.
• In 2013, it resulted in 260,000 deaths, up from 251,000 deaths in 1990. Of
these deaths, 46,000 were due to silicosis, 24,000 due to asbestosis and 25,000
due to coal workers pneumoconiosis.
• The first recorded mention of breathlessness among handlers of grain was
done by Ramazzini, the father of occupational medicine, in 1713.

4. • The term "black lung" was coined when medical professionals
discovered the blackening of miners' lungs in post-mortem.
• The first documented case of an asbestos-related death was reported in
1906 when the autopsy of an asbestos worker revealed lung fibrosis.

6. PATHOGENESIS
For clinical pneumoconiosis to develop, 3 essential factors are
required:
• Exposure to specific substance: coal, appear relatively inert and may
accumulate in considerable amounts with minimal tissue response;
while silica and asbestos, have potent biologic effects.
• Particles of appropriate size to be retained in lung (1-5μm)
• Exposure for a sufficient length of time (usually around 10 years)

8. CLASSIFICATION
Depending upon the type of dust, the disease is given different names:
• Coal worker's pneumoconiosis (also known as miner's lung, black lung or anthracosis) — coal,
carbon
• Asbestosis — asbestos
• Silicosis— crystalline silica dust
• Bauxite fibrosis — bauxite
• Berylliosis — beryllium
• Siderosis — iron
• Byssinosis — cotton
• Silicosiderosis — mixed dust containing silica and iron
• Labrador lung (found in miners in Labrador, Canada) — mixed dust containing iron, silica and
anthophyllite, a type of asbestos

9. SILICOSIS
• Silicosis (previously miner's phthisis, grinder's asthma, potter's rot and
other occupation-related names) is a form of occupational lung disease
caused by inhalation of crystalline silica dust, and is marked by
inflammation and scarring in the form of nodular lesions in the upper
lobes of the lungs. It is a type of pneumoconiosis.
• Silicosis resulted in 46,000 deaths globally in 2013 down from 55,000 deaths
in 1990.

11. CLASSIFICATION
Three forms of silicosis:
• Acute silicosis: occurs with exposure to fine dust with high quartz content;
very heavy exposure for months, shows symptoms within weeks to months
of exposure,
• Accelerated silicosis: shows rapidly progressive symptoms after 5 to 10 years
of high exposure to fine dust of high silica content.
• Chronic silicosis: the most common form, results from long-term exposure
(10 to 20 years or longer) to dust containing less than 30% silica content.

12. CLINICAL FEATURES
• Chronic cough
• Dyspnea (shortness of breath) that worsens with exertion.
• Fatigue
• Loss of appetite
• Chest pains
• Acute silicosis patients may also have fever and experience rapid, unintended
weight loss.
Silicotuberculosis: Pulmonary tuberculosis occurs in about 25% of patients
with acute or classic silicosis

13. DIAGNOSIS
Positive indications on patient assessment:
• Shortness of breath
• Chest X-ray may show a characteristic patchy, subpleural, bibasilar
interstitial infiltrates or small cystic radiolucencies called honeycombing.
Pneumoconiosis in combination with multiple pulmonary rheumatoid
nodules in rheumatoid arthritis patients is known as Caplan's syndrome.

14. • For uncomplicated silicosis, chest x-ray will confirm the presence of
small (< 10 mm) nodules in the lungs, especially in the upper lung
zones. Using the ILO classification system, these are of profusion 1/0 or
greater and shape/size "p", "q", or "r". Lung zone involvement and
profusion increases with disease progression. In advanced cases of
silicosis, large opacity (> 1 cm) occurs from coalescence of small
opacities, particularly in the upper lung zones. With retraction of the
lung tissue, there is compensatory emphysema. Enlargement of the
hilum is common with chronic and accelerated silicosis. In about 5-10%
of cases, the nodes will calcify circumferentially, producing so-called
"eggshell" calcification. This finding is not pathognomonic (diagnostic)
of silicosis. In some cases, the pulmonary nodules may also become
calcified.

15. • PA chest radiograph of an 80-
year-old man who was a miner
decades ago shows multiple large
opacities (arrows, large opacity =
parenchymal opacity greater
than 1 cm) and several tiny
rounded opacities in the right
lower and left mid/lower lung
zones. With the history of
exposure, adequate lag time and
chest radiographic findings, the
patient has findings consistent
with coal worker
pneumoconiosis.

21. • Image shows small nodules
predominantly in the
middle-to-upper lung zones,
several of which are
calcified. Eggshell
calcification is present in the
bilateral hilar lymph nodes.
The large mass in the
infrahilar region of the right
lung is consistent with
progressive massive fibrosis.

22. • Silicosis with progressive
massive fibrosis. Image
shows large, conglomerate
nodules in both the middle
and upper lung zones.
Peripheral hyperlucency
represents emphysematous
lung tissue secondary to
central migration of the
large nodules. Bilateral
upper lobe volume loss is
also noted.