Pneumoconiosis

Pneumoconiosis is the general term for a class of interstitial lung disease where inhalation of dust (for example, ash dust, lead particles, pollen grains etc) has caused interstitial fibrosis.<ref name=":1">Template:Cite web</ref><ref name=":2">Template:Cite journal</ref> The three most common types are asbestosis, silicosis, and black lung disease.<ref>Template:Citation</ref> Pneumoconiosis often causes restrictive impairment,<ref>Template:Cite journal</ref> although diagnosable pneumoconiosis can occur without measurable impairment of lung function.<ref name=":1" /><ref name=":2" /> Depending on extent and severity, it may cause death within months or years, or it may never produce symptoms. It is usually an occupational lung disease, typically from years of dust exposure during work in mining;<ref>Template:Cite journal</ref> textile milling; shipbuilding, ship repairing, and/or shipbreaking; sandblasting; industrial tasks; rock drilling (subways or building pilings);<ref name="NYTimes">Template:Cite news</ref> or agriculture.<ref name=":0">Template:Cite book</ref><ref>Template:Cite journal</ref> It is one of the most common occupational diseases in the world.<ref>Template:Cite book</ref>

Types

Depending upon the type of dust, the disease is given different names:

• Coalworker's pneumoconiosis (CWP) / Black Lung Disease: Resulting from prolonged inhalation of coal dust, CWP leads to lung inflammation and fibrosis. Over time, this scarring impairs respiratory function, causing symptoms such as chronic cough and shortness of breath.<ref>Template:Cite web</ref> Predominantly affects coal miners, especially those engaged in underground mining operations where coal dust exposure is significant.<ref>Template:Cite web</ref>

• Aluminosis – Aluminium
• Asbestosis – asbestos: Develops from inhaling asbestos fibers, leading to lung tissue scarring and reduced lung function. Symptoms include shortness of breath, persistent cough, and chest tightness.<ref>Template:Cite web</ref> Historically prevalent among workers in shipbuilding, construction, and manufacturing, especially those handling insulation materials containing asbestos.<ref>Template:Cite web</ref>
• Silicosis (also known as "grinder's disease" or Potter's rot) – crystalline silica dust: Caused by inhalation of crystalline silica particles, silicosis leads to lung inflammation and scarring. Early symptoms include coughing and shortness of breath, which can progress to severe respiratory impairment.<ref>Template:Cite web</ref> Common among workers in construction, mining, and tunneling, particularly those involved in activities like stone cutting, sandblasting, and drilling, where silica dust is prevalent.<ref>Template:Cite web</ref>
• Bauxite fibrosis – bauxite
• Berylliosis – beryllium: A chronic lung disease caused by inhaling beryllium dust or fumes, leading to granuloma formation and lung scarring. Symptoms include cough, shortness of breath, fatigue, and chest pain.<ref>Template:Cite web</ref> Common in aerospace, nuclear, and manufacturing industries where beryllium is used, such as in the production of electronics and precision instruments.<ref>Template:Cite web</ref>
• Siderosis – iron
• Byssinosis – Byssinosis: (Brown Lung Disease) is caused by cotton dust inhalation and typically demonstrates a different pattern of lung abnormalities from most other pneumoconiosis. Associated with exposure to cotton, flax, or hemp dust, byssinosis causes chest tightness, coughing, and wheezing. Symptoms often worsen at the beginning of the workweek, a phenomenon known as "Monday fever".<ref>Template:Cite web</ref> Primarily affects textile workers, particularly those involved in processing raw cotton or other fibers in mills and factories.<ref>Template:Cite web</ref>
• Chalicosis – fine dust from stonecutting
• Silicosiderosis (also sometimes called iron miner's lung<ref>Template:Cite web</ref>) – mixed dust containing silica and iron<ref>Template:Cite web</ref>
• Labrador lung (found in miners in Labrador, Canada) – mixed dust containing iron, silica and anthophyllite, a type of asbestos
• Stannosis – tin oxide
• Talcosis – talc
• Baritosis - a benign type of pneumoconiosis caused by barium inhalation; it typically causes little or no overgrowth, hardening, and/or fibrosis.<ref>Template:Cite web</ref>
• Mixed-dust pneumoconiosis<ref name=":13">Template:Cite web</ref>

Pathogenesis

The reaction of the lung to mineral dusts depends on many variables, including size, shape, solubility, and reactivity of the particles.<ref>Template:Cite journal</ref> For example, particles greater than 5 to 10 μm are unlikely to reach distal airways, whereas particles smaller than 0.5 μm move into and out of alveoli, often without substantial deposition and injury.<ref>Template:Cite journal</ref> Particles that are 1 to 5 μm in diameter are the most dangerous, because they lodge at the bifurcation of the distal airways. Coal dust is relatively inert, and large amounts must be deposited in the lungs before lung disease is clinically detectable. Silica, asbestos, and beryllium are more reactive than coal dust, resulting in fibrotic reactions at lower concentrations. Most inhaled dust is entrapped in the mucus blanket and rapidly removed from the lung by ciliary movement. However, some of the particles become stuck at alveolar duct bifurcations, where macrophages accumulate and engulf the trapped particulates. The pulmonary alveolar macrophage is a key cellular element in the initiation and perpetuation of lung injury and fibrosis. Many particles activate the inflammasome and induce IL-1 production. The more reactive particles trigger the macrophages to release a number of products that mediate an inflammatory response and initiate fibroblast proliferation and collagen deposition. Some of the inhaled particles may reach the lymphatics either by direct drainage or within migrating macrophages and thereby initiate an immune response to components of the particulates and/or to self-proteins that are modified by the particles. This then leads to an amplification and extension of the local reaction. Tobacco smoking worsens the effects of all inhaled mineral dusts, more so with asbestos than with any other particle.<ref name=":0" />

Diagnosis

Typical indications on patient assessment include:<ref>Template:Cite web</ref>

• Cough
• Shortness of breath
• Chest tightness
• Chest X-ray may show a characteristic patchy, subpleural, bibasilar interstitial infiltrates or small cystic radiolucencies called honeycombing, particularly in advanced disease.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Pneumoconiosis in combination with multiple pulmonary rheumatoid nodules in rheumatoid arthritis patients is known as Caplan's syndrome.<ref>Andreoli, Thomas, ed. CECIL Essentials of Medicine. Saunders: Pennsylvania, 2004. p. 737.</ref><ref>Template:Cite web</ref>

Epidemiology

The prevalence as of 2021 of pneumoconiosis is around 527,500 cases, with over 60,000 new patients reported globally in 2017. Prevalence has trended somewhat downward since 2015.<ref name=":2" /> The mortality of pneumoconiosis patients remained at a high level in recent years, with over 21,000 deaths each year since 2015.<ref name=":2" /> It is likely that pneumoconiosis is under-diagnosed and under-reported, especially in countries without highly developed healthcare systems.<ref name=":2" />

Treatment and prognosis

Lung damage due to pneumoconiosis cannot be reversed.<ref name=":3">Template:Cite web</ref> However, some steps can slow down disease progression and relieve symptoms. These include the prescription of medications and breathing treatments to open airways and reduce inflammation.<ref name=":3" /> Pulmonary rehabilitation and supplemental oxygen may also be recommended.<ref name=":3" /> A lung transplant may be needed in cases of serious diseases. If the patient smokes, smoking cessation is also important.<ref name=":3" /> Regular testing, such as X-rays or lung function tests, may be indicated to monitor disease progression.

Prevention

To reduce the likelihood of developing pneumoconiosis, individuals working in affected industries should wear a mask, wash skin that comes in contact with dust, remove dust from clothing and wash the face and hands before eating or drinking.<ref name=":3" /> In addition, governments often regulate industry, especially mines, to limit how much dust is in the air.<ref>Template:Cite web</ref> In the United States, coal miners injured by pneumoconiosis and their families may receive monthly payments and medical benefits under the Black Lung Benefits Act.<ref>Template:Cite web</ref>

See also

• Aluminosis
• Black Lung Benefits Act of 1972
• Chalicosis
• Philip D'Arcy Hart
• Pneumonoultramicroscopicsilicovolcanoconiosis
• Popcorn workers' lung disease — diacetyl emissions and airborne dust from butter flavorings used in microwave popcorn production

Further reading

• Template:Cite book (Paperback ed. (2009) Cardiff University Template:ISBN.

External links

• Template:Cite web
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• Template:MerckManual
• Black Lung — United Mine Workers of America
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• A Conversation about Mining and Black Lung Disease
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• The Institute of Occupational Medicine and its research into pneumocomiosis
• Template:Cite tech report