23. Pneumoconiosis Part 2: Silica, Coal, and Asbestos

Full Scope Human Longevity

Lecture Summary
Pneumoconioses are fibrotic interstitial lung diseases caused by the inhalation of inorganic mineral dusts. Occupational exposure to asbestos, silica, and coal over many years are the most common causes. Sadly, this preventable disease is on the rise world-wide and no targeted treatments exist.

Key Points
- Lung diseases are very common in the workplace and include occupational asthma, COPD, Metal-induced lung injury, acute inhalation injuries, bronchiolitis obliterans, hypersensitivity pneumonitis, tumor formation, as well as other diseases.
- Pneumoconiosis is caused by the inhalation of inorganic mineral dusts, often over many years.
- Those effected develop a fibrotic interstitial lung disease that is progressive.
- Pneumoconiosis is increasing worldwide, particularly in developing nations. It is thought to kill approximately 250,000 people every year.
- Crystalized silica, asbestos, coal, graphite, kaolin, diatomatious earth, aluminum oxide, nylon floc, talc, and mica are all known culprits.
- Silicosis is the most common cause. Silicon dioxide makes up 60% of earth’s crust.
- Generally, disease takes years to develop, but can occur more acutely over months to years.
- Dry cough and progressive shortness of breath are the most common symptoms
- Chest xray are often used for surveillance of disease in workers. The International Labor Organization has published standards to guide readers. CTs are more sensitive for disease and should be pursued following any diagnosis.
- Prevention with engineering and environmental controls, personal protective equipment, and medical surveillance is key.
- No treatment exists in 2020. Treatment is supportive with oxygen, improved physical fitness, and lung transplant in severe cases. Research is being done on antifibrotic medications.
- Workers should be educated about the dangers of working with respirable minerals as well as the additive negative effects of smoking tobacco.

References
- Shi P, Xing X, Xi S, Jing H, Yuan J, Fu Z, Zhao H. Trends in global, regional and national incidence of pneumoconiosis caused by different aetiologies: an analysis from the Global Burden of Disease Study 2017. Occup Environ Med. 2020 Jun;77(6):407-414.
- Drbeen Medical Lectures – Pneumoconiosis. Available at: https://www.youtube.com/watch?v=DVQP4wKN7RQ
- Pulmonary Fibrosis Foundation – Pneumoconiosis: Pulmonary Fibrosis Caused by Occupational Lung Exposures. Available at: https://www.youtube.com/watch?v=k3AQyx3_ElU&t=2739s
- Wikipedia – Pneumoconiosis
- Ladou and Harrison. Occupational & Environmental Medicine: Current Diagnosis and Treatment, 5th Editiona. Balmes. Occupational Lung Diseases. 378 – 382. McGraw Hill. 2007
- Asbestos Contractor/Supervisor Manual. OSHA and EPA. 2015
- NIOSH/CDC B Reader Online Training. https://www.cdc.gov/niosh/learning/b-reader/radiograph/subset2/4.html
- ILO Standard Radiograms 2011
- DeLight and Sachs. Pneumoconiosis. Stat Pearls. 2020. https://www.ncbi.nlm.nih.gov/books/NBK555902/