Australia’s emerging occupational health epidemic – silicosis

Resources References Online activity

Silicosis and the housing boom

Silicosis is a progressive, irreversible and incurable fibrotic pulmonary disease that is caused by the inhalation of respirable crystalline silica dust.10 It is the oldest of the pneumoconioses (dust diseases) and was thought to be almost obsolete in Australia until very recently. It is now appearing in increasingly large numbers of young people – mostly men (as young as 21 years), who are early in their working careers and often have dependent families.17

In a recent health surveillance program in two Queensland stone masonry businesses, 34% (12 out of 35) of the workers assessed had accelerated silicosis, including several with the most severe form of the disease – progressive massive fibrosis, which involves very active inflammation and scarring in the lungs and the worker is highly likely to become permanently disabled or die.13,17

This emerging epidemic is thought to be due to worker exposure to respirable crystalline silica while cutting, polishing and grinding artificial stone kitchen and bathroom benchtops.10 Increased demand for these benchtops has been stimulated by the housing boom and many new companies have been set up to deal with this demand, some of which have poor compliance with regulatory requirements.17

More cases are expected to be detected soon.17

What is silica?

Silica, or silicon dioxide (SiO2), is a naturally occurring and widely abundant mineral that forms the major component of most rocks and soils. Silica can occur in non-crystalline and crystalline forms.14

Crystalline silica is dangerous to health when dust is generated, becomes airborne and is then inhaled by a worker.14

Click on the boxes below to learn about the amount of silica in different types of rocks and rock products and work activities that generate crystalline silica.



Types of silicosis and other silica dust diseases

Exposure to silica dust can present as a range of diseases based on time of exposure. See the table below for more information.



Table: Types of silicosis based on time exposure6,11,13,14

Silicosis type

Time of exposure

Features

Acute silicosis (silicoprotenosis)

less than 3 years

  • Induced by short term exposure to very high levels of silica dust.
  • Presents with rapidly progressive dyspnoea and respiratory failure.
  • High probability of death.

Accelerated silicosis

3–10 years

  • Associated with high intensity silica exposure.
  • Radiological and pathological features of both chronic and acute silicosis may be present.
  • Likely to be associated with a greater rate of disease progression than chronic silicosis.

Chronic silicosis

over 10 years

Can exist as:

  • Simple silicosis: often asymptomatic with small, predominately upper lobe nodules less than 1cm in size. It may progress to complicated silicosis.
  • Complicated silicosis (also known as progressive massive fibrosis (PMF)): nodules conglomerate into masses greater than 1cm in size. Calcification in masses and in hilar and mediastinal lymph nodes in common. As the condition progresses, lung function becomes impaired with development of dyspnoea, and potentially cor pulmonale, respiratory failure and death.

Exposure to silica dust can also cause and contribute to:14

  • chronic bronchitis
  • emphysema
  • lung cancer
  • kidney disease
  • scleroderma and other autoimmune conditions
  • tuberculosis.



GP’s role in the Australian silicosis epidemic

As a GP, you are in the ideal situation to detect possible silicosis and refer patients appropriately for assessment and diagnosis.

To best manage this emerging epidemic, your role involves:

routinely taking an occupational history of patients

detecting risk factors and symptoms for silicosis in history and examination

referring potential cases of silicosis early using the correct referral pathway in your jurisdiction, eg this may involve referring to a respiratory physician, occupational physician or for screening through your local regulatory workplace safety authority

providing ongoing psychosocial support and counselling for patients affected with silicosis and their families

providing general medical treatment to help manage symptoms and reduce complications (eg smoking cessation and influenza vaccination)

promoting awareness of silicosis and encouraging safe work practices.



Presenting features of silicosis and silica-related conditions

A person with advanced silicosis will generally present to you with dyspnoea and a dry cough which has progressed gradually.6,11,17 They may also have constitutional symptoms, such as fever, fatigue and weight loss, and if the disease is severe, they may present with respiratory failure.6,11 However, many patients may present at an early stage and will be asymptomatic. Silicosis can also present as an incidental finding on imaging for another indication.5

While most causes of shortness of breath in general practice are not from workplace exposures to silica or other occupational hazards, certain clinical features should alert you to a potential diagnosis of silicosis. These include:8

  • working in a high risk environment, eg working in the stone benchtop industry
  • new onset respiratory symptoms, eg persistent cough, shortness of breath or wheeze
  • worsening of a previously stable respiratory condition, eg exacerbations of asthma or chronic obstructive pulmonary disease (COPD)
  • presentation with any form of chronic lung disease
  • outbreak of similar symptoms or disease in a group with shared exposure.


Taking an occupational and environmental history

It is vital to take a thorough occupational and environmental history to help you identify cases of silicosis and differentiate them from other workplace-related or commonly occurring respiratory diseases (eg asthma, lung cancer). This will involve covering the areas listed below. Click on each box for more information.

Signs of silicosis on physical examination

Physical findings are usually normal in early silicosis. Signs are more common in severe disease or in the presence of related conditions. Click on the boxes below for more information on the characteristic findings of silica exposure related conditions.



Referral for assessment

While you may detect potential cases, the assessment and diagnosis of silicosis and other workplace respiratory conditions are best undertaken by respiratory physicians. Occupational physicians may also be involved in the health screening/assessment process; however, this will depend on the state or territory in which you live.

The Royal Australasian College of Physicians (RACP) recommended that health assessments for silica lung disease occur in conjunction with full lung function testing, including diffusing capacity of the lungs (DLCO), and imaging (ILO chest x-ray and CT scanning, where indicated).13

As a GP, initial investigations involve spirometry and standard chest x-ray. However, in some cases these can result in false negatives readings.13 Therefore, if there is a high likelihood of silicosis due to silica exposure, referral to a specialist with experience in diagnosis and management of silicosis or interstitial lung disease is vital.

Click on the boxes below for more information about silicosis assessment and diagnosis.


KEY PRACTICE POINT:

Normal results on spirometry and standard x-ray does NOT exclude silicosis.



Silicosis medical management

The prevention of further crystalline silica inhalation is the mainstay of management.

While there is no specific curative treatment for silicosis, GPs can assist in:11

  • smoking cessation
  • influenza and pneumococcal vaccines, where indicated, to reduce complications
  • prescription of bronchodilators for symptomatic patients with airflow obstruction
  • early treatment of chest infections
  • weight control and exercise programs.

For severe disease under the care of a respiratory physician, the following may be considered in select patients:11

Psychosocial support

GPs can also provide psychosocial support and counselling to their patients with silicosis and their families. Patients with silicosis have been found to experience significant anxiety and depression related to:7,15,18

  • dealing with the morbidity and mortality of the disease
  • the financial impact of their inability to work or changes to their income.

Where patients are unable to continue in a job involving silica exposure, you might also suggest they seek assistance from unions, workers compensation schemes or seek out potential vocational assistance in retraining and assessment of transferable skills.

Psychological support may also be available through state/territory-based regulatory/work insurance authorities and you may want to refer selected patients to the Lung Foundation support groups.



If you would like to do a short case study on this topic, you can enrol in the Australia’s emerging occupational health epidemic – silicosis activity on gplearning. Completion of the online activity is worth 2 Category 2 QI&CPD points.

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Additional resources

General


Australia-wide


State and Territories

Australian Capital Territory

  • See here to find an occupational health consultant
  • Further information: Silica Dust
  • For Silica Dust ACT information contact:
    • T: 13 22 81

New South Wales


Northern Territory


Queensland


South Australia


Tasmania


Victoria


Western Australia

  • See here to find an occupational health consultant
    • Western Australia health surveillance must be supervised by an Appointed Medical Practitioner (AMP) under specific legislative requirements contained in the Occupational Safety & Health Regulations 1996 (OSH Regulations).
    • While GPs are not excluded, they must contact WorkSafe’s Occupational Physicians before they conduct health surveillance so that they understand their legislative requirements under the OSH Regulations.
    • Further information on WA requirements for health surveillance can be found here.
  • In Western Australia Workers Compensation is covered by a separate government department – WorkCover WA.
  • WorkSafe WA call centre for doctors to WorkSafe WA occupational physicians:
    • Phone: 08 6251 2200 OR 1300 307 877

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References

  1. Brenner S, Guder G. The patient with dyspnea. Rational diagnostic evaluation. Herz. 2014;39(1):8-14.
  2. Cullinan P, Reid P. Pneumoconiosis. Primary care respiratory journal: journal of the General Practice Airways Group. 2013;22(2):249-52.
  3. DePaso WJ, Winterbauer RH, Lusk JA, Dreis DF, Springmeyer SC. Chronic dyspnea unexplained by history, physical examination, chest roentgenogram, and spirometry. Analysis of a seven-year experience. Chest. 1991;100(5):1293-9.
  4. DynaMed Plus [Internet]. Dyspnea - Approach to the Patient, Record No. T576478. Ipswich (MA): EBSCO Information Services. 1995 - . [updated November 2018] [Accessed August 2018]
  5. DynaMed Plus [Internet]. Silicosis. Record No. T115037. Ipswich (MA): EBSCO Information Services. 1995 - . [updated November 2018] [Accessed August 2019]
  6. Fernandez Alvarez R, Martinez Gonzalez C, Quero Martinez A, Blanco Perez JJ, Carazo Fernandez L, Prieto Fernandez A. Guidelines for the diagnosis and monitoring of silicosis. Archivos de bronconeumologia. 2015;51(2):86-93.
  7. Han B, Yan B, Zhang J, Zhao N, Sun J, Li C, et al. The influence of the social support on symptoms of anxiety and depression among patients with silicosis. The Scientific World Journal. 2014;2014:724804.
  8. Hoy R. Respiratory problems Occupational and environmental exposures. Australian Family Physician. 2012;41:856-60.
  9. Karnani NG, Reisfield GM, Wilson GR. Evaluation of chronic dyspnea. American family physician. 2005;71(8):1529-37.
  10. Leso V, Fontana L, Romano R, Gervetti P, Iavicoli I. Artificial Stone Associated Silicosis: A Systematic Review. Int J Environ Res Public Health. 2019;16(4):568.
  11. Leung CC, Yu IT, Chen W. Silicosis. Lancet 2012;379(9830):2008-18.
  12. Munakata M, Homma Y, Matsuzaki M. Rales in silicosis. A correlative study with physiological and radiological abnormalities. Respiration 1985;48(2):140-4.
  13. Royal Australasian College of Physicians. Accelerated Silicosis: Overview. RACP, 2018.
  14. Safe Work Australia. Crystalline silica and silicosis. Safe Work Australia, 2019. [Accessed August 2019]
  15. Shusterman DJ, Dager SR. Prevention of psychological disability after occupational respiratory exposures. Occupational medicine (Philadelphia, Pa). 1991;6(1):11-27.
  16. Wahls SA. Causes and evaluation of chronic dyspnea. American family physician. 2012;86(2):173-82.
  17. Yates D et al. Artificial stone workers’ silicosis: Australia’s new epidemic. Medical Journal of Australia, 2018.
  18. Yildiz T, Essizoglu A, Onal S, Ates G, Akyildiz L, Yasan A, et al. Quality of life, depression and anxiety in young male patients with silicosis due to denim sandblasting. Tuberkuloz ve toraks. 2011;59(2):120-5.

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