Silicosis is part of a group of diseases termed pneumoconioses which means “lung dust”. This group of diseases are caused by inhaling mineral dust over a long period of time.
Industries such as construction, stone cutting, brick and ceramics making expose workers to respirable crystalline silica (RCS), which are airborne particles of silica that are small enough to be inhaled into the lungs. Silicosis is considered an occupational lung disease. Inhalation of silica causes inflammation and scarring of the lungs which over time leads to respiratory difficulties. Though there is no cure for silicosis, steps can be taken to prevent it through the use of safety equipment and the observation of proper protocols.
If you want to know more about silicosis and its impact, read on for additional information, including prevention methods, symptoms, treatment options, and complications.
Causes of silicosis
Silicosis is caused by exposure to silica particles over time, hence the name “silicosis”. When airborne particles of silica, also known as silicon dioxide are inhaled, they get trapped in the lungs and cause inflammation which eventually leads to fibrosis. Silica exists naturally as quartz. Quartz is a very common mineral in the earth’s crust and has a lot of industrial uses. It can be found in places like beaches, geodes, and mines. A lot of exposure to silica dust occurs during quartz mining.
Types of silicosis
Silicosis is typically grouped into three types, according to the duration of exposure.
- Acute silicosis: Also known as silicoproteinosis, this is a rapidly progressive form of the disease that is associated with sustained high-intensity exposure to silica dust. Symptoms can begin to appear anywhere from weeks to 5 years after first exposure. It is characterised by chest pain, shortness of breath, fatigue, fever, and weight loss, with eventual progression to respiratory failure and the inability of the lungs to supply oxygen to the body. A few occupations that are associated with acute silicosis include surface drilling, silica flour processing, and tombstone sandblasting. These occupations are considered to have high-intensity exposure to inhaled silica particles
- Accelerated silicosis: This form of silicosis results from moderate to high-level exposure, and differs from the acute form in that it develops within 10 years of the first contact. It may eventually lead to decreased lung function and can continue to progress even after exposure to silica is removed. There have been proven links between accelerated silicosis and the development of autoimmune diseases. The presence of a foreign agent (silica) within the lungs activates the body’s immune system which over time begins to attack the body1
- Chronic silicosis: Occurs 10 years after low to moderate exposure. There are two forms in which it can present: progressive massive fibrosis (PMF) or simple (nodular) silicosis. Simple nodular silicosis is slowly progressing with X-ray findings of nodules in the lungs that are < 1 cm in size. Most symptoms do not manifest until years after the patient has left where the exposure occurred. PMF results in chronic lung scarring, and eventually pulmonary hypertension
Signs and symptoms of silicosis
Presentation varies depending on the stage and type of disease. Some of the more common signs and symptoms are;
- Weight Loss
- Chest pain
Diagnosis of silicosis
Diagnosis of silicosis relies on the history of exposure, symptoms, clinical manifestations, and chest X-ray findings like lung nodules that suggest silicosis. Because some of the radiologic findings of silicosis might mimic those of other lung diseases, it is important to eliminate the possibility of those before making a diagnosis.
- X-rays are a non-invasive way to visualise the lungs for any abnormal changes that may be caused by silicosis. Lung nodules are a common X-ray finding in silicosis
- Bronchoscopy is a procedure where a long, thin tube with a camera is inserted into your lungs to assess the cause of your symptoms
- Biopsy entails inserting a needle into the lungs to obtain some lung tissue which is observed under a microscope to determine the presence of inhaled mineral particles
It is essential to consult a pulmonologist for evaluation of lung function and to estimate the degree of disease progression.
Treatment and management of silicosis
There is currently no cure for silicosis. Therapy is supportive, and often varied depending on the stage of disease and the body’s response.
- Oxygen: Supplemental oxygen therapy is sometimes needed to improve shortness of breath and increase oxygen delivery to the body
- Steroids: Steroids are used as additional treatment along with oxygen to help improve breathing in patients. However, steroids do not significantly improve overall disease or decrease mortality2
Antimicrobials: Because silicosis wears down your lungs and makes them more vulnerable to infections, it is common for patients with silicosis to acquire bacterial or viral lung infections that require antimicrobial therapy.
- Lung transplant: This is the only definitive treatment for late-stage silicosis, as it provides a healthy donor lung
- Lifestyle modifications: Stopping exposure to inhaled silica ensures no new harmful particles are being inhaled. However, it does not nullify past exposure and has no effect on the already ongoing disease. Unfortunately, most patients suffering from silicosis discover the disease years after they began to be exposed
Patients with silicosis may develop other respiratory diseases like asthma, chronic obstructive pulmonary disease, pulmonary hypertension, and right-sided heart failure. Because silicosis affects your immune system, it could also make you more vulnerable to tuberculosis and lung cancer.3 Most people who suffer from late-stage silicosis often eventually need a lung transplant.
Who is at risk of silicosis?
- Coal miners
- People working in construction
- Quarry workers
- Cement and glass manufacturing
- Stone cutting
- Dental laboratory work
How common is silicosis?
Despite it affecting millions of people worldwide, it is difficult to estimate exactly how many people develop silicosis. Inconsistent reporting and the amount of time it takes from silica dust exposure to the manifestation of the disease significantly affects reported numbers. There were an estimated 12,887 deaths attributed to silicosis globally in 2019, with 655,763 more individuals disabled by the disease.4
Is silicosis contagious?
Since silicosis is not caused by an infection but rather an irritation from foreign matter, it is not contagious. Only individuals who have had long-term contact with silica can develop it.
When should I see a doctor?
Regular follow-ups with your doctor are recommended if you work in an industry that exposes you to inhaled mineral particles. Also, if you have been exposed to silica and experience symptoms like cough, shortness of breath, chest pain, or unexplained weight loss. Because these symptoms may equally be caused by other respiratory illnesses, it is important to see a doctor as soon as they present to get an accurate diagnosis.
How do I avoid developing silicosis?
- Decrease or avoid exposure to silica dust
- Wear proper personal protective gear when working with or around silica dust
- Safety protocols like wet cutting and adequate ventilation to minimise the formation of inhalable particles
- Getting regular checkups if working in industries that put you at risk
Silicosis is a debilitating disease caused by inhaling silica dust over a long period of time. It is an occupational lung disease common in mining, construction, and manufacturing industries. There are three forms of silicosis; acute silicosis, accelerated silicosis, and chronic silicosis. The disease often becomes apparent with non-specific symptoms like cough, shortness of breath, and weight loss. Diagnosis is reliant on a history of exposure, X-ray findings, and clinical manifestations. There is currently no cure for silicosis, but therapy is supportive and multifaceted depending on the stage of disease, and the body’s response. Lung transplantation is an option reserved for end-stage disease. Unfortunately, most patients only discover the disease years after they began to be exposed to silica. Regular follow-ups with a doctor are recommended for individuals in occupations that expose them to inhaled mineral particles.
- Pollard KM, Cauvi DM, Mayeux JM, Toomey CB, Peiss AK, Hultman P, et al. Mechanisms of environment-induced autoimmunity. Annu Rev Pharmacol Toxicol [Internet]. 2021 Jan 6 [cited 2023 Mar 31];61(1):135–57. Available from: https://www.annualreviews.org/doi/10.1146/annurev-pharmtox-031320-111453
- Silicosis treatment & management: approach considerations, medical care, surgical care. 2021 Jun 11 [cited 2023 Mar 31]; Available from: https://emedicine.medscape.com/article/302027-treatment#d5
- Association AL. Silicosis symptoms, causes, and risk factors [Internet]. [cited 2023 Mar 31]. Available from: https://www.lung.org/lung-health-diseases/lung-disease-lookup/silicosis/symptoms-diagnosis
- Gbd results [Internet]. Institute for Health Metrics and Evaluation. [cited 2023 Mar 31]. Available from: https://vizhub.healthdata.org/gbd-results