People develop difficulty breathing during exercise that sometimes progresses to shortness of breath even at rest, and some people also have a cough that may or may not produce sputum.
Diagnosis is made with a chest x-ray or computed tomography.
Doctors can sometimes give drugs to help keep airways clear.
Silicosis is the oldest known environmental lung disease Overview of Environmental Lung Diseases Environmental lung diseases are caused by harmful particles, mists, vapors, or gases that are inhaled, usually while people work. If the lung disease is due to inhaled particles, the term pneumoconiosis... read more . It is caused by inhalation of tiny particles of the mineral silica (usually quartz) or, less commonly, by inhalation of silicates, such as talc.
Workers at greatest risk are those who move or blast rock and sand (miners, quarry workers, stonecutters) or who use silica-containing rock or sand abrasives (sand blasters; glass makers; foundry, gemstone, and ceramic workers; potters). Recently, silicosis has been identified in workers who fabricate or install countertops manufactured from engineered silicates (silica conglomerate). Coal miners are at risk of mixed silicosis and coal workers’ pneumoconiosis Coal Workers’ Pneumoconiosis Coal workers’ pneumoconiosis is a lung disease caused by deposits of coal dust in the lungs. People generally have no symptoms, but people who have severe disease cough and become short of breath... read more .
Silicosis may be
Acute silicosis may develop after intense exposures over several years or months.
Chronic silicosis is the most common form and generally develops only after exposure over decades.
Accelerated silicosis, which is rare, may develop after more intense exposures over several years or months (like acute silicosis). Silica is also a cause of lung cancer.
When inhaled, silica dust passes into the lungs, and scavenger cells such as macrophages engulf it (see Overview of the Immune System Overview of the Immune System The immune system is designed to defend the body against foreign or dangerous invaders. Such invaders include Microorganisms (commonly called germs, such as bacteria, viruses, and fungi) Parasites... read more ). Enzymes released by the scavenger cells cause the lung tissue to scar.
Simple chronic silicosis is the first stage of chronic silicosis. In this stage, the scarred areas are tiny round lumps.
Eventually, complicated chronic silicosis occurs when the scarred areas combine into larger masses. Sometimes these larger masses come together into even larger masses (progressive massive fibrosis). These scarred areas cannot transfer oxygen into the blood normally. The lungs become less flexible, and breathing takes more effort.
Symptoms of Silicosis
In acute silicosis, shortness of breath worsens rapidly. People also lose weight and have fatigue. Respiratory failure often develops within 2 years.
Chronic silicosis often does not cause symptoms for years, but many people eventually develop difficulty breathing during exercise. Sometimes the breathing difficulty progresses to shortness of breath even during rest. Some people have a cough that may produce sputum. Breathing may worsen for years after the person stops working with silica. The lung damage can lead to lower levels of oxygen in the blood and can also strain the right side of the heart. This strain can lead to a type of heart failure called cor pulmonale Pulmonary Hypertension Pulmonary hypertension is a condition in which blood pressure in the arteries of the lungs (the pulmonary arteries) is abnormally high. Many disorders can cause pulmonary hypertension. People... read more , which can be fatal.
People with accelerated silicosis experience the same symptoms as people with chronic silicosis, but symptoms develop and worsen over a shorter period.
People with silicosis are many times more likely to develop tuberculosis Tuberculosis (TB) Tuberculosis is a chronic contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. It usually affects the lungs, but almost any organ can be involved. Tuberculosis... read more or nocardiosis Nocardiosis Nocardiosis is an infection (typically of the lungs) caused by the gram-positive bacteria Nocardia. Nocardia bacteria can infect the lungs when they are inhaled, and they can infect... read more when exposed to the organisms that cause these disorders than are people without silicosis. They are also at risk for progressive systemic sclerosis Systemic Sclerosis Systemic sclerosis is a rare, chronic autoimmune connective tissue disorder characterized by degenerative changes and scarring in the skin, joints, and internal organs and by blood vessel abnormalities... read more , chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more , and lung cancer Lung Cancer Lung cancer is the leading cause of cancer death in both men and women. About 85% of cases are related to cigarette smoking. One common symptom is a persistent cough or a change in the character... read more .
Diagnosis of Silicosis
Diagnosis is made when someone who has worked with silica has chest computed tomography (CT) that shows distinctive patterns consistent with the disease. A chest x-ray can also be done to help diagnose silicosis. When imaging findings are unclear, samples of lung tissue can help confirm the diagnosis. Additional tests are done to distinguish silicosis from other disorders.
Prevention of Silicosis
Controlling silica dust in the workplace is key to preventing silicosis. When dust cannot be controlled, as may be true in the sandblasting industry, workers should wear protective gear, such as hoods that supply clean external air or special masks that efficiently filter out tiny particles. Such protection may not be available to all people working in a dusty area (for example, painters and welders), so whenever possible abrasives other than sand should be used.
Workers exposed to silica dust should have regular chest x-rays so that problems can be detected early. Workers who smoke should be encouraged to stop. Other preventive measures include pneumococcal vaccine and an annual influenza vaccination to help protect against infections to which workers may be more vulnerable.
Treatment of Silicosis
Whole lung lavage
For acute or accelerated silicosis, corticosteroids
Treatments for symptoms and complications, such as drugs that open the airways and sometimes lung transplantation
Silicosis cannot be cured, but its progression can be slowed if exposure to silica is avoided, especially at an early stage of the disease.
A whole lung lavage (washing) can be used to treat both acute and chronic silicosis. During this procedure, doctors fill the lung with a salt (saline) solution and then drain it to clear material from the air spaces.
Some people with acute or accelerated silicosis benefit from taking corticosteroids.
People who have difficulty breathing may benefit from drugs to keep the airways open and free of mucus (bronchodilators Treatment of symptoms Chronic obstructive pulmonary disease is persistent narrowing (blocking, or obstruction) of the airways occurring with emphysema, chronic obstructive bronchitis, or both disorders. Cigarette... read more ). Lung transplantation Lung and Heart-Lung Transplantation Lung transplantation is the surgical removal of a healthy lung or part of a lung from a living person and then its transfer into someone whose lungs no longer function. Heart-lung transplantation... read more is a last resort.
People should be monitored and treated for low oxygen levels in the blood. Pulmonary rehabilitation Pulmonary Rehabilitation Pulmonary rehabilitation is the use of supervised exercise, education, support, and behavioral intervention to improve how people with chronic lung disease function in daily life and to enhance... read more may help people carry out activities of daily living.