Pneumoconiosis

Pneumoconiosis refers to a group of diffuse interstitial lung diseases caused by the inhalation and subsequent accumulation of inorganic dusts in high concentrations in the lungs. Most are related to occupational exposure.

Pneumoconiosis types are classified based on the causative agent. Some of the most common are:

• Silicosis: crystalline silica (quartz, cristobalite, tridymite, moganite, sistovite). It is the most common type of pneumoconiosis.
• Coal workers' pneumoconiosis: coal and crystalline silica. It is also called black lung disease.
• Asbestosis: asbestos.
• Berylliosis: beryllium.
• Siderosis: iron.
• Hard metal lung disease: alloy of cobalt, tungsten, and carbon.
• Stannosis (or estanniosis): tin.
• Baritosis: barium.

Symptoms

Pneumoconiosis has a variable and usually prolonged latency period, potentially manifesting up to 20 years after exposure to the causative dust has ceased. Generally, in the early stages of the disease, no symptoms appear, which makes recognition difficult. When symptoms appear, they can vary depending on the type:

• Presence of pulmonary nodules or granulomas: all types of pneumoconiosis form nodules of varying sizes and compositions.
• Pulmonary fibrosis: formation of scarring and thickening of the tissue surrounding the pulmonary alveoli (interstitium). This develops in most cases of pneumoconiosis.
• Interstitial pneumonitis: inflammation of the pulmonary interstitium. It appears in silicosis and berylliosis.
• Dry cough, dyspnea (shortness of breath), and expectoration, with or without chest pain, in the case of silicosis, asbestosis, berylliosis, and hard metal lung disease.
• Pulmonary crackles (abnormal sounds heard during auscultation): these occur in asbestosis and hard metal lung disease.
• Clubbing (drumstick fingers): in cases of berylliosis, asbestosis, and hard metal lung disease.
• Asthenia, weight loss, fever, night sweats, cutaneous granulomas, joint pain, and muscle pain when it comes to berylliosis, which has a clinical presentation nearly identical to sarcoidosis.
• Bronchospasm: sudden narrowing of the bronchial tube due to bronchial muscle contraction, causing difficulty breathing. It manifests in baritosis.

Causes

When dust particles are inhaled, larger particles (greater than 10 microns) are deposited in the upper airways, but smaller particles penetrate the respiratory bronchioles and pulmonary alveoli, from where they can pass into the pulmonary interstitium. The accumulation of these particles in the lungs leads to the formation of nodules due to the action of immune system cells, which phagocytize and isolate foreign or harmful substances. These nodules progressively increase in size, cluster together, and result in fibrosis, causing the disease symptoms.

Risk Factors

The main risk factor for pneumoconiosis is exposure to the causative inorganic substances. This exposure is associated with certain professional sectors, including:

• Mining, quarrying, construction, and public works.
• Manufacture of glass, ceramics, refractories, and other ceramic products.
• Steel and metallurgy industry.
• Manufacturing of abrasives, paper, paints, plastics, and rubber.
• Dismantling and demolition of facilities or equipment that may contain asbestos.
• Automobile manufacturing and maintenance.
• Aerospace, shipping, and port industries.

Additionally, the duration of exposure, the concentration levels of the substance, and the patient’s immune susceptibility influence the severity of the disease. Smoking is also associated with worsening symptoms and an increased risk of complications.

Complications

Despite their extended latency period and the usual absence of symptoms, pneumoconiosis is a disease that causes severe and progressive deterioration. The most common complication is respiratory failure and decreased pulmonary diffusion capacity (the process of oxygen and carbon dioxide exchange), characteristic of chronic obstructive pulmonary disease (COPD).

Furthermore, the various pathologies encompassed by pneumoconiosis can lead to other diseases of varying severity:

• Chronic silicosis:
• Pulmonary hypertension or spontaneous pneumothorax (collapsed lung), both of which are life-threatening conditions.
• Tuberculosis.
• Scleroderma.
• Lung cancer, as silica is considered a Class 1 carcinogen.
• Acute silicosis, which has rapid progression and can be fatal.
• Coal workers' pneumoconiosis:
• Tuberculosis.
• Rheumatoid arthritis.
• Siderosis: increases the risk of developing neoplasms (tumors, which can be malignant).
• Asbestosis: causes damage to the pleura, the tissue that lines the lungs and the inside of the chest cavity.
• Pleural mesothelioma, due to the development of pleural plaques. It is a rare but highly aggressive and fatal cancer.
• Bronchogenic carcinoma, a cancer affecting the trachea or bronchi.
• Cor pulmonale, caused by respiratory failure, resulting in right ventricular hypertrophy and subsequent heart failure.
• Berylliosis:
• Cor pulmonale.
• Myocarditis (inflammation of the heart muscle).
• Kidney stones due to the systemic effects of the disease, which causes granulomas in the lungs, lymph nodes, skin, and other organs.

Prevention

The only effective way to prevent occupational pneumoconiosis is by using appropriate personal protective equipment and clothing to handle such substances, implementing ventilation and extraction systems, and maintaining medical surveillance for workers exposed throughout their entire working life and after employment ends, to facilitate early disease detection.

What doctor treats pneumoconiosis?

Pneumoconiosis is evaluated and treated in pneumology and occupational medicine units.