Related articles: Silicosis
Definition
Silicosis is a pneumopathy caused by the inhalation of dust containing silica.
This condition is one of the professional pathologies; the workers most at risk are those involved in the production of glass and ceramics, miners and workers in stone quarries.
At the base of silicosis there is an exposure to free silica or silicon dioxide in the crystalline state.
The development of a silicosis depends on the duration and intensity of the exposure to the silica particles and on the possibility of the same to reach the alveoli (correlated to the size and respirable fraction of the dust). The risk increases in the presence of individual factors, such as pre-existing airway infections and insufficient filtration of the air inhaled through the nose.
Silicosis is characterized by a pathological process that leads to nodular pulmonary fibrosis. Following inhalation, the finest silica particles can reach the pulmonary alveoli and exert a damaging effect on them. Here, in fact, alveolar macrophages engulf the crystals and trigger the release of inflammatory mediators. When the macrophages that have incorporated the silica die, they release the particles in the tissue that surrounds the small bronchioles, further stimulating the inflammation of the lung parenchyma; in the long run, the persistence of the inflammatory process leads to the formation of nodular cicatricial lesions (fibrotics), called silicotic nodules.
The silicotic nodule has the appearance of a dense round mass: a central area of hyaline necrosis is surrounded by fibrotic scar tissue and an outer layer of inflammatory cells (macrophages, lymphocytes, granulocytes, etc.). In the early stages, these nodules remain isolated and do not compromise respiratory function. Over time, however, their confluence can lead to progressive fibrosis, which distorts the normal structure of the lung. Silicosis, therefore, can develop into respiratory failure, pulmonary hypertension and heart failure.
Most common symptoms and signs *
- Anorexia
- Arrhythmia
- Asthenia
- palpitations
- Catarrh
- Cyanosis
- Dyspnoea
- Chest pain
- Temperature
- Shortness of breath
- Hypoxia
- Mediastinitis
- Multiple pulmonary nodules
- orthopnea
- Weight loss
- pneumothorax
- Wheezing breath
- Reduction of respiratory noise
- tachypnoea
- Cough
Further indications
Silicosis generally develops only after several years of exposure to silica dust (chronic silicosis). Acute silicosis, on the other hand, is rarer and starts after intense exposure for short periods (some months or years).
The acute forms of the disease are characterized by sudden wheezing and rapid progression. Fever, weight loss and fatigue may appear. Often, respiratory failure develops within a few months and can lead to death.
Chronic silicosis, on the other hand, initially causes no symptoms or causes only mild exertional dyspnea. However, over the years, the condition can progress to involve most of the lung and cause marked respiratory difficulties, cough, hypoxemia, pulmonary hypertension and respiratory failure (whether or not associated with right ventricular failure).
Possible complications of silicosis include emphysema, spontaneous pneumothorax, broncholithiasis and tracheobronchial obstruction. Silicosis involves an increased predisposition to bronchopulmonary infections and a high risk of developing tuberculosis, progressive systemic sclerosis and lung cancer.
The diagnosis is based on the anamnesis and chest radiograph report. Complementary examinations include lung biopsy and bronchoalveolar lavage. Pulmonary function tests and blood gas analysis help monitor disease progression.
Silicosis therapy is supportive and involves the use of bronchodilators, anticholinergics and corticosteroids. For severe cases, lung transplantation may be indicated.
Workers who develop silicosis must avoid further exposure.
