Silicosis Clinical Presentation

Updated: Dec 05, 2019
  • Author: Bathmapriya Balakrishnan, MBBS, BMedSc(Melb); Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Presentation

History

In obtaining a detailed occupational history for suspected silicosis and other pneumoconioses, note chronologically the periods of exposure, the type of work exposure, any respiratory protective devices used, and whether other people working in the same environment have any similar symptoms or disease.

Silicosis is typically divided into three distinct forms characterized by the duration of occupational exposure. [1, 2, 8]  

Acute silicosis

Acute silicosis, also known as silicopronteinosis, is typically associated with high-intensity exposure. Patients present within weeks up to 5 years from the initial insult. Specific occupations have been associated with acute silicosis, including silica flour processing, tombstone sandblasting, and surface drilling. The dose of exposure required to develop acute silicosis is poorly studied but thought to be in the order of 1-10 mg/m3/year. [36]

Presenting complaints include dyspnea, fatigue, weight loss, fever, and pleuritic pain. Clinical progression is often dramatic, with rapid progression to respiratory failure due to a decline in gas exchange and pulmonary function.

Accelarated silicosis

Accelerated silicosis develops within 10 years of moderate to high-level exposure. Disease progression may occur despite removal of the silica exposure. Accelerated silicosis is associated with autoimmune disorders. [9]

Chronic silicosis

Chronic silicosis occurs after 10 years or more following low- to moderate-level exposure. Patients either present with simple (nodular) silicosis or progressive massive fibrosis (PMF). Patients with simple silicosis can be asymptomatic, whereas those with PMF may have symptoms and signs of chronic respiratory failure. There is typically a long latency period for simple silicosis, in which most symptoms manifest after leaving the employment where exposure occurred. [12]

Simple silicosis is characterized radiologically by the presence of nodules (size < 1 cm), usually predominant in the upper lobes. Some case series report up to 70% of patients having symptoms of dyspnea, chronic cough, and sputum production. [37]

Silicotic nodules may coalesce to form conglomerate fibrotic masses (>1 cm), leading to the development of PMF. Central cavitation may occur, leading to complications like mycobacterial infections.

Mediastinal and hilar lymphadenopathy may be seen in up to 75% of patients with silicosis. Fibrosis and lung scarring lead to distortion of lung architecture and peribronchial vessels, resulting in pneumothoraces, pulmonary hypertension, and cor pulmonale. Pleural thickening may also be seen. [38]

Silicotic patients also develop airway diseases like asthma and chronic obstructive airway disease (COPD). Symptoms such as wheezing, exertional dyspnea and cough predominate.

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Physical Examination

The symptoms and signs of chronic silicosis may be minimal. The main symptom is breathlessness, but in chronic silicosis, in the absence of other respiratory disease, even this symptom may be absent. In a small French observational study, the finger clubbing was noted in three patients and two patients had rales and crepitations on auscultation. [39] Four patients also had general debility with weight loss. Note that clubbing is typically not a feature associated with silicosis and should raise concern for lung cancer. [39]

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