Asbestosis

Asbestosis is a chronic lung disease caused by the inhalation and retention of asbestos fibres, leading to long-term inflammation and scarring of lung tissue.

This condition primarily affects individuals with significant exposure to asbestos, typically those who have worked in industries using this material. Asbestosis is a form of pneumoconiosis and is classified under interstitial pulmonary fibrosis.

Signs and Symptoms

The clinical presentation of asbestosis often manifests decades after the initial exposure. The primary symptom is a gradual onset of shortness of breath, especially during physical exertion. Other symptoms include a persistent cough, wheezing, and chest tightness. Advanced cases may progress to respiratory failure. During a physical examination, inspiratory crackles can often be heard with a stethoscope.

Pulmonary function tests typically reveal a restrictive ventilatory defect, characterised by reduced lung volumes such as essential capacity (VC) and total lung capacity (TLC). Severe reductions in TLC can lead to right-sided heart failure (cor pulmonale). Additionally, there may be a decrease in diffusion capacity and arterial oxygen levels.

Cause and Risk Factors

The inhalation of microscopic asbestos fibres is the primary cause of asbestosis. The risk is significantly higher for individuals who worked in industries such as asbestos mining, construction, and automotive repair before the late 1970s. The risk also extends to families of exposed workers through secondary exposure from asbestos fibres carried on clothing and hair.

Pathogenesis

Asbestosis involves the scarring of lung tissue starting around the terminal bronchioles and extending into the alveolar walls. Both amphibole (thin and straight) and serpentine (curly) fibres can penetrate deep into the lungs, causing an inflammatory response. Macrophages ingest the fibres and release signals that stimulate fibroblasts to produce scar tissue. This fibrosis thickens alveolar walls, reducing lung elasticity and impairing gas exchange, leading to symptoms such as shortness of breath.

Diagnosis

Diagnosis is based on a history of asbestos exposure and imaging studies. Chest X-rays often reveal irregular parenchymal opacities, mainly in the lung bases. CT or high-resolution CT scans are more sensitive in detecting pulmonary fibrosis and pleural changes. The presence of pleural plaques supports the diagnosis. Lung biopsy, showing asbestos bodies in association with fibrosis, can confirm the diagnosis, though it is not always necessary.

Treatment

There is no cure for asbestosis. Management focuses on supportive care, including oxygen therapy to alleviate shortness of breath and correct hypoxaemia. Respiratory physiotherapy helps clear lung secretions. Patients are advised to receive pneumococcal and influenza vaccinations due to their increased susceptibility to these infections. Smoking cessation is very important to prevent further lung damage. Regular follow-ups with pulmonary function tests, chest X-rays, and clinical evaluations, including cancer screenings, are recommended.

Legal and Historical Context

The link between asbestos exposure and lung disease was first noted in the early 20th century. Notably, the death of Nellie Kershaw in 1924 from asbestosis spurred recognition of the disease and led to the Asbestos Industry Regulations of 1931 in the UK. Numerous lawsuits have since been filed against asbestos manufacturers for neglecting safety measures, resulting in significant financial liabilities and the establishment of asbestos personal injury trusts.

Notable individuals who have succumbed to asbestos-related diseases include actor Steve McQueen and social justice advocate Bernie Banton.

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Self-assessment MCQs (single best answer)

What is the primary cause of asbestosis?

Which of the following industries is NOT commonly associated with a higher risk of asbestosis?

What is the primary symptom of asbestosis?

During a physical examination, what sound might be heard in a patient with asbestosis?

Which imaging technique is more sensitive in detecting pulmonary fibrosis and pleural changes in asbestosis?

Which of the following is NOT a common management strategy for asbestosis?

Asbestosis is a form of which broader category of lung diseases?

What histological feature is characteristic of asbestosis?

Which legal regulation was established in the UK in response to the recognition of asbestosis?

Which of the following notable individuals succumbed to asbestos-related diseases?