Pneumoconiosis

Question 1

What is pneumoconiosis?

Answer 1

The pneumoconioses are a group of interstitial lung diseases, mostly of occupational origin, caused by the inhalation of mineral or metal dusts.

Question 2

What are the main types of pneumoconiosis?

Answer 2

The pneumoconioses are chronic lung diseases caused by exposure to a mineral dust or metal

• Asbestosis
• Silicosis
• Coal workers’ pneumoconiosis (black lung disease)
• Chronic beryllium disease

Many are less common, and are benign, with chest x-ray (CXR) changes but without respiratory impairment

• Aluminosis
• Baritosis
• Graphite pneumoconiosis
• Oil shale pneumoconiosis
• Siderosis
• Stannosis
• Talcosis

Question 3

What is the aetiology of pneumoconiosis?

Answer 3

The cause of the pneumoconioses is the inhalation of the mineral or metal

• Silica
• Coal
• Beryllium (used to make alloys or ceramics)

Question 4

Name some risk factors for pneumoconiosis?

Answer 4

• Occupational exposure to silica, coal, or beryllium
  
  • latency period of 10-20yrs post-inhalation
• high cumulative dose of inhaled silica or coal
• Cigarette smoking
  
  • associated with development of obstructive pulmonary changes on pulmonary function testing in people exposed to coal and silica
• Genetics:
  
  • presence of glutamic acid at position 69 of the HLA-DP1 beta chain is strongly associated with chronic beryllium disease.

Question 5

Summarise the epidemiology of pneumoconiosis?

Answer 5

• The average number of deaths from silicosis in the US is just over 100 per year.
• The incidence of silicosis appears to be decreasing in Great Britain and the United States
• Although the number of deaths has been decreasing, the prevalence of coal workers’ pneumoconiosis, advanced coal workers’ pneumoconiosis, and lung transplants for coal workers’ pneumoconiosis has been increasing in the US since the 1990s
• These data are not available for chronic beryllium disease
• With the development of a blood test to determine sensitisation to beryllium in the 1980s, there has been increased recognition of the condition

Question 6

What are the presenting symptoms of pneumoconiosis??

Answer 6

• dyspnoea on exertion
  
  • Typically the first sign of pneumoconiosis.
  • increases with progression
• cough
  
  • Dry, non-productive; frequency increases with progression.
  • not always seen in early disease
  • A productive cough may be seen if the patient has also developed COPD as a complication.

uncommon

• chest tightness and/or wheezing
  
  • May be present in silica- and coal-exposed workers who have developed COPD.
• haemoptysis, fever, or night sweats
  
  • Symptoms of pulmonary TB
  • which is a complication of silica exposure
• weight loss
  
  • ​As with other respiratory diseases, as the disease progresses the patient may be cyanotic, develop a barrel chest, and have weight loss.
  • May occur with pulmonary TB, which may occur in silica-exposed workers
• signs of rheumatoid arthritis or scleroderma
  
  • complications of silica or coal exposure
  • =Raynaud’s phenomenon, joint tenderness and swelling, skin changes, sclerodactyly [with scleroderma] )
• signs of renal failure (e.g., weight gain, oedema, hypertension)
  
  • ​The complication of renal failure may be the presenting condition.

Question 7

What can an acute form of berylliosis present as?

Answer 7

may present as pneumonitis:

• acute wheezing
• chest tightness
• shortness of breath

Question 8

What are the signs of pneumoconiosis O/E?

Answer 8

• normal respiratory examination O/A
  
  • in early disease
• crackles O/A
  • May be heard in people with chronic beryllium disease.
• prolonged expiration and wheezing on chest auscultation
  
  • May be present in silica- and coal-exposed workers who have also developed COPD.
  • Chest auscultation will be normal early in these diseases.
• areas of dullness on chest percussion
  
  • ​May occur with progressive massive fibrosis (in coal- or silica-exposed people).
• cyanosis (low O2 sats)
  
  • ​As with other respiratory diseases, as the disease progresses
• barrel chest
  • ​​As with other respiratory diseases, as the disease progresses
• clubbing
  
  • ​Only found in advanced pneumoconiosis.
  • Not specific to pneumoconiosis

Question 9

What are some primary investigations for ?pneumoconiosis?

Answer 9

• CXR (posteroanterior and lateral)
  
  • ​Less sensitive than high-resolution CT (HRCT) scan
  • more specific than pulmonary function testing
  • presence of non-calcified, multiple (in the hundreds), rounded opacities in the upper zones is highly suggestive of silicosis or coal workers’ pneumoconiosis.
  • Progressively involves all lung zones, and may conglomerate to form large opacities. With advanced conglomeration, there may be distortion of lung and heart shape, and a thin layer of calcification around hilar lymph nodes (‘egg shell calcification’).
  • opacitiies seen in chronic beryllium disease are linear, rounded opacities have been described
• spirometry
  
  • ​Non-specific test.
  • Useful to determine severity and pharmacological treatment
  • Indicated in all patients with radiographic changes; significant silica, coal, or beryllium exposure; or shortness of breath
  • may be normal or demonstrate restrictive changes; may show obstructive or mixed pattern
  • Restrictive pattern: reduced FVC, normal FEV1/FVC ratio, reduced slow vital capacity, reduced total lung capacity (TLC), reduced lung diffusion capacity testing (DLCO).
  • Obstructive changes: reduced FEV1, reduced FEV1/FVC ratio, increased residual volume/TLC ratio, reduced DLCO.
  • The risk of obstructive changes is increased in patients who have a history of mineral dust exposure and cigarette smoking
  • Reduced DLCO is the most sensitive pulmonary function change.
• beryllium lymphocyte proliferation test (BeLPT)
  
  • Essential component of the diagnosis of chronic beryllium disease.
  • Sensitive test that identifies individuals sensitised to beryllium
  • Typically performed on a blood sample first, and confirmed with a repeat test.
  • = if sensitised to beryllium: positive response

Question 10

What are some possible secondary investigations for ?pneumoconiosis?

Answer 10

• bronchoscopic biopsy and/or lavage
  
  • A routine part of the diagnostic work-up for chronic beryllium disease.
  • = chronic beryllium disease: granulomas present
• high-resolution CT (HRCT) scan chest
  
  • ​more sensitive than CXR in identifying interstitial fibrosis
  • Should be performed if the patient has shortness of breath not explained by the CXR or pulmonary function test results.
  • Because of issues of cost, not typically performed in asymptomatic individuals if the CXR and pulmonary function tests are normal.
  • = upper zone interstitial fibrosis; progressively involves the entire lung
• oxygen saturation
  
  • ​= may be reduced
• arterial blood gases (ABG)
  
  • ​rarely performed
  • = may be a reduced pO2; in presence of COPD, may be an elevated pCO2
• open lung biopsy
  
  • Rarely needed for diagnosis. Its use should be limited to when cancer is suspected, or when there is an absence of a known history of exposure to mineral dust.
  • = variable findings
• tuberculin skin test
  
  • ​Individuals with silicosis should be tested for TB
  • = positive if TB is present
• interferon gamma-release assay (IGRA)
  
  • ​Individuals with silicosis should be tested for TB
  • = if TB present: may be positive
• sputum smear and culture
  
  • ​Individuals with silicosis should be tested for TB.
  • If skin or blood tests are positive, or if the patient has systemic symptoms of fever, malaise, and haemoptysis, then sputum microscopy and culture for TB and atypical mycobacteria need to be checked.
  • = if TB present: positive for acid-fast bacilli