Asbestos-related lung disease (RESP)

Question 1

What is asbestos-related lung disease?

Answer 1

Restrictive interstitial lung disease with symptoms caused by fibrotic changes in the lungs

Question 2

What is asbestosis?

Answer 2

Type of pneumoconiosis that presents as diffuse interstitial fibrosis of the lung following exposure to asbestos fibres

Question 3

When does asbestosis occur?

Answer 3

Typically 5-10 years after heavy exposure
Latent period typically 15-30 years

Question 4

When is asbestos-related lung disease called asbestosis?

Answer 4

• when it has led to interstitial lung disease
• if there are just plaques, it is not called asbestosis

Question 5

Describe the aetiology of asbestos-related lung disease (low yield).

Answer 5

• asbestos was commonly used in building trade (shipyard workers) and exposure results in diffuse parenchymal fibrosis after macrophage cytotoxicity, with the degree of exposure relating to degree of pulmonary fibrosis
• inflammation gradually causes mesothelial plaques in pleura which increases risk of bronchial adenocarcinoma and mesothelioma
• mesotheliom is a thin epithelium that lines several body cavities including pleura, peritoneum, mediastinum and pericardium

Question 6

What lung changes can asbestos-related lung disease cause? (5)

Answer 6

• pleural plaques
• pleural thickening
• asbestosis
• mesothelioma
• lung cancer

Question 7

What are pleural plaques in asbestos-related lung disease?

Answer 7

• pleural plaques are benign and do not undergo malignant change
• do not require any follow-up
• most common form of asbestos-related lung disease and generally occur after latent period of 20-40 years

Question 8

What is pleural thickening in asbestos-related lung disease?

Answer 8

• asbestos exposure may cause diffuse pleural thickening in a similar pattern to that in empyema or haemothorax
• underlying pathophysiology not fully understood

Question 9

What is the severity of asbestosis related to?

Answer 9

The length of asbestos exposure

Question 10

What does asbestosis typically cause?

Answer 10

Lower lobe fibrosis

Question 11

What are some features of asbestosis? (5)

Answer 11

• dyspnoea/SOB
• reduced exercise tolerance
• clubbing
• bilateral end-inspiratory crackles
• PFTs show restrictive pattern with reduced gas transfer

Question 12

How is asbestosis managed?

Answer 12

Treated conservatively - no interventions offer a significant benefit

Question 13

What is mesothelioma (asbestos-related lung disease)?

Answer 13

Malignant disease of the pleura

Question 14

What are some clinical features of mesothelioma? (3)

Answer 14

• progressive SOB
• chest pain
• pleural effusion

Question 15

How do we manage mesothelioma?

Answer 15

Patients usually offered palliative chemotherapy - poor prognosis with median survival 8-14 months from diagnosis

Question 16

What form of cancer is most commonly associated with asbestos exposure?

Answer 16

• whilst mesothelioma is in some ways synonymous with asbestos, lung cancer is most common form
• also has a synergistic effect with cigarette smoke increasing risk
• smoking cessation is very important as risk of lung cancer in smokers with Hx of asbestos exposure is very high

Question 17

Which part of the lung is most commonly affected in asbestos-related lung disease?

Answer 17

Pleura

Asbestosis –> lower lobe fibrosis

Question 18

What are the three types of asbestos, and how fibrogenic are they?

Answer 18

• chrysotile (white, least fibrogenic)
• crocidolite (blue, most fibrogenic)
• amosite (brown, intermediate fibrogenecity)

Question 19

What are the clinical features of asbestos-related lung disease? (5)

Answer 19

• dyspnoea on exertion (progressive)
• dry cough - progresses to productive cough
• chest pain - dull, diffuse, pleuritic
• red flags e.g. weight loss, fatigue, fever, night sweats, bone pain, abdominal pain, bloody sputum (if tumour invades blood vessel)
• digital clubbing

Question 20

What is the typical latent period for asbestos-related lung disease?

Answer 20

Most patients asymptomatic 15-20 years after exposure to asbestos

Question 21

What if you see FLAWS + haemoptysis in asbestos-related lung disease?

Answer 21

Malignancy

FLAWS = Fever, Lethargy, Appetite loss/anaemia, Weight loss, Sweats

Question 22

What might be seen on examination in asbestos-related lung disease? (4 + 7)

Answer 22

• clubbing
• fine end-inspiratory crackles
• pleural effusion or RHF
• red flags - palpable chest wall mass, recurrent pleural effusions, lymphadenopathy, hepatomegaly, bone tenderness, abdo pain/obstruction, pneumothorax

Question 23

What are some risk factors for asbestos-related lung disease? (2)

Answer 23

• cumulative dose of inhaled asbestos - occupations involving manufacture; demolition of ships; plumbing; roofing; insulation
• cigarette smoking

Question 24

What are the 1st-line (and other) investigations for asbestos-related lung disease? (2 + 3)

Answer 24

• CXR - PA and lateral
• pulmonary function tests
• (HRCT)
• (lung biopsy for malignancy)
• (bronchial lavage - presence of asbestos bodies)

Question 25

What would you see on CXR in asbestos-related lung disease? (5)

Answer 25

• lower zone linear interstitial fibrosis (progressively involves entire lung)
• pleural thickening
• reticular nodular shadowing +/- pleural plaques
• ground-glass opacification (fibrosis)
• mesothelioma / lung cancer

Question 26

What might you see on HRCT in asbestos-related lung disease? (3)

Answer 26

• pleural thickening
• pleural plaques
• fibrotic changes

Question 27

What do we see on pulmonary function tests in asbestos-related lung disease?

Answer 27

Restrictive pattern

Question 28

In acute asbestos-related lung disease, what would we see on ABG?

Answer 28

Type 1 respiratory failure (hypoxaemia with normocapnia)

Question 29

What are some differential diagnoses for asbestos-related lung disease? (7)

Answer 29

• other types of pneumoconiosis (coal workers’, silicosis - dry cough, black sputum)
• idiopathic pulmonary fibrosis
• connective tissue disease
• hypersensitivity pneumonitis
• hard metal lung disease
• sarcoidosis
• medication/radiation-related pulmonary fibrosis (amiodarone, nitrofurantoin, methotrexate, bleomycin, cyclophosphamide)

Question 30

How do we diagnose asbestos-related lung disease? (3)

Answer 30

• CXR changes
• occupational Hx
• exclusion of other differentials

Question 31

What is the general management plan for asbestos-related lung disease? (4)

Answer 31

• no curative treatment
• oxygen therapy
• immunisation against influenza and pneumococcal pneumonia
• smoking cessation

Question 32

How do we manage pleural plaques in asbestos-related lung disease?

Answer 32

Do nothing - they are benign and do not require follow up

Question 33

How do we manage asbestosis? (6)

Answer 33

• smoking cessation
• pulmonary rehabilitation
• oxygen therapy
• lung transplant (end-stage respiratory failure)
• pleural decortication (extreme diffuse pleural thickening)
• immunisation against pneumococcal pneumonia and influenza

Question 34

What biomarker can distinguish individuals with asbestosis from mesothelioma?

Answer 34

Fibulin-3 (not recommended for screening)

Question 35

How do we manage asbestos-related cancer?

Answer 35

Operable disease:

• extra-pleural pneumonectomy / pleurectomy with decortication
• pre/post-operative radiotherapy (with cisplatin, pemetrexed, cyanocobalamin + folic acid)
• post-extrapleural pneumonectomy radiotherapy

Recurrent/incurable disease:

• chemotherapy (cisplatin/carboplatin, pemetrexed, cyanocobalamin + folic acid)
• bevacizumab
• radiotherapy
• palliative care (therapeutic thoracentesis and pleurodesis)

Question 36

What are some complications of asbestos-related lung disease? (5)

Answer 36

• cor pulmonale - due to pulmonary hypertension
• lung cancer
• mesothelioma - mets to lung, hilar lymph nodes, other pleural spaces
• colon cancer
• laryngeal cancer

Question 37

What is the main complication of asbestos-related lung disease?

Answer 37

Mesothelioma (malignant tumour of mesothelial cells of pleura) 20-40 years after exposure

• dry chronic cough
• SOB
• chest pain
• weight loss

Question 38

How can we investigate mesothelioma? (5)

Answer 38

• pleural tap
• thoracoscopy - preferred over bronchoscopy as peripherally located
• histology for diagnosis
• if pleural effusion - send for MC&S, biochemistry and cytology
• CXR - pleural effusion, pleural thickening, mass along pleura