Asbestos- related lung disease Flashcards
What is meant by asbestos- related lung disease?
asbestosis and mesothelioma:
● Both are industrial dust diseases
● Asbestosis: long-term inflammation and scarring of the lungs caused by inhalation of asbestos fibres
● Mesothelioma: aggressive tumour of mesothelial cells that usually occurs in the pleura (90%), and sometimes in peritoneum, pericardium or testes.
Note – the mesothelium is a thin epithelium that lines several body cavities including the pleura, peritoneum, mediastinum and pericardium
What causes asbestosis?
⇒ There are three different types of asbestos
Chrysotile (white asbestos) is the least fibrogenic.
Crocidolite (blue asbestos) is the most fibrogenic.
Amosite (brown asbestos) has intermediate fibrogenicity.
⇒ Asbestos was commonly used in the building trade hence always ask about OCCUPATION in resp history – commonly in shipyard workers!
⇒ Degree of asbestos exposure is related to degree of pulmonary fibrosis.
⇒ Inflammation gradually causes mesothelial plaques in the pleura
⇒ Causes increased risk of bronchial adenocarcinoma and mesothelioma
What causes mesothelioma?
⇒ It is associated with occupational exposure to asbestos but the relationship is complex.
⇒ 90% report previous exposure to asbestos, but only 20% of patients have pulmonary asbestosis. The latent period between exposure and development of tumour can be up to 45 years.
⇒ Malignant pleural mesothelioma rarely spreads to distant sites but most patients present with locally advanced disease.
Summarise the epidemiology of asbestos-related lung disease ?
● Mesothelioma is rare – more common in elderly
● Asbestos exposure is documented in 90% of cases
● Latent period between exposure and mesothelioma = up to 50 yrs
What are the presenting symptoms of asbestos- related lung disease?
- Asbestosis:
o Progressive dyspnoea- typically exertional - Mesothelioma:
o Most common symptoms: SOB, Chest pain (dull, diffuse, developing), weight loss
o Fatigue
o Fever
o Night sweats
o Bone pain
o Abdominal pain
o Sometimes, bloody sputum – if tumour invades blood vessel
What signs of asbestos-related lung disease can be found on physical examination?
- Asbestosis:
o Clubbing,
o Fine end-inspiratory crackles - Mesothelioma:
o Occasional palpable chest wall mass
o Finger clubbing – due to underlying asbestosis (pulmonary fibrosis)
o Recurrent pleural effusions
o Signs of metastases: Lymphadenopathy, Hepatomegaly, bone tenderness
o Abdominal pain/obstruction (peritoneal malignant mesothelioma)
o Can rarely cause pneumothorax
What investigations are used to diagnose/ manage asbestos-related lung disease?
- Asbestosis: history and exam
o CXR: reticular-nodular shadowing +/- pleural plaques - Mesothelioma:
o CXR/CT: pleural thickening/effusion. Bloody pleural fluid. May show pleural mass and rib destruction
o MRI and PET
o Pleural fluid: can be sent for cytological analysis and may be blood stained
o Pleural biopsy
o Diagnosis is made on histology, usually following a thoracoscopy (pleural biopsy) – often done post-mortem
Biopsy of the tumour can be immunostained with a stain that reacts with CALRETININ
How is asbestos-related lung disease managed?
- Oxygen Therapy
- Immunization against influenza & pneumococcal pneumonia
What complications may arise from asbestos-related lung disease?
Mesothelioma (malignant tumour secondary to asbestos exposure)
- Malignant tumour of mesothelial cells of the pleura. Occurs 20-40 years after exposure.
- Ix ⇒ can do pleural tap. Thoracoscopy (preferred over bronchoscopy as peripherally located) and Histology for diagnosis.
-Presents with dry chronic cough, SOB, chest pain and weight loss
- May see pleural effusion or pleural thickening on CXR (may raise initial suspicion). If pleural effusion is present, fluid should be sent for MC&S, biochemistry and cytology.
- CXR will also show mass along the pleura
