Respiratory - Interstitial lung disease Flashcards
What is interstitial lung disease?
An umbrella term used to describe conditions that affect the lung parenchyma causing inflammation and fibrosis
What is fibrosis?
Normal lung tissue replaced by scarred tissue that is stiff and doesn’t function effectively
General management for interstitial lung disease
Remove/treat underlying cause
Home oxygen if hypoxic at rest
Smoking cessation
Physiotherapy and pulmonary rehabilitation
Pneumococcal and flu vaccine
Advanced care planning and palliative care where appropriate
Lung transplant is an option but the risks and benefits need careful consideration
What are the three broad classes of interstitial lung disease/ pulmonary fibrosis? Plus three others?
Idiopathic
Drug-induced
Secondary
But also:
- Hypersensitivity pneumonitis
- Cryptogenic organising pneumonia
- Asbestosis
What is idiopathic pulmonary fibrosis?
Progressive pulmonary fibrosis with no clear cause
How does idiopathic pulmonary fibrosis present?
Insidious onset SOB and dry cough
Typically affects adults over 50
Examination - bibasal fine inspiratory crackles and finger clubbing
Poor prognosis 2-5 years from diagnosis
What can slow the progression of idiopathic pulmonary fibrosis?
Pirfenidone - antifibrotic and anti-inflammatory
Nintedanib - monoclonal antibody targeting tyrosine kinase
What medications can cause pulmonary fibrosis?
Amiodarone
Cyclophosphamide
Methotrexate
Nitrofurantoin
What conditions can pulmonary fibrosis occur secondary to?
Alpha-1-antitryspin deficiency
Rheumatoid arthritis
SLE
Systemic sclerosis
What is Hypersensitivity Pneumonitis (AKA Extrinsic Allergic Alveolitis)?
A type 3 hypersensitivity reaction to an environmental allergen
Causes parenchymal inflammation and destruction
Investigations in suspected extrinsic allergic alveolitis?
CXR - upper/mid zone fibrosis
Bronchoalveolar lavage - involves collecting cells from the airways during bronchoscopy by washing the airways with fluid then collecting that fluid for testing.
- Would show raised lymphocytes and mast cells
Blood tests - no eosinophilia
Specific causes of extrinsic allergic alveolitis/hypersensitivity pneumonitis?
Bird-fanciers lung is a reaction to bird droppings
Farmers lung is a reaction to mouldy spores in hay
Mushroom workers’ lung is a reaction to specific mushroom antigens
Malt workers lung is a reaction to mould on barley
Management of hypersensitivity pneumonitis
Removal of the allergen
Oxygen as needed
Steroids
What is Cryptogenic Organising Pneumonia?
It involves a focal area of inflammation of the lung tissue.
This can be idiopathic or triggered by infection, inflammatory disorders, medications, radiation or environmental toxins or allergens.
Very similar to infectious pneumonia in presentation and CXR findings so diagnosis often delayed
What are the investigations and treatments for Cryptogenic Organising Pneumonia?
Lung biopsy is the definitive investigation
Treatment is with systemic corticosteroids
