Fibrotic lung disease

Question 1

What is fibrotic lung disease?

Answer 1

a.k.a interstitial lung disease
- An inflammatory condition of the lung resulting in fibrosis of the alveoli and interstitial.
- Excess collagen in connective and interstitial tissue causing thickening.

Question 2

What are the different causes of fibrotic lung disease?

Answer 2

1. Drugs:
   - Amiodarone (anti-arrhythmic- slows nerve impulses in the heart)
   - Nitrofurantoin (AB used for UTI’s)
   - Sulfasalazine (lowers inflammation, IBD/ RA)
2. Hypersensitivity:
   - Extrinsic allergic alveolitis (extreme reaction to outer substance= inflammation of alveoli)
   - Silicosis (lung disease caused by breathing in tiny bits of silica)
   - Abestosis (disease caused by inhaling asbestos fibers)
3. Associations:
   - Sarcoidosis (small patches of swollen tissue, called granulomas, commonly in the lungs)
   - Rheumatoid arthritis
   - SLE
   - Ankylosing Spondylitis
4. Idiopathic:
   - Idiopathic pulmonary fibrosis

Question 3

What are the risk factors for fibrotic lung disease?

Answer 3

• Family history 
• Smoking 
• Advanced age 
• Occupational exposure to metal or wood
• Male 
• (weak risk factor = organic and inorganic dust exposure) 

Question 4

What is Idiopathic pulmonary fibrosis?

Answer 4

• most common type of ILD.
• When there is no other identifiable cause.
• Affects mostly men 50-70 years old.

Question 5

What is Extrinsic Allergic Alveolitis?

Answer 5

• Can occur in people with chronic exposure to bird droppings.
• Condition caused by hypersensitivity induced lung damage due to a variety of inhaled organic particles.
• Type III hypersensitivity reaction.

Question 6

What is Coal Worker’s Pneumoconiosis?

Answer 6

• Occupational lung disease caused by long term exposure to coal dust particles.
• Most commonly experienced by people in coal mining industry.
• Typically asymptomatic, however may lead to progressive massive fibrosis which is symptomatic.
• Causes upper zone fibrosis.

Question 7

What are the 2 ways to classify fibrotic lung diseases? what are some examples of both?

Answer 7

1. Upper Zone Fibrosis:
   - CHARTS ⇒ coal workers pneumoconiosis, histiocytosis/hypersensitivity pnuemonitis, ankylosing spondylitis, radiation, TB, sarcoidosis/silicosis
2. Lower Zone Fibrosis:
   - DIAL ⇒ drugs (methotrexate, nitrofurantoin, amiodarone), idiopathic, asbestosis, lupus

Question 8

What are the presenting symptoms/ signs of fibrotic lung diseases?

Answer 8

• Progressive Dyspnoea → initally exertional dyspnoea, that progresses to dyspnoea at rest
• Chronic Dry Cough
• Bibasal fine-end inspiratory crackles on auscultation
• Digital Clubbing
• Fatigue

Question 9

What investigations are used to diagnose/ monitor fibrotic lung disease?

Answer 9

1. Spirometry → restrictive lung disease pattern (reduced FEV1, significantly reduced FVC, increased FEV1/FVC ratio >0.7)
   - Reduced TLCO
2. CT Scan (Ix of choice to make diagnosis of IPF) → honeycombing (multiple cystic lesions within the lung parenchyma due to fibrosis, ‘ground glass’ appearance)
3. CXR (IPF) → bilateral lower zone reticulo-nodular shadowing

Question 10

How is fibrotic lung disease managed?

Answer 10

1. Supportive Care → oxygen therapy, pulmonary rehabilitation, vaccinations (influenza and pneumococcal vaccines)
2. Pirfenidone → antifibrotic agent that may slow disease progression in Idiopathic Pulmonary Fibrosis
3. Lung Transplantation → indicated in end-stage ILD. Only definitive treatment available.