Resp - ILD

Question 1

what is ILD? what is the pathophysiology?

Answer 1

Diverse group of lung diseases affecting the interstitium around alveoli, which may result in pulmonary fibrosis if prolonged. Depending on aetiology, disease may be more inflammatory (cryptogenic organising pneumonia), more fibrotic (UIP) or mixed (non-specific intersitial pneumonitis).

Macrophages release TNFa and TGFb… fibroblast recruitment and collagen deposition in intersitium (fibrosis)… traction atelectasis, pulmonary restriction and poor gas echange… decreased TLC and VC, and hypoxia.

Question 2

name the common causes of ILD

Answer 2

1. Idiopathic pulmonary fibrosis (most common, esp. in elderly)
2. Sarcoidosis (most common in young)
3. Drug-induced: methotrexate, amiodarone, nitrofurantoin
4. Environmental exposure: asbestosis, silicosis, coal worker’s pneumoconiosis, extrinsic allergic alveolitis
5. Connective tissue disease: RA, SLE (autoimmune-mediated inflammation)

Question 3

Describe the symptoms and signs seen in ILD/pulmonary fibrosis

Answer 3

Symptoms:

• progressive exertional SOB
• dry cough
• fatigue

Signs:

• clubbing
• fine, late inspiratory crackles
• hypoxia/cyanosis (late disease)

Question 4

Which investigations would you require in a pt with suspected ILD?

Answer 4

1. Bloods: ANA, ENA, RhF, ANCA, anti-GBM, ACE, anti-CCP
2. Lung function tests:
   - spirometry
   - gas transfer
   - 6min walk test (SaO2)
3. Imaging:
   - CXR
   - HRCT
4. Other:
   - bronchoalveolar lavage
   - cryobiopsy

Question 5

which findings on CXR and HRCT suggest UIP-IPF?

Answer 5

CXR: basal reticular patterns/shadowing +/- small irregular opacities/cysts +/- traction bronciectasis

HRCT:

• honeycombing cysts
• reticular septal thickening
• ground glass appearance
• traction bronchiectasis

Question 6

how would you treat a pt with IPF?

Answer 6

1. Supportive: physiotherapy, regular exercise, weight control, smoking cessation, O2 therapy (if sig. resting hypoxaemia)
2. Medical therapy to slow disease progression:
   - PIRFENIDONE - ?anti-TGFb, anti-fibrotic properties
   - NINTEDANIB - anti-TNFa, anti-fibrotic properties
3. Lung transplant - may be considered for young pts who fail to respond to medication (no GORD)