Interstitial lung disease

Question 1

What is meant by ‘ILD’?

Answer 1

ILD is a generic term used to describe a number of conditions that primarily affect the lung parenchyma in a diffuse manner. They are characterised by chronic inflammation and/or progressive interstitial fibrosis and share a number of clinical and pathological features.

Question 2

What are the features of ILD?

Answer 2

Clinical Features: 
• Dyspnoea on exertion
• No-productive paroxysmal cough
• Abnormal breath sounds
• Abnormal CXR or high-resolution CT
• Restrictive pulmonary spirometry with decreased carbon dioxide diffusing capacity. 

Pathological features:
• Fibrosis and remodelling of the interstitium
• Chronic inflammation
• Hyperplasia of type II epithelial cells or type II pneumocytes

Question 3

Some ILD have a known cause. List the known causes.

Answer 3

1. Occupational/ environmental: asbestosis, berylliosis, silicosis, cotton wool lung (byssinosis)
2. Drugs e.g. nitrofurantoin, bleomycin, amiodarone, sulfasalazine, busulfan
3. Hypersensitivity reactions e.g. extrinsic allergic alveolitis
4. Infections e.g. TB, Fungi, viral
5. Gastro-oesophageal reflux

Question 4

Which systemic disorders are associated with ILD?

Answer 4

1. Sarcoidosis
2. Rheumatoid arthritis
3. SLE, systemic sclerosis, mixed connective tissue disease, sjogren’s syndrome
4. Ulcerative colitis, renal tubular acidosis, autoimmune thyroid disease

Question 5

What are the 3 idiopathic ILDs?

Answer 5

1. Idiopathic pulmonary fibrosis
2. Cryptogenic organising pneumonia
3. Lymphocytic interstitial pneumonia

Question 6

What are the symptoms and signs of idiopathic pulmonary fibrosis?

Answer 6

Symptoms: dry cough, exertional dyspnoea, malaise, weight loss, arthralgia

Signs: cyanosis, finger clubbing, fine end-inspiratory crepitations

Question 7

What are the complications of idiopathic pulmonary fibrosis?

Answer 7

1. Respiratory failure

2. Increased risk of lung cancer

Question 8

How do you test for idiopathic pulmonary fibrosis?

Answer 8

ABG: PaO2↓, if severe PaCO2↑

CRP ↑

Immunoglobulin ↑

ANA (40% positive)

Rheumatoid factor (10% positive)

CXR: reduced lung volume, bilateral lower zone reticulonodular shadows, honeycomb lung (advanced).

CT scan:

Spirometry; restrictive pulmonary function

Lung biopsy

Question 9

How is idiopathic pulmonary fibrosis managed?

Answer 9

Best supportive care: oxygen, pulmonary rehabilitation, opiates, palliative care input
DO NOT USE High dose steroids
Lung transplant consideration

Prognosis: 50% 5-year survival rate