Idiopathic pulmonary fibrosis

Question 1

What are the epidemiological features of IPF?

Answer 1

20/100,000
Mean onset is late 60s
More common in males

Question 2

What are the risk factors for IPF?

Answer 2

Tobacco smoking
Chronic aspiration
Antidepressants
Wood/metal dust
EBV infection

Question 3

What is the pathogenesis of IPF?

Answer 3

Unknown

Theory suggests repeated injury from exogenous and endogenous unknown stimuli - multiple micro injuries cause alveolar cells to secrete growth factors that secrete fibroblasts

Question 4

What are the symptoms of IPF?

Answer 4

Progressive breathlessness
Non-productive cough
Cyanosis

Question 5

What are the signs of IPF?

Answer 5

Fine bilateral end-inspiratory crackles
Gross finger clubbing

(other signs associated with pulmonary hypertension and cor pulmonale)

Question 6

What are the end-stage complications of IPF?

Answer 6

Pulmonary hypertension
Cor pulmonale
Respiratory failure

Question 7

What investigations would you perform?

Answer 7

CXR- initially shows ground glass appearance, followed by irregular reticulonodular shadowing and then honeycomb lung

High-res CT

Spirometry - lung volumes reduced, FEV1 to FVC ratio is normal to high (with both values being reduced) and CO gas transfer is reduced.

Peak flow - may be normal

Blood gases - anti-nuclear Ab and rheumatoid factors present in 1/3 of patients. ESR and Ig mildly elevated

Bronchoalveolar lavage - increased no of cells, particularly neutrophils and macrophages

Histological confirmation sometimes necessary.

Question 8

What are the differential diagnoses?

Answer 8

Hypersensitivity pnuemonitis
Brochiectasis
Chronic left heart failure
Sarcoidosis
Industrial lung disease
Lymphangitis carcinomatosa

Question 9

What would you tell the patient?

Answer 9

Need to explain the condition is progressive and irreversible ie terminal.

Explain that lung tissue is becoming increasingly stiff making it difficult to breath and putting pressure on the right side of the heart and the blood vessels within the lungs.

Question 10

What treatment is available?

Answer 10

Prednisolone (provides little benefit)
Azathiopride or cyclophosphamide (also of little benefit)
Pirfenidone (experimental)

Domicillary oxygen

Lung transplant (in young pts)

Question 11

What is the prognosis?

Answer 11

Median survival time = 5 years after diagnosis