Idiopathic pulmonary fibrosis

Question 1

Define idiopathic pulmonary fibrosis

Answer 1

Inflammatory condition of the lung resulting in fibrosis of the alveoli & interstitium

Previously known as cryptogenic fibrosing alveolitis

Question 2

Aetiology of idiopathic pulmonary fibrosis

4

Answer 2

Occurs in genetically predisposed individuals

Recurrent injury to alveolar epithelial cells results in secretion of cytokines & growth factors

Leads to fibroblast activation, recruitment, proliferation, differentiation into myofibroblasts & increased collagen synthesis & deposition

Certain drugs can produce similar illness (e.g. methotrexate, amiodarone)

Question 3

Risk factors for idiopathic pulmonary fibrosis

4

Answer 3

Smoking
Occupational exposure to metal or wood
Chronic microaspiration
Animal & vegetable dusts

Question 4

Epidemiology of idiopathic pulmonary fibrosis

prevalence x2, gender

Answer 4

RARE
6/100,000
More common in males

Question 5

Presenting symptoms of idiopathic pulmonary fibrosis

5

Answer 5

Gradual onset, progressive dyspnoea on exertion
Dry irritating cough
NO wheeze
Symptoms may be preceded by viral type illness
Fatigue & weight loss common

Question 6

Signs of idiopathic pulmonary fibrosis on physical examination
(3)

Answer 6

Clubbing (50%)
Bibasal fine late inspiratory crackles
Signs of right heart failure in advanced stages of disease

Question 7

Investigations for idiopathic pulmonary fibrosis

7 types

Answer 7

Bloods
CXR
High resolution CT
Pulmonary function tests
Bronchoalveolar lavage
Lung biopsy
Echocardiography

Question 8

Investigations for idiopathic pulmonary fibrosis - bloods

2

Answer 8

ABG

• normal in early disease
• PO2 increases w/ exercise
• normal PCO2 which rises in late stage disease

ANA & rheumatoid factor
- 1/3 patients positive for ANA or RF

Question 9

Investigations for idiopathic pulmonary fibrosis - CXR

3

Answer 9

Usually NORMAL at presentation
Early disease may show ground glass shadowing
Later stage disease shows reticulonodular shadowing, signs of cor pulmonale & eventually honeycombing

Question 10

Investigations for idiopathic pulmonary fibrosis - high resolution CT

Answer 10

More sensitive to early disease than CXR

Question 11

Investigations for idiopathic pulmonary fibrosis - pulmonary function tests
(4)

Answer 11

Restrictive features (reduced FEV1 & FVC, w/ preserved or increased FEV1/FVC)
Decreased lung volumes
Decreased lung compliance
Decreased total lung capacity

Question 12

Investigations for idiopathic pulmonary fibrosis - bronchoalveolar lavage

Answer 12

Exclude infections & malignancy

Question 13

Investigations for idiopathic pulmonary fibrosis - lung biopsy

Answer 13

GOLD STANDARD for diagnosis

Question 14

Investigations for idiopathic pulmonary fibrosis - echocardiography

Answer 14

To check for pulmonary hypertension