Pulmonary Fibrosis

Question 1

Definition

Answer 1

interstitial fibrosis of the lung parenchyma and has a number of causes. Idiopathic pulmonary fibrosis (IPF) is the most common cause.

Question 2

Epidemiology

Answer 2

Advanced age: 60-70 years of age
Male

Question 3

Risk factors

Answer 3

Smoking
Family history
Dust exposure: raising birds, metal, wood

Question 4

Aetiology of upper zone pulmonary fibrosis

Answer 4

Coal worker’s pneumoconiosis
Silicosis
Hypersensitivity pneumonitis (extrinsic allergic alveolitis)
Ankylosing spondylitis
Cystic fibrosis
Sarcoidosis
Tuberculosis

Question 5

Aetiology of lower zone pulmonary fibrosis

Answer 5

Idiopathic pulmonary fibrosis
Asbestosis
Drug-induced: amiodarone, bleomycin, methotrexate, nitrofurantoin
Most connective tissue disorders, such as SLE, (excluding ankylosing spondylitis)
Radiation

Question 6

Pathophysiology

Answer 6

Aetiology is unknown,
Different stimuli have been speculated to induce a pro-inflammatory and pro-fibrotic response.
The new hypothesis suggests a complex interaction between the epithelium and fibroblasts. Various factors including genetics and environmental triggers, such as smoking, promote lung damage and subsequent fibroblast activation, migration and differentiation into myofibroblasts. These newly differentiated cells secrete collagen, resulting in scarring and fibrosis.

Question 7

Signs

Answer 7

Bibasal fine end-inspiratory crackles, predominantly in lower zones
Clubbing

Question 8

Symptoms

Answer 8

Progressive dyspnoea
Non-productive cough
Malaise

Question 9

Investigations

Answer 9

FIRST LINE = CXR: bilateral reticulonodular opacification mainly affecting the lower zones
GOLD STANDARD = High-resolution CT thorax = increased reticulation and honeycombing, mainly in the lower zoneS

Spirometry: a restrictive pattern is seen =
- FEV 1 = normal or low
- FVC = very low
- FEV1/FVC > 80% = normal
Impaired gas exchange: reduced transfer factor (TLCO)

Question 10

Treatment

Answer 10

Supportive care:
- Pulmonary rehabilitation
- Ambulatory oxygen therapy and/or long-term oxygen therapy
- Vaccinate against pneumococcus and influenza
Anti-fibrotic agents:
- Pirfenidone or nintedanib
Lung transplantation

Question 11

Complications

Answer 11

Lung cancer: there is an increased risk of bronchogenic carcinoma
Pulmonary hypertension and cor pulmonale: 30-50% of patients with IPF have pulmonary hypertension