Pulmonary Fibrosis

Question 1

Idiopathic pulmonary fibrosis is the most common type of which interstitial lung disease?

Answer 1

Idiopathic interstitial pneumonia of unknown cause

Question 2

What are the signs and symptoms of Idiopathic pulmonary fibrosis?

Answer 2

Symptoms:
Dry cough
Exertional dyspnoea
Malaise
Weight loss
Arthralgia 

Signs:
Finger clubbing
Cyanosis
Bi-basal fine end-inspiratory crepitations/crackles

Question 3

What is the histological appearance for idiopathic pulmonary fibrosis?

Answer 3

Usual interstitial pneumonia is the histological finding in idiopathic pulmonary fibrosis.

Key features are:
Areas of normal lung and areas of marked fibrosis

Honey-combing in sub pleural areas

Fibroblastic foci (dense proliferations of fibroblasts and myofibroblasts)

Question 4

What is the underlying pathogenesis as a result of pulmonary fibrosis?

Answer 4

Repetitive injury to the alveolar epithelium caused by unknown stimuli => activation of repair pathways

Wound healing in pulmonary fibrosis becomes uncontrolled => over-production of fibroblasts and deposition of increased extracellular matrix in the interstitium when there is only small amount of inflammation

=> lung parenchyma destroyed, loss of elasticity => gas exchange impairment => progressive respiratory failure

Question 5

What are the complications of pulmonary fibrosis?

Answer 5

Type 1 Respiratory failure (low O2)

High risk of lung cancer

Question 6

What investigations are carried out for pulmonary fibrosis?

Answer 6

Blood test: high CRP, immunoglobulins, ANA (+ve in 30%), rheumatoid factor (+ve in 10%)

ABG: low O2, if severe high CO2

Chest X-ray: decreased lung volume, bi-lateral base reticular shadowing, honeycomb lung if severe

CT: same finding as chest X-ray but is more sensitive and needed for diagnosis

Spirometry: restrictive

Bronchoalveolar lavage: necessary if infection / malignancy suspected - may indicate activity if alveoli’s
=> increased lympocyte = good prognosis ; increased neutrophils or eosinophil = bad prognosis

Lung biopsy: usual interstitial pneumonia found in histology. Biopsy may needed for diagnosis.

Question 7

What are the differential diagnosis for
pulmonary fibrosis ;
findings of x-ray in pulmonary fibrosis ;
bi-basal fine crackles on auscultation?

Answer 7

i. Other interstitial lung disease

ii. Differentials for chest x-ray findings =>
Interstitial pulmonary oedema,
Infection
Lymphangitis carcinomatosa.

iii. Differentials for bi-basal fine crackles =>
Heart failure
Recurrent chest infections

Question 8

What is the management for pulmonary fibrosis?

Answer 8

Supportive i.e. oxygen, pulmonary rehab, opiates.

All patients should be considered for clinical trials for anti-fibrotic agents i.e. pirfenidone and other or lung transplantation

Steroids are not recommended in confirmed disease!!

Question 9

What is the prognosis?

Answer 9

Pulmonary fibrosis is a life limiting disease.

Mean survival time is 2-5 years.