Idiopathic Pulmonary Fibrosis

Question 1

Definition

Answer 1

Inflammatory condition leading to fibrosis of interstitium and alveoli.

Question 2

Aetiology

Answer 2

In genetically predisposed individuals (surfactant/telomerase mutations), but in response to a recurrent injury to alveolar epithelial cells. This leads to release of cytokines and GFs (ie. TNFa, IL1 and MCP1) which cause fibroblast activation, recruitment, proliferation, and differentiation into myoibroblasts which
synthesise collagen.
Profibrogenic molecules are secreted by inflammatory,
epithelial and endothelial cells (ie. PDGF/TGFb)

Drugs can CAUSE this: methotrexate, amiodarone, bleiomycin

Question 3

Histological patterns

Answer 3

• Usual interstitial pneumonia UIP (worse prognosis) – patchy interstitial fibrosis with honeycomb lung
• Desquamative interstitial pneumonia DIP – diffuse intra alveolar macrophage accumulation, thickening of alveolar septa.
• Non specific interstitial pneumonia NSIP

Question 4

Risk factors

Answer 4

smoking (75%), exposure to metals, exposure to wood shavings, chronic microaspitation, animal and vegetable dusts

Question 5

Epidemiology

Answer 5

Rare in the Uk. 6/100k.

Question 6

Presenting symptoms

Answer 6

Gradual onset of progressive symptoms
SOB
Dry irritating cough with no wheeze.

Question 7

Signs on physical examination

Answer 7

Bibasal fine late inspiratory crepitaitons

Finger clubbing in 50%

Right ventricular heave, signs of heart failure

Question 8

Investigations

Answer 8

Bloods: ABG (normal initially, low pO2 and high pcO2 later on). RF and ANA

CXR: Early disease shows ground glass shadowing. Later disease shows
reticulodular shadowing, signs of cor pulmonale and, in advanced disease,
honeycombing.

High res CT: early detecton of disease. Emphysema and fibrosis in subpleural
basal areas.

Bronchoalveolar lavage: exclude infection

Lung biopsy: gold standard for diagnosis but debated

Echocardiography: check for pulmonary hypertension

Question 9

Management plan

Answer 9

3 month course of oral glucocorticoids, azathriopine and acetylcysteine. Reassess
after 3m and if no improvement, withdraw and give analgesia and palliative treatment.

Supportive care: home oxygen, lung rehab, opiates to relieve pain and
breathlessness

Acute exacerbations: antibiotics and high dose glucocorticoids

Surgical: single lung transplant

Question 10

Possible complications

Answer 10

Right heart failure,
Lung cancer.
Death from respiratory failure.
PE.

Question 11

Prognosis

Answer 11

Not going to improve, usually 3y life expectancy post diagnosis.

Usually better for younger patients, female, responding to steroids, with ground glass shadowing, and DIP/NSIP.