Idiopathic pulmonary fibrosis

Question 1

Define:

Answer 1

Chronic inflammatory condition of the lung resulting in fibrosis of the intersitium and alveoli

Idiopathic = unknown origin
Fibrosis - excessive deposition of collagen in intestinal tissue causing thickening.

Question 2

Aetiology:

Answer 2

Genetically predisposed individuals

Recurrent injury to alveolar epithelial cells leads to the release of cytokines and growth factors especially TGFb1

Cytokines cause fibroblast activate –> myofibroblasts which release collagen and this leads to the thickening of interstitium

Also leads to stiffer alveoli

RESTRICTIVE LUNG DISEASE

Loss of alveoli leads to fluid filled cysts = honeycombing

Question 3

Risk factors:

Answer 3

Male
Age
Smoking
Occupational exposure to metal and wood
animal or vegtable dusts
chronic microaspiration

Question 4

Epidemiology:

Answer 4

More common in males

6/100,000 incidence

Rare

Question 5

Symptoms:

Answer 5

Gradual onset progressive dysponea on exertion

Dry irritation cough

NO wheeze

May be proceeded by a viral illness

Fatigue

weight loss

Question 6

Signs:

Answer 6

Clubbing (50%)

Fine bibasal late inspiratory crackles

Signs of right sided heart failure

Question 7

Investigations:

Answer 7

Bloods - increased CRP and immunoglobulins

ABG (normal in early disease, PO2 decreases with exercise. PCO2 increases in later disease)

ANA and rheumatoid factor

CXR - normal in early disease or may show ground glass shadowing. In later disease there is bilateral lower zone reticulonodular shadowing

Lung biopsy - THIS IS THE GOLD STANDARD BUT NOT COMMONLY DONE.

Pulmonary function test - Decreased FEV1 and FVC bur normal or increased FEV1/FVC. Decreased lung compliance and TLC.

Bronchoalveolar lavage

TC-DTPA test

High rest CT scan

Echo to check for pulmonary hypertension