Restrictive (a bit from UW) 12/07

Question 1

IPF - causes?

Answer 1

unknown, but like related to CYCLICAL lung injury (eg smoking, acid reflux)

Question 2

IPF - what cytokine?

Answer 2

injured penumocytes -> TGF-beta -> fibrosis

Question 3

IPF - what other causes?

Answer 3

secondary damage: eg drugs - bleomycin, amiodarone; radiation therapy

Question 4

IPF - clinical features?

Answer 4

Progressive dyspnea
Nonproductive cough
Finger clubbing
Inspiratory crackles

Question 5

IPF - where is predominant fibrosis?

Answer 5

Subpleural and perilobular areas

Question 6

IPF - what patter is seen?

Answer 6

Honney comb pattern with FIBROTIC WALLS AND CYSTIC SPACES lines by BRONCHIOLAR epithelium

Question 7

IPF - patches are consisted of?

Answer 7

Patchy areas of interstitial fibrosis with chronic interstitial inflammation INTERMIXED with normal lung

Question 8

IPF - early lesion?

Answer 8

Fibrotic foci that becomes increasingly collagenous with time

Question 9

IPF - fibrosis is bilateral on lung CT.

Answer 9

.

Question 10

What is thickened in fibrotic lung disease?

Answer 10

INTERSTITIUM (not bronchiolar wall)

Question 11

Why there supernormal expiratory flow rates in pulmonary fibrosis?

Answer 11

Due to increased outward pulling from center to periphery due to hard hibrotic tissue -> increased radius of terminal bronchioles (widdening of airway) -> decreased airflow resistance -> inc. flow rates

Question 12

Why there subnormal expiratory flow rates in obstruction (eg empysema)?

Answer 12

Damaged alveolar walls -> decreased strenght of traction -> decreased radius (narrowing of airway) -> increased airflow resistance -> dec. flow rates

Question 13

in fibrosis what’s about elastic recoil?

Answer 13

increased

Question 14

IPF. Repetitive lung microinjuries leads to loss of what?

Answer 14

pneumocytes type I

Question 15

What happens with pneumocytes type I once they are damaged?

Answer 15

They cannot replicated by themselves. Normal repair requires pneumocytes type II -> the differentiation to type I.

Question 16

IPF. What happens with penymocytes type II?

Answer 16

Undergo hyperplasia (since its stem cells), but FAIL TO DIFFERENTIATE TO TYPE I pneumocytes

Question 17

Why pneumocytes II cannot differentiate into type I? 2

Answer 17

1. Dysfunctional cell fate pathways (WNT/TGF-beta)
2. Abnormalities of the underlying basement membrane

Question 18

IPF. What about basement membrane?

Answer 18

Abnormal

Question 19

IPF. Impaired reepitelization. What happens next?

Answer 19

Fibroblasts (increased) undergo FOCAL PROLIFERATION -> begin to secrete excessive amount of collagen > Fibrosis