Cystic Fibrosis

Question 1

cystic fibrosis

Answer 1

defective Cl- transport across cell membrane –> hypersecretion of fluid OR abn composition of secretion that affects GIT, resp system, and reprod tract

Question 2

etiology

Answer 2

• Mutated cystic fibrosis transmembrane gene regulator (CFTR) on Chr 7
• autosomal recessive
• inc rates in Caucasian ppl

Question 3

what is cystic fibrosis transmembrane gene regulator (CFTR) and why does it cause CF

Answer 3

Gene that codes for transport proteins; if mutated, transmembrane exchange is altered (specifically the exchange of chloride)

Question 4

patho

Answer 4

• Thick mucus –> dec ciliary Fx –> a/w obstr –> dec breathing (dyspnea)
• Bacterial infect –> inflm –> damage
• Hypercapnia & hypoxemia

Question 5

what results from inflm cells releasing proteases

Answer 5

tissue destr –> bronchiectasis, chronic bronchitis & resp failure (cause of death in majority of CF pts [>90%)

Question 6

how does thick mucus occur

Answer 6

• defective Cl- transport d/t mutated CFTR gene –> mucus has no Cl- –> Cl- builds up in cell rather than a/w –> imbal conc causes water to move from mucus into cell –> Na+ follows water –> thick, viscous, sticky mucus lining a/w

Question 7

consequences of thick mucus lining a/w

Answer 7

• Thick mucus can’t be swept by cilia & remains along the lining of a/w –> ideal enviro for microbial growth –> infect –> inflm –> inflm damage –> vasodilation & hypermia
• inflm cells release proteases –> tissue destr –> bronchiectasis, chronic bronchitis & resp failure (cause of death in majority of CF pts [>90%)

Question 8

Dx

Answer 8

• resp & GI mnfts
• sweat test
• trypsinogen test (NB)
• sibling Hx

Question 9

sweat test results

Answer 9

[NaCl] inc

• In CF, the Cl- can’t be transported out in the reabsorptive duct, so NaCl stays in the sweat producing hypertonic (more conc) sweat

Question 10

trypsinogen test results

Answer 10

• High levels of trypsinogen in blood b/c there is secretory obstr in pancreas

Question 11

when is trypsinogen screening test done

Answer 11

Screening test done esp if NB’s sibling has CF (strong possibility other siblings will have it)

Question 12

Tx

Answer 12

• no cure
• dec progression of disease
• Abx, y globulins
• diet modification & pancreatic Es supplements
• mucolytics, anti-inflm & chest physiotherapy
• DNAase

Question 13

why Abx & y globulins for Tx

Answer 13

to control/prevent infect

Question 14

why are mucolytics, anti-inflm & chest physiotherapy used for Tx

Answer 14

Help expectorate mucus to inc gas exchange & dec infect

Question 15

why are DNAase used for Tx

Answer 15

Breaks down DNA present in mucus (d/t broken down or epith cells that released their genetic content) making mucus more mobile (helps w/ expectoration)