GV4: Cystic Fibrosis

Question 1

which organ is affected in cystic fibrosis

Answer 1

pancreas

CF is a defect in ion transport

Question 2

what is cystic fibrosis

Answer 2

impaired function of organs with secretory function (eccrine sweat glands, epididymis & vas deferens, nasal polyps, pancreas (lack of enzyme secretion, reduced insulin))
digestive system (meconium ileus & obstruction; failure to thrive in newborns)

Question 3

how is nutrition managed in cystic fibrosis

Answer 3

patients have pancreatic insufficiency (lack of protease, amylase, lipase) and are unable to digest food properly
managed by diet & enzyme supplements like pancreatin (lipase, protease, amylase; in e/c capsules)

Question 4

how does cystic fibrosis lead to lung disease

Answer 4

chronic infection, mucus plugging, structural changes, massive neutrophil infiltration in airways, epithelial damage

Question 5

what structural changes occur in lung disease associated with cystic fibrosis

Answer 5

bronchial wall thickening, bronchiectasis (abnormal dilation of bronchial tree), pneumothorax

Question 6

what are the consequences of neutrophil infiltration in lung disease associated with cystic fibrosis

Answer 6

frustrated phagocytosis, failure to clear bacteria and dying neutrophils, inflammatory damage to airway tissue, decline in lung function

Question 7

what screening takes place in cystic fibrosis

Answer 7

immunoreactive trypsinogen, genetic screening, sweat test

Question 8

what is the IRT test for CF

Answer 8

immunoreactive trypsinogen (Guthrie test)
all newborns in the UK; trypsinogen made by pancreas and secretion into gut imapired in CF which is elevated in blood

Question 9

what genetic screening takes place in CF

Answer 9

IRT positive (and siblings) screened for most common mutations

Question 10

what happens in the sweat test for CF

Answer 10

elevated skin Cl- levels
below 30mM means CF unlikely
above 60 mM means CF is likely

Question 11

what does CFTR stand for

Answer 11

cystic fibrosis transmembrane conductance regulator

Question 12

what are the consequences of low volume of CFTR

Answer 12

sticky viscous mucous, difficult to clear by cilia, provides growth environment for bacteria, partial correction with inhaled hypertonic saline

Question 13

why is DNA found in mucin in CF

Answer 13

mostly from dying neutrophils attempting to clear bacteria; so very viscous mucous because of dehydration and large amount of DNA

Question 14

what bacteria can cause a lung infection in CF

Answer 14

pseudomonas aeruginosa
staphylococcus aureus
haemophilus influenza
burkholderia cepacia

Question 15

what antibiotics are used in CF

Answer 15

prophylactic flucloxacillin in infants for s. aureus
regular swab or sputum cultures
early oral or IV intervention
inhaled antibiotics useful

Question 16

what are the established therapies in CF

Answer 16

early recognition using neonatal screening, antibiotics against pathogens, beta-adrenoreceptor agonists, anti-inflammatory, osmotic agens, mucolysis (recombinant DNAase, N-acetyl cysteine)

Question 17

what is the function of recombinant DNAase

Answer 17

breaks down very viscous mucous, CF mucous contains large amounts of DNA from inflammatory cells and bacteria

Question 18

what anti-inflammatory therapies are used in CF

Answer 18

glucocorticoids, macrolides, high dose NSAIDs

Question 19

how are glucocorticoids used in CF

Answer 19

inhaled no proof of a reduction in inflammation

IV prednisolone has some benefit but significant adverse effects (imapired growth and cataracts)

Question 20

how are macrolides used in CF

Answer 20

non-antibiotic effect of azithromycin

risk of myobacterium infection

Question 21

how are high dose NSAIDs used in CF

Answer 21

e.g. ibuprofen

some slowing of lung function decline