cystic fibrosis Flashcards
what type of mutation is cystic fibrosis?
CFTR gene mutation (chromosome 7)
- this is a chloride channel mutation (energy dependant channel)
describe the normal action of the chloride channel?
- when the Cl channel open on the lung epithelial membrane, chloride moves out into the lumen of the airway
- this pulls Na with it. (maintaining neutrality)
This creates a salt of Na+Cl = osmotic pressure that pulls water out into the lumen.
goblet cells in the airway?
how does the moisten the airway?
how do cilia act here?
produce mucopolysaccharide material.
- this will combine with water
this is what moisten the airways= airway surface liquid that traps bacteria.
cilia will move anything away that gets stuck here.
how does all of this change in cystic fibrosis?
not enough water gets pulled out due to a defect in the chloride channel.
- this makes heavy mucus that will not move very well.
But we still want to get rid of the bacteria
how does the body get rid of the bacteria in cystic fibrosis?
neutrophils will try to breakdown the bacteria = secretion of inflammatory molecules. THIS WILL DAMAGE LUNG TISSUE.
where does this also happen in the body?
pancreas
liver
sweat glands
reproductive tract
what is the main diagnostic technique for TB?
what genes are they looking for?
newborn screening for genes.
IRT (immunoreactive trypsinogen)
- this enzyme is produced by the pancreas (it should not be found in the blood, it is a sign that the pancreas is being destructed.
what are some symptoms of cystic fibrosis?
recurrent chest infections
- infertility
- dibetes type 3
- pancreatitis
- liver dysfunction
how does the sweat test work for screening for TB?
- uses the Pilocarpine ionotoporesis tenchnique (electrical current is applied)
- measure the minimum sweat volume and the chloride concentration of the sweat will be analysed.
- sweat chloride concentration >60 = CF
40-60mmol/l Is borderline high
<40 mmol/l is normal
what are other tests that can be done to look for CF?
- stool elastase
- genetics
what kind of doctors would be on the team for CF?
- respiratory
- GI/Liver
- Endocrine - diabetes
what is CF exacerbation?
an exacerbation is defined as the need for. additional antibiotic treatment based on the presence of 2 or more of:
- change in sputum volume
- increased cough
- anorexia
- X-ray changes
what are examples of:
viruses
bacteria
fungi
that we are concerned about in cystic fibrosis?
viruses = flu, rhinovirus
bacteria = s.aureus, pseudomonas
fungi = aspergillus
what are 3 mechanisms of new CF therapies?
1) suppressors of premature stop codons
2) CFTR correctors
3) CFTR potentiators
what are 5 things will make up treatment in the early years of CF?
1) airway clearance (mucolytic therapy delivery through nebulisers)
2) nutritional management (calories, vitamins, salt)
3) management of chest exacerbations
4) regular MDT clinic
5) Ad-hoc reviews