cystic fibrosis Flashcards
how many pts in the uk with CF?
10,837
life expectancy of CF
50.6 years
what is the pathophysio of CF?
defects in the gene for the cystic fibrosis transmembrane regulator (CFTR)
what is the most common mutation in CF?
delta F508
what is the function of the CFTR protein?
control chloride transport across epithelial membranes such as mucous, sweat, saliva, tears, and digestive enzymes
causes dehydration of mucous
what is the main problem in CF?
thicker, viscous produced mucous
what type of inheritance pattern is CF?
autosomal recessive condition
- both parents must pass on a faulty CFTR gene
- 25% chance that the child is born with two normal genes
- 50% chance that the child is born with one normal and one abnormal (carrier)
- 25% chance that the child is born with two abnormal genes.
what are the 9 conditions newborns are screened for?
cystic fibrosis
sickle cell
congenital hypothyroidism
phenylketonuria (PKU)
medium-chain acyl-CoA dehydrogenase deficiency (MCADD)
maple syrup urine disease (MSUD)
isovaleric acidaemia (IVA)
glutaric acuduria type I (GAI)
homocystinuria (pyridoxine unresponsive) (HCU)
when are newborns screened for congenital conditions?
5 days after birth
4 drops
what is the diagnostic test for CF?
sweat test
- +ve screening test
- CF kids are salty
- pilocarpine and current
- collect sweat
- measure chloride content
- can be confirmed with gene testing
what are the symptoms of CF in a baby?
meconium ileum = erogenic bowel - appears bright white on scan.
failure to thrive = due to bowel issues; cannot get nutrients from food
sinusitis
recurrent LRTIs
greasy/bulky stools = due to lack of getting rid of fats
prolapse
what is bronchiectasis?
a long-term condition where the airways of the lungs become widened, leading to a build-up of excess mucus that can make the lungs more vulnerable to infection.
why are pts with CF more prone to infection?
due to clogging of thick mucous in the airways which can cause collection of bacteria.
bronchiectasis
common causes of infection in CF (bacteria, fungi etc)
pseudomonas
aspergillus fumigateurs - allergic bronchopulmonary aspergillosis leads to scarring and bronchiectasis
when there is infection, this can progress to colonisation.
what is the treatment for CF?
antibiotics - inhaled, oral and IV
pulmonary rehab - physio, airway clearance techniques
pneumatic vest which puts pressure on chest wall to clear gunk (however little evidence)
DNAse which is an inhaled medicine which helps to break down the fragments in the mucous so it’s less thick
transplant - heart and lung
what are the gastrointestinal effects of CF?
gastro-oesophageal reflux disease caused by coughing which increases thoracic pressure and causes stomach contents to come back up
pancreatic blockage - exocrine dysfunction
- inability to gain weight due to poor absorption, malnourishment, bulky stools and fat soluble vitamin deficiency.
can progress to “diabetes lite” - produce insulin but not enough and can cause pancreatic endocrine problems
what is the treatment for the gastrointestinal effect?
dietician input
high calorie diet
creon! - amylase, lipase and protease -> taken with food to help breakdown food
ADEK vitamins -> fat soluble
why does CF cause infertility?
effects 97% of men due to the absence of the vas deferent (not developed in the testes) so they are infertile but not sterile as they are able to produce but not transport
women are also effected - thick cervical mucous and low BMI which affects the menstrual cycle and unable to gain weight.
what is kalydeco?
ivacaftor
acts on a specific protein that is only present in 5% of CF pts
costs a lot
what is kaftrio?
ivacaftor, tezacaftor and elexacaftor
works on CFTR gene and makes the protein more common
works on the deltaF508 mutation
less expensive than kalydeco
can CF patients socialise together?
NO
what is the most common AR inherited condition in the UK?
haemochromatosis
how does CF affect mucous?
reduced chloride outside cell = reduced water outside of cell = dehydrated sticky mucous
why do people with CF require ADEK supplements?
fat malabsorption, ADEK are fat soluble
How does pilocarpine work?
muscarinic cholinergic agonist
