Cystic Fibrosis Flashcards
cystic fibrosis cause?
which gene mutated
delta f508 mutated (80% of cases) on CFTR gene of chromosome 7
what is CFTR?
Cl- channel
CFTR stands for what?
cystic fibrosis transmembrane regulator gene
cystic fibrosis mode of inheritance?
Autosomal recessive
Pathophys of cystic fibrosis?
step by step
CFTR shape is malformed > Cl- can not pass through CFTR channel > Cl- cannot get int lung mucus (or any secretion really) > water does not follow > mucus becomes very thick
If Cl- can not move what other electrolytes can not move into skin?
Na+
Lung mucus very thick, what will this cause?
-2
breathing is difficult + infections
recurrent lung infections will eventually cause what complication?
bronchiectasis
Lung mucus very thick, what can happen to pulmonary vasculature blood pressure?
pulmonary HTN
pulmonary HTN will lead to what eventually?
cor pulmonale
in cystic fibrosis what happens to pancreas?
Pancreas secretion are very thick
Pancreas secretion are very thick, effect of this?
thick secretions block exocrine enzyme leaving pancreas > malabsorption
what happens at the liver in CF?
Bile very thick > bile ducts blocked
blocked bile ducts will cause what complications?
-2
liver fibrosis
cirrhosis
liver fibrosis eventually leads to what?
Portal HTN
what happens to sweat in CF?
sweat is high in chloride
why is there high Cl- sweat in CF?
CFTR not functioning > ions from sweats ducts can not be resorbed > instead Cl- in sweat ducts gets trapped and then pumped into skin
what CF problem happens to men specifically?
why?
Male infertility
do not have vas deferens
why do men not have vas deferens?
when in womb the thick mucus blocks vas deferens being made
vas deferens not being made is called what medically?
vas deferens agenesis
what CF problem happens to women specifically?
why?
female subfertility
mucus in cervix way too thick
Thick mucus in sinus will cause a lot of what?
-1
infections (easily infected)
recurrent sinus infections will cause what in the sinuses to be formed?
nasal polyps
how many CF pts are diagnosed over 18?
5%
when are most CF pts diagnosed?
as babies
which organisms which may colonise CF patients lungs?
-4
Staphylococcus aureus
Pseudomonas aeruginosa
Burkholderia cepacia
Aspergillus
features (signs and symptoms) of CF?
Lots of chest infections
Malabsorption (30%): steatorrhoea, failure to thrive
Foul smelling stool Short stature Diabetes mellitus Delayed puberty – can’t get fat Rectales prolapse (due to bulky stools) Nasal polyps Male infertility Female subfertility Liver disease
why is there: Foul smelling stool Short stature Diabetes mellitus Delayed puberty – can’t get fat ??
No pancreas enzymes
which test can you use to diagnose CF antenatally?
chorionic villus sampling or amniocentesis
which test is used to diagnose CF neonatally?
Guthrie heel-prick test
which test is used to diagnose CF in children?
sweat test
suspected CF neonate will have what test?
this test is looking for what?
Guthrie heel-prick test
serum immunoreactive trypsinogen (IRT)
suspected CF child will have what test?
this test is looking for what?
Sweat Test
high Cl- in sweat
normal Cl- levels in sweat?
< 40 mEq/l
abnormal Cl- levels in sweat?
> 60 mEq/l
if CF confirmed in child what test do you do with family?
what mutation are you looking for?
Gene test pt/relatives/partners
Δ-F508 - (this is most common mutation)
why do CF pts have skin oedema?
Hypoalbuminaemia
skin oedema can cause what problems when Ix CF?
False negative sweat test
what IX can you consider?
and why/ what are you looking for?
-6
Spirometry – <0.7 obstructive
Sputum sample – do if infected or want to check if pt been colonised
Faecal elastase – pancreatic insufficiency
CXR – check bronchiectasis
CT scans – signet rings + tram tracks (diagnostic for bronchiectasis and Gold.S)
LFTs – check liver health
how do you manage the mucusy lungs?
-3
chest physiotherapy + postural drainage 2x a day
deep breathing is good
acute breathing
exacerbation – salbutamol
how do you manage the lack of pancreas enzymes/ malabsorption?
-4
Eat lots of calories
Eat lots of fat
Take vitamins supplement (ADEK)
Take pancreatic enzyme supplements (pancreatin)
how do you manage increased risk of infections in CF patients?
-3
CF people ought not meet other CF people – risk of cross infection
Extra vaccine doses
Prophylactic antibiotics given sometimes
Last line Mx for CF?
lung transplant
what drugs can be used to specifically target the CFTR protein?
-2
Lumacaftor
Ivacaftor
what drugs can be used to specifically target the CFTR protein?
-2 named e.g.
how does each work?
Lumacaftor - ↑number of CFTR protein transported into cell surface
Ivacaftor - lets CFTR open and allow Cl- in
most CF pts die at what age?
40
CFTR gene located on which chromosome?
chromosome 7
