Cystic Fibrosis Flashcards
what is cystic fibrosis (CF)
genetic disorder that affects mostly the lungs. Long-term issues: difficulty breathing and coughing up mucus as a result of frequent lung infections.
- common
What type of inherited condition is CF
autosomal recessive
What is the gene prevalence of CF? ie what is a person’s chance of having CF?
1:25
how many CFTR mutation classes are there
6
what fertility issues exist with CF in males
> 95% males infertile - blocked/absence of vas deferens (ducts that carry sperm before ejaculation)
what fertility issues exist with CF in females
may affect chances of conception even though they may have poor nutrition anyways
CF has no effect on _____ in males and women
sexual function
Intra-cytoplasmic sperm injection
intra-cytoplasmic sperm injection ICSI (single sperm cell is injected directly into the cytoplasm of an egg)
- only 25-30% success rate
- 3 attempts on the NHS
female fertility issues that need to be considered before trying through NHS (3)
screening of partner
counselling re long term impact of condition on family
need optimum health (lung function / weight)
does pregnancy affect the survival of women with CF
low numbers found in research/studies
what are some issues with lung transplantation?
it is the last resort treatment option- when things turn really bad
it doesn’t always work
no lung transplant centers in Scotland- have to travel to Newcastle
what is the criteria used to determine when patients require a transplant (6)
if their FEV1 is <30% weight loss hypoxia at rest or O2 levels dropping during exercise high CO2 levels recurrent worsening sepsis worsening QOL
what 5 categories/outcomes are possible for CF patients after team discussion about lung transplant possibility
put on active list - need transplant urgently
passive list- not emergency but probably require in future
too well
patient decides they don’t want to go through with it
team decide not to put patient on it
too ill - won’t cope with big surgery
what new list is there in the last 18 months or so within the NHS regarding lung transplant
ultra-urgent list - can be as quick as 24 hours
name some absolute contra-indications (reasons against) to transplant (6)
Other organ failure
Malignancy within 5 years
Significant peripheral vascular disease
Drug, nicotine, alcohol dependency - Newcastle won’t see anyone who has been smoking in the last 6 months
Active systemic infection
Microbiological issues (eg. M. abscessus- big worry)
which organism causing infection is worrying at the moment
M. abscessus - rapidly growing, multidrug-resistant NTM species that are found in soil and water
relative contra-indications to transplant? 2 or 3 needed to not go ahead with transplant (6)
Other organ dysfunction
Non-compliance
Steroids >20mg daily
Absence of recognised social support
Osteoporosis
Low BMI - anyone <18 won’t get transplant in Newcastle
Surgical risks (previous thoracic surgery)
what is the most common CFTR mutation class
dF508 70% N. europeans have this
what happens in class 1 CFTR mutations
synthesis of MRNA does not occur so no functional CFTR protein is made. This is due to non-sense mutation
what happens in class 2 CFTR mutations
CFTR protein is created, but misfolds, keeping it from
moving to the cell surface.
what is the normal function of CFTR protein
CFTR protein is created, moves to the cell surface and
allows transfer of chloride and water.
what happens in class 3 CFTR mutations
channel gate doesn’t open so no movement of water or Cl- ions
What happens in class 5 CFTR mutations
Normal CFTR protein is created and moves to the
cell surface, but there’s just not enough of it to function
What happens in class 4 CFTR mutations
CFTR protein is created and moves to the cell surface, but the function of the channel is faulty
in what ways can CFTR function be affected
if the movement of Cl- out of the cell is reduced then there can be a change in the concentration of fluid that bathes the cilia. Any change in this concentration or volume even can lead to cilial collapse, thick, sticky mucus or excessive inflammation
describe Cl- and Na+ movement when CFTR is mutated
Cl- efflux decreases
more Na+ is taken into the cell
how does cilial collapse lead to infection
the thick,sticky mucus that is no longer being beaten away starts to trap organisms this leads to recruitment of neutrophils and excessive DNA due to apoptosis performed by these neutrophils