cystic fibrosis Flashcards
what type of dusease is CF
Autosomal recessive
what is the main cause of mot ifity and morgaligu
pulmonary dusease and resp failure causes death un 90%
what haopens if both parents are carriers
1/4 chnace a chikd will be affected
2/4 chance carrier
1/4 chance unaffected
what does CF occur due to
a mutation in the transmembrane conductance regulator protein (CFTR) which is coded on chromosome 7
what does abnormal transport of cl- and na due to mutation on CFTR lead to
reduced airway surface liquid (dehydrates mucous layer)
thicky sticky mucous
shesring
impaired bacterual killing via neutrophils
how many mutation classes is there
6, based in synthesis, processing/trafficking and fucntion of CFTR. class 1-3 cause severe disease and 4-6 cause milder disease the most common id F508 which is class 2
what is some antenatal testing for CF
done follwing identifucation of CF parent or sibling
pre implantatkon genetic diagnosus
chorionic villous sampling
amniocentesis
what is neonatal screening for CF
newborn bloodspot day 5
(guthrie test)
screen positive - regerred for clinical assessment and sweat test
proportion of disgnoses missed
when is sweat testing done
any time postnatally
measures concentration of cl- excreted in the sweat which would be elevated in CF
> 60 mm per litrr is abnormal
what are the three diagnostic outcomes of testing
CF
NOT CF
CF - screen positive inconclusive diagnosis (SPID)
where does CF effect
it is a multisystem disease and can affect any part od the body eg pancreatuc insifficiency diabetes infection and bronchiectasis
how does CF cause pancreatic insufficiency
CFTR mutation also affects the pancreas
the oactess produces enzymes that digest food. lack of rnzymes causes:
1. malabsorption
2. abnormal stools- pale, offensive, float
3. failure to thrive
impirtance of record, groth charts
what are the levels of pancreatic fucntion
class 1-3 are pancreatic insuffucient and 4-6 have some pancreatic function
we only need about 5% of CFTR fucntion to have sufficient oancreatic function and be asymptomatic
what can recurrent bronchipulmonary infection cause
pneumonia
bronchiectasis
scarring
abscesses
why does pulmonary infection occur
CFTR causes
- abnormal electrolyte transport across cell membrane
- degydratkon of airway surface layer (water later which allows mucoys to slide easiky uo airways to be coughed up)
- decreases mucociliary clearance
- mucous sticks to mucosal surface and causes shearing damage
- increased bacterial adherence
- decreased bacterial killing
so u are more prone to chest infectjons
what is the circke of events in resp infections
- decrease muco clearance increase bact adherance decrease endocytosis of bacteria ——————> - bacterial colonisation—————————-> - inflammation mucous plugging airway ulceration airway damage ————————————> - bronchiectasis
what happens as a resukt of recurrent chest infectjons
progressive respiratory decline occurs
what will a CT show
tramlines
signet rings
mucous plugging
consolidation (infection)
how do you manage CF
regured a MDT to imroove longterm ourcome eg physicians nurses physio dietician psychologist pharmacists microbiologust gacstroenterologist diabetes
surveillance
early treatment of infectjons
how do you treat pancreatic pancreatic insufficiency in CF
boost nutrition
replace wnzymes (CREON)
diet: high energy plus high calorie supplement drinks
nutritional supplements: fat-soluble vitamin and mineral supplements
how do yoy treat muchs obstricgion and inflammatiln
airway clearnace via ohysiotherapy
mucokytucs
bronchodikators
how do you treat chronic infection
antibiotics(oral, IV or nebulised)
how do you treat increases inflammation
azithromycin
how do yoy treat fibrosis/scareing/bronchiectasis
supportive treatment and management of synptoms - much of this is unreversible
what are other aspects of CF
diabetes
osteoporosis
pneumothorax
haemoptysis
describe diabetes in CF
The type of diabetes in CF, and its management, didfers from non CF patients
join diabetic/CF clinics and CF dietician vital
T2 DM is the most common type seen in CF - not emouvh insulin from pacreas or insulin not working orioetly
T1 - no insulin made, very rare
what are soecific issues w CF and diabetes
compliance w diet a probkem
need hugh calorie diet (unline non CF diabetes)
insukin of benefit but not so much oral drug
explain osteopososis in CF
bone mineral density (BMD) falls in oatients w CF
what are prefictors od low BMD
low FEV1 freq antibiotic course steroids low BMI: malnutrition low exercise age male diabetes vit D/ deficienct delayed piberty
explain pneumotjorax in CF
the oresence of air on the cavity between the lungs ans the chest wall, causing collape of the lunv
affects 3-4% of CF patients during their lifetime
what is the causes of haemoptysis in CF
Bronchial wall destruction causing coughing of blood
minor haemoptysis is very common (60%)
- blood streaking, no soecific treatment
madsive in 1% of oatients
- mat be preceeded by gurgling in chest
- admit, resuscitate
- may need bronchial angiogram and embolisation
what is the impact of CF on family
cough miss school diff diet take deugs increased depeession/ anxiety sibkings time consuminh treatments incrwaes cost to familt
what do modulator drugs do
addeess diff oarts of CFTR production, processing, folding, transport and insertion into the membfane
mll benefits in lung fucntion. more signifucant benefit is fall in chest exacerbations, weught gain wnd QOL
when would a patient get a doibke lung transplant
rapidlt deteriorating lung fucntion
FEV1 <30% preducted
life threatnenong exacerbations
estimated survival <2years
what are contra inductions to transplant
other organ failure makignancy within 5 years significant perioheral vascular disease dependency or addiction active systemic infection microbiological issues
when would u have to use clinicak judgment
other organ dysfunction non compliance steroids >20 mg daily absence of recovnised social support osteoporosis low or high BMI sirgical risks (prevoiys thoracuc surgery) psychological instability
what can be used to improve qualitu of life
o2 and NIC exercise support advanced care plans DNAR discusskons
