cystic fibrosis Flashcards
what is CF
a genetic disease
leads to abnormally viscous mucus which blocks structures such as the airways and GI tract
leads to recurrent chest infections and chronic colonisation
what is the aetiology of CF
autosomal recessive mutation in the CFTR protein (FT transmembrane regulator)
most common in caucasians
what does the CFTR protein do in a healthy individual
forms a channel on mucosal surfaces that allows chloride ions out of the cell and into the lumen (e.g. airway or GIT)
what does failure of the CFTR protein cause
lungs and GIT - results in reduced Cl- secretion into the lumen
Na+ normally follows Cl- into the cell so Na+ secretion is also reduced
less Na+ in the lumen means increased water reabsorption from the lumen into the epithelial cells
results in more viscous mucus which blocks ducts and impairs mucosal defence
sweat glands - excess Cl- and Na+ in the sweat
how have CFTR mutations been classified
according to their effect on the function of CFTR
what can CF patients be colonised by
pseudomonas - most common, worst prognosis
staph aureus
streptococcus
describe the typical CF patient on initial presentation
child aged 0-2 with recurrent infections, large offensive stools and failure to thrive with a FHx of CF
describe the respiratory symptoms of CF
recurrent respiratory infection
chronic daily cough and sputum production
dyspnoea
nasal polyps
haemoptysis
describe the GI symptoms of CF
failure to thrive, low BMI in adults
meconium ileus in infancy
distal intestinal obstruction
voracious appetite in kids
malabsorptive stool with steatorrhoea - due to pancreatic insufficiency
describe the non respiratory and non GI symtoms of CF
salty sweat
infertility in males - bilateral absence of vas deferens
CF related diabetes
describe the clinical signs of CF
cyanosis
clubbing
chest hyperinflation
bilateral coarse crackles on auscultation
what investigations would take place in CF
sweat test
genetic testing for CFTR mutation
describe the respiratory management of CF
in the early, preinfected stages - mucus clearence, infection prevention, maintaining good lung function is priority
chest physio twice a day
regular sputum samples for bacterial culture
prophylactic antibiotics - staph aureus prevention/ reduction (e.g. flucloxacillin)
CFTR modulators - improve flow through CFTR protein - Kaftrio is now used - ivakaftor, tazakaftor and elexakaftor
consider lung transplant when FEV1 is <40%
describe the non respiratory management of CF
pancreas
exocrine failure- CREON
endocrine failure - diabetes monitoring
bowels - mucus blocks intestine so hydration, laxatives and fluids
liver- TIPSS (transjugular intrahepatic portosystemic shunt) for portal hypertension
dietician - ensure adequate nutrition and hydration
describe the management for an acute exacerbation of cystic fibrosis
increase chest physio
add 2 weeks of antibiotic appropriate to the most recent sputum sample
