cystic fibrosis Flashcards
what is the genetics of CF?
autosomal recessive genetic condition affecting mucus glands
- Genetic mutation on cystic fibrosis transmembrane conductance regulatory on chromosome 7 CFTR
what is the most common mutation in CF?
- Genetic mutation on cystic fibrosis transmembrane conductance regulatory on chromosome 7 CFTR
- Most common Is delta-F508 mutation
what does the CFTR gene encode?
- This gene encodes for cellular channels Cl channel
how many people are carriers of CF?
1 in 25
how many children have CF?
1 in 2500
what does CF affect - systems?
pancreas
airways
fertility
how does CF affect pancreas?
- Thick pancreatic and biliary secretions causing blocking of ducts = lack of digestive enzymes eg pancreatic lipase in digestive tract
how does CF affect airways?
- Low volume thick airway secretions that reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
how can CF cause infertility?
- Congenital bilateral absence of vas deferens in males: have healthy sperm but sperm can not get to testes to ejaculate ad this causes male infertility
how may CF present?
newborn blood spot test
meconium ileus
can be later in childhood: recurrent LRTI, failure to thrive, pancreatitis
what is meconium ileus in CF ?
- Meconium ileus: first sign this is lack of first stool passing
- Meconium is usually black and should be passed within first 24hrs
- CF: meconium is thick and sticky and gets stuck
what are symptoms of CF?
- Chronic cough
- Thick sputum production
- Recurrent resp tract infections
- Loose, greasy stools (steatorrheoa) due to lack of fat digesting lipase enzymes
- Abdo pain and bloating
- Parents may report child taste salty when they kiss them conc salt in sweat
- Poor weight and height – failure to thrive
what are signs of CF?
– Low weight/ height on growth chart
- Nasal polpys
- Finger clubbing
- Crackles and wheeze on auscultations
- Abdo distention
- greasy pale stools
what can cause clubbing in children?
hereditary, cyanotic HD, infective endocarditis, CF, TB, inflam bowel disease, liver cirrhosis
how may CF be diagnosed?
newborn blood spot
sweat test
genetic testing
what is the newborn blood spot?
Newborn blood spot testing: all children get tested after birth picks up most cases
what is the sweat test?
Sweat test: a patch of skin is chosen to test (arm/ leg)
- Pilocarpine is applied to skin at that particular patch
- Electrodes are placed either side and small cureet is passed between electrodes – causes skin to sweat
- Sweat is absorbed with lab issued gauze/ filter paper and sent to lab for testing for CL conc
what score on an seat test would indicate CF?
- CF = >60mmol/L
what causative organisms can colonise within airways of CF?
Causative organisms: staph. A, h.influenza, klebsiella, e.coli, burkhoderia cepacian and p.aeruginosa
why is there microbial colonisation in CF?
Microbial colonisers: CF pt struggle to clear secretions in airways perfect bacteria environment
what is the issue with p. aeruginosa in CF?
- Pseudomonas aeruginosa: troublesome coloniser and hard to treat and worsens prognosis of CF
- They are resistant to many Abx increase morbidity and mortality
- CF pts should not meet with other CF pts as risk of spreading p.aeruginosa need separate rooms to minimise risk of transmission
how do you manage p. aeruginosa infections within CF patients?
- Need nebulised AB eg tobramycin or oral ciprofloxacin
what management is used in CF?
specialist
chest physio
exercise
high calorie diet
CREAN tablets
prophylactic fluclox
treat chest infections
bronchodilators
nebulised DNA ase (dornase)
nebulised hypertonic saline
vaccinations
end stage management
what is chest physio used for?
Chest physio: several times a day to clear mucus and reduce risk of infection and colonisation
