Cystic Fibrosis Flashcards
Inheritance
autosomal recessive
What does cystic fibrosis cause to happen to secretions?
increased viscosity of secretions (e.g. from lungs and pancreas)
Genetic defect in CF
defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR)
This encodes a cAMP-regulated CHLORIDE channel
Chromosomal abnormality most commonly found in CF
delta F508 on the long arm of chromosome 7
Organisms which commonly colonise patients with CF
Staphylococcus aureus
Pseudomonas aeruginosa
Burkholderia cepacia*
Aspergillus
If patients present with CF as a neonate, how do they normally present?
- meconium ileus
- Less commonly prolonged jaundice
Ways in which CF can present
- recurrent chest infections
- malabsorption: steatorrhoea, failure to thrive
- other features: liver disease
What percentage of patients with CF are diagnosed after the age of 18?
around 5%
(most are picked up during newborn screening programmes or in early childhood)
Common clinical features of cystic fibrosis (not related to secretions)
- short stature
- diabetes mellitus
- delayed puberty
- rectal prolapse (due to bulky stools)
- nasal polyps
- male infertility, female subfertility
Non-pharmacological management of CF
- Regular chest physio and postural drainage
- high calorie+fat diet,
- minimise contact with others with CF to prevent cross infection
- vitamin supplementation
- pancreatic enzyme supplements
- lung transplantation
Describe the mechanism of Lumacaftor/Ivacaftor (Orkambi)
which is used to treat cystic fibrosis patients who are homozygous for the delta F508 mutation.
Lumacaftor - increases number of CFTR proteins that are transported to the cell surface
Ivacaftor - potentiator of CFTR that is already at the cell surface, increasing probability that the defective channel will open and allow chloride ions to pass through
