Cystic Fibrosis Flashcards
What is cystic fibrosis?
An autosomal recessive disease which affects the CFTR gene on chromosome 7.
What is the most common mutation in CF?
CFTR gene mutation - DeltaF508.
How many children have CF?
1 in 25000
How many children are carriers of CF?
1 in 25
What are the statistics of children if both parents are carriers?
1 in 4 - have CF
1 in 4 - don’t have CF or gene
1 in 2 - CF gene carrier
If a sibling has CF, the likelihood if you have a 2 in 3 chance of being a carrier
What are the tests for CF?
- Newborn blood spot test
- Sweat test (gold standard)
- Genetic testing for CFTR gene
How is genetic testing done?
Pregnancy - amniocentesis or chorionic villus sampling
Post birth - blood test
How is the sweat test done?
Patch is chosen on leg or arm, Pilocarpine is rubbed on, electrodes are placed and a current is passed through.
This creates sweat which is collected in gauze.
What results of a sweat test show CF?
Chloride >60mmoles/L.
What are the signs and symptoms of CF?
Chronic cough Thick sputum Recurrent RTI abdominal pain, bloating Steatorrhoea Lack of weight/height gain Nasal polyps crackle and wheeze clubbing pancreatitis
What are the causes of finger clubbing in children?
Hereditary clubbing Cystic fibrosis Liver cirrhosis Tuberculosis Irritable bowel disease Infective endocarditis Cyanotic heart disease
What is the gold standard test for CF diagnosis?
Chloride sweat test.
What is a sign of CF in babies?
Meconeum ileum (not passing first stool) within 24hrs. Causing stomach distention and bloating.
Which enzymes are missing?
Fat digesting enzymes - Lipase.
What are the main organisms causing infection in CF?
Staph aureus (prophylactic flucloxacillin) Pseudomonas aeruginosa (increase in morbidity and mortality)
