Cystic Fibrosis Flashcards
what is cystic fibrosis?
an autosomal recessive condition affecting the mucous glands.
what mutation causes cystic fibrosis?
a genetic mutation of the CFTR gene on chromosome 7
What is the most common genetic mutation?
Delta F508
how many people are carries of CF?
1 in 25
How many people are affected by CF?
1 in 2500
what is the pathophysiology of CF?
theres increased sodium absorption and abnormal chloride secretion.
What problems are seen in CF?
- thick pancreatic and biliary secretions causing blockages (and lack of digestive enzymes)
- Low volume of thick airway secretions (leading to bacterial colonisation)
- Bilateral absence of the vas deferent in males
how does CF present in neonates?
Meconium Ileus -
Theres usually abnormal passage of the meconium. Its thick and gets stuck in the bowel. Causes abdominal distention.
How does CF present in later childhood if it hasn’t presented at birth?
Recurrent LRTI steatorrhoea abdominal pain and bloating concentrated salt in the sweat poor weight gain poor height gain finger clubbing crackles an wheeze abdominal distention nasal polyps rectal prolapse
what are the common causes of finger clubbing?
Cystic fibrosis hereditary Cyanotic heart diseease infective endocarditis IBD tuberculosis Liver cirrhosis
What investigations are there for CF?
Birth - blood spot testing (immunoreactive trypsinogen)
Sweat test - gold standard.
Genetic testing -done during pregnancy.
how is the sweat test carried out?
Pilocarpine is applied to the skin, electrodes are placed at either side of the patch and an electric current is passed through which makes the patient sweat.
The sweat is collected and is tested in the lab for chloride concentration.
What chloride concentration suggests CF?
> 60mmoles/L.
What sign is basically diagnostic for CF?
Meconium ileus
what are the most common microbial colonisers?
Staphylococcus aureus
Pseudomonas aeruginosa.
