Cystic fibrosis

• What is cystic fibrosis?


  Autosomal recessive condition -> mutations in cystic fibrosis transmembrane conductance regulator (CFTR) gene

  Involved thickened mucosal secretions
• What is the prevalence of CF carriers?


  1 in 25 people
• What chromosome in the CFTR gene on?


  Chromosome 7
• Pathophys - CF

  Dysfunctional/absent CFTR protein on cell membrane of epithelial cells -> impaired Cl- & bicarb transport -> Cl- & water retention inside cells -> Na+ rich environment outside the cell -> promotes Na+ & H2O reabsorption -> mucous becomes dehydrated & thickened

  In sweat glands, Cl- is transported opposite way -> excess Cl- transported onto the skin -> raised sweat chloride
• What are the causes of clubbing in children?


  Hereditary clubbing

  Cyanotic heart disease

  IE

  Cystic fibrosis

  TB

  IBD

  Liver cirrhosis
• How can mutations in CFTR affect various systems within body?


  Pancreas

  • reduced Cl- absorption -> viscous secretions & ducts can be become occluded

  Biliary tree

  • concentration of biliary secretions blocks biliary ducts -> inflammation

  GIT

  • bowel absorption is impaired due to biliary disease, pancreatic insufficiency & thicker secretions within bowel

  Resp system

  • thicker secretions impair mucociliary clearance of bacteria -> enables colonisation
• What are the signs & symptoms of CF in neonates?


  Meconium ileus (doesn't pass meconium within 48 hrs of birth)
• What are the signs & symptoms of CF?


  Chronic cough

  Thick sputum

  Recurrent resp tract infections

  Steatorrhoea (due to lack of lipase enzymes)

  Abdo pain & bloating

  Parents may report child having salty sweat when they kiss them

  Failure to thrive

  Nasal polyps

  Clubbing

  Crackles & wheeze on auscultation

  Abdo distension
• What are the DDx of CF?


  Bronchiectasis

  Asthma

  COPD

  GORD

  Coeliac disease
• What are the Inx of CF?


  Screened in heel prick test (raised blood immunoreactive trypsinogen)

  Sweat test (given cholinergic first - pilocarpine applied first)

  Genetic testing

  Sputum culture

  Stool elastase (for pancreatic insufficiency)

  Spirometry

  CT thorax
• What are the possible complications of CF?


  Bronchiectasis

  Cor pulmonale

  Malnutrition

  Bowel obstruction

  Hepatosplenomegaly

  CF-related diabetes

  Infertility (esp in males)

  Osteoporosis
• What are some common colonisers in CF?


  Staph aureus

  Haemophilus influenza

  Klebsiella pneumoniae

  E.coli

  Burkhodheria cepacia

  Pseudomonas aeruginosa
• What is the treatment & management of CF?


  Chest physio

  Exercise

  High calorie diet

  CREON tablets

  Prophylactic flucloxacillin

  Treat chest infections when occur

  Bronchodilators (when bronchoconstriction)

  Nebulised DNase

  Nebulised hypertonic saline

  Vaccines (pneumococcal, flu & varicella)

  Transplantation (lung, liver)

  Fertility treatment

  Genetic counselling
• Why is chest physio done in CF?


  Mucus clearance

  Reduce risk of infection & colonisation
• What is exercise important in CF?


  Improves resp function & reserve

  Helps clear sputum
• What are CREON tablets? Why are they given in CF?


  Pancreatic enzyme replacement therapy

  Replace enzymes in pts with pancreatic insufficiency
• What is nebulised DNase? Why is it given in CF?


  Enzyme that can break down DNA material in resp secretions

  Makes secretions less viscous & easier to clear
• What is the median life expectancy of CF?


  47 years
• CF stats 


  • 90% of patients with CF develop pancreatic insufficiency
  • 50% of adults with CF develop cystic fibrosis-related diabetes and require treatment with insulin
  • 30% of adults with CF develop liver disease
  • Most males are infertile due to absent vas deferens