Cystic Fibrosis Flashcards
Describe the inheritance pattern of cystic fibrosis
•autosomal recessive trait
What is the disease prevalance?
1 : 2,500
Where is the CTFR gene?
On the long arm of chromosome 7
What is the commonest mutation for CF?
•phe508del (DF508)
–70% N europeans
Look
Look
What is the function of the CTFR gene?
•Active transport channel for chloride
–Regulates liquid volume on epithelial surface
- Reduced chloride efflux
- Increased sodium influx via ENaC
–Cilia collapse
–Excessive inflammation
Look
What are the clinical features for CF at antenatal, neonatal, infants and young children, older children and adults?
What is involved in the neonatal screeing for cystic fibrosis?
- Newborn bloodspot day 5 (Guthrie test)
- Initial screen - immuno-reactive trypsinogen
- If positive, mutation analysis performed (5 in Scotland, 4 in rest of UK)
- Screen positive referred sweat test
- Both stages miss a proportion of cases
What is mortality in CF?
–“Probably” reduces infant mortality
What is lung function in CF?
•Lungs
–Wisconsin study no difference in FEV1 at 7-8y (confounding factors may add bias)
–Small Australian study better lung function at 15y
What is the effect of CF on the brain?
•Brain
–Vitamin E deficient at diagnosis had lower Cognitive Skills Index and head circumference
What is sweat chloride in CF?
Much higher than normal
What is management of CF?
–Specialist multi-disciplinary team - since multi-organ disease
Shared care with local clinics
•Primary care
–Surveillance
–Early treatment of infection
What are the effects of CF on Pancreas and Stools and Thrive?
•Pancreatic insufficiency (85-90%)
–Abnormal stools
- Pale or orange
- Very offensive
- Greasy or oily
–Failure to thrive
- May thrive quite well on breast milk
- May have deficiencies of fat soluble vitamins
What is the treatment of pancretic insufficiency?
Enteric coated pellets
High energy diet (not - low fat)
Fat-soluble vitamin and mineral supplements
H2 antagonist or proton pump inhibitors*
What is the effect of CF on lung pathology?
•Recurrent bronchopulmonary infection
–Pneumonitis
–Bronchiectasis
–Scarring
–Abscesses
How do control CF pre-infection?
- Segregation/cohorting to prevent cross-infection
- Airway clearance and adjuncts
- Mucolytics¶
- Prophylactic antibiotics (against Staph aureus)¶
- Annual influenza vaccination
Eradication of early infection imperative
What are the common respiratory pathogens in CF?
–Staphylococcus aureus and Haemophilus influenzae in early years
–Pseudomonas aeruginosa later
What are the less common organisms in CF later in life?
•Less common organisms
–Burkholderia cepacia
–Stenotrophomonas maltophilia
–Alcaligenes xylosoxidans
–Atypical mycobacteria e.g. M abscessus
What is the treatment of chronic infection?
- Suppress bacterial load¶
- Treat infective exacerbations (elective v symptomatic use*)
- Reduce inflammation
–Ibuprofen*
–Azithromycin¶
–Prednisolone
(inhaled antibacterial?) - nebulisers, inhalers?
What is predicted median survival for cystic fibrosis in the 21st century?
Over 50 years
What are the GI manifestations of CF?
–Dysmotility
- Meconium ileus
- Gastro-oesophageal reflux
- Distal intestinal obstruction
- Constipation/rectal prolapse
–Co-existent disease
•Crohn’s and coeliac
Also Hepatopathy
