Cystic fibrosis

Question 1

CF pathology

Answer 1

Mutation in CF transmembrane conductance regulator (CFTR) gene on chromosome 7
Cl- channel, when defective increased na absorption across airway so more pulmonary infections + bronchiectasis

Question 2

CF clinical features

Answer 2

Failure to thrive, rectal prolapse in neonates

Cough, recurrent pulmonary infections

Pancreatic insufficiency

Cyanosis
Clubbing
Bilateral coarse crackles

Question 3

CF diagnosis

Answer 3

Sweat test - Sweat Na + Cl >60mmol, Cl normally > Na
Genetic screening
Faecal elastase screening for exocrine pancreas dysfunction

Question 4

CF tests

Answer 4

FBCs, ADEK levels
Cough swab, sputum culture

CXR shows hyperinflation + bronchiectasis
Abdo US shows fatty liver + chronic pancreatitis

Obstructive defect on spirometry

Question 5

CF management

Answer 5

Chest physio
Abx for acute infective exacerbations + prophylaxis
Mucolytics + bronchodilators may help
Diuretics for cor pulmonale in severe

Pancreatic enzyme replacement
ADEK supplements
Liver transplantation if severe cirrhosis

OGTT for CF diabetes
Osteoporosis treatment

Question 6

CF mutation specific treatments

Answer 6

Ivacaftor for gating defects in disease
Lumacaftor for deletion errors
Gene therapy work ongoing but showing significant improvement in trials

Question 7

CF prognosis

Answer 7

~41 yrs currently but children born today expected to be longer
Chronic pseudomonas infection is important survival predictor