Cystic Fibrosis

Question 1

What is cystic fibrosis?

Answer 1

An genetic condition where the chloride channel does not work correctly, resulting in the production of thick sticky mucus from mucosal membranes

Question 2

Epidemiology of cystic fibrosis?

Answer 2

commonest genetically transmitted disease in caucasians
1:2000 births

Question 3

Genetics of cystic fibrosis?

Answer 3

autosomal recessive condition
defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene

Question 4

Pathophysiology of cystic fibrosis?

Answer 4

Cl- channels do not open
More CL- leaves cell
More Na and water up taken by cell
V thick chloride-rich mucus
Obstructs airways
Affects organs (pancreas especially)

Question 5

Why does cystic fibrosis make you susceptible to resp infections?

Answer 5

defensins (natural antibiotic peptides) inactivated as salt sensitive

Question 6

What resp infection are Cf pts likely to get?

Answer 6

pseudomonas aeruginosa and staph aureus

Question 7

Presentation of cystic fibrosis?

Answer 7

GI:
Meconium ileus/ rectal prolapse/ diarrhoea/failure to thrive/ greasy and offensive stools

Resp:
recurrent broncho pulmonary infection / bronchiectasis
chronic cough
sputum production

Others:
clubbing and dyspnoea
Salty sweat
nasal polyps

Question 8

Investigations for cystic fibrosis?

Answer 8

Lung function tests - if old enough
Sputum
Sweat test - high cl- levels (salty)
Genetics - gurthrie heel prick test (neonatal screening) and genetic testing for CFTR gene
Imaging - CXR and HRCT
Genetic counselling

Question 9

Management of cystic fibrosis?

Answer 9

chest physio
exercise
inhaled bronchodilators
mucolytics
lung fuctions
Nebulised DNase (lyses accumulated neutrophils in lung lining)
Steroids
CREON tablets to digest fats

Question 10

Prognosis of cystic fibrosis?

Answer 10

median survival = 47 years
die of resp complications

Question 11

Complications of cystic fibrosis?

Answer 11

Blockage of ducts in pancreas = loss of digestion enzymes

thick airway secretions = bacterial colonization

Congenital bilateral absence of the vas deferens = male infertility

Pseudomonas Aeruginosa infections

Develop insulin managed diabetes

Question 12

How to prevent a CF patient getting Pseudomonas Aeruginosa infection?

Answer 12

Give prophylactic flucloxacillin
PA infection = hard to treat and worsens prognosis

Question 13

Why is it discouraged other CF pts being in close contact?

Answer 13

High risk of infection spreading that the pts cannot fight off