Cystic Fibrosis

Question 1

How many in Caucasian live births

Answer 1

1 in 2000-2500

Question 2

Commonest mutation

Answer 2

DeltaF508 (70%, is also most severe)

Question 3

Cause of death in 90%

Answer 3

Respiratory failure

Question 4

What is the protein affected called and what chromosome is it on

Answer 4

Transmembrane conductance regulator protein (CFTR) on chromosome 7

Question 5

What goes wrong with CFTR protein

Answer 5

It has reduced chlorine secretion from epithelium and reduce Na absorption from lumen causing reduced airway surface liquid and thick sticky mucus which can cause shearing. Also impaired bacterial killing by neutrophils

Question 6

5 classes of mutations

Answer 6

1- No synthesis
2- block in processing (delta F508)
3- block in regulation 
4- altered conductance 
5- reduced synthesis

Question 7

How is CF usually diagnosed

Answer 7

Antenatal testing by preimplantation genetic diagnosis, Chorionoic villus sampling or amniocentesis. After someone in family is identified or newborn Guthrie bloodspot

Question 8

Postnatal testing for CF

Answer 8

Sweat testing measures Cl concentration in sweat. Abnormal is >60mm

Question 9

Two cardinal features of CF

Answer 9

Pancreatic insufficiency and recurrent bronchopulmonary infection

Question 10

Pancreatic insufficiency

Answer 10

Abnormal stools, failure to thrive, diabetes (classes 4-6 have some pancreatic function)

Question 11

How much CFTR function do we need to be asymptomatic

Answer 11

5%

Question 12

Consequences of recurrent bronchopulmonary infections

Answer 12

Pneumonia, bronchiectasis, scarring, abscesses

Question 13

Why do CF patients have recurrent pulmonary infection

Answer 13

Decrease in mucociliary clearance and bacteria endocytosis, increase in bacterial adherence

Question 14

Bronchiectasis in CXR

Answer 14

Tramlines and signet rings and mucous plugging and consolidation

Question 15

Nail clubbing

Answer 15

Low O2

Question 16

Who manages CF

Answer 16

MDT

Question 17

Treatment of pancreatic insufficiency

Answer 17

Enteric coated enzyme pellets, high energy diet, fat soluble vitamin and mineral supplements

Question 18

Treatment of respiratory features in CF

Answer 18

Physio for airway clearance, mucolytics and bronchodilators, antibiotics, azithromycin for inflammation, support

Question 19

Extra things CF can cause

Answer 19

Diabetes, osteoporosis, pnuemothorax, haemoptysis

Question 20

Issues with diabetes in CF

Answer 20

Diet compliance is difficult, but insulin helps.

Question 21

Osteoporosis in CF

Answer 21

1/3 fall in bone mineral density, slower gain and faster loss. Occurs due to malnutrition and low bmi, and vitamin D/K deficiency and cytokines and delayed puberty. Treated with bone protection medication and weight bearing exercises

Question 22

Pneumothorax in CF

Answer 22

Affects 3-4%, treated same as usual

Question 23

Haemoptysis in CF

Answer 23

Destruction of bronchial wall, can get chest gurgling. Massive classes as 100mls an hour or over 240mls in 24 hours. Treated with bronchial angiogram and embolisation

Question 24

Most common organisms in children

Answer 24

Staphylococcus aureus and haemophilus influenzae and Pseudonomas aerigunosa

Question 25

Most common organisms in adults

Answer 25

Pseudonomas and staphylococcus aureus

Question 26

Pseudonomas aerigunosa in CF

Answer 26

By 18 years old 80% have it, colonisation increases with age. Forms a biofiolm

Question 27

New drugs for CF

Answer 27

Ivacaftor,
Ivacaftor/lumacaftor (orkambi)
Ivacaftor/tezacaftor (symkevi)

Help with CFTR production but don’t really benefit lung function

Question 28

Double lung transplants

Answer 28

If rapid deterioration, FEV1<30%, life threatening exacerbations, survival <2y. 30-40% die on waiting list, survival 62% for 5 years

Question 29

Contra-indications for lung transplants

Answer 29

organ failure, malignancy, drugs, systemic infection

Question 30

Median survival of CF patients

Answer 30

40, over 50% in UK are now over 18.