Cystic fibrosis

Question 1

What is cystic fibrosis?

Answer 1

Genetic condition causing mucus clogging of the lungs and digestive system

Question 2

What are the genetics behind cystic fibrosis?

Answer 2

Autosomal recessive disorder
Chromosome 7
CFTR gene- CF transmembrane conductance regulator

Question 3

What does abnormal CFTR protein function lead to?

Answer 3

Chloride is trapped in the cell
Sodium and water then flow into the cell
This dehydrates the airway surface liquid (ASL)
Thick mucus sticks to the mucosal surface causing shearing
Mucus collects bacteria causing infection

Question 4

What are the types of CFTR protein mutations?

Answer 4

6 different classes
Most common is class 2 (DektaF508)

Question 5

What do classes I-III mutations present with?

Answer 5

Severe disease with no functioning protein

Question 6

What do classes IV-VI mutations present with?

Answer 6

Some residual CFTR function
Milder symptoms

Question 7

What are the clinical manifestations of CF?

Answer 7

Pancreatic insufficiency
Chest infections
Diabetes
Osteoporosis
Haemoptysis
Pneumothorax

Question 8

What does pancreatic insufficiency lead to?

Answer 8

Malabsorption
Pale, offensive, greasy stools
Failure to thrive

Question 9

What does recurrent chest infections lead to?

Answer 9

Pneumonia
Bronchiectasis
Scarring
Abscesses

Question 10

What is the antenatal diagnosis for CF?

Answer 10

Preimplantation genetic diagnosis
Chronic villous sampling- placenta
Amniocentesis- amniotic fluid

Question 11

What is neonatal diagnosis for CF?

Answer 11

Guthrie test- blood spot on day 5

Question 12

What is postnatal diagnosis for CF?

Answer 12

Sweta test- measures concentration of Cl-
>60= high chance of CF
30-59= inconclusive
<30= not CF

Question 13

What does CF show on CXR?

Answer 13

Consolidation
Mucus plugging
Signet rings
Tramlines

Question 14

What is the treatment for CF?

Answer 14

Creon- replace pancreatic enzymes
High calorie diet
Nutritional supplements
Physiotherapy- airway clearance
Mucolytics- mucous plugs
Bronchodilators- airway clearance
Oral azithromycin- airway inflammation
Antibiotics- infections
Supportive treatment for lung fibrosis
Double lung transplant

Question 15

What are the indications for lung transplant?

Answer 15

Rapidly deteriorating lung function
FEV1<30%
Life threatening exacerbations
Recurrent pneumothorax
Recurrent severe haemoptysis

Question 16

What are the contraindications for lung transplant?

Answer 16

Other organ failure
Malignancy within 5 years
Significant peripheral vascular disease
Drug/alcohol/nicotine dependency