Respiratory

Question 1

What is the mean survival age for patients with CF?

Answer 1

42-50 years

Question 2

What is the carrier rate for CF?

Answer 2

1/25
*Most common life-limiting recessive genetic trait amongst Caucasians*

Question 3

What is the most common CF mutation?

Answer 3

Delta F508; class II mutation

Question 4

What is the inheritance of CF?

Answer 4

AR
Mutations in the CFTR (expressed in epithelial cells of airways, GIT, sweat glands + GIT)
Gene on chromosome 7

Question 5

Creon

• Mode of action
• Indications
• Side effects
• Counselling

Answer 5

Mode of action
Pancreatic enzymes are essential for fat, carbohydrate and protein digestion. Supplements aim to correct enzymatic deficiency. All products are of porcine origin.

Indications
Pancreatic enzyme insufficiency (eg cystic fibrosis, chronic pancreatitis, post gastrectomy/pancreatic surgery)
Adverse effects
Common (>1%)
nausea, vomiting

Infrequent (0.1–1%)
irritation of skin around mouth and anus

Rare (<0.1%)
hyperuricaemia, hyperuricosuria, fibrosing colonopathy (bowel stricture) in children with cystic fibrosis taking high doses

Counselling
- Take with food

Question 6

Dornase alfa (Pulmozyme)

• Mode of action
• Indications
• Side effects
• Counselling

Answer 6

Mode of action
Reduces mucus viscosity in cystic fibrosis by cleaving extracellular DNA.

Indications
Prevention of respiratory complications in cystic fibrosis

Side effects
- Voice alteration, pharyngitis, rash

Counselling
- Nebulised

Question 7

Orkambi (Lumacaftor + Ivacaftor) - Mode of action

• Indications
• Side effects
• Counselling

Answer 7

Mode of action
Lumacaftor increases the amount and function of cystic fibrosis transmembrane conductance regulator (CFTR) protein on the cell surface, while ivacaftor increases channel opening of the CFTR protein to facilitate chloride transport across cell membranes.

Indications
Cystic fibrosis in patients with a certain mutation in the CFTR gene

Precautions
Poor lung function (eg FEV1 <40%)—consider using a lower dose in the first couple of weeks.

Advanced liver disease (eg cirrhosis or portal hypertension)—worsening liver function (including fatal hepatic failure) has been reported.

Other drugs
Patients already taking a strong CYP3A4 inhibitor (eg clarithromycin, itraconazole, posaconazole, voriconazole) require lower initial doses of lumacaftor with ivacaftor.

Question 8

CF Background History + Investigations

Answer 8

Age of diagnosis
Mode of presentation
Genotype
Class

Investigations
Sweat chloride result
CXR
CT
Lung function testing
OGTT (start from 10yrs of age)
Micro
ABPA screening
- IgE level (will be high)
- Anti-Aspergillus IgE
- Skin test

Question 9

CF Annual Screening Review

Answer 9

• CT chest
• Liver + abdominal ultrasound
• Blood test:
• OGTT
• BMD test
• Food diary
• CF physio review