Cystic Fibrosis

Question 1

What are the different chances that a person will have CF?

Answer 1

Caucasians - 1 in 2500.
Carriers - 1 in 25.

Question 2

What causes morbidity and mortality in CF?

Answer 2

Pulmonary disease - main cause.
Respiratory failure - causes death in 90%.

Question 3

What causes CF?

Answer 3

An autosomal recessive disorder, caused by a mutation in the CFTR protein (chromosome 7).
Abnormal function of the protein channel means Cl- is trapped in the cell, so Na+ and H2O also flow into the cell.

Question 4

What happens to the mucous layer in CF?

Answer 4

Dehydrated and thickened.
Sticks to the mucosal surface, causing shearing.
Difficult to cough up.
Collects bacteria - has a reduced ability to fight infection.

Question 5

What are the different mutation classes of CFTR?

Answer 5

I, II, and III - severe (most common = II).
IV, V, and VI - milder.

Question 6

What are antenatal tests for CF?

Answer 6

Pre-implantation genetic diagnosis.
Chorionic villus sampling.
Amniocentesis.

Question 7

What is a neonatal test for CF?

Answer 7

Guthrie test - a blood spot taken on day 5.
Positive - refer for assessment, do sweat test.
Proportion of diagnoses missed.

Question 8

What is a postnatal test for CF?

Answer 8

Sweat test - measures [Cl-] excreted in sweat.
>60 - high chance of CF.
30-59 - inconclusive.
<30 - low chance of CF (in an infant over 6 months old).

Usually repeated to confirm.
Less reliable above 6 months of age.

Question 9

What are the clinical manifestations of CF?

Answer 9

Psychosocial.
Nasal - sinusitis.
Nutrition - increased energy need, reduced intake, vitamin deficiency.
GI and liver - pancreatic insufficiency.
Lungs - chest infections.
Reproductive - male infertility, delayed puberty.

Question 10

What does pancreatic insufficiency in CF cause?

Answer 10

A lack of enzyme absorption - malabsorption, stools (pale, offensive, floating), failure to thrive.

Question 11

What mutation classes of CF are pancreatic insufficient?

Answer 11

I, II, and III.
IV, V, and VI have some pancreatic functions.

Question 12

What chest infections occur in CF?

Answer 12

Pneumonia.
Bronchiectasis.
Abscesses.
Scarring.

Question 13

How do repeated respiratory infections occur?

Answer 13

Decreased mucociliary clearance.
Increased bacterial colonisation.
Inflammation and mucus plugging occurs.
Airways become ulcerated and damaged.
Bronchiectasis occurs - airways thicken, stiffen, and dilate; the mucous is retained, becomes infected, and impairs gas exchange.

Question 14

How does progressive respiratory decline occur in CF?

Answer 14

Progressive bronchiectasis - chronic sputum.
Recurrent chest infections.
Progressive airway obstruction - survival is related to FEV1; increased SOB; treated with multiple drugs.
Respiratory failure - oxygen, nocturnal NIV, lung transplants (in some).

Question 15

How can you improve QoL in CF?

Answer 15

Oxygen and NIV.
Exercise.
Support.
Alternative therapies.
Advanced care plans.
DNACPR discussions.

Question 16

What is the management in CF?

Answer 16

An MDT - improves long-term outcomes.
Members of primary care survey patients with CF for early treatment of infection.

Question 17

How is nutrition boosted in CF?

Answer 17

Replacement enzymes - Creon.
High energy and high-calorie drinks.
Fat-soluble vitamins and minerals.

Question 18

What is the treatment in CF?

Answer 18

Physiotherapy - airway clearance.
Mucolytics and bronchodilators.
Antibiotics - oral, IV, nebulised.
Azithromycin - decreases inflammation.
Supportive treatment of symptoms.

Question 19

How is T2DM linked to CF?

Answer 19

Management - compliance with a high-calorie diet and insulin use.
Complications - same risks as non-CF patients, but lung disease affects them first.
Most common type of diabetes in CF.

Question 20

How is osteoporosis linked to CF?

Answer 20

A slower gain and faster loss in BMD.
Worsens during illness.
Increases risk of fractures.
May exclude lung transplants.
Treatment - bone protection drugs, weight-bearing exercise.

Question 21

What are the predictors of BMD?

Answer 21

Low FEV1, BMI, and exercise.
Frequent antibiotic courses or steroids.
Diabetic.
Male.
Vitamin D deficient.
Delayed puberty.
Age.

Question 22

How is pneumothorax linked to CF?

Answer 22

Affects ~3% of CF patients during their lifetime (especially if they are older of have more severe obstructive lung disease). 50% recur.

Question 23

How is haemoptysis linked to CF?

Answer 23

Minor (60%) - streaks of blood.

Massive (1%) - may precede gurgling in the chest. Admit and resuscitate.
May need a bronchial angiogram and embolisation.

Question 24

What are the risk factors for haemoptysis in CF?

Answer 24

CF severity.
A high number of exacerbations.
Fungal lung infection.
Liver disease.
Vitamin K deficiency.
Anticoagulants.

Question 25

What are the social impacts of CF?

Answer 25

Barriers to making friends.
Increased depression and anxiety.
Increased costs to family members.
Restrictions on careers and hobbies.
Cross infections and other conditions.

Question 26

What are the new modulator drugs for CF?

Answer 26

Addresses different parts of CFTR mechanisms.
Small benefits in lung function.
More significant benefits in decreasing chest exacerbations, increasing weight and improving QoL.

Question 27

What are the indications for lung transplantation?

Answer 27

Rapidly deteriorating lung function.
FEV1 < 30% predicted.
Life-threatening exacerbations.
Estimated survival of <2 years.
Recurring pneumothorax.
Severe haemoptysis.

Question 28

Why is the window of opportunity narrow in CF patients wanting a lung transplant?

Answer 28

30-40% die on the waiting list.
Is the condition bad enough?
Is the rest of the body good enough?
Does the patient want to gamble?

Question 29

What are the relative contraindications for a lung transplant in CF?

Answer 29

Other organ dysfunction.
Non-compliance.
Steroids >20mg daily.
Absence of recognised social support.
Osteoporosis.
Low or high BMI.
Surgical risks (previous surgery).
Psychological instability.

Question 30

What are the absolute contraindications for a lung transplant in CF?

Answer 30

Other organ failure.
Malignancy within 5 years.
Significant peripheral vascular disease.
Drug / nicotine / alcohol dependency.
Active systemic infection.
Microbiological issues.

Question 31

What is the median survival of CF?

Answer 31

Improved due to - CF centres, MDTs, physiotherapy, nutrition, enzymes, antibiotics, aggressive approaches, and annual vaccines.
If colonised by bacteria, MS decreases.

50% in the UK are now >18yrs old.
MS = ~40.

Question 32

What are the common bacterial infections in CF?

Answer 32

0-10 - H. Influenzae.
10-20 - S. Aureus.
20+ - P. Aeruginosa.
Low % - B. Cepacia.

Question 33

What is P. Aeruginosa?

Answer 33

Decreased life expectancy and lung function.
First isolation - attempt eradication.
Acquired from hospitals and other CF patients (may have a role in repeated abx).

Question 34

What is B. Cepacia?

Answer 34

Decreased life expectancy and lung function.
Worse in pregnancy.
Cepacia syndrome - rapid decline over a few weeks, then death.
Resistant to most antibiotics.
Acquired from onion rot and other CF patients.

Question 35

What is Non-Tuberculous Mycobacteria?

Answer 35

Doesn’t need treatment if well.
M. Abscessus - grows rapidly; a contraindication to lung transplant; treated by 1 month in hospital, highly resistant.