Cystic Fibrosis Flashcards
What are the different chances that a person will have CF?
Caucasians - 1 in 2500.
Carriers - 1 in 25.
What causes morbidity and mortality in CF?
Pulmonary disease - main cause.
Respiratory failure - causes death in 90%.
What causes CF?
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.
What happens to the mucous layer in CF?
Dehydrated and thickened.
Sticks to the mucosal surface, causing shearing.
Difficult to cough up.
Collects bacteria - has a reduced ability to fight infection.
What are the different mutation classes of CFTR?
I, II, and III - severe (most common = II).
IV, V, and VI - milder.
What are antenatal tests for CF?
Pre-implantation genetic diagnosis.
Chorionic villus sampling.
Amniocentesis.
What is a neonatal test for CF?
Guthrie test - a blood spot taken on day 5.
Positive - refer for assessment, do sweat test.
Proportion of diagnoses missed.
What is a postnatal test for CF?
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.
What are the clinical manifestations of CF?
Psychosocial.
Nasal - sinusitis.
Nutrition - increased energy need, reduced intake, vitamin deficiency.
GI and liver - pancreatic insufficiency.
Lungs - chest infections.
Reproductive - male infertility, delayed puberty.
What does pancreatic insufficiency in CF cause?
A lack of enzyme absorption - malabsorption, stools (pale, offensive, floating), failure to thrive.
What mutation classes of CF are pancreatic insufficient?
I, II, and III.
IV, V, and VI have some pancreatic functions.
What chest infections occur in CF?
Pneumonia.
Bronchiectasis.
Abscesses.
Scarring.
How do repeated respiratory infections occur?
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.
How does progressive respiratory decline occur in CF?
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).
How can you improve QoL in CF?
Oxygen and NIV.
Exercise.
Support.
Alternative therapies.
Advanced care plans.
DNACPR discussions.
What is the management in CF?
An MDT - improves long-term outcomes.
Members of primary care survey patients with CF for early treatment of infection.
How is nutrition boosted in CF?
Replacement enzymes - Creon.
High energy and high-calorie drinks.
Fat-soluble vitamins and minerals.
What is the treatment in CF?
Physiotherapy - airway clearance.
Mucolytics and bronchodilators.
Antibiotics - oral, IV, nebulised.
Azithromycin - decreases inflammation.
Supportive treatment of symptoms.
How is T2DM linked to CF?
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.
How is osteoporosis linked to CF?
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.
What are the predictors of BMD?
Low FEV1, BMI, and exercise.
Frequent antibiotic courses or steroids.
Diabetic.
Male.
Vitamin D deficient.
Delayed puberty.
Age.
How is pneumothorax linked to CF?
Affects ~3% of CF patients during their lifetime (especially if they are older of have more severe obstructive lung disease). 50% recur.
How is haemoptysis linked to CF?
Minor (60%) - streaks of blood.
Massive (1%) - may precede gurgling in the chest. Admit and resuscitate.
May need a bronchial angiogram and embolisation.
What are the risk factors for haemoptysis in CF?
CF severity.
A high number of exacerbations.
Fungal lung infection.
Liver disease.
Vitamin K deficiency.
Anticoagulants.
What are the social impacts of CF?
Barriers to making friends.
Increased depression and anxiety.
Increased costs to family members.
Restrictions on careers and hobbies.
Cross infections and other conditions.
What are the new modulator drugs for CF?
Addresses different parts of CFTR mechanisms.
Small benefits in lung function.
More significant benefits in decreasing chest exacerbations, increasing weight and improving QoL.
What are the indications for lung transplantation?
Rapidly deteriorating lung function.
FEV1 < 30% predicted.
Life-threatening exacerbations.
Estimated survival of <2 years.
Recurring pneumothorax.
Severe haemoptysis.
Why is the window of opportunity narrow in CF patients wanting a lung transplant?
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?
What are the relative contraindications for a lung transplant in CF?
Other organ dysfunction.
Non-compliance.
Steroids >20mg daily.
Absence of recognised social support.
Osteoporosis.
Low or high BMI.
Surgical risks (previous surgery).
Psychological instability.
What are the absolute contraindications for a lung transplant in CF?
Other organ failure.
Malignancy within 5 years.
Significant peripheral vascular disease.
Drug / nicotine / alcohol dependency.
Active systemic infection.
Microbiological issues.
What is the median survival of CF?
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.
What are the common bacterial infections in CF?
0-10 - H. Influenzae.
10-20 - S. Aureus.
20+ - P. Aeruginosa.
Low % - B. Cepacia.
What is P. Aeruginosa?
Decreased life expectancy and lung function.
First isolation - attempt eradication.
Acquired from hospitals and other CF patients (may have a role in repeated abx).
What is B. Cepacia?
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.
What is Non-Tuberculous Mycobacteria?
Doesn’t need treatment if well.
M. Abscessus - grows rapidly; a contraindication to lung transplant; treated by 1 month in hospital, highly resistant.
