Cystic fibrosis Flashcards
What is cystic fibrosis
Autosomal recessive condition causing thicker mucus
What casues cystic fibrosis
Genetic mutation of CF transmembrane conductance regulatory gene on chromosome 7
Most commonly delta-F508 mutation
Codes - cellular channels
What does the delta-F508 mutation effect
Chloride channnels in mucus menbranes
Key consequences of CF mutation
Thick pancreatic and biliary secretions
Low volume thick AW secretions
Congenital bilateral absence of vas deferens in males
What does thick pancreatic and biliary secretions in CF cause?
that cause blockage of the ducts, resulting in a lack of digestive enzymes such as pancreatic lipase in the digestive tract
What does oow volume thick AW secretions cause?
hat reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
What causes male infertility in CF?
- Congenital bilateral absence of the vas deferens in males. Patients generally have healthy sperm, but the sperm have no way of getting from the testes to the ejaculate,
How is CF screened for?
Newborn bloodspot test
What is often the first sign of CF?
Meconium ileus
What is meconium ileus?
thick and sticky meconium prevents meconium passing in first 24 hours
How does meconium ileus present?
No meconium passing in 24 hours
Abdominal distension and vomitting
How does meconium ileus present?
No meconium passing in 24 hours
Abdominal distension and vomitting
How does CF present later if undiagnosed at birth?
Recurrent lower respiratory tract infections
FTT
Pancreatitis
Symptoms of CF
Chronic cough
Thick sputum production
Recurrent repiratory tract infections
Steatorrhea
Abdo pain and bloating
Salty taste to skin
Poor weigth and height gain - FTT
Signs of CF
Low weight/height on growth vharts
Nasal polyps
Finger clubbing
Crackles and wheezing
Abdo distension
Causes of clubbing in children
- Hereditary clubbing
- Cyanotic heart disease
- Infective endocarditis
- Cystic fibrosis
- Tuberculosis
- Inflammatory bowel disease
- Liver cirrhosis
Diagnosis of cystic fibrosis
Newborn blood spot testing
Sweat test - gold standard
Genetic testing for CFTR gene by amniocentesis, chronic villous sampling
What is the gold standard test for CF?
Sweat test
How is the skin test carried out?
Patch of skin chosen
Pilocarpine applied to skin on patch
Electrodes placed either side + small current passed between electrodes -> skin sweats
Sweat absorbed with lab gauze or filter paper -> tested for chloride concentration
Diagnostic chloride concentration for CF
> 60mmol/l
Microbial colonisers in CF
- Staphylococcus aureus
- Haemophilus influenza
- Klebsiella pneumoniae
- Escherichia coli
- Burkhodheria cepacia
- Pseudomonas aeruginosa
Key colonisers in CF
S.aureus
Pseudomonas
Key colonisers in CF
S.aureus
Pseudomonas
What do people with CF take long term flucloxacillin for?
Prevent S.aureus infection
What coloniser worsens prognosis of patients with CF?
Pseudomonas Aeruginosa
How is pseudomonas colonisation in CF patients treated?
Long term nebulised antibiotics eg tobramycin
Oral ciprofloxacin
What can be done to clear mucus and reduce risk of infection in patients with CF?
Chest physiotherapy several times a day
What lifestyle do people with CF need to do?
Exercise
High calorie diet
How does exercise help CF
Improves respiratory function and reserve and helps clear sputum
Why is a high calories diet required in CF>
malabsorption, increased respiratory effort, coughing, infections and physiotherapy
What are creon tablets used for?
Digest fats in patients with pancreatic insufficiency - replace lipase enzymes
What is nebulised DNase?
An enzyme that can break down DNA material in respiratory secretions, making secretions less viscous and easier to clear
What medication can only be used for F508del mutation type in oatients over 12
Kaftrio
Non pharmacological treatment options for CF
Lung transplantatoon
Liver transplant
Fertility treatment - testicular sperm extraction
Genetic counselling
What are people with CF screened for?
Diabetes
Osteoporosis
Vitamin D deficiency
Liver failure
What is median life expectancy with CF?
47
Prognosis with CF
- 90% of patients with CF develop pancreatic insufficiency
- 50% of adults with CF develop cystic fibrosis-related diabetes and require treatment with insulin
- 30% of adults with CF develop liver disease
- Most males are infertile due to absent vas deferens
Prognosis with CF
- 90% of patients with CF develop pancreatic insufficiency
- 50% of adults with CF develop cystic fibrosis-related diabetes and require treatment with insulin
- 30% of adults with CF develop liver disease
- Most males are infertile due to absent vas deferens
