Cystic Fibrosis Flashcards
Cystic Fibrosis is
an autosomal recessive genetic condition affecting the mucus glands.
It is characterised by defects in the
CFTR on chromosome 7.
CFTR codes for
Cystic Fibrosis Transmembrane conductance Regulator protein.
The CFTR protein regulates
the flow ions, particulary chloride, across cell membranes
Most common variant is
the delta-F508 mutation , in the CFTR gene.
The delta-f508 mutation causes
productions of thick vicious mucus in organs such as, lungs, pancreas, and reproductive tract.
Prevalence
1in 25 are carries of the mutation.
1 in 2500 children have CF.
Accumulation of mucus can cause
obstructions in the airways, leading to respiratory problems. Such as: bacterial colonisation, chronic lung infections and bronchiectasis.
CF can also cause (Malnutrition)
pancreatic insufficiency, resulting in malnutrition and impaired fat and protein absorption.
In the reproductive system, CF can cause
congenital bilateral absence of vas deferens in males, resulting in male infertility
Secretions in airways creates (environment)
the perfect environment with plenty of moisture and oxygen for colonies of bacteria to live and replicate.
Common colonisers include
Staphylococcus aureus
Pseudomonas aeruginosa
Once patients become colonised with pseudomonas it can be difficult to
get rid of, thus long-term nebulised antibiotics, such as ciprofloxacin can be used
Diagnosis of CF in babies
typically screened for at birth using the newborn blood spot test.
20% of babies with CF have meconium ileus (condition where the meconium is thick and sticky, causing it to get stuck and obstruct the bowel).
Meconium ileus is pathognomonic for CF.
Gold standard diagnosis
Gold standard = the sweat test - measures concentration of chloride in the sweat.
The diagnostic chloride concentration for CF is no more than 60mmol/L.
Diagnosis techniques include what three
clinical presentation, laboratory tests and genetic testing
Physical examination may reveal
recurrent respiratory infections, poor growth and development (failure to thrive), steatorrhea, thick sputum production, crackles and wheezes on auscultation, nasal polyps, pancreatitis and salty skin.
Lab tests also include
measurement of serum electrolytes particularly chloride levels
analysis of stool samples for pancreatic enzymes levels.
genetic testing can confirm the diagnosis by identifying pathogenic mutations in the CFTR gene.
Management involves (A to H)
A - antibiotics (to treat bacterial infections)
B - bronchodilators (to improve airway function)
C - chest physiotherapy (essential to clear mucus and reduce risk of infection and colonisation)
D _ digestive enzymes (CREON tablets replace missing lipase enzymes)
E - exercise (improves respiratory function)
F - flu vaccines and pneumococcal
G - growth hormones
H - high calorie diet.
Goal of treatment (PMI)
manage symptoms, prevent complications, and improve quality of life.
Further treatments include
lung transplantation (end of life care)
liver transplant (liver failure)
fertility treatment
genetic counselling
Monitoring
follow up appointments every 6 moths for the monitoring of sputum colonisation of bacteria like pseudomonas
screening for diabetes, osteoporosis, vit D deficiency and liver failure.
Life expectancy
CF trust gives a median life expectancy of 45 years
CF pathophysiology sum up
is an autosomal recessive genetic condition affecting the mucus glands. It is caused by a genetic mutation of the cystic fibrosis transmembrane conductance regulatory gene on chromosome 7. There are many different mutations the most common is the delta- F508 mutation. This gene codes for the cellular channels, particularly the chloride channel.
Aetiology of CF
Gene mutation of the CFTR gene on chromosome 7
Genetic component
Recessive = child needs to inherit one copy from each parent
Risk Factors of CF
Family history
Most common in Northern European Ancestry
CF diagnosis
New-born blood spot testing - performed at birth
The sweat test is gold standard
Genetic testing for the CFTR gene can be performed via amniocentesis or chorionic villous sampling or blood test
meconium ileus is pathognomonic for cf
CF Key-biochem
Chloride concentration is more than 60mmoL/L
CF clinical features (long list)
Chronic cough
Meconium ileus
Thick sputum production
recurrent respiratory tract infections
steatorrhoea - due to lack of fat-digesting enzymes
abdominal pain and bloating
salty skin
failure to thrive
pancreatitis
nasal polyps
finger clubbing
crackles and wheezes on auscultation
abdominal distention
CF medication
CREON tablets = digest fats in patients with pancreatic insufficiency (these replace missing lipase enzymes)
Prophylactic flucloxacillin - reduces risk of infections like staph aureus
Nebulised DNase - breaks downs DNA material in respiratory secretions less viscous and easier to clear
Nebulised hypertonic saline
insulin - 50% of adults with CF develop cystic fibrosis-associated diabetes
CF Management (A to H)
A - Antibiotics
B - Bronchodilator, subutamol inhalers
C - Chest physiotherapy
D_ Digestive enzymes - CREON tablets to replace missing lipase enzymes
E - Exercise, improves function
F - Flu + pneumococcal vaccine
G- Growth hormone
H - High calorie diet
Surgery options for CF
Lung transplant (option in end-stage respiratory failure)
Liver transplant in liver failure
