Cystic fibrosis Flashcards
What is the inheritance pattern of cystic fibrosis
Autosomal recessive - 25%
Cystic Fibrosis Sx
- Failure to thrive
- Chronic productive cough
- Abdominal pain and bloating
- Recurrent respiratory tract infections
- Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Define CF
Cystic fibrosis is a multi-system genetic disorder affecting the lungs, pancreas, liver and intestine
CF prevalence
Caucasians 1 in 25
CF pathophysiology in the respiratory tract
CFTR channel protein:
- on airway epithlial cells
- pumps Cl- ions out of the cell to attracts water into mucus secretion for fluid balance
- mutation –> fluid balance of mucus dyregulated –> hyperactive ENaC –> excessive Na+ absorption –> thick, dehydrated mucus obstructing the airways
CF pathophysiology in the pancreas
Thick secretions/mucus occlude the panceatic duct –> pancreatic insufficieny
How does CF affects the GI tract
- Meconium ileus: small intestine secretes viscous mucus which can cause bowel obstruction (medical emergency)
- cholestasis: leads to neonatal jaundice
How does CF affects the pancreas
Pancreatic inssuficiency:
- thick secretions occlude the pancreatic duct = NO pancreatic enz. –> unable to abosorb fat / proteins
CF complications
- Acute/chronic pancreatitis
- insulin depent (cystic-fibrosis-related)DM
- Bronchiectasis
- Underweight
- Meconium ileus
- Chronic liver disease
- Reduced bone density (OP)
- Infertility: Men (absence of the vas deferens) Women (thick cervial mucus)
Common causative bacteria in CF exacerbation
- Staphy aureus (gram +ve)
- Psuedomonas aeruginosa (gram -ve)
what do the heel prick test detects
Pancreatic enz: Immunoreactive trypsinogen (IRT)
released into the plasma by damaged pancreas
CF diagnostic tests
- Heel prick test in newborn
- Cl- sweat test (needs 2 positive results to confirm CF)
- Genetic testing
What is the suggestive of CF criteria in a Cl- sweat test
Sweat Cl- >60
Outline the genetics of CF
an autosomal recessive disease caused by a mutation in the Cystic Fibrosis transmembrane conductance regulator gene (CFTR), leading to the production of thick, sticky mucus that can clog airways and lead to respiratory and digestive problems
Which chromosome is CTFR located on
Chromosone 7
what is the most common mutation of CF called
ΔF508
CF clinical presentations
Resp Sx
- productive cough
- wheezing
- SOB
- recurrent resp infections
- resp distress
GI Sx
- Abdo distention
- abdo pain
- not passing meconium
- steatorrhoea
- Salty sweat
- Failure to thrive (malabsorption of fat/protein)
CF examination findings
- ## Nasal polyps
what vitamins or minerals is most likely to be deficient in CF patient?
vitamin A, D, E, K
fat soluble vitamins
Life expectancy for CF
around 44 years of age
CF Mx
- Chest physiotherapy
- Exercise
- High calorie diet
- CREON tablets to digest fats (replace the missing lipase enz)
- Prophylactic flucloxacillin (reduce risk of infection)
- Treat chest infections
- Bronchodilators (help treat bronchoconstriction)
- dornase alfa (break down DNA material in secretions)
- Vaccinations including pneumococcal, influenza and varicella
Prognosis for people 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
How is Pseudomonas treated in CF patients
- Tobramycin nebs
- PO ciprofloxacin
What agent is applied on to the skin during the sweat test
Pilocarpine
cholinergic agonist
