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29 Cards in this Set
- Front
- Back
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What is the sweat test? |
pilocarpine iontrophoresis test stimulate electrode on skin analyze sweat that goes on filter paper look for Cl- concentrations |
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Where is the CFTR gene |
long arm chromosome 7 |
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Where is CFTR in the cell |
apical membrane of epithelial cells - airways - biliary tree - intestines - vas deferens - sweat glands - pancreatic ducts doesn't affect kidneys or brains |
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What is class I CF? |
no CFTR |
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What is class II CF |
processing is abnormal |
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Class III CF |
abnormal channel function |
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Clas IV CF |
abnormal channel function G85E and R117H mutations - Ivacaftor-Kalydeco treatment |
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Class V |
works the best reduced synthesis of CFTR = reduced quantity CFTR |
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If you have a deltaF508 mutation what determines the phenotype? |
other mutation - need two severe mutations to cause classic CF |
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Clas VI CF |
high turnover of CFTR at channel surface rare |
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What is the most sensitive organ to CF |
vas deferens in male infertility - asospermia (low sperm count) |
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What is the least sensitive organ to CF |
pancreas - most are not affected, but much greater likelihood to be if two deltaF508 mutations |
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When were you expected to live to if you were pancreatic sufficient vs. pancreatic insufficient? |
insufficient - 30 - 35 sufficient - 50 |
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What are environmental factors that influence CF? |
allows variability in severity within classes - cigarette smoke or other pollutants - allergens - viral pathogens - pathogen acquisition: type and timing - socioeconomic status |
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What is a theory for why there are varying phenotypes in CF class? |
- mutations in other genes (helper genes) = genetic differences - environmental factors |
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Why is there such a high rate of CF carriers? |
carriers are healthy may be less likely to die from cholera and other gastrointestinal diseases |
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What established a CF diagnosis? |
- >1 typical phenotypic feature of CF, sibling with CF, positive newborn screening test AND - elevated sweat Cl- on two occasions, 2 identified CFTR mutations, abnormal nasal potential difference |
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Why does CF probably get untreated at first? |
children more likely to have asthma |
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What are normal and CF sweat test Cl- levels? |
infant: 30 adult: 40 anything with sweat Cl- above 60 is indicative of CF do two tests to rule out false positive |
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What is the newborn screening test |
- filter paper with drops of blood - IRT elevated in CF (immunoreactive trypsinogen) - do IRT/DNA - elevated IRT and then look for mutations in DNA - mutations dictate whether CF or not |
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What can cause a false positive with IRT/IRT |
IRT can be elevated in infants due to neonatal stress - need DNA |
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What are advantages of NB screening for CF |
- early referral - early nutritional intervention - improved pulmonary function - cost effective due to improved outcomes - genetic counseling for the family |
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What is nutrition therapy in CF babies |
- enteric coated pancreatic enzymes - high calorie and protein diet - supplemental vitamins A, D, E, K - acid suppression - salt supplementation - oral nutritional supplements - noctural gastrostomy tube feeding - fiber and stool softeners |
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mechonium ileus |
bowl obstruction in CF patients resulting in thick, tarry stool - due to pancreas not making proper digestive enzymes |
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pathophysiology of CF lung disease |
most CF patients due to lung disease - abnormal CFTR - reduced airway surface liquid and impaired mucociliary clearance - obstruction, infection, inflammation downward spiral: - structural damage - bronchiectasis - pulmonary insufficiency - respiratory failure |
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What happens to the lung in a transplanted patient |
donor cells have normal CFTR function - produce normal mucous patients will not get lung disease, but at higher risk for infection due to immunosuppressants still have other CF problems |
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Why does defect in CFTR result in high sweat Cl- |
sweat gland: CFTR is backwards of other CFTR, sucks Cl- and salt back in if CFTR doesn't work, sweat gland can't re-absorb Cl- or salt = high sweat Cl- levels and dehydration (hypochloremia and hyponatremia) |
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What are CF patients at risk for |
diabetes - less likely to get if pancreatic sufficient osteoporosis recurrent pancreatitis - more likely if pancreatic sufficient |
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Why do CF patients get diabetes |
pancreas autodigests itself - fibrosis of pancreas chokes up pancreatic beta cells CF related diabetes mellatius (CFRDB) |
