Cystic Fibrosis Flashcards
CF is a ______ disease
multisystem progressive
CF characterized by:
abnormal Na and Cl and bicarbonate transport across epithelial cells and exocrine glands–>thick mucus secretions affecting rest, pancreas, intestine, hepatobiliary, sweat, repro tracts
CF is an ____ genetic disorder
autosomal recessive
CF caused by defect in gene encoding ____ on chromosome # ____
cystic fibrosis transmembrane conductance regulator (CFTR) protein ; 7
90% of CF patients have mutation in ___ gene
DeltaF508
there are ____ classifications of mutations
6
class 1 mutation
absent CFTR protein
class 2 mutation
protein misfolding
class 3/4 mutation
defective CFTR channel regulation
class 5 mutation
reduced functional CFTR
class 6 mutation
decreased CFTR stability at cell membrane (rare)
prevalence in caucasian population:
1:3000
prevalence in Africans ____ and Asians ____
1:15000 ; 1:32000
tests to diagnose include :
genetic testing/counselling, neonatal screening, measuring trypsinogen (if high, confirmatory test), sweat chloride test, sputum cultures, pancreatic function tests, pulmonary fun test
abnormal CFTR causes _______
inadequate Cl reabsorption, so it is retained and traps sodium ions on skin surface
gold standard test
sweat chloride test performed on both forearms, measures abnormality of salt in sweat
normal values of Cl in sweat chloride test is ___, in “classic” presentation it is > ___ mmol/L
<30 mmol/L; >60
respiratory pathophysiology?
sinusitis, cough/wheezing, mucus plugging in lungs, rest infection, bronchiectasis (scarring recurrent inflammations in lung’s airways), pulmonary insufficiency, pulmonary failure
pancreas pathophysiology?
secondary to mucus accumulation and blocked ducts, digestive enzymes can’t reach small intestine so malabsorb fat-sol its–>steatorrhea, poor growth, nutrition deficiency, pancreatitis, DM
what does healthy pancreas look like?
CFTR channels allow passage of Cl and HCO3 ions into pancreatic ducts, secretions contain digestive enzymes that breakdown pro/fat/cho in small intestine
digestive pathophysiology?
can’t fully absorb nutrients –>reduced Cl and H2O secretion –>GERD, meconium ileum (intestinal obstruction at terminal ileum) at birth–> distal intestinal obstruction syndrome (DIOS) later in life –>short intestinal bacterial overgrowth (SIBO)
SIBO ^ ____ and v ____
infection ; tolerance to sugars/CHO
in CF, pancreatic exocrine secretions have v _____
bicarbonate, pH , volume
why osteoporosis in CF?
malabsorption vit D
hepatobiliary pathophysiology?
^ viscosity of bile that obstructs hepatic ducts and cause biliary cirrhosis, inflammation, scarring, fibrosis –> blocked ducts and impaired bile flow/bile acid metabolism, v total bile salt pool –>gallbladder inflammation and gallstones
sweat pathophysiology?
elevated sweat chloride–> abnormal CFTR inhibits reabsorption of Cl from sweat into cells lining sweat duct –> retention of chloride traps Na on skin surface
reproductive pathophysiology?
males 98% infertile cuz abnormal development vans deferens in utero (dysfunctional CFTR channels on surface of sperm, mucus, atrophy); females have v fertility cuz of comorbidities of poor nutrition and inadequate CF diabetes mngmt
BMI < or > sensitivity to lung function than %IBW?
>
BMI recommendations for men/women and ppl < 21:
women maintain a BMI of at least 20, ideally 22 and men, a BMI of at least 23. For people under age 20, BMI should be at or above the 50th percentile on the CDC growth chart
goals for nutrition status:
normal fat sol vitamin and micronutrient status, EFAs monitored
nutrition goals include:
promoting optimal growth, muscle strength, wt maintenance, enhance quality of life
why increased energy requirements?
pancreatic insufficiency, lung function deteriorating causes increased workload, lung infection
why reduced absorption?
pancreatic insufficiency: SIBO, CF-related liver disease
why inadequate intake?
anorexia, GERD, DIOS (constipation), psychosocial, med side effects
protein requirements:
1.5-2x DRI for age
fat requirement %:
35-40% kcal
which equation to calculate Daily Energy Expenditure?
WHO equation with activity and disease coefficients
pancreatic enzyme supplements contain:
lipase, amylase, protease
what is the function of pancreatic enzyme therapy?
digest CHO/pro/fat; assist with wt gain, promote nutrient absorption
enzymes taken ___ and ____ all meals and snacks
before; during
small children mix beads with ___
applesauce
how know if enzyme dose correct?/
healthy wt gain, less stools
which foods not require enzymes?
fruit snacks, fruits, juices, popsicles, jello, sports drinks, sugary items
why caution with 10 000 lipase units/kg/day for all ages?
fibrosing colonopathy
why malabsorption of fat sol vitamins?
patients lack bile so cannot produce adequate bile salts due to Cl channels blocked with thick mucus and clogging liver where bile produced, difficult absorb vitamins
adequate Na reduces:
headache, fatigue, poor concentration, salt crystals on skin, muscle cramps, hyponatremia, nausea, v appetite
additional Na may be needed based on:
activity lvl, climate, diet intake, symptoms
calcium requirement is ___ mg/day
1500
why low BMD?
medications (glucocorticoids), malnutrition/malabsorption, inflammation, inactivity
why delayed growth and puberty for CF ppl?
hormone levels affected with CF
phosphorus homeostasis regulated by ____, magnesium absorption is abnormal in ____, magnesium excretion is ^ cuz ____, iron is ___, zinc is needed for ___
vit D; pancreatic insufficiency ; antibiotics; often deficient; support other nutrients to promote growth, maintain appetite, fight infection
examples of meds:
targeted to specific mutation as CFTR potentiator and corrector; oral pancreatic enzymes, mucolytic agents, antibiotics, anti-inflammatory, bronchodilators, insulin
if BMI for age - growth charts < ___ percentile can identify nutrition risk
10th
last therapeutic option, end-stage lung disease
lung transplant
nutrition intervention post transplant:
promote wound healing, treat electrolyte imbalances, achieve optimal BG control
