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20 Cards in this Set
- Front
- Back
Persistent or recurrent hypoglycemia can lead to what?
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neurologic sequelae
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What % of normal newborns can't maintain a plasma glucose concentration above 30 mg/dL if first feeding is delayed 3 to 6 hrs?
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10%
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What is definition of hypoclycemia?
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It's controversial. Depends on gestational and postnatal age.
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At birth, how does umbilical venous plasma glucose conc compare to maternal venous glucose conc?
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60 to 80% of mom's
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What happens to gluc conc after birth in normal baby?
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Drops after 2hrs to nadir of no less than 40 mg/dL and stabilizes to 45-80 mg/dL by 4 to 6hrs.
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How is gluc maintained after birth?
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breakdown of hepatic glycogen (glycogenolysis) in response to epinephrine and glucagon; also falling insulin levels
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When is glycogen depleted after birth?
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8 to 12hrs and then glucose levels are maintained by synthesis of gluc from LAG [lactate, alanine, glycerol (gluconeogenesis)]
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2 basic reasons for hypoglycemia?
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diminished glucose supply (problem with glycogenolysis or gluconeogenesis) or overconsumption
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When is glycogen deposited during pregnancy? Why is that relevant?
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3rd trimester
premature babies will have diminished reserves |
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Why do babies with intrauterine growth restriction (IUGR) have reduced glycogen stores?
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low insulin levels and chronic intrauterine hypoxia, which leads to inefficient anaerobic utilization of glucose
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What endocrine disorders can cause hypoglycemia?
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Deficiency in hormones regulating glucose homeostasis:
- cortisol - growth hormone - epinephrine - glucagon Can be isolated or associated with pituitary, hypothalamic or adrenal insufficiency |
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How does a hypothermic infant get hypoglycemic?
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overuse of glucose
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What medication taken by mom can lead to infant hypoglycemia?
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propranolol, due to the interruption of stimulation of glycogenolysis by epinephrine
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What is the most common clinical situation in which hyperinsulinism causes infant hypoglycemia?
Is the hypoglycemia persistent or transient? |
IDM (infant of diabetic mother), but the hypoglycemia is usually transient
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Name 4 situations associated with hyperinsulinism and transient infant hypoglycemia.
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1. IDM
2. Beckwith-Wiedemann syndrome 3. erythroblastosis 4. perinatal asphyxia |
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About what fraction of IDM's get hypoglycemia (<40 mg/dL)?
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1/4 (27% to be exact)
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What is one theory on the cause of hypoglycemia in IDM's?
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Pedersen hypothesis: intermittent maternal hyperglycemia causes fetal hyperglycemia, leading to premature maturation of pancreatic islet cells and hypertrophy of beta cells
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What is Beckwith-Wiedermann syndrome?
What % have intermittent or persistent hypoglycemia? |
fetal overgrowth syndrome causing:
- Macroglossia - Abdominal wall defects - Renal abnormalities - Growth >90th %ile - Ear creases or pits 50% have transient or prolonged hypoglycemia due to hyperinsulinism |
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Many hypoglycemic infants are asymptomatic, but, if symptomatic, what are clinical manifestations?
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- jitteriness
- hypotonia - altered consciousness - apnea, bradycardia, cyanosis - tachypnea - poor suck or feeding - hypothermia - seizures |
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What are risk factors for hypoglycemia?
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- premies
- SGA or LGA - IDM's - infants requiring intensive care (eg. sepsis or asphyxia) - infants whose mothers took beta adrenergic or oral hypoglycemic agents |