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HD 3 > Endocrine - to final > Flashcards

Endocrine - to final Flashcards

0
Q

Factors for head growth

A

= DIRECTLY determined by brain size

    • genetics, nutritional and environmental,
  • NOT hormones (affect brain dvpt but not size)
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1
Q

Factors in growth

A

1. genetics - complex, affects all other factors

  1. nutritional - availability, intake, absorption, metabolism…
  2. environmental - internal and external (physical AND psychosocial)
  3. hormonal (insulin, IGF, thyroid, GH)
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2
Q

Microcephaly

A

head size < 2.5 SD below mean for age & sex
*usually w/ abnormal brain structure
=> mental retardation, seizures, aud/visual deficits
*primary (at birth) or secondary (fall off growth curve)

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3
Q

Macrocephaly

A

Head size >2.5 SD from mean for age & sex,

Some causes: hydrocephalus, subdural effusion, hematoma, genetic syndromes/familial trends

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4
Q

Factors influencing weight in infants/children

A

(all 4)

genetics, nutrition, environment, and hormones

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5
Q

Short stature

A

height >2.5 SD below mean for age & sex

* most common reason for referral, usually a normal variant (vs. pathological)

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6
Q

Genetic short stature

A

normal variant of short stature,
within midparental height range prediction.
- normal birth size, slow growth 6 mo - 3 yrs
- normal growth velocity 4 yrs - puberty
* bone age = chronological age

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7
Q

Constitutional Delay of Growth

A

“Late bloomers,” = normal variant of short stature, normal final height.

  • normal birth size,
  • deceleration in weight gain 6 mo - 3 yrs
  • normal growth rate 4 yrs - puberty, but puberty occurs at later age.
  • bone age delayed (-1 to -3 SD)
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8
Q

Genetic etiologies of pathologic short stature

A
  1. Chromosomal macrodeletions/duplications (Turner’s = 45 XO, Down syndrome, other trisomies)
  2. Chromosomal microdeletions/mutations
    (intrauterine growth retardation, metabolic pathway defects)
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9
Q

Intrauterine Growth Restriction

A
  • Nonspecific: maternal factors, poor nutrition, infection (CMV, rubella, toxoplasmosis), toxins (EtOH, cigarettes)
  • Specific: rare, usually genetic. w/ dymorphic features, +/- mental retardation. *if going to catch up, will by 9-12 mo.!
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10
Q

normal height velocity cut-offs for age (below this is concerning)

A 
0-1 yr: 11 cm/yr
1-2 yrs: 7 cm/yr
2-3 yrs: 5 cm/yr
4-puberty: 4.5 cm/yr
puberty: 5.5 cm/yr
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11
Q

Normal variants of short stature

A
  1. genetic
  2. constitutional growth delay
    * may be both factors.
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12
Q

Characteristics of genetic short stature

A
  • short family,
  • slow growth - 3yrs, normal after;
    normal bone age
    puberty at normal age
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13
Q

characteristics of Constitutional delay –> short stature

A
  • low weight gain to age 3, normal growth velocity 4-puberty
  • delayed puberty
  • bone age -1 to -3 (less if combined w/ genetic short stature)
    normal end height
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14
Q

Non-specific causes of intrauterine growth restriction

A
  1. maternal factors
  2. poor nutrition
  3. infection (CMV, rubella, toxoplasmosis)
  4. toxins (EtOH, cigarettes)
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15
Q

environmental factors for short stature

A

internal - chronic disease

external – psychosocial, chronic drugs (glucocorticoids, steroids)

16
Q

growth effects of congenital hypothyroidism

A

normal fetal weight, length;

* delayed skeletal maturation, and brain if prolonged in utero

17
Q

Acquired hypothyroidism – effect on growth

A

NO mental retardation if after age 3-5;

  • linear growth and skeletal maturation profoundly decreased during disease (abrupt halt on growth curve!)
    also: fatigue, lack of energy
18
Q

when to evaluate for GH deficiency/pathological short stature

A
  1. height < 1st percentile
  2. height velocity < 4 cm/yr
  3. bone age 2+ SDs from mean
19
Q

How to work up GH deficiency

A
  1. check thyroid
  2. GH response test to 2 diff stimuli! (GH <10 ng/mL= deficit)
  3. look for response to GH replacement
20
Q

possible etiologies for GH resistance

A
  • GH R absent/abnormal (Laron syndrome)
  • STAT5B mut (signal transduction -> interrupted Jak/STAT cascade)
  • IGF-1 or IGFBP3 or ALS gene deficits
  • “ALS” = Acid Labile Subunit
    • IGF-1 gene def => sensorineural hearing loss & other Sxs**
21
Q

non-endocrine causes of pathological tall stature

A
  1. cerebral gigantism
  2. Marfans
  3. homocysteinuria
    * Obese children (increased nutrition, but final height = ~normal)
22
Q

Endocrine causes of pathological tall stature

A
  1. Precocious sexual dvpt –> early puberty, higher velocity before puberty. **usually end up ~short compared to peers!
  2. GH excess (gigantism/acromegaly)
  3. Gonadal steroid deficit –> longer pre-pubertal stage (extra growth), *failure of epiphyses to close!
23
Q

Craniosynostosis

A

premature closure of skull suture(s) –> only cosmetic problem if 1 (multiple = more growth limitation)

24
Q

organic causes of childhood obesity

A

= VERY rare (<0.1%!) * will have low GHBP

  1. genetic, hypothalamic dysfunction
  2. glucocorticoid excess
  3. insulin excess
    * hypothyroidism: weight disproportionate to height, but not excessive
25
Q

Failure to thrive

A

= lack of weight gain, but continued head circumference growth.
95% bc insuff. nutrition
…others: malabsorption, chronic disease, genetic, etc.

26
Q

Prenatal growth hormones

A

MANY (IGF-2, FGF, CGF, NGF, etc.)… but NOT GH or TH

27
Q

IGF binding proteins

A

IGFBP-1: regulates IGF-1 in utero
IGFBP-2: high in fetus
IGFBP-3: most important post-natal, GH/IGF-dep. synthesis

28
Q

ALS (Acid Labile Subunit)

A

binding protein that forms ternary circulating complex with IGF-1 & IGFBP-3

  • synthesized in liver
  • maintains circulating IGF-1, but no effect on IGF synthesis

HD 3 (8 decks)

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