Childhood growth and puberty

Question 1

The most rapid growth occurs during the _______ phase

Answer 1

in utero

Question 2

What drives growth during fetal life?

Answer 2

IGF-1, insulin

Question 3

What drives growth during childhood?

Answer 3

growth hromone

Question 4

What drives growth during infancy?

Answer 4

nutritional status

Question 5

What drives growth during the pubertal growth spurt?

Answer 5

stimulation of growth plate by androgens, estrogen, GH

Question 6

List factors that stimulate GH secretion

Answer 6

GHRH

estrogen and androgens enhance GH response to GHRH

Question 7

What factors inhibit GH secretion

Answer 7

somatostatin
high levels of glucocorticoids
GH and IGF-1 feedback, which increases somatostatin

Question 8

What might explain the poor correlation of total IGF-1 levels with growth?

Answer 8

circulating IGF-1 is likely not the most important mediator of GH effect- GH stimulates local production of IGF-1 in tissues, which exerts an autocrine growth promoting
effec

Question 9

Describe the effects of GH and IGF-1 on bone

Answer 9

GH: linear growth by action at epiphyseal growth plate

Question 10

Describe GH effects on adipose tissue

Answer 10

utilization of fat for energy, sparing lean body mass
increase synthesis of hormone sensitive lipase (hydrolyzes TGs)
inhibits lipoprotein lipase

Question 11

Describe GH effects on muscle

Answer 11

increased muscle mass, increased protein synthesis

Question 12

Describe GH effects on carbohydrate metabolism

Answer 12

insulin resistance and glucose sparing

Question 13

Differences in childhood _______ largely determine differences in adult height

Answer 13

growth velocity

disparity in heights of children at start of puberty= disparity in height in adulthood

Question 14

Growth velocity is most rapid in utero and during the first year of life, when ______ factors predominate

Answer 14

nutritionally- derived, ex insulin

Question 15

As the transition to GH dependent growth occurs, growth velocity ________

Answer 15

decreases

Question 16

The greater the delay in the onset of puberty, the _______ the pre-pubertal growth rate

Answer 16

slower

Question 17

Crossing of growth percentiles is common during _______ years of life

Answer 17

first 2 years- baby “seeks out” appropriate growth channel based on genetics
not normal to cross percentile lines from age 3- adolescence

Question 18

What growth pattern is suspected if:

• growth velocity is steady along low percentile lines
• bone age= chronological age

Answer 18

intrinsic short stature

check MPH to verify

Question 19

If a child has intrinsic short stature but is significantly smaller than predicted by MPH, what causes should be considered?

Answer 19

mild hypochondroplasia
chromosomal disorders- Turners
in utero insults

Question 20

What growth pattern is suspected if:

• growth velocity along low percentile lines
• bone age

Answer 20

constitutional delay of growth and puberty

Question 21

What causes short stature during childhood in constitutional growth delay?

Answer 21

transition from the rapid growth phase of infancy to the slower growth of childhood occurs much earlier than normal

• expect crossing down of percentiles at 10-30 months

Question 22

In ________ growth pattern, growth velocity is abnormally slow

Answer 22

attenuated

Question 23

What are some causes of attenuated growth pattern

Answer 23

• nutritional deficiencies
• chronic disease
• severe emotional disorders
• medications- corticosteroids, methylphenidate

Question 24

Hormonal alterations tend to cause marked retardation in linear growth with what effects on weight?

Answer 24

continued weight gain- usually stays along the same weight percentile

Question 25

Accelerated growth is usually associated with _______

Answer 25

obesity

Question 26

Why are infants with GH deficiency usually a normal size at birth

Answer 26

GH is not critical for in utero growth

Question 27

What clinical signs might indicate Gh deficiency

Answer 27

multiple midline defects including cleft palate, poor development of nasal bridge cherubic faces lack of phallic growth in males

Question 28

What are some FDA approved uses for GH therapy

Answer 28

- GH deficiency - Turner, Prader-Willi - IUGR - chronic renal insufficiency

Question 29

Define gonadarche, thelarche, adrenarche, menarche

Answer 29

- gonadarche: maturation of testes or ovaries to produce hormones - thelarche: breast budding (nl-10 yrs) - adrenarche: maturation of adrenal gland (age 6-8 yrs) - menarche: normal is about 12 yrs

Question 30

What are the findings in premature thelarche?

Answer 30

Early breast development without growth acceleration, bone age advancement, other signs of puberty

Question 31

Describe transient gynecomastia common in boys

Answer 31

breast development- high testosterone in puberty is aromatized to estradiol, stimulates temporary growth in breast tissue

Question 32

What are the findings in premature adrenarche?

Answer 32

early maturation of adrenal gland, but no gonadal changes so no bone advancement, acceleration in growth velocity

Question 33

________ is a hypothalamic protein that signals GnRH pulses to begin in puberty

Answer 33

kisspeptin

Question 34

What is the current definition of precocious puberty?

Answer 34

hanges occurring before the age of 7 to 8 years in girls and 9 years in boys

Question 35

What is the current definition of delayed puberty?

Answer 35

For girls, no thelarche by age 14 or menarche by age 16 years. For boys, no testicular changes by age 15 years

Question 36

Describe the two categories of delayed puberty

Answer 36

Hypogonadotropic: Low LH and FSH, due to CNS defect. Hypergonadotropic: High LH and FSH, due to defect in gonad.

Question 37

What are some causes of hypogonadotropic delayed puberty?

Answer 37

hypothalamic or pituitary disease, malnutrition, chronic disease, familial syndromes, and endocrine diseases.

Question 38

What are some causes of hypergonadotropic delayed puberty?

Answer 38

chemotherapy, radiation, trauma, inflammation, or infiltration of the gonads, and chromosomal disorders such as Turner syndrome.

Question 39

Differentiate central vs peripheral precocious puberty

Answer 39

CPP is caused by premature activation of the HP axis. Gonadotropins are in pubertal ranges. PPP is not under the control of the central nervous system. Can arise in a gonad, a tumor, or another organ. Gonadotropins are low- suppressed by feedback from the abnormal sex hormone production

Question 40

How is CPP diagnosed?

Answer 40

increased LH/FSH secretion in response to GnRH stimulation testing

Question 41

How is CPP treated?

Answer 41

long acting GnRH analogs, which stop pulsatile release

Question 42

What is McCune-Albright syndrome?

Answer 42

G-protein activating mutation that can present as PPP, Cushing syndrome, or thyrotoxicosis. Children have characteristic caféau- lait macules, polyostotic fibrous dysplasia, rapid growth

Question 43

What is familial testotoxicosis?

Answer 43

male disorder with penile enlargement, pubic hair, behavior problems due to constitutively active LH receptor