Childhood growth / puberty Flashcards
Speed / control of intrauterine growth
Very fast
IGF1 / 2, insulin
Speed / control of early infancy growth
Rapid, but declining
Controlled by nutrition (insulin, IGF)
Get post-natal “mini puberty”
Speed / control of childhood growth
Gradually slows until puberty
Controlled by GH. TH necessary for GH secretion.
Speed / control of pubertal growth
Rapid growth until fusion of epiphyseal plates.
Androgens stimulate growth plate.
Estrogens stimulate GH secretion and growth plate closure.
GH effects on adipose tissue (5)
Increased lipolysis, stimulated hormone sensitive lipase, inhibited lipoprotein lipase, decreased glucose transport, decreased lipogenesis
Genetics of CDGP
Autosomal dominant. Often strong family history.
3 general causes of non-familial intrinsic short nature
Genetic / chromosomal problems: Turner, Russel-Silver syndromes
Prenatal: IUGR
Postnatal: spinal radiation
Endocrine vs disease-causing attenuated growth
- Endocrine problem – stature is affected more than weight. Ex: Hypothyroid, low GH, or glucocorticoid excess
- If both height and weight are increasing percentiles, it is NOT an endocrine cause.
•Underlying disease – weight affected more than stature. Often a calorie problem. Ex: renal disease, IBD.
What happens if GH is low in utero?
No lack of growth, but hypoglycemia may occur
2 physical effects of low GH (not height-related)
- Males may exhibit lack of phallic growth b/w 6-12 months of age.
- Faces are typically fair and “cherubic” and may manifest in midline defects such as hypotelorism, cleft palate, poor nasal bridge development, or single central incisor.
Which diseases is GH FDA-approved for? (4)
GH deficiency, familial short stature, IUGR, Turner syndrome
What is the most common cause of accelerated growth?
Over-nutrition. Weight usually affected more than height.
What is adult height if CAH or precocious puberty is not treated?
Short due to premature closure of epiphyseal growth plates.
When does adrenarche usually occur?
Age 6-8
When does telarche usually occur?
Age 10
What determines testicular size?
FSH / LH
Not testosterone
Avg age of menarche
Age 12.5
What does Kisspeptin do?
Releases blockage on GnRH –> increased GH, IGF1, FSH, LH, estrogen, and testosterone.
Pituitary also becomes more sensitive to GnRH.
Tanner breast stage II
Breast budding
Tanner breast stage III
Glandular tissue develops
Tanner breast stage IV
Areola and papilla form secondary mound
Tanner breast stage V
Mature breast
What tanner stage are most kids at at start of puberty?
Stage III
Tanner hair stage II
Sparse, pigmented, long, straight hair mainly along labia and base of penis
Tanner hair stage III
Darker, courser, curlier
Tanner hair stage IV
Adult hair, but not full distribution yet
Tanner hair stage V
Adult hair w/ spread to medial thighs
Tanner hair stage VI
Midline hair up abdomen. Abnormal in females.
Ages of precocious puberty
White / AA girls
Boys
- Under 8 Caucasian girls
- Under 7 African American girls
- Under 9 boys
Central precocious puberty Male causes Female causes Associations Treatment
- Males – CNS causes are predominant, such as tumors, injury, or other sex steroids.
- Females – often idiopathic. Many are caused by hypothalamic hamartomas.
- Associated w/ hydrocephalus, closed head injuries, and cerebral palsy
- Treat w/ long-acting GnRH analogs
3 gonadal causes of peripheral precocious puberty
Sex hormone-secreting gonadal tumors
McCune-Albright Syndrome
Familial testotoxicosis
McCune-Albright Syndrome
Cause
Sxs (3)
- Etiology - G protein defect in gonadotropin receptor.
* Sxs - Kids have café-au-lait spots, polyostotic fibrous dysplasia, and rapid growth.
Familial testotoxicosis Etiology Inheritance Sxs Prognosis
- Etiology - Testes contain a constitutively activated LH receptor.
- Inheritance - Transmitted from father to son.
- Sxs - Toddlers present w/ penile enlargement, pubic hair, and behavior problems.
- Prognosis - Without treatment, these boys are below 3rd percentile for height due to rapid bone age advancement.
2 adrenal causes of precocious puberty
Treatment
CAH and virilizing adrenal tumors
Treat w/ glucocorticoids to lower ACTH
Ages of delayed puberty
Breast
Menses
Boys
> 14 years (breast)
16 years (menses)
15 years in boys
Most common cause of delayed puberty in US vs worldwide
US: constitutional growth delay
World: malnutrition
Causes of secondary hypogonadotropic hypogonadism (7)
Anorexia, athlete triad, male obesity (fat tissue has aromatase activity, converting testosterone to estrogen), chronic disease, malnutrition, endocrine disease (HYPOTHYROID, HYPERPROLACTINEMIA), celiac disease.
Athlete triad
Disordered eating, amenorrhea, osteoporosis
Causes of hypergonadotropic hypogonadism
- Intrinsic gonadal dysgenesis – Turner and Klinefelter are 2 most common
- Gonadal damage – chemo, radiation, galactosemia
- Others – trauma, autoimmune, inflammation / infection, infiltration
Characteristics of Klinefelter
Tall stature, gynecomastia, visceral adiposity
Treating delayed puberty in girls vs boys
- Girls – increasing doses of estradiol over 9-12 months to promote normal puberty w/o rapidly advancing bone age. Progesterone is added after 9-12 months to induce menses cyclically.
- Boys – monthly testosterone therapy in increasing doses.
Premature thelarche / adrenarche
Population
- This is a normal variation. Do NOT remove breast tissue b/c it will not grow back later.
- Premature thelarche usually occurs in 1-3 y/o girl without any other signs of puberty.
- Premature adrenarche is more common in AA’s and obese children.
Characteristics of isolated pubertal changes
- Not true CNS puberty. Premature thelarche / adrenarche may occur.
- No gonadotropin activation
- Minimal / no growth or bone age acceleration
- Increased risk for metabolic syndrome and PCOS.
- Normal age of onset of true puberty
Constitutional growth delay
Growth velocity
What drug do they qualify for?
- Normal growth velocity.
- Do NOT qualify for GH.
- Oxandrolone is weak male hormone that does NOT get converted to estrogen (closes growth plate). Promotes growth and weight. Catches kids up to peers, but doesn’t make them taller than they would have been w/o it.
Familial short stature
Do they cross percentiles?
Cross percentiles downward in first 3 years after nutrition –> GH / genetics phase.
Non-familial genetic short stature Cross percentiles? Bone age #1 cause Other cause Treatment
Yes cross percentiles Bone age = chronological age #1 cause is Turner syndrome Other cause is IUGR GH is approved
Characteristics of Turner Syndrome (7)
- Ovarian insufficiency → no estrogen → no puberty
- Edema of hands due to congenital problems of lymphatic drainage
- Ear infections: facial features are downturned, possibly leading to increased predisposition to infection
- Webbed neck also due to anomaly in lymphatic drainage
- Wide carrying angle
- Coarctation of the aorta
- Renal problems may involve horseshoe kidney and double ureters (increased risk of UTI)
Endocrine-related attenuated growth Cross percentiles? Bone age Adult height Does birth weight play a role?
Yes cross percentiles
Bone age less than chronological age
Adult height is less than mid-parental height
Birth weight does NOT play a role
4 clues for GH deficiency
- Microphallus (due to low FSH / LH)
- High arched palate
- Subcutaneous fat
- May present w/ hypoglycemia due to lack of counter-regulatory hormones (ACTH, GH)
GH effects on muscle / fat
GH plays a role in increasing lean body mass and decreasing fat. Low GH → short fat baby
Genetics of Kallman syndrome
May be autosomal dominant (FGFR1 gene), recessive, or X linked (KAL1 gene)
