Paediatric Growth And Development Flashcards
Phases of growth
Foetal/prenatal: most rapid phase of growth dependant on placental supply if nutrients and oxygen, determinants if birth size are maternal nutrition and intrauterine environment (not genetics)
Infantile (0-2y): rapid but decelerating. Double birth weight by 4 months, triple birth weight by 12m, grow 25cm in first year,, HC increases 12cm first year, 90% SGA infants will catch up by 1-2y
Childhood: constant growth, half adult height by 24-30m, GH dependant growth, 5-6cm/y from 4-puberty, 2kg/y from 2-pub
Puberty all growth spurt: driven by gonadal/adrenal steroids and GH, accounts for 20% final height, preceded by a reduction in growth velocity, girls 23-28cm, boys 26-28cm
Target height aka mid-parental height
Girls: (paternal height-13cm +maternal height)/2
Boys: (maternal height + 13cm + paternal height)/2
Body proportions
Arm span within 6cm of height Upper:lower segment ratios: - birth 1.7 - 3y 1.33 - 5y 1.19 - 10y 1.0
Gonadarche
Breast development in girls (telarche) and ovarian volume >4mls
Testicular volume > 4mls
Results from activation of hpg axis
Adrenarche
Androgen secretion from adrenal glands causing pubic hair and apocrine secretion
Puberty in girls (onset, order, total height gain)
Onset between 8-13y
Menarche 2-3y post onset of puberty
Avg total height gain 20cm (8cm post menarche)
Breast development, then pubic hair growth then menarche
Boys puberty (onset, height gain, order)
Onset 9-14y
Avg total height gain 28cm (peak in tanner4, 2 years later than girls)
Testicular enlargement followed by penile enlargement and pubic hair growth
Differentials for short stature
Familial/genetic short stature Constitutional delay Skeletal dysplasias(achondroplasia, hypochondroplasia) Rickets Turners syndrome Noonan's syndrome Russell silver syndrome (dwarfism) GH deficiency Cushing syndrome Hypothyroidism Precocious puberty (early accelerated growth, short adults) Chronic disease (renal, nutritional. GI) IUGR Emotional deprivation/psychosocial Idiopathic (most coon esp in girls)
Tall stature differentials
Dysmorphic: - Marfan syndrome - homocystinuria - Klinefelter syndrome - 47XYY, 47XXX Non-dysmorphic - precocious puberty - hyperthyroidism - pituitary gigantism - familial tall stature - hypogonadism - obesity - e2 deficiency or insensitivity -
Familial short stature v constitutional delay
Both are normal variants, not pathological
Familial: normal growth velocity (following pattern of chars) but consistently shorter than peers (usually on 3rd percentile), height is appropriate for mid-parental height, bone age = chronological age, pubertal spurt at appropriate time
Constitutional delay:
Short during childhood but adult height consistent with target height, pubertal spurt later than peers (difficult to diagnose until after growth spurt), bone age
GH eligibility
GH deficiency
Turner syndrome
Height
Differentials for precocious puberty
Raised gonadotropin levels (true/central)
- idiopathic (>90% females, 25% males
- intracranial pathology (hypothalamic/pituitary tumours, irradiation)
- familial
- treated congenital adrenal hyperplasia
Gonadotropin independent precocious puberty
- ingestion of sex steroids
- adrenal (CAH, tumour)
- ovarian (mccune Albright, tumours, follicular cysts)
- testicular ( testicular or germ cell tumours, mccune Albright syndrome)
- tumours secreting non pituitary gonadotropin e.g. hCG
Definition of precocious puberty
Pubertal development in ALL domains before 8 In girls or 9 in boys
I.e accelerated growth, breast development and pubic hair development in girls
Accelerated growth, genital and testicular growth and pubic hair development in boys
Premature Adrenarche
Isolated pubic hair development (+body odour, oily hair, pimples)
Adrenal androgens slightly elevated
LH, FSH, and gonadal steroids all prepubertal levels
Premature thelarche
Isolated unilateral or bilateral breast development
Commonly seen between 6m-4y
Manage with observation and follow-up