Problems of Puberty Flashcards
puberty - defined
*a complex series of physical changes (secondary sex characteristics)
*transition to sexual maturity (when reproduction is possible)
*activation of gonads by pituitary hormones → estrogen/testosterone production
adrenarche - defined
*activation of adrenal glands to make androgens
thelarche - defined
*onset of breast development
pubarche - defined
*onset of pubic hair development
menarche - defined
*onset of menstrual cycles
key players & hormones in puberty
- hypothalamus → gonadotropin releasing hormone (GnRH)
- pituitary gland → luteinizing hormone (LH) & follicle-stimulating hormone (FSH)
- gonads (ovary/testis) → estradiol (E2) or testosterone (T)
hypothalamic-pituitary-gonadal axis & puberty
*hypothalamus releases GnRH → stimulates pituitary to release LH & FSH → stimulates gonads (ovaries/testes) to release estradiol or testosterone
*activation of the GnRH pulse generator stimulates the pubertal axis
*TONIC GnRH suppresses the pubertal axis
Tanner Pubertal Staging - breasts
*Tanner 1: pre-pubertal
*Tanner 2: palpable breast bud
*Tanner 3: breast tissue extending beyond areola
*Tanner 4: areola expands and creates a secondary mound
*Tanner 5: adult female contour with enlarged areola
note - PALPATION is crucial for this, not just visualization
first sign of normal puberty in most females
*thelarche (breast development)
first sign of normal puberty in most males
*testicular enlargement
Tanner Pubertal Staging - testicles
*Tanner 1: < 2
*Tanner 2: 4-8
*Tanner 3: 9-12
*Tanner 4: 12-20
*Tanner 5: > 20
note - this is measured in volume (mL); uses beads
Tanner Pubertal Staging - pubic hair
*Tanner 1: pre-pubertal / no hair, +/- vellus hair
*Tanner 2: scant, coarse hair along labia majora or scrotum
*Tanner 3: increasing, now curling hair on mons pubis
*Tanner 4: increasing hair with lateral spread
*Tanner 5: hair spreading to medial thighs, adult quantity
precocious (early) puberty - defined
*puberty is too early in:
-girls younger than 8
-boys younger than 9
recall: earliest signs are breast development / testicular enlargement
delayed puberty - defined
*puberty is delayed in patients with no signs of puberty in:
-girls 13+
-boys 14+
recall: earliest signs are breast development / testicular enlargement
important pubertal milestones - females
*peak growth spurt velocity: ~ 1 year after breast budding
*onset of menses: 2.4 years after breast budding
important pubertal milestones - males
*peak growth spurt velocity: ~ 2.5 years after testicular enlargement begins
growth in puberty - overview
*ESTROGEN (+ testosterone converted to estrogen by enzyme aromatase) affects skeletal maturation and augments growth hormone secretion
*females start and finish growing earlier, peak growth velocity is lower
precocious (early) puberty - epidemiology
*1 in 5-10K
*strong female predominance
*CNS tumors are more common in males with early puberty
general causes of precocious (early) puberty
- something triggers early LH/FSH production
OR - children are exposed to estradiol and testosterone action by some other mechanism
*central (from pituitary gland): idiopathic, CNS tumor / malformation
*peripheral (from somewhere else): McCune-Albright Syndrome, gonadal cyst/tumor, adrenal source, exogenous testosterone / estradiol exposure
central vs. peripheral precocious puberty
*central: normal sequence of pubertal events, normal timing / tempo
*peripheral: abnormal sequence of pubertal events, rapid timing / tempo
diagnostic evaluation of early puberty - LABS
*LH
*FSH
*estradiol or testosterone
*depending on exam, consider 17-hydroxyprogesterone, DHEA-S, androstenedione, thyroid studies to assess for other peripheral causes of early puberty
diagnostic evaluation of early puberty - IMAGING
*bone age x-ray first
*consider MRI of pituitary gland if LH/FSH are elevated
bone age x-ray
*hand x-ray to evaluate maturity of growth centers
*estrogen matures growth centers, so early exposure to estrogen causes growth centers to appear older than the child’s chronological age
*plotting height (growth chart) by bone age gives a better prediction of height potential
management of central precocious puberty
- idiopathic central precocious puberty:
-GnRH analog injection (recall: continual/tonic release of GnRH suppresses the pubertal axis) - CNS tumors:
-hamartoma: treat with GnRH analogue
-other: referral for surgery, radiation, chemotherapy
*treatment goals:
-prevent compromise of final adult height
-prevent continued advancement of puberty and menses
-minimize psychosocial impact of early puberty
McCune-Albright Syndrome - classic findings
*polyostotic fibrous dysplasia
*cafe au lait lesions
*precocious puberty
*multiple endocrinopathies
McCune-Albright Syndrome - genetics
*post-zygotic/somatic mutation of GNAS gene resulting in activation of G-protein signaling
McCune-Albright Syndrome - mosaicism
*classic example of mosaicism
*genetically distinct cell lines in the same individual
*patients have heterogenous clinical manifestations depending on tissue expression
McCune-Albright Syndrome - management
- puberty management:
-aromatase inhibitors
-E2 receptor blocker - treatment as needed for:
-bone lesions
-hyperthyroidism
-growth hormone excess
-Cushing syndrome
-renal phosphate wasting
Kallman syndrome - overview
*delayed/absent puberty and impaired sense of smell
*due to impaired GnRH synthesis
*more common in males > females
*treatment: testosterone replacement to induce secondary sex characteristics, infertility treatments
Turner syndrome - overview
*partially/completely missing X chromosome (45, X)
*diagnosis is confirmed by karyotype
*fairly common: 1 in 2,000 live births
Turner Syndrome - features
*SHORT STATURE
*gonadal dysgenesis
*cardiac and renal malformations
*webbed neck
*thyroid disease
*sometimes delayed/stalled puberty
Turner Syndrome - management
*estrogen replacement to induce secondary sex characteristics
*growth hormone therapy for short statue (if growth plates are not already fused)
*screening / treatment for associated diseases:
-cardiac abnormalities (coarctation, bicuspid aortic valve)
-renal malformations
-hypothyroidism/autoimmune diseases
-learning issues
-hearing problems
