Disorders of Puberty Flashcards
Hallmark of puberty
Increase LH pulses at night
Prepuberty
FSH > LH
Adrenarche
Result of the development of the zona reticularis (produces DHEA-S and androstenedione)
Generally happens about 2 years before gonadarche)
Onset of menses
Generally ~2years after onset of breast development (between Tanner Stage 2-3)
First test if concerned about pubertal development
Bone age
hCG
Critical for genital development in the first trimester
Prader-Willi
Defect on Chr 15 (missing paternal allele); congenital cause of hypogonadotropic hypogonadism
First physical signs of puberty
Testicular enlargement > 3mL in boys
Breast bud development in girls
Girls- pubertal changes
- Breast development
- Genital growth (labia minora)
- Maturation of vaginal mucosa
- Uterine/ endometrial growth
- Female fat distribution changes
- Androgen changes (pubic hair, axillary hair, body odor, and pimples)
- Growth velocity increases
Boys- pubertal changes
- Testicular growth (scrotal changes)
- Penile growth
- Prostatic growth
- Seminal vesicle growth/ sperm production
- Deepening of voice
- Sexual hair- upper lip, chin, side burns, axilla, pubic area
- Growth velocity increases
Assessment of delayed puberty
If FSH/LH levels are:
High- indicates primary problem (constitutional delay of growth, Klinefelter, Turner, gonadal dysgenesis, Noonan syndrome)
Low- indicates secondary problem (Kallman syndrome, Prader-Willi, excessive exercise, anorexia, chronic illness, malnutrition, hypothyroidism, radiation, trauma, autoimmune)
Symptoms of delayed puberty
Girls: No menses by age 16
Boys: No increase in testicular size by age 14
Features of precocious puberty
S&S of puberty in
Boys: before 8-9, Girls: before 7-8
Causes of precocious puberty
Central: Premature activation of the HPG axis (due to CNS abnormality- 5% in girls and 50% in boys)
Peripheral:
Girls- ovarian cysts, granulosa cell tumor, Sertoli-Leydig tumors, exogenous estrogens
Boys- Adrenal tumor or CAH (pubic hair, growth acceleration, small testes)- increased androgens but low FSH and LH, Leydig cell tumor (unilateral large testicle), hCG secreting tumor (increased T prod, but testes are same size), familial testotoxicosis (LH receptor mutation that self-activates; virilization at 2-3 yrs)
Causes in both genders:
Primary hypothyroidism (TSH cross-reacts with FSH receptor); symptoms- poor linear growth
McCune Albright Syndrome: precocious puberty, >4 cafe au lait spots, polyostotic fibrous dysplasia (bone becomes fibrotic)
Evaluation
Hx, growth chart, physical (tanner stage, skin, near), bone age, GnRH sim test or random gonadotropins, karyotype
GnRH stim test results
If stim test results in low LH level (<5mIU/dL) : indicates central axis has not been “activated” –> therefore peripheral cause of precocious puberty
If stim test results in high LH level (»5mIU/dL): indicates central axis has been “activated” –> therefore central cause of precocious puberty
Opposite for delayed puberty
