05. Endocrine Disorders

• androgen insensitivity syndrome is where XY have normal testes and secrete androgens, but the fetus is insensitive so the wolffian ducts degenerate and they have external female genitalia

  • due to mutations in androgen receptor
  • periods don't start which leads to diagnosis
• mutations in 5-a-reductase means that testosterone isn't converted into DHT so no male external genitalia develops in XY, leads to virilisation at puberty
• kallman syndrome = GnRH neurones don't migrate properly in development so no GnRH is released in puberty

  • associated with lack of smell
• precocious puberty is an onset of sexual characteristics before 8 in female and 9 in males

  • short stature due to premature fusion
• precocious puberty central causes = sex hormones produced too early via HPG

  • idiopathic, environmental endocrine disruptors or obesity
• precocious puberty peripheral causes = sex hormones produced by atypical means

  • adrenal hyperplasia or tumour
• delayed puberty = absence of sexual characteristics by 14 in females and 16 in males

  • pituitary tumours, Turner syndrome, Kallman syndrome, androgen insensitivity
• adult female endocrine disorders may present with

  • galactorrhea, amenorrhea, infertility, oestrogen deficiency, hot flushes, low libido

  FSH/LH levels tested to show ovarian reserve and issues with HPG axis, progesterone tested to show if ovulation is occuring
• progesterone withdrawal bleed = synthetic progesterone given for 5 days then taken away - causes bleed and allows cycle to be timed
• primary causes of adult female endocrine disorders = peripheral causes, gonadal damage/failure

  • normal gonadotropin secretion
  • high FSH/LH due to low oestrogen
• secondary causes of adult female endocrine disorders = central causes, hypothalamic or pituitary disease

  • low gonadotropins, low FSH/LH, low oestrogen
• premature ovarian failure = low oestrogen, high FSH/LH before 40

  • often unknown cause
  • can be caused by chemo
• turner syndrome = XO leads to oocyte death as XX needed for oocyte growth

  • ovarian dysgenesis occurs as normal ovarian development requires normal germ cells

  growth hormone given in childhood and oestrogen given to initiate puberty
• hyperprolactinaemia = too much prolactin from anterior pituitary suppresses HPG axis leading to low FSH/LH

  • can be natural (post pregnancy) or caused by prolactin secreting tumours

  dopamine = natural prolactin antagonist (low dopamine = high prolactin)
• PCOS = must have three symptoms from

  • oligo/amenorrhea
  • hyperandrogenaemia
  • polycystic ovaries

  increased risk of ovarian hyperstimulation syndrome (OHSS)
• adult male endocrine disorders may present with

  • loss of libido, impotence, infertility, gynaecomastia, low body hair

  primary symptoms = testicular insensitivity, high FSH/LH due to low testosterone

  secondary symptoms = low gonadotropins, low FSH/LH, low testosterone
• klinefelter syndrome = XXY

  • azoospermia, small testes, low testosterone, high FSH/LH
• androgen abuse causes prostate cancer, atrophy of testes, hypertension, cardiac muscle hypertrophy, arrhythmia