Functional hypothalamic amenorrhea is a cause of secondary amenorrhea.
Clinical and laboratory features:
(1) amenorrhea
(2) reduced GnRH (gonadotropin release hormone) secretion from the hypothalamus
(3) hypogonadotropic hypogonadism with reduced estradiol production
(4) variable polycystic ovary syndrome (PCOS)
(5) chronic anovulation with infertility
(6) osteopenia or osteoporosis
(7) exclusion of other causes of amenorrhea
Serum LH levels may show different patterns:
(1) from reduced to near normal serum concentrations
(2) absent to increased LH pulsatility
Possible underlying causes:
(1) low dietary intake
(2) intense physical exercise
(3) severe psychological stress
(4) genetic mutations in FGFR1, PROKR2, GNRHR or KAL1
