530 obstetrics and Gynecology Board review •••
❍ What is the most common manifestation of hypogonadotropic hypogonadism?
Constitutional delay of puberty.
❍ What is the treatment of this?
reassurance.
❍ What is Kallmann syndrome?
Hypogonadotropic hypogonadism due to a lack of gonadotropin-releasing hormone (GnrH) due to failure of
migration of the GnrH neuron from the olfactory bulb. These patients are anosmic and have primary amenorrhea.
❍ What is the most common CNS tumor that can lead to primary amenorrhea?
Craniopharyngioma. It is an extracellular mass that interferes with the production and secretion of GnrH or the
stimulation of pituitary gonadotropins. Usually, these patients have disorders of other pituitary hormones as well.
❍ What one test can distinguish hypergonadotropic and hypogonadotropic forms of hypogonadism?
FSH.
❍ If FSH is elevated, the next appropriate test would be?
A karyotype.
❍ Is an elevated FSH an absolute indicator of infertility?
No.
❍ Why does FSH rise prior to menopause?
Because of decreased inhibin.
❍ In amenorrhea, what are the causes of high gonadotropins?
- Tumors producing gonadotropins (often lung cancer, but rare).
- Single gonadotropin deficiencies, homozygous mutations in gonadotropin genes.
- Gonadotropin-secreting pituitary adenoma (not associated with amenorrhea).
- Perimenopause, menopause, and premature ovarian failure.
- resistant or insensitive ovary syndrome and mutations in gonadotropin receptor genes.
- Galactosemia, direct toxic effect of galactose metabolites on germ cell migration.
- 17 a-hydroxylase deficiency.
❍ What three tests are helpful in diagnosing 17a-hydroxylase deficiency?
Serum progesterone—elevated (>3 ng/mL).
17 a-hydroxyprogesterone—low (<0.2 ng/mL).
Serum deoxycorticosterone (DoC)—low.
❍ What is the confirmatory test and what is the response in a patient with 17a-hydroxylase deficiency?^
ACTH stimulation test. These patients will have an increase in serum progesterone and no change in
17 a-hydroxyprogesterone.