TAILIEUCHUNG - Chapter 050. Hirsutism and Virilization (Part 4)

PCOS is the most common cause of ovarian androgen excess (Chap. 341). However, the increased ratio of LH to follicle-stimulating hormone that is characteristic of carefully studied patients with PCOS is not seen in up to half of these women due to the pulsatility of gonadotropins. If performed, ultrasound shows enlarged ovaries and increased stroma in many women with PCOS. However, polycystic ovaries may also be found in women without clinical or laboratory features of PCOS. Therefore, polycystic ovaries are a relatively insensitive and nonspecific finding for the diagnosis of ovarian hyperandrogenism. Although not usually necessary, gonadotropin-releasing hormone agonist. | Chapter 050. Hirsutism and Virilization Part 4 PCOS is the most common cause of ovarian androgen excess Chap. 341 . However the increased ratio of LH to follicle-stimulating hormone that is characteristic of carefully studied patients with PCOS is not seen in up to half of these women due to the pulsatility of gonadotropins. If performed ultrasound shows enlarged ovaries and increased stroma in many women with PCOS. However polycystic ovaries may also be found in women without clinical or laboratory features of PCOS. Therefore polycystic ovaries are a relatively insensitive and nonspecific finding for the diagnosis of ovarian hyperandrogenism. Although not usually necessary gonadotropin-releasing hormone agonist testing can be used to make a specific diagnosis of ovarian hyperandrogenism. A peak 17- hydroxyprogesterone level nmol L gg L after the administration of 100 gg nafarelin or 10 gg kg leuprolide subcutaneously is virtually diagnostic of ovarian hyperandrogenism. Because adrenal androgens are readily suppressed by low doses of glucocorticoids the dexamethasone androgen-suppression test may broadly distinguish ovarian from adrenal androgen overproduction. A blood sample is obtained before and after administering dexamethasone mg orally every 6 h for 4 days . An adrenal source is suggested by suppression of unbound testosterone into the normal range incomplete suppression suggests ovarian androgen excess. An overnight 1-mg dexamethasone suppression test with measurement of 8 00 . serum cortisol is useful when there is clinical suspicion of Cushing s syndrome Chap. 336 . Nonclassic CAH is most commonly due to 21-hydroxylase deficiency but can also be caused by autosomal recessive defects in other steroidogenic enzymes necessary for adrenal corticosteroid synthesis Chap. 336 . Because of the enzyme defect the adrenal gland cannot secrete glucocorticoids efficiently especially cortisol . This results in diminished negative feedback inhibition of .