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Difficulty: Very hardReproductive Endocrinology and Infertility

Evaluate the following clinical and laboratory profiles of patients presenting with amenorrhea. Match each profile to the most likely underlying diagnosis.

  • 16-year-old phenotypic female with primary amenorrhea, Tanner stage V breast development, and absent pubic hair. Pelvic ultrasound reveals an absent uterus. Laboratory studies show male-range testosterone, normal FSH, and elevated LH.Complete androgen insensitivity syndrome
  • 17-year-old phenotypic female with primary amenorrhea and absent breast development. Blood pressure is 155/95 mmHg. Pelvic ultrasound reveals a prepubertal uterus. Laboratory studies show profound hypokalemia, elevated FSH, and elevated LH.17-alpha-hydroxylase deficiency
  • 28-year-old female with secondary amenorrhea and galactorrhea. She had a massive postpartum hemorrhage 18 months ago but successfully breastfed her infant for 8 months. Laboratory studies show low FSH, low LH, elevated prolactin, and elevated TSH.Primary hypothyroidism
  • 15-year-old phenotypic female with primary amenorrhea and absent breast development. Blood pressure is 110/70 mmHg. Karyotype is 46,XY. Pelvic ultrasound reveals a small uterus. Laboratory studies show elevated FSH, elevated LH, and low female-range testosterone.Swyer syndrome

Answer

Profile 1 matches Complete androgen insensitivity syndrome. Profile 2 matches 17-alpha-hydroxylase deficiency. Profile 3 matches Primary hypothyroidism. Profile 4 matches Swyer syndrome.
Each profile highlights a distinct pathophysiologic mechanism of amenorrhea. Profile 1's androgen resistance causes an absent uterus (due to active AMH) with male testosterone. Profile 2's enzyme deficiency shifts adrenal synthesis toward mineralocorticoids, causing hypertension alongside hypogonadism. Profile 3 demonstrates primary hypothyroidism, where elevated TRH stimulates prolactin, which in turn inhibits GnRH; prior lactation explicitly rules out pituitary necrosis. Profile 4 shows a failure of testicular differentiation (Swyer syndrome), resulting in a lack of both AMH (allowing uterus formation) and testosterone, leading to hypergonadotropic hypogonadism.

Step-by-Step Solution

1
Analyze the first clinical profile focusing on the absent uterus and male-range testosterone.
The profile is identified as a 46,XY disorder of sex development where testes are present (producing AMH to regress the uterus) but peripheral tissues do not respond to androgens.
This uniquely describes complete androgen insensitivity syndrome.
2
Evaluate the second profile's combination of primary amenorrhea, hypertension, and hypokalemia.
The hypertension and hypokalemia reflect mineralocorticoid excess, while the primary amenorrhea reflects absent sex steroids.
This specific enzymatic block identifies 17-alpha-hydroxylase deficiency.
3
Examine the third profile, noting the high TSH and prolactin levels, and carefully evaluate the postpartum hemorrhage history.
The ability to breastfeed rules out ischemic necrosis of the pituitary. The laboratory profile demonstrates TRH-induced hyperprolactinemia.
This correctly identifies primary hypothyroidism as the cause of the secondary amenorrhea.
4
Assess the fourth profile's 46,XY karyotype in the presence of a uterus and hypergonadotropic hypogonadism.
The presence of a uterus confirms no AMH was produced, meaning testes never formed. Streak gonads produce no hormones, leading to high FSH/LH.
This presentation defines Swyer syndrome (46,XY complete gonadal dysgenesis).

Key Concept

Integration of karyotype, Mullerian anatomy, and distinct hormone panels (gonadotropins, sex steroids, TSH, and mineralocorticoids) is required to differentiate complex etiologies of amenorrhea.
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Topics

Reproductive Endocrinology and Infertility

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