Amenorrhea: Pathology review

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A 35-year-old woman comes to the office with complaints of irregular menstruation. She has had only two periods in the last year. Menarche was at age 12, and she had a regular menstrual cycle until 12 months ago. The patient also reports feeling flushed at night without provocation and experiencing occasional dyspareunia with post-coital spotting. Past medical history is noncontributory. Temperature is 36.9°C (98.5°F), pulse is 70/min, respirations are 13/min, and blood pressure is 118/76 mmHg. Cardiopulmonary and abdominal exams are unremarkable. The patient has Tanner stage V breasts and pubic hair. Pelvic examination reveals a small anteverted uterus and minimal vaginal rugations. Abdominal examination is within normal limits. Urine pregnancy test is negative. Serum TSH is 3.2 µU/mL. Which of the following set of hormonal changes will most likely be observed in this patient?

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Two people come to the clinic one day. First you see Ana, a 17 year old teenage girl. Ana comes with her mother, who’s worried because Ana hasn’t had her first period yet.

Upon physical examination, you notice that Ana is quite short for her age. In addition, she has a wide neck, broad chest, and poorly developed breasts with widely spaced nipples. You decide to perform a blood test, which reveals low estrogen levels and high FSH and LH.

Next, comes María, a 25 year old female who’s concerned because she hasn’t had her period for nine months now.

She’s sexually active, so the first thing you do is ask for a pregnancy test, which comes up negative.

When asked about physical activities, she refers to going for a 2-hour run every single day, plus swimming and then tennis on weekdays.

Regarding her diet, she’s very strict when it comes to avoiding fatty foods. On physical examination, you realize that María is underweight, and a blood test reveals low levels of estrogen, LH, and FSH.

Okay, now both Ana and María have amenorrhea, which is generally defined as the absence of menstruation in females of reproductive age.

Now, for menstruation to happen, an individual must have a regular female reproductive anatomy and sexual development, which is normally under control of the hypothalamic-pituitary-gonadal axis.

First, the hypothalamus secretes gonadotropin-releasing hormone, or GnRH for short, which goes to the anterior pituitary to stimulate the release of gonadotropic hormones, which are luteinizing hormone or LH, and follicle-stimulating hormone or FSH.

LH and FSH then stimulate the gonads to produce sex hormones; in females, LH and FSH stimulate the ovaries to secrete estrogen and progesterone, which are responsible for the female primary sexual characteristics.

These are the changes necessary for reproduction, including menstruation, ovulation, and uterine development.

Summary

Amenorrhea is the absence of menstrual periods in a woman of reproductive age. There are two types of amenorrhea: primary and secondary. Primary amenorrhea is defined as the failure to achieve menarche by age 16 in the absence of any secondary sexual characteristics, or by 14 if there are secondary sexual characteristics present. Secondary amenorrhea is defined as a cessation of menses for 3 months in a woman with previously established normal menstrual cycles.

Sources

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  3. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
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  9. "Menstrual Cycles: Fatness as a Determinant of Minimum Weight for Height Necessary for Their Maintenance or Onset" Science (1974)
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