Anovulation and Amenorrhea 2 Flashcards

Describe how the normal function of the hypothalamic pituitary-ovarian axis is altered with the common causes of anovulation/amenorrhea.

1
Q

What is are the major roles of FSH?

A
  • Stimulates proliferation of granulosa cells
  • Stimulates aromatase and estradiol
  • Increases granulosa cell FSH and LH receptors
  • Produces autocrine-paracrine factors, especially activin and inhibin
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2
Q

What is the role of LH in the early and late follicular phase?

A
  • Early on, triggered by estradiol positive feedback to induce ovulation
  • Late follicular phase:
    • final follicular maturation and continued steroidogenesis in the face of declining FSH
    • initiates luteinization and progesterone production in granulosa cells
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3
Q

What are the most common hypothalamic causes of secondary amenorrhea?

A
  • Stress
  • Weight loss
  • Exercise
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4
Q

What do the causes of hypothalamic amenorrhea have in common?

A
  • Increase opioid activity of the hypothalamic-pituitary-adrenal axis
  • Inhibits the GnRH pulse generator
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5
Q

What are common findings in hypogonadotropic hypogonadism?

A
  • Low/normal FSH and LH
  • Hypoestrogenic
    • thin endometrial stripe
    • failure to withdraw to progestins
    • immature vaginal cytology
    • low estradiol level
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6
Q

What is the most common pituitary cause of secondary amenorrhea and what are its characteristics?

A
  • Hyperprolactinemia
    • rises throughout pregnancy in response to high levels of estrogens
    • elevated prolactin inhibits pulsatile GnRH release, in part via hypothalamic opioid activity
    • always check TSH to rule out primary hypothyroidism
    • take a careful drug history
    • MRI to evaluate for tumor
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7
Q

What are the common causes of hyperprolactinemia?

A
  • Pharmacologic agents
    • drugs that inhibit dopamine synthesis, release, or action
    • antipsychotics
      • phenothiazines and haloperidol - 4x increase until drug is stopped
      • Clozapine and olanzapine - transient before normalizing
      • Risperidone - effect similar to phenothiazines
  • Prolactin-secreting microadenoma/macroadenoma
  • Idiopathic
  • Primary hypothyroidism
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8
Q

What are the common ovarian causes of amenorrhea?

A
  • PCOS
    • anovulation
    • androgen excess
    • polycystic ovaries
      • 12 or more follicles 2-9 mm in diameter
      • ovarian volume more than 10.5 cc
  • Premature ovarian failure
    • ovarian fialure with elevated FSH (two above 40 mIU/mL one month apart) before 40
    • result of premature depletion of oocyte-follicle complex
    • Causes:
      • chromosomal
      • autoimmune
      • idiopathic
      • iatrogenic (oophrectomy, chemotherapy, radiation therapy)
    • 50% have evidence of follicles
    • 20% have evidence of ovulation
    • Pregnancy reported in 8%
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9
Q

What are the chromosomal abnormalities that result in premature ovarian failure?

A
  • Mosaics and deletions of the X chromosome
  • Pubertal development and menstruation occurs in about 3% of 45X and in about 12% of 45,X/46,XX individuals
  • Menstruation occurs in over half of individuals with X chromosome deletions
  • If 45,X/46,XX mosaicism is present, patient should be evaluated for cardiovascular abnormalities
    • deletions of the X chromosome may result in familial POF
    • recommend peripheral blood karyotype
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10
Q

What are the findings in autoimmune causes of POF?

A
  • Patients with concomitant Addison’s disease
  • Evidence of autoimmune disease in 15% to 30% of women with POF
  • 20% hypothyroid and 2% had diabetes
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11
Q

What are the genetic causes of POF?

A
  • Genes responsible are unkown
  • 10-15% of cases associated with FMR1 gene premutation
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12
Q

What are the tests done for an individual with POF?

A
  • Karyotype for individuals under 30, risk for CV disease and X chromosome deletions
  • Fragile X analysis in all under 40
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13
Q

What effect does POF have on bone mineral density?

A
  • 43% noromal
  • 44% osteopenia
  • 14% osteoporosis
  • primary amenorrhea, BMI, and duration of POF associated with BMD
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14
Q

What is Asherman syndrome?

A
  • Result of partial or complete obliteration of uterine cavity by adhesions
  • Only common uterine cause of secondary amenorrhea
  • Causes:
    • curettage for a spontaneous or induced abortion or for postpartum hemorrhage
    • uterine survage
    • pelvic tuberculosis
  • Only common non-anovulatory cause of secondary amenorrhea
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15
Q

How does primary hypothyroidism result in hyperprolactinemia?

A

TRH stimluates prolactin as well as TSH

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