L05 - Endocrine Disorders Affecting Reproduction Flashcards
(34 cards)
Describe the pattern of GnRH release.
What is the consequence of this?
- GnRH is released in a pulsatile manner throughout the day
- This results in pulsatile FSH and LH release
- Continuous GnRH release decreases release of FSH and LH
What is the most common cause of secondary amenorrhoea?
Pregnancy
List 3 symptoms of oestrogen deficiency.
1 - Hot flushes
2 - Poor libido
3 - Dyspareunia
What factors should be considered when assessing the function of the HPG axis in females?
1 - Menstrual history (oligomenorrhoea / amenorrhoea)
2 - Oestrogen deficiency
3 - Hirsutism
4 - Acne
5 - Androgenic alopecia
6 - Weight changes
7 - Galactorrhoea
List 3 central causes of amenorrhoea.
1 - Hypothalamic responses due to anorexia excessive exercise and stress
2 - Pituitary tumours
3 - Hypogonadotropic hypogonadism (failure of FSH / LH secretion)
List 2 ovarian causes of amenorrhoea.
1 - Turner’s syndrome
2 - Premature ovarian failure
List 2 miscellaneous causes of amenorrhoea.
1 - PCOS
2 - Thyrotoxicosis
When does leptin secretion increase and why?
- Following weight gain
- Because there is more adipose tissue secreting it
Which cells secrete prolactin and how is its release controlled?
- Lactotrophs
- It is negatively regulated by tonic release of dopamine
- TSH also stimulates prolactin release
- Prolactin inhibits FSH and LH
Why is hyperprolactinaemia difficult to diagnose in postmenopausal women?
- Because prolactin inhibits FSH and LH, therefore oestrogen production
- The effects of a lack of oestrogen are normally the indicators of hyperprolactinaemia
- In postmenopausal women, oestrogen isn’t being released anyway
What are the symptoms of hyperprolactinaemia in premenopausal women?
1 - Oligo/amenorrhoea
2 - Vaginal dryness
3 - Flushes
4 - Sweats
5 - Galactorrhoea
What are the causes of hyperprolactinaemia?
1 - Prolactinomas
2 - Compression of the infundibulum and loss of dopamine
3 - Dopamine antagonists
4 - Secondary hypothyroidism
What is premature ovarian insufficiency?
- Elevated LH and FSH (menopause) <45 years of age
- Oestrogen deficiency
- Amenorrhoea
What are the causes of premature ovarian insufficiency?
- Congenital causes e.g. Turner’s syndrome (45 XO)
- Autoimmune diseases e.g. thyroid disorders, Addison’s disease, and diabetes
- Iatrogenic causes e.g. chemo/radiotherapy, surgery
- Mutations in the FSH receptor, galactosemia, or Fragile X
How might autoimmune diseases cause premature ovarian insufficiency?
- Likely due to inflammatory infiltration of follicles & production of anti-ovarian antibodies, apoptosis & atrophy
- Sharing auto antigens between the ovary & adrenals may explain the link between POI & Addison’s
How is premature ovarian insufficiency managed?
- Diagnosed based on serial FSH & oestrogen (E2) levels, karyotyping & FMR1 premutation analysis, screening for autoimmune diseases, DEXA scan (for osteopaenia)
- Treated with oestrogen replacement (+ progesterone if the patient still has a uterus due to the risk of endometrial hyperplasia with oestrogen alone)
What are the signs and symptoms of polycystic ovary syndrome?
- Oligoamenorrhoea
- Hirsutism
- Obesity
- Anovulatory infertility
- Polycystic ovaries (on ultrasound)
- Acanthosis nigricans
- Androgenic alopecia
- Hyperandrogenism (↑ testosterone, androstenedione (DHEA), & ↑ LH/FSH ratio)
- Won’t be oestrogen deficient (can be shown by withdrawing progesterone which will lead to menstrual bleeding)
How is PCOS diagnosed?
2 of the following 3 criteria:
- Oligo/amenorrhoea
- Clinical or biochemical signs of hyperandrogenaemia
- Polycystic ovaries
What risks can PCOS cause for pregnancy?
- PCOS presents difficulties in getting pregnant - oligo/amenorrhoea and infertility
- Large increase in the risk of gestational diabetes and pregnancy related hypertension
- IVF can be offered, but there is an increased risk of ovarian hyperstimulation syndrome & subsequently fertilisation of more than one egg
How can the clinical features of PCOS be treated?
- Obesity, oligo/amenorrhoea treated with metformin & lifestyle changes
- Hirsutism = male hormone-dependent hair growth, treated with Yasmin, Vaniqua cream, cosmetic removal, spironolactone
- Anovulatory infertility treated with metformin or metformin combined with clomiphene (selective oestrogen receptor modulator) or letrozole (aromatase inhibitor)
- Anti-androgenic oral contraceptives e.g. Dianette or Yasmin
What is androgen insensitivity syndrome?
- A spectrum of disorders due to a mutation in the androgen receptor which can lead to anything between a poorly virilised infertile man to men with complete testicular feminisation (46XY “females”)
What are the signs and symptoms of complete androgen insensitivity syndrome and how might patients present?
- Female external genitalia
- Short blind-ending vagina
- No uterus
- Abdominal/ inguinal testes
- Absent prostate
- Absent pubic and axillary hair
- Gynaecomastia
Patients would usually present with symptoms of an inguinal hernia (testes), and/or primary amenorrhoea
What hormone levels would a patient with androgen insensitivity syndrome have?
- Elevated levels of LH, testosterone & oestrogen
- Due to testosterone aromatisation & LH-driven gonad secretion
What is 5-alpha-reductase deficiency?
- A lack of 5α-reductase results in an inability to convert testosterone to DHT, meaning that there is a lack of virilisation of the external genitalia
- This causes a female external appearance with a normal male karyotype (46XY)
- At puberty, patients will present with primary amenorrhoea and virilisation
