L14 - Hormonal Abnormalities 1 Flashcards
1. Describe normal female menstrual cycle, including hormones involved, where they're secreted from and their effect on the uterus and ovary. 2. Describe the common hormonal and chemical abnormalities associated with PCOS 3. Explain how these lead to common clinical manifestations of PCOS. 4. Describe the further investigations and management of women with PCOS. 5. Define normal puberty and describe the hormonal changes that occur relating these to clinical changes. 6. Briefly describe what
What does the term menarche refer to?
Between ages of 12 - 15 where the first period will occur
What are the phases of the ovarian cycle?
Follicular
Ovulation
Luteal
Phases of the uterine cycle?
Menstruation
Proliferative
Secretory
What is kisspeptin?
aka metastin
- human metastasis supressor gene.
- able to supress melanoma & breast cancer metastasis
- role in initiating secretion of GnRH
What is anovulation?
Ovaries do not release an oocyte during a menstrual cycle.
How may a diagnosis of anovulation be confirmed?
2 of the following needed:
- Biochemical / clinical hyperandrogenism (hirsutism, acne, alopecia)
- Menstrual irregularity
- Poly-cystic ovaries
Which hormones predominantly drive androgen production from poly-cystic ovaries?
Obese females: Insulin
Slimmer females: LH
Amenorrhoea
Lack of periods.
No menstruation occurring
State some female features of puberty?
- Breast development
- pubic hair growth, height
- menarche
What are some male features of puberty?
- Testicular enlargement (measured with orchidometer)
- Pubic hair growth
- Rapid height growth
- Growth spurt
What are features of puberty that affect both sexes?
- Acne, axillary hair, body odour, mood
What is precocious puberty?
Puberty that occurs earlier than expected?
Which sex is more likely to experience precocious puberty?
Girls
- ovaries very sensitive to secretion of gonadotrophin from the pituitary gland
- usually familial or idiopathic
Describe the importance in management of young patients going through precocious puberty?
- Reducing rate of skeletal maturation
- as early growth spurt may cause early cessation of growth
- and reduction in adult height.
Thelarche
Premature breast development
How might we distinguish Thelarche from gonadotrophin dependent precocious puberty?
Thelarche
- there is an absence of axillary and pubic hair and significant growth spurt.
Describe primitive pubarche?
Adrenarche
- early stage in sexual maturation
- Pubic hair develops in girls before age of 8 and 9 in males.
What hormone may cause delayed puberty?
Low gonadotrophin secretion.
High gonadotrophin secretion.
In which sex is delayed puberty more common in?
Males
- due to delay in growth and puberty.
Oligomenorrhoea
Irregular periods
Features of PCOS? (5)
Endocrine disorder :
- Hirutism (excessive hair growth typically in a male pattern)
- Acne
- Oligomenorrhoea (irregular periods)
- Amenorrhoea (no periods)
- multiple cysts in ovary
What are some complications associated with PCOS?
- Impaired glucose tolerance and type 2 diabetes.
2. Infertility due to anovulation.
What hormone is PCOS related to?
Insulin!
- decreased peripheral insulin sensitivity (insulin resistance)
- higher levels produced to overcome this
- consequent compensatory hyperinsulinaemia
Describe hyperinsulinaemia?
Insulin acts with LH to increase androgen production from theca cells and the adrenal gland.
- Theca cells convert androgen precursors to testosterone
What happens when LH increases relative to FSH?
Ovaries synthesize androgens rather than oestrogens.
- excess androgens stop follicular development
- and ovaries do not release oocyte.
What is the role of SHBG?
Sex hormone binding globulin
Glycoprotein which regulates bioavailability of sex steroid hormones.
- binds to testosterone
- hormones in bound state aren’t available for body to use.
What effect does insulin have on SHBG?
- Insulin inhibits hepatic production of SHBG.
- SHBG reduced in insulin resistance
- hence bioavailable testosterone is often on the high side.
Describe effects of an elevated oestrogen level in women with PCOS?
- Follicular development arrested pre full maturation of ovulatory follicle.
- no ovulation but oestrogen production continues.
- Endometrium does not shed, hence gets thicker
- may lead to endometrial hyperplasia (overgrowth)
Aromatization
Process converting testosterone to oestrogen.
On what criteria is PCOS diagnosed?
2/3 Rotterdam criteria met
- Anovulation
- Hyperandrogenism
- Polycystic ovaries on ultrasound (do not have to present to make diagnosis)
Ways of managing PCOS?
- limiting carbs
- maintaining healthy weight
- be active
What are the two categories of Precocious puberty?
- Central precocious puberty
2. Peripheral precocious puberty
Describe central precocious puberty?
Gonadotrophin-dependent, triggered by premature secretion of gonadotropins from brain.
Affecting more girls
Girls exhibit signs before 8, boys before 9.
Idiopathic.
Describe peripheral precocious puberty?
Gonadtrophin independent. Triggered by androgen and oestrogen production..
What may lead to peripheral precocious puberty in girls and boys?
- tumor in adrenal glands
- / pituitary glands that release oestrogen or testosterone
- McCune-Albright syndrome (genetic disorder affecting skin colour and bones)
- Ovarian cysts and tumors in girls.
Compare peripheral and central precocious puberty in relation to LH and FSH?
Periperal
- suppressed
Central
- Elevated
Describe management of precocious puberty?
- Slow growth velocity and avoid early skeletal maturation
- GNRH analogues to suppress pubertal development
