Hormonal Abnormalities Flashcards
How does the contraceptive pill work?
The pill causes high oestrogen levels, oestrogen gives negative feedback, halting the menstrual cycle.
What hormone causes thickening of the endometrium?
Oestrogen
What hormone maintains the thickened endometrium?
Progesterone
What are the clinical features of polycystic ovarian syndrome?
Hirsuitism Acne Oligomenorrhoea / Amenorrhoea Multiple cysts in the ovary Infertility
Hirsuitism
Excessive hair growth
Oligomenorrhoea
Irregular periods
What causes the clinical presentation of hirsuitism and acne?
Hyperandrogenism (excess testosterone)
What hormone produced by the anterior pituitary is seen raised in women with PCOS?
LH
What is the effect of raised LH in women with PCOS?
When LH increases relative to FSH it causes the ovaries to synthesise androgens instead of oestrogen.
What is the effect of excess androgens on the menstrual cycle?
The excess androgen stops follicular development and causes anovulation.
What is thought to be the main cause of PCOS?
Insulin insensitivity
How does insulin insensitivity cause PCOS?
The insulin insensitivity results in hyperinsulinaemia.
Insulin acts synergistically with LH causing increased androgen production from the theca cells and the adrenal gland.
What is the role of theca cells in PCOS?
The theca cells are responsible for converting androgen precursors into testosterone.
How does insulin indirectly increase testosterone levels in the blood?
Insulin inhibits production of SHBG (sex hormone binding globulin).
Therefore there is more testosterone available in the blood as SHBG cannot bind to testosterone.
How are oestrogen levels affected in PCOS?
Oestrogen levels are sometimes increased as production normally continues and additionally some testosterone is converted into oestrogen in peripheral fat (aromatisation).
What is the Rotterdam criteria for diagnosing PCOS?
2/3 of the following:
Oligo / anovulation
Hyperandrogenism - elevated testosterone
Polycystic ovaries seen on ultrasound
Why are prolactin levels also tested in PCOS?
Prolactinaemia causes oligo/anovulation therefore a pituitary tumour must be ruled out.
Why are TSH levels also tested in PCOS?
Hypothyroidism can cause PCOS like symptoms.
What lifestyle change is PCOS commonly associated with?
Weight gain
How is PCOS managed?
Conservative management e.g healthier lifestyle
Glucose and cardiovascular disease screening (due to risk of developing type 1 diabetes).
Weight loss
Endometrial protection through induction of periods.
Insulin sensitising drugs
How does the treatment plan for PCOS change if you are trying for a baby?
Weight loss
Assessment of causes
Secondary care for fertility treatment
What are the risks if you are pregnant and have PCOS?
Risk of developing gestational diabetes
Pre-eclampsia (PIH)
Preterm labour
PIH
Pregnancy induced hypertension (pre-eclampsia)
What is pre-eclampsia?
Preeclampsia is a condition during pregnancy where there is a sudden rise in blood pressure and swelling, mostly in the face, hands, and feet.
Androgen production from the polycystic ovary is driven predominantly by luteinising hormone in slim women and insulin in overweight women.
Androgen production from the polycystic ovary is driven predominantly by luteinising hormone in slim women and insulin in overweight women.
How can anorexia cause amenorrhoea?
Lack of the endocrine messenger leptin, which is secreted from fat, prevents pulses of gonadotrophin releasing hormone being released from the hypothalamus.
HPO axis
Hypothalamus - pituitary - ovarian axis
What is the role of leptin in the HPO axis?
Leptin causes pulsatile releases of GnRH which then stimulates LH production.
When do secondary sexual characteristic begin to develop in women?
8.5-13 years of age
What is the average ago of menarche?
12 years
Mean age of puberty for boys
11.6 years
Thelarche
Breast development
Adrenarche
Pubic hair growth
What are the tanner stages?
The tanner stages represent the stages of physical change seen in puberty.
Precocious puberty
Early onset of puberty
What is considered precocious puberty for girls?
< 8 years
What is considered precocious puberty for boys?
< 9 years
What are the two categories of precocious puberty?
Central precocious puberty
Peripheral precocious puberty
What can cause central precocious puberty?
Hypothalmic - pituitary gonadal axis activated.
Idiopathic
Central nervous system lesions
What can cause peripheral precocious puberty?
Congenital adrenal hyperplasia Ovarian cysts Severe primary hypothyroidism Tumours (adrenal and gonadal) Hepatoblastomas McCune-Albright syndrome Testotoxicosis
What are the investigations of precocious puberty?
LH and FSH testing TSH testing GnRH stimulation test Brain imaging for tumours Pelvic and abdominal imaging Bone age and x-ray
How are LH and FSH levels different in central and peripheral precocious puberty?
LH and FSH are supressed in peripheral precocious puberty.
LH and FSH are elevated in central precocious puberty.
Who manages precocious puberty?
Precocious puberty must be managed by a paediatric endocrinologist.
How is precocious puberty managed?
Slow growth velocity to avoid early skeletal maturation.
Potential surgical resection
Pubertal development supressed by GnRH analogues
Hypothyroidism - thyroid replacement
What is central precocious puberty?
Premature activation of the hypothalamic–pituitary–gonadal axis. (Gonadotropin dependant).
What is peripheral precocious puberty?
From excess sex steroids outside the pituitary gland e.g adrenal tumour (Gonadotropin independant).
The onset of puberty is initiated by pulsatile releases of what hormone?
GnRH
What substance is responsible for period cramps and pain during the menstrual cycle?
Prostaglandins
Labial adhesions are normally caused by what?
Hypo-oestrogenic state.
Lichen Sclerosis
Lichen sclerosus is an inflammatory skin condition that occurs in postmenopausal women and pre-pubertal girls. It can affect any part of the body but it most frequently occurs on the genitalia. It can cause itching and discomfort, which can be quite severe. White plaques occur typically in a figure-of-eight pattern around the vulva and anus.
