OB-GYN Revision 12 Flashcards
Primary amenorrhoea is defined as not starting menstruation by … [2]
What is the definition of secondary amenorrhoea? [1]
Primary:
* By 13 years when there is no other evidence of pubertal development
* By 15 years of age where there are other signs of puberty, such as breast bud development
Secondary:
* cessation of menstruation for 3-6 months in women with previously normal and regular menses, or 6-12 months in women with previous oligomenorrhoea
Explain the pathophysiology of hypogonadotropic hypogonadism [3]
Deficiency of LH and FSH, leading to deficiency of the sex hormones (oestrogen)
- LH and FSH are produced in the anterior pituitary gland in response to gonadotropin releasing hormone (GnRH) from the hypothalamus.
- Since no gonadotrophins are simulating the ovaries, they do not respond by producing sex hormones (oestrogen).
- Therefore, “hypogonadotropism” causes “hypogonadism”
A deficiency of LH and FSH is the result of abnormal functioning of the hypothalamus or pituitary gland. This could be due to what? [+]
- Hypopituitarism (under production of pituitary hormones)
- Damage to the hypothalamus or pituitary, for example, by radiotherapy or surgery for cancer
- Significant chronic conditions can temporarily delay puberty (e.g. cystic fibrosis or inflammatory bowel disease)
- Excessive exercise or dieting can delay the onset of menstruation in girls
- Constitutional delay in growth and development is a temporary delay in growth and puberty without underlying physical pathology
- Endocrine disorders such as growth hormone deficiency, hypothyroidism, Cushing’s or hyperprolactinaemia
- Kallman syndrome
Explain the pathophysiology of hypergonadotropic hypogonadism [3]
Hypergonadotropic hypogonadism is where the gonads fail to respond to stimulation from the gonadotrophins (LH and FSH).
Without negative feedback from the sex hormones (oestrogen), the anterior pituitary produces increasing amounts of LH and FSH.
Consequently, you get high gonadotrophins (“hypergonadotropic”) and low sex hormones (“hypogonadism”).
Hypergonadotropic hypogonadism is the result of abnormal functioning of the gonads. This could be due to [3]
Previous damage to the gonads (e.g. torsion, cancer or infections such as mumps)
Congenital absence of the ovaries
Turner’s syndrome (XO)
Describe what is meant by congenital adrenal hyperplasia [1]
How does it present in mild [4] and severe cases [1]
congenital deficiency of the 21-hydroxylase enzyme:
- underproduction of cortisol and aldosterone, and overproduction of androgens from birth.
Mild cases - typically present at childhood or puberty:
- Tall for age
- Facial hair
* Absent periods (primary amenorrhoea)
* Deep voice
* Early puberty
Severe:
* unwell shortly after birth, with electrolyte disturbances and hypoglycaemia.
NB: In a small number of cases, it involves a deficiency of 11-beta-hydroxylase rather than 21-hydroxylase.
Describe the diagnosis [2] and management [3] of ASS
Diagnosis
* buccal smear or chromosomal analysis to reveal 46XY genotype
* after puberty, testosterone concentrations are in the high-normal to slightly elevated reference range for postpubertal boys
Management
* counselling - raise the child as female
* bilateral orchidectomy (increased risk of testicular cancer due to undescended testes)
* oestrogen therapy
Describe what is meant by Androgen insensitivity syndrome [2]
X-linked recessive condition due to end-organ resistance to testosterone causing genotypically male children (46XY) to have a female phenotype
- the tissues are unable to respond to androgen hormones (e.g. testosterone), so typical male sexual characteristics do not develop
- It results in a female phenotype, other than the internal pelvic organs.
- Patients have normal female external genitalia and breast tissue.
- Internally there are testes in the abdomen or inguinal canal, and an absent uterus, upper vagina, fallopian tubes and ovaries.
Which structural pathologies can prevent menstruation? [5]
- Imperforate hymen
- Transverse vaginal septae
- Vaginal agenesis
- Absent uterus
- Female genital mutilation
How do you treat Kallmann’s syndrome? [2]
Treatment:
* pulsatile GnRH can be used to induce ovulation and menstruation. This has the potential to induce fertility
* Where pregnancy is not wanted, replacement sex hormones in the form of the combined contraceptive pill may be used to induce regular menstruation and prevent the symptoms of oestrogen deficiency.
Describe the pathophysiology and presentation of Kallmann’s syndrome
Kallmann’s syndrome is thought to be caused by failure of GnRH-secreting neurons to migrate to the hypothalamus - causing hypogonadotropic hypogonadism
Presentation:
* ‘delayed puberty’
* hypogonadism, cryptorchidism
* anosmia - clue in many qs
* sex hormone levels are low
* LH, FSH levels are inappropriately low/normal
* patients are typically of normal or above-average height
What is the most common cause of secondary amenorrhea? [1]
What are other common causes [4]
Pregnancy is the most common cause
Menopause and premature ovarian failure
Hormonal contraception (e.g. IUS or POP)
Hypothalamic or pituitary pathology
Ovarian causes such as polycystic ovarian syndrome
Uterine pathology such as Asherman’s syndrome
Thyroid pathology
Hyperprolactinaemia
What are pituitary causes of secondary amen. ? [2]
Pituitary tumours, such as a prolactin-secreting prolactinoma
Pituitary failure due to trauma, radiotherapy, surgery or Sheehan syndrome
Describe how hyperprolactinaemia influences the hypothalamus and causes amenorrhea?
- High prolactin levels act on the hypothalamus to prevent the release of GnRH.
- Without GnRH, there is no release of LH and FSH.
- This causes hypogonadotropic hypogonadism.
What are the most common causes of hyperprolactinaemia? [1]
pituitary adenoma secreting prolactin.
- . Often there is a microadenoma that will not appear on the initial scan, and follow up scans are required to identify tumours that may develop later.
What are the features of prolactinomas in women? [4]
excess prolactin in women
* amenorrhoea
* infertility
* galactorrhoea
* osteoporosis
Assessment of secondary amenorrhoea involves? [3]
- Detailed history and examination to assess for potential causes
- Hormonal blood tests
- Ultrasound of the pelvis to diagnose polycystic ovarian syndrome
s
Desribe the hormonal tests are used to assess secondary amenorrhoea [5]
Beta human chorionic gonadotropin (HCG) urine or blood tests are required to diagnose or rule out pregnancy.
Luteinising hormone and follicle-stimulating hormone:
* High FSH suggests primary ovarian failure
* High LH, or LH:FSH ratio, suggests polycystic ovarian syndrome
Prolactin can be measured to assess for hyperprolactinaemia, followed by an MRI to identify a pituitary tumour.
Thyroid stimulating hormone (TSH) can screen for thyroid pathology. This is followed by T3 and T4 when the TSH is abnormal.
Raised testosterone indicates polycystic ovarian syndrome, androgen insensitivity syndrome or congenital adrenal hyperplasia.
TOM TIP: The key to HRT is to remember the principles, so that you can counsel women and look up the specific regimes when required.
The best way of delivering oestrogen is with [], due to the reduced risk of venous-thromboembolism.
The best way of providing progesterone is with an []
TOM TIP: The key to HRT is to remember the principles, so that you can counsel women and look up the specific regimes when required.
The best way of delivering oestrogen is with patches, due to the reduced risk of venous-thromboembolism.
The best way of providing progesterone is with an intrauterine device, for example, the Mirena coil. The coil has the added benefits of contraception and treating heavy menstrual periods. Additionally, women will not experience progestogenic side effects.
You’ve been asked to counsel someone about HRT.
Explain the risks vs benefits of HRT
Describe the differences in symptoms from perimenopause –> early menopause –> menopause [+]
What is a really important non-HRT use for menopause? [1]
Clonidine is one non-hormonal treatment that can be used for vasomotor symptoms.
Explain how another drug can be used
Fezolinetant
- Neurokinin 3 receptor antagonist
- Acts at level of hypothalamus on temp regulation
Which types of HRT specifically increase the risk of VTE? [2]
Oral oestrogen
Oral synthetic progesterones
