Basic science Flashcards
What is the definition of puberty
Onset of sexual maturity marked by development of secondary sexual characteristics
What is precocious puberty
Early onset puberty. Onset before age 8 in girls and before age 9 in boys
How is delayed puberty classified
Girls: absence of breast development by age 13 or absence of menarche by age 16
Boys: absence of testicular enlargement by age 14
Describe the female reproductive axis
Hypothalamus releases gonadotrophin releasing hormone which stimulates the anterior pituitary to release LH and FSH. LH and FSH stimulate the ovaries to produce oestrogen and progesterone. These hormones then feed back to the hypothalamus and pituitary to control the release of GnRH and LH/FSH.
Describe the male reproductive axis
Hypothalamus releases gonadotrophin releasing hormone which stimulates the anterior pituitary to release LH and FSH. LH and FSH stimulate the testes to produce testosterone which feeds back to the hypothalamus and pituitary to control further production.
What is the first physical change in puberty (girls/boys)
Girls - breast development
Boys - testicular enlargement
5 physical changes in puberty specific to boys
testicular enlargement, ejaculation (nocturnal), widened shoulders, facial and body hair, deepening of voice (enlargement of larynx and laryngeal muscles)
3 physical changes in puberty specific to girls
breast development, widened hips, menarche
3 physical changes in puberty which happen in both genders
growth spurt (females = 26cm most age 9-10, males = 28cm most age 11-12), pubic hair development, body fat changes
3 biochemical changes in puberty
- blood lipids (males = higher LDL and lower HDL)
- haematological indices (Hb rises in boys and falls in girls)
- maturation of P450 enzymes
Which staging system is used to assess pubertal development
Tanner stages
Difference between primary and secondary amenorrhoea
Primary = no menarche before age 16. If no secondary sexual characteristics then consider hormonal issue, if 2 sexual characteristics are present consider an outflow obstruction. Secondary = normal cycle previously developed then absence of menstruation for >6 months (think athletes, low BMI, ED)
Non-pathological causes of primary and secondary amenorrhoea
Primary - constitutional delay, drugs
Secondary - pregnancy, lactation, menopause, drugs
Pathological causes of both primary and secondary amenorrhoea
Anorexia nervosa, psychological, athleticism, hyperprolactinaemia, hypo/hyperthyroidism, adrenal tumours, PCOS, premature ovarian failure
Pathological causes of primary amenorrhoea only
Adrenal hyperplasia, Turner’s syndrome, androgen insensitivity, imperforate hymen, transverse vaginal septum
Pathological causes of secondary amenorrhoea only
Asherman’s syndrome (adhesions in uterine cavity), cervical stenosis
Which investigations should you do for amenorrhoea
Prolactin, TFTs, FSH, androgens, USS ovaries, pregnancy test
Describe the structure of an ovarian follicle
Granulosa cells inside, have receptors for FSH
Theca cells outside, have receptors for LH
Contains an oocyte inside
What are the 3 main stages of the menstrual cycle
Follicular phase (day 1 to 15) Ovulation (day 14) Luteal phase (day 15-28)
Main features of the follicular phase of menstrual cycle
Menstruation (day 1-5), shedding of endometrial lining and fall in progesterone due to loss of corpus luteum
Rapidly growing follicles in the ovaries
Dominant follicle selected (day 5-7) and produces oestrogen which prevents selection of other follicles
Main features of ovulation
LH surge causes release of the egg from the dominant follicle
Thickening of the endometrium
High levels of oestrogen and progesterone
Main features of luteal phase of menstrual cycle
Endometrial lining continues to thicken to prepare for menstruation
Corpus luteum forms from empty follicle
Hormones begin to decrease again
What is the corpus luteum
Formed from the leftover follicle after an egg has matured and left the follicle (ovulation)
In the ovaries
A surge in which hormone causes egg release
LH
What is menorrhagia
Heavy bleeding in normal cycle
What is dysmenorrhoea
Painful bleeding in normal cycle
What is oligomenorrhoea
Irregular bleeding/cycle
6 structural issues that may cause menorrhagia
Fibroids, polyps, endometriosis, endometrial hyperplasia, endometrial carcinoma, adenomyosis
What is adenomyosis
Endometrial lining invades into myometrium causing bleeding
What is DUB
Dysfunctional uterine bleeding, diagnosis of exclusion when no other cause of menorrhagia is present
7 medical methods for managing menorrhagia
Mirena coil, TXA, mefenamic acid, COC, norethisterone (progesterone), Depo-Provera, GnRH analogues
4 surgical methods for managing menorrhagia
Endometrial ablation, uterine artery embolisation, hysteroscopic myomectomy, hysterectomy
Vaginal causes of IMB/PCB/PMB
Trauma, vaginitis, vaginal/vulval cancer
Cervical causes of IMB/PCB/PMB
Cervicitis (STI), polyps, ectropion, cancer, cervical intrahelical neoplasia (CIN)
Uterine causes of IMB/PCB/PMB
Endometritis, fibroids, polyps, adenomyosis, cancer
Iatrogenic causes of IMB/PCB/PMB
Contraception, tamoxifen, anticoagulants, gynaecological procedures
How is infertility classified
Failure to conceive after two years of regular unprotected sexual intercourse with no contraception
What is primary infertility
Couple has never conceived at any stage
What is secondary infertility
Couples who have previously conceived (pregnancy may not have been successful)
3 categories of female factor infertility
- ovarian factor (anovulation)
- tubal factor
3, uterine/structural factor
3 groups of ovarian factor infertility
Group 1: hypothalamic-pituitary failure
Group 2: hypothalamic-pituitary-ovarian dysfunction
Group 3: ovarian failure
Examples of hypothalamic-pituitary failure
Anorexia Stress Hypogonadotrophic hypogonadism Hypopituitarism Hyperprolactinaemia
Examples of hypothalamic-pituitary-ovarian dysfunction
PCOS
Examples of ovarian failure
Premature
Menopause
Turner’s syndrome
Main investigation for ovarian factor infertility
Need to check is woman is ovulating
Mid-luteal progesterone level taken 7 days before expected menses
>30nmol/L = proof of ovulation
Other investigations for ovarian factor infertility
Serum FSH, LH, oestradiol (day 2-6)
TSH
Prolactin
Testosterone and SHBG
Raised FSH and LH in ovarian factor infertility
Ovarian failure
Low FSH and LH in ovarian factor infertility
Hypopituitarism
Hypogonadotrophic hypogonadism
Examples of tubal factor infertility
Hydrosalpinx (blockage of fallopian tube leading to accumulation of clear fluid) due to PID, HIV etc. Tubal occlusion (e.g. via hydrosalpinx) Tubal dysfunction
Investigation for tubal factor infertility
Hysterosalpingogram
Examples of uterine/structural factor infertility
Uterine: endometriosis, uterine malformation, fibroids, asherman’s syndrome
Cervical: cervical stenosis, non-receptive cervical mucus
Vaginal factor: vaginismus
Investigation for uterine/structural factor infertility
Ultrasound
3 main categories of male factor infertility
Pre-testicular
Testicular
Post-testicular
Pre-testicular causes of male factor infertility
Smoking
Drugs decreasing FSH e.g. phenytoin
Secondary hypogonadism: hypothalamic or hypopituitarism
Hypothalamic causes of pre-testicular male factor infertility
Obesity
Kallmann syndrome
Hypopituitarism causes of pre-testicular male factor infertility
Adenoma Brain tumours Infection Inflammation (autoimmune) Radiation Congenital
Testicular causes of male factor infertility
Testicular cancer Trauma Radiotherapy Drugs decreasing sperm mobility e.g. sulfasalazine Genetic factors Primary hypogonadism
Post-testicular causes of male factor infertility
Obstruction of vas deferens CAVD (congenital absence of vas deferens) Prostatitis Ejaculatory duct obstruction Retrograde ejaculation Impotence
Main investigation for male factor infertility
Semen analysis
What is azoospermia
Total absence of sperm
What is oligozoospermia
Too few sperm within ejaculate
What is teratozoospermia
Abnormal sperm morphology
What is asthenzoospermia
Reduced sperm motility
Other investigations for male factor infertility
Endocrine tests Cystic fibrosis screening Karyotype and chromosome studies Genital tract infections Imaging of genital tract
Mechanism of action of clomifene
Selective oestrogen receptor modulator
Inhibits oestrogen receptors in the hypothalamus, inhibiting negative feedback therefore LH/FSH are continually synthesized and released
Promotes ovulation
What is the regime for clomifene
Prescribed on day 3 of menstrual cycle and continued for 5 days
Ovulation should occur 6-7 days after course of clomifene
What is AMH
Anti-mullerian hormone
Produced by granulosa cells in small ovarian follicles - measure of ovarian reserve
4 causes of high serum hCG
- multiple pregnancy
- molar pregnancy
- hCG-producing tumour e.g. germ-cell tumour
- Down’s syndrome/genetic abnormality
2 causes of low serum hCG
- early stage of pregnancy
2. plateauing +/- falling hCG indicates pregnancy which is no longer viable (confirm with USS)
3 causes of false-positive urinary pregnancy tests
- hCG producing tumour (germ cell)
- use of fertility medication
- use of chlorprozamine or methadone
causes of false-negative urinary pregnancy test
- use of diuretics or promethazine
2. not testing first urination of the morning
