CWH 4 intro to gynae Flashcards
What is puberty in females?
Puberty is the maturation of secondary sexual characteristics and the onset of menstruation. It is triggered by changes in the HPO pathway and by the effect that growth hormone (GH) has on insulin production. This rise in insulin causes a drop in SHBG, with higher levels of free sex steroids in the blood.
Breast development - Stages 1-5 with enlargement of the areola and breast bud. Investigate if no sign by 14 years. Mainly oestrogen dependent
Pubic hair grades 2-5 in association with androgens
Menache usually towards the end of pubertal development
Puberty may relate to achieving a specific body weight or fat percentage with heavier girls having an earlier menarche and leaner girls being later. Onset of puberty is earlier in developed countries.
Name the hormones in the HPO axis
Hypothalamus: GnRH, TRH, GHRH, CRH (Gonadotropin, thyrotropin, growth hormone, corticotropin releasing hormones) PIF (Prolactin inhibitory factor)
Posterior Pituitary:
Vasopressin
Oxytocin
Neurophysin
Anterior Pituitary: ACTH Prolactin Luteinising Hormone Follicle Stimulating Hormone Growth Hormone Thyroid Stimulating Hormone
Ovary: Granulosa Cells Oestrogen Theca Cells Androgens Regulated by Inhibin and Activin
What hormones do granulosa and theca cells make?
Granulosa (FSH stimulated):
Oestrogen, inhibin
Theca (LH stimulated):
Androgen, progesterone
When is adrenache?
↑ adrenal androgens → growth pubic/axillary hair
↑ adrenal cortical function expressed by ↑ circulating DHA, DHAS and androstenedione associated with ↑ adrenal 17αhydroxylase and 17,20-lyase activity occurs progressively from age 6-6 to 13-15
Generally, the beginning of adrenarche precedes by 2 years the linear growth spurt, the ↑ E2 and gonadotrophins of early puberty and menarche at mid-puberty
Why is overweight associated with earlier menarche?
Leptin is secreted in adipose tissue and circulates in blood bound to a family of proteins and acts on CNS neurons that regulate eating behaviour and energy balance
? threshold level necessary for puberty to begin
Higher level of leptin → earlier age of menarche
hormone surge required fro ovulation?
The final endocrine hallmark of puberty is the development of +ve E2 feedback on the pituitary and hypothalamus which stimulates mid cycle surge of LH required for ovulation
Menses following menarche are usually anovulatory, irregular and occasionally heavy (12-18 months)
Signs of McCune-Albright syndrome
Multiple café au lait spots and fibrous dysplasia of bones, ovarian enlargement or testicular abnormalities on ultrasonography; may have menstrual bleeding before other development
Precocious puberty
Test for late onset CAH
Elevated Serum 17-hydroxyprogesterone: nonclassic (late onset) congenital adrenal hyperplasia
Test for adrenal source of premature adrenache
Serum dehydroepiandrosterone sulfate
Elevated: adrenal source, premature adrenarche (mild elevation) vs. peripheral precocious puberty
What does a germ cell tumour secrete?
BHCG
What do advanced vs delayed bone age results mean?
Advanced (> 2 standard deviations): more likely to be central or peripheral precocious puberty, less likely to be benign pubertal variant
Delayed: constitutional delay of growth and puberty, underlying chronic disease
How to treat these causes of precocious puberty? Central causes McCune Albright Endogenous causes CAH
Central causes - suppress GnRH with analogues
McCune Albright - cyproterone acetate (inhibits action of androgens on target organs), ketoconazole or spironolactone (all suppress gonadal steroid action)
Endogenous causes - treat tumour
CAH - replace steroids
causes of delayed puberty?
Hypergonadotrophin hypogonadism
- gonadal deficiency eg. Turner’s
Sickle cell disease, 20% delayed
LH and FSH Kallmans Pituitary disorders Hyperprolactinoma Or Physiological delay (10-30%)
Craniopharyngioma- most common neoplasm associated with delayed puberty originating from pituitary stalk with suprasellar extension, Peak incidence: 6-14 years
Imaging: abnormal sella and calcification (70%)
Treatment: surgery and irradiation
in puberty, an increase in insulin causes SHBG to increase or decrease?
Decrease
Causes of primary amennorhoea?
Gonadal dysgenesis MKRH, mullarian agenesis Physiological Imperforate hymen Obstructing anatomy Anorexia Hypothyroidism GnRH deficiency hypopituitarism Craniopharyngioma
