Puberty Flashcards
1
Q
Which hormones control puberty?
A
- GnRH
- LH
- FSH
- Neuroendocrine hormones
2
Q
Which female steroid hormones are involved in puberty
A
- Oestradiol
- Progesterone
- Adrenal androgen precursors
3
Q
Which male steroid hormones are involved in puberty?
A
- Testosterone
- Dihydrotestosterone( DHT)
- Adrenal androgens
- Oestradiol
4
Q
What does testosterone get aromatised to?
A
Oestrogen—> This gives us our growth spurt( growth plates fuse together)
5
Q
Define gonadarche
A
Activation of the gonads by the pituitary hormones FSH-LH
6
Q
Define adrenarche
A
Increase in production of androgens by the adrenal cortex
7
Q
Define Thelarche
A
Appearance of breast tissue—-> oestradiol(ovaries)
8
Q
Define Menarche
A
First menstrual bleed-oestradiol on endometrial lining-non ovulatory
9
Q
Define spermarche
A
First sperm production- nocturnal sperm emissions FSH,LH—> testosterone
10
Q
Define pubarche
A
- Appearance of pubic hair —> androgens from adrenal gland
- First appearance of axillary hair, apocrine body odour& acne
11
Q
What is estradiol responsible for?
A
- Breast development
- Growth acceleration
- Skeletal maturation
12
Q
What is estradiol together with progesterone responsible for?
A
-Menstruation
13
Q
Outline the hypothalamic-pituitary-ovarian axis
A
- Hypothalamus releases GnRH which stimulates the gonadotroph cell
- The gonadotroph cell releases FSH&LH which stimulate folliculogenesis in the ovary
14
Q
Which hormones inhibit the activity of the gonadotroph in females?
A
- Inhibin
- Progesterone
- Estrogens ( primarily estradiol)
15
Q
Outline the hypothalamic-pituitary-testicular axis
A
- Hypothalamus releases GnRH which stimulates the gonadotroph cell
- The gonadotroph cell releases FSH&LH which stimulate spermatogenesis in the testis
16
Q
Which cells produce testosterone?
A
The Leydig cells of the testis
17
Q
Which hormones inhibit the activity of the gonadotroph in males?
A
-Inhibin B
18
Q
Which hormones inhibit the activity of the hypothalamus in females?
A
- Progesterone
- Estogens (primarily estradiol)
19
Q
Which hormones inhibit the activity of the hypothalamus in males?
A
-testosterone
20
Q
Describe the pattern of testosterone conc on a graph
A
- Spikes
- As you go on in puberty, the spikes become higher& bigger and they become diurnal
- Girls also get oestrogen which also spikes but not to the same extent
21
Q
Outline the tanner stages for genitalia
A
- ) Pre-pubertal
- ) Beginning of onset of puberty; testes enlarges from 3ml–>4ml
- ) darker colour-redness
- ) even darker and larger,scrotal sac comes down more
- ) darkest and largest
22
Q
Outline the tanner stages for pubic hair in boys
A
- 5 stages
- 5 has the most pubic hair
- Pubic hair starts at the base of the penis
23
Q
Outline the mammary/breast tanner stages
A
- 5 stages
- gradual growth of breast tissue
- areolar+ nipple increase in size
- 5th stage: theres is a smooth contour of the breast; the growth is complete
24
Q
What is one of the first testicular difference in puberty for boys
A
Testicular stages increases from 3ml to 4ml
25
Outline the tanner stages for pubic hair in females
- 6 stages
- gradual increase in amount of pubic hair
- Starts along the labial line
- If it starts elsewhere it isnt true puberty
26
What pubertal tanner stages exist for boys?
- (A) Axillary hair( A1-A3)
- (P) Pubic hair (P1-P5)
- (G) Genitalia (G1-G3)
27
Which pubertal tanner stages exist for girls?
- (A) Axillary hair (A1-A3)
- (P) Pubic hair (P1-P6)
- (B) Breast development (B1-B5)
- (M) Monarche; menstrual, the onset of the menses (M1-M2)
28
What determines pubertal timing ?
- Genetics eg mum& daughter have their period around the same time
- Environment eg insectides, pesticides, hormone disrupters, phytooestrogens found in soya milk
- Nutritional status eg anorexia delays it
- Health status eg immunocomprimisation
29
What other changes apart from those outlined by the tanner stages, are associated with puberty?
1. ) Anaemia
- more likely in girls
2. ) Gynecomastia
3. ) Acne
- caused by androgenic stimulation
- Higher serum levels of dehydroepiandrosterone sulfate( DHEAS)
30
What is precocious puberty?
- 2 or 2.5 SD earlier than the population norms
- May range from variants of normal development to pathologic conditions; may be genetics
- BOYS: before 9yrs
- GIRLS: before 8yrs
31
What is true central precocious puberty (TCPP)?
- Gonadotrophin dependent
- Early maturation of the HPG axis
- Sequential maturation
- Pathologic 40-75% of boys
- Pathologic in 10-20% of girls
- Sexual characteristics are appropriate for the child's gender
32
What is peripheral precocity?
- Gonadotrophin independent
- Excess of secretion of sex hormones-gonads,adrenal glands, exogenous sources of sex steroids, ectopic production of gonadotropin from a germ cell tumor
- Non sequential maturation
- Isosexual or contrasexual
33
What are benign pubertal variants?
-Premature thelarche
-Isolated androgen-mediated sexual characteristics
( precocious adrenarche)
-Can be a variant of normal puberty
34
What are the characteristics of central precocious puberty
- Accelerated linear growth
- Advanced bone age
- Pubertal levels of LH
- Pubertal levels of FSH
35
What causes TCPP
1. )Idiopathic
2. )CNS lesions- neurogenic TCPP
- Hamartomas
- other cns tumours: astrocytomas,ependyomas, pinealomas, optic& hypothalamic gliomas
- CNS irradiation
- other CNS lesions: hydrocephalus, cysts, trauma, CNS inflammatory disease, congenital midline defects
3. ) Genetics
- Gain of function mutation in the KISS1 &KISS1R
4. ) Previous excess sex steroid exposure/miscellaneous
- Priming from adrenarche
- Mc cune albright
- Extreme prematurity
5. )Pituitary gonadotrophin-secreting tumours
- Elevated levels of LH& FSH
36
What causes peripheral precocity in girls?
1. ) Ovarian cysts
- most common
- breast development, vaginal bleeding-Ovarian torsion
2. ) Ovarian tumours
- Rare cause
- Granulosa cell tumors---> isosexual precocity
- Sertoli/leydig cell tumours, pure leydig cell tumours, gonadoblastoma---> contrasexual precocity( virilisation)
37
What causes peripheral precocity in boys?
1. ) Leydig cell tumors
- asymmetric testicular enlargment
- Testosterone secreting tumor, benign
- Rx usually radical orchiectomy
2. )Germ cell tumours
- they secrete hCG
- hCG secretion activates LH receptors on Leydig cells---> testosterone production
- located in gonads,brain,liver,retroperitoneum, anterior mediastinum
3. ) Familial male-limited precocious puberty (testotoxicosis):
- Activating mutation in the LH receptor gene---> premature Leydig cell maturation& testosterone secretion
38
What consequences can primary hypothyroidism have on puberty?
- Early breast development, galactorrhoea, recurrent vaginal bleeding-premature testicular enlargement
- Cross-reactivity & stimulation of the FSH receptor by high serum TSH levels -common alpha subunit
39
Outline McCune Albright syndrome
- Triad of peripheral precocious puberty, irregular cafe au lait spots, fibrous dysplasia of bone
- Sequence of pubertal progression may be abnormal often presenting with vaginal bleeding
- Tends to be within the midline, not crossing over
40
What is premature thelarche?
- A benign pubertal variant
- Idiopathic
- Arounds 2yrs of age
- waxes and wanes, doesn't progress
- Isolated breast development/ Not beyond tanner stage 3
- Absence of other secondary sexual characteristics
- Normal height velocity for age
- Normal or near normal bone age
- LH& FSH between normal range
41
What is premature adrenarche?
- Pubic &/or axillary hair---> pubarche
- Acne, BO, greasy skin
- Mild increase in growth velocity& advanced bone age
- Mild elevation in serum DHEAS for age
- More common in girls, Afro caribbean & hispanic females
- In patients with obesity & insulin resistance
- Risk factor for later development of PCOS in girls
- Can cause priming resulting in TCPP
42
How can we treat premature preocity
- Depends on cause
- Reasurrance if it's normal benign variation
- Gonadotrophin independent: Anti-androgens/aromatase inhibitors
- Gonadotrophin dependent : block with GnRH analogues
43
Outline delayed puberty in girls
- 13 yrs old and no breast development
- No pubic hair by 14 yrs
- More than 5 years between thelarche& menarche
- No menarche by 16 years old without secondary sexual characteristics
44
Outline delayed puberty in boys
- Testicular volume less than 4ml by age 14
- No pubic hair by 15 yrs old
- More than 5 yrs to finish penile and testicular growth
45
What are the different forms of gonadal failure
1. ) Primary failure
- hypergonadotrophic hypogonadism
- increased levels of FSH&LH stimilating the gonads
- Gonads not working; increased LH& FSH levels due to hypothalamus and pituitary still working
2. ) Secondary failure:
- hypogonadotrophic hypogonadism
- hypothalamus/pituitary stops working so no testosterone release---> no stimulation of gonads
- May stop due to trauma to the brain or craniofacial anomalies
46
Explain the different types of secondary hypogonadism
- Normal/low gonadotrophins
- hypogonadotropic hypogonadism
1. ) Congenital:
- craniofacial anomalies/midline defects
- GnRH deficit (eg Kallman, Prader Willi, Alteration of GnRH receptor)
2. ) Acquired:
- function loss: Eating disorders/athletes; chronic illness; Cushing;diabetes;hyperprolactinaemia;hypothyroidism
- Physical: CNS tumors; Infiltrative disease; head trauma; head radiation
47
What are the hypogonadotrophic hormones?
GnRH
FSH
LH
48
Explain the different types of primary hypogonadism
- High gonadotrophins
- hypergonadotrophic hypergonadism
1. ) Congenital:
- Chromosome anomalies: Turner syndrome; Klinefelter syndrome
- Testicular regression syndrome
- Synthesis & action of sexual steroids
2. ) Acquired:
- surgery/trauma
- chemo/radiotherapy
- Autoimmune
- Post infection
- Metabolic galactosemia
49
How can we diagnose delayed/early puberty?
- Clinical history
- growth charts
- family history
- Exercise,chronic illness, food habits
- LH, FSH, testosterone, oestrogens, prolactin, TSH, karyotype
- Bone age, brain MRI, pelvic Ultrasounds
