T2 L20: Physiology at puberty

Question 1

define puberty and the 3 categories of physical changes

Answer 1

The stage of physical maturation in which an individual becomes physiologically capable of pro-creation (sexual reproduction)​

Physical changes​:
-Growth spurt​
-Secondary sex
characteristics​
-Menarche/spermatogenesis

Question 2

what are pubic hairs a result of

Answer 2

androgens

Question 3

look at slide 4 for normal ranges of physical changes in girls

Answer 3

how was it

Question 4

what axis is involved with the endocrine changes in puberty

Answer 4

H-P-G synchrony – established in fetal life​

Until puberty – neural mechanisms suppress GnRH release​

At 6-9 yrs – pulsatile nocturnal GnRH release​

Question 5

what does mini-puberty prepare the body for

Answer 5

prepares genitalia for maturation​

Question 6

what endocrine changes occur in puberty

Answer 6

Pulsatile GnRH release (nocturnal) every 90-120 min - 6 to 9 y​

increase GnRH leads to increase FSH and LH​

Ovaries/testes become sensitized to the effects of FSH and LH​

Final phase: development of positive/negative feedback mechanism

ACTH stimulates the adrenals – Pubic & Axillary hair​​

Question 7

how do you test the levels of glucagon or insulin levels

Answer 7

involves the stimulation of GH

Urinary adrenal profile to check if adrenals are stimulated ​

Question 8

what occurs to testosterone in the bones

Answer 8

converted to oestrogen for bone growth

Question 9

what occurs in the testes

Answer 9

Production of gametes (sperms)​
-Sertoli cells under FSH control​

Production of androgens (Testosterone)​

• Leydig cells under LH control​
• 95% from testes, 5% from adrenals​

Testosterone in blood – converted to DHT in the target organs​

Question 10

what occurs in the follicular phase of the ovarian cycle

Answer 10

Follicular phase​

• Initially E rises (FSH) with LH surge in mid cycle​
• Ovulation occurs​

Question 11

what occurs in the luteal phase of the ovarian cycle

Answer 11

Luteal phase​

• Negative feedback after ovulation​
• No further ovulation in the same cycle​

Question 12

look at slides 10-11 to review the ovarian cycle

Answer 12

how was it

Question 13

what is menarche

Answer 13

final phase of puberty in a girl

Question 14

describe the features of menarche

Answer 14

-Related to general health, genetic and nutritional factors​

Mean age is falling at a rate of 4 months per decade​

Mean age in 1840 = 16.5 y; 1990 = 12.8 y​

One in 8 girls now reaches menarche while at primary school ​

Body weight and % fat is also important​

• Mean weight at menarche is 47.8kg​
• 16-24% fat​

-Athletes, patients with anorexia – late onset​
​

Question 15

define adrenarche

Answer 15

Adrenarche- hair development due to puberty ​

Question 16

describe the features of adrenarche

Answer 16

Adrenal androgens – responsible for axillary and pubic hair​

ACTH stimulates zona reticularis of adrenal cortex​

DHEAS & Androstenedione ​

• Girls – starts by 6, adequate levels by 8​
• Boys – starts by 8, adequate levels by 10​

Question 17

what is the order of pubertal events in girls

Answer 17

• Growth spurt​
• Breast development​
• Pubic hair​
• Axillary hair​
• Menarche-breast stage 4 ​

Question 18

what is the order of pubertal events in boys

Answer 18

Testicular volume​

Penile length​

Pubic hair​

Growth spurt​

Axillary / Facial hair​]
Deep voice​

Question 19

what is the LHERH test used for

Answer 19

LH/RH test- for axis – if early puberty due to testicular enlargement>9 years old ​

Question 20

look at slide 15 for a summary of pubertal changes in girls and boys

Answer 20

how was it

Question 21

what are the ages for the delay and early onset of puberty for girls and boys

Answer 21

early:
Girls – under 8 yrs​
Boys – under 9 yrs​

Delayed:
Girls – over 14 yrs​
Boys – over 14 yrs​​

Question 22

define the difference between central/true precocious puberty and peripheral/pseudo-precocious puberty and what normal variants are

Answer 22

Central or True precocious puberty​
-Gonadotrophin dependent​

Peripheral or Pseudo-precocious puberty​
-Gonadotrophin independent​
​
Normal variants​

• Premature Thelarche​
• Premature Adrenarche​

Question 23

where are the locations of 5he tumours that may be the pathology of central and peripheral …

Answer 23

central- hypothalamic

peripheral- gonads

Question 24

define a hypothalamic hamartoma

Answer 24

Non-neoplastic, homogenous sessile mass, iso-intense to brain parenchyma in the region of the tuber cinerium in the hypothalamus​
​
Treat with LHRH analogue

Question 25

what are the features of a hypothalamic hamartoma

Answer 25

``` Blood clots in nappy​ Bilat breast buds​ Ht & Wt >97th centile​ LH 2.2, FSH 3.2, ​ 17β estradiol 432​ Uterus – enlarged​ Bone age – 2.8 yrs​ MRI scan​ ```

Question 26

how do you treat precocious puberty

Answer 26

Long acting LHRH analog therapy​ -Sustained supra-physiological LHRH levels ​ -Paradoxical cessation of gonadotrophin release​ ​ Stops further pubertal progression​ ​ Pubertal progression resumes when treatment stopped (at 10-12 yrs)​

Question 27

describe the different normal variants

Answer 27

``` Premature thelarche​ : Isolated breast development​ -Usually seen in children <2-3 yrs of age​ ​ Premature adrenarche​: ``` - Isolated pubic hair development​ - Caution: first sign of puberty in some​

Question 28

describe the problems that can occur in females to do with pseudo-precocious puberty

Answer 28

``` Females:​ -Iso-sexual or feminising​ -MAS, Ovarian/Adrenal​ ​ -Hetero-sexual or masculinising​ -CAH, Ovarian/Adrenal ``` ​

Question 29

describe the problems that can occur in males to do with pseudo-precocious puberty

Answer 29

``` Males​ -Iso-sexual or masculinising​ CAH, Adrenal/Leydig cell tumor​ ​ -Hetero-sexual or feminising​ Adrenal​ ```

Question 30

how does CAH present itself

Answer 30

``` Mairna, 6 yrs​ -Obese​ -Pubic hair stage 2​ -No breast bud​ ​ -LH <1, FSH 1.4, ​ 17β estradiol 32​ -Steroid profile​ ​ ```

Question 31

look at slide 24 to review steroid biosynthesis

Answer 31

how was it

Question 32

what is a long term sequelae that occurs as a result of delayed puberty

Answer 32

reduced bone mineralization

Question 33

how does Klinefelter syndrome present itself

Answer 33

Steven, 16 yrs​ - No pubertal progress​ - Learning difficulties​ - Tall, 98th centile​ - PH-2, G-2, TV-6ml​ - LH 12, FSH 16, T 40​ -Bone age – 14.5 yrs​ ​ -Karyotype​

Question 34

what are the clinical features of Klinefelter syndrome

Answer 34

1 in 1000 male infants​ 47 XXY / Multiple X​ Behavioural problems​ Androgen deficiency​ Azoospermia / Infertility​ (Micro genitalia  Sex change)​ Lifelong testosterone replacement therapy​

Question 35

how does turners syndrome present itself

Answer 35

Short Stature​ No pubertal onset​ Recurrent ear infections​ Increased carrying angle​ Widely spaced nipples​ LH 56, FSH 95, ​ 17β estradiol 45​ ​ Karyotype​

Question 36

what are the clinical features of turners syndrome

Answer 36

1 in 2000 live female births​ Triad - Short stature, streak gonads, primary amenorrhoea​ Dysmorphic features – Webbing of neck, cubitus valgus​ Coarctation of aorta, horse shoe kidneys​ ``` Early clue - Lymphedema​ ​ Surprisingly normal !!!​ ​ Turner Mosaic​ ```

Question 37

how do you treat tuners syndrome

Answer 37

Exclude co-existing congenital anomalies​ Growth Hormone therapy​ Pubertal induction + ongoing HRT​ Active monitoring to detect co-morbidities​ Assisted conception​3

Question 38

what are the clinical features of Gonadotrophin deficiency​

Answer 38

Absent smell sensation​ PH-1, G-1, AxH-1, TV-2ml each​ LH <1, FSH 1.2, T 0.8​ LHRH stimulation test – peak LH remained <1​ HCG stimulation test – min. increase in T​ MRI scan – Normal​ Kallman gene analysis – Negative​

Question 39

does puberty occur in syndromes

Answer 39

In syndromes there is no puberty but androgens are high because problems are at the gonads

Question 40

how do normal variants present themselves

Answer 40

Constitutional delayed growth & puberty​ More common in boys​ Small & Short in school days​ ``` Late onset of puberty​ Bone age delayed slightly​ ​ Family history – often present​ ​ Normal adult height​ ``` Pubertal induction – sometimes