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RED > L22: Puberty And Sex Development > Flashcards

L22: Puberty And Sex Development Flashcards

1
Q

What is the definition of puberty

A

The physiological, morphological, behavioural changes as the gonads switch from the infertile to adult forms

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2
Q

When does growth at puberty occur

A

Adolescent growth spurt

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3
Q

What is a adolescent growth spurt

A

Rapid increase in individuals height and weight as a consequence of gonadal sex steroids

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4
Q

What are the 3 phases of adolescent growth spurt

A

1) Time of minimum growth velocity
2) peak height velocity
3) time of decreasing growth velocity (epiphyseal fusion)

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5
Q

When does the time of minimum growth velocity occur

A

Just before puberty starts

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6
Q

What occurs during peak height velocity

A

Maximum height velocity is reached

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7
Q

What occurs in time of decreasing velocity

A

Growth rate decreases until the epiphyseal fusion of long bones occur

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8
Q

What is the average height gain during puberty in boys

A

28cm

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9
Q

What is the average height gain in females

A

25cm

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10
Q

Which sex has growth occuring before

A

Female

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11
Q

What are the secondary sexual characteristics of girls

A

Breast development

Pubic hair and axillary hair

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12
Q

What is breast development controlled by

A

Ovarian oestrogens

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13
Q

What is the pubic hair and axillary hair controlled by

A

Ovarian and adrenal androgens

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14
Q

What are the secondary sexual characteristics that occurs in males during puberty

A

Development of penis, scrotum
Pubic hair
Enlargement of larynx (deepening voice)
Increase in body muscle mass

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15
Q

Which hormones controls the secondary sexual characteristics in males

A

Androgens such as testosterone and DHEA

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16
Q

How do we rate the development of secondary sexual characteristics as clinicians

A

Tanner stage

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17
Q

How many stages does the tanner stage involve

A

5 stages

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18
Q

With the tanner stage what do we asses in males

A

Pubic hair

Growth of penis

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19
Q

In girls using the tanner stage what do we assess

A

Pubic hair

Breast development

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20
Q

What is the timing of puberty stages in girls like

A

1) pubic hair and breast development occur first
2) this is accompanied by onset of growth spurt
3) after the peak of height velocity periods occur

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21
Q

What is the timing of puberty in males

A

1) pubic hair and increase in testicular volume of 4cm occurs
2) this results in penile growth
3) peak height then occurs later on

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22
Q

In boys what indicates that puberty has started

A

Testicular volume of 4cm at average age of 10-14 years

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23
Q

In girls what indicates that puberty has started

A

Breast development tanner stage of 2 at average age of 9.2-13.2 years

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24
Q

What are the factors that are needed for puberty to occur

A

Sex chromosomes
Functioning HPG axis
Responsiveness of tissue to hormones

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25
Q

What are the physical changes controlled by

A

Gonadal sex steroids

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26
Q

Which gonadal sex steroid control the physical changes in females

A

Oestrogen

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27
Q

Which gonadal sex steroid control the physical changes in males

A

Testosterone

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28
Q

What hormones are the gonadal sex steroids regulated by

A

LH/FSH from the anterior pituitary gland

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29
Q

What is the LH/FSH secretion regulated by

A

GNRH Pulsatile secretion from the hypothalamus

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30
Q

During puberty what does LH levels show

A

Circadian rhythms

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31
Q

What is the circadian rhythm of LH like in puberty

A

Early- mid puberty: low spikes and less frequent LH

Mid-late puberty: high spike and more frequent LH

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32
Q

What is the definition of precocious puberty

A

Onset of secondary sexual characteristics before 8 years in female and 9 years in males or menarche before 9 years in females

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33
Q

What is the definition of delayed puberty

A

Absence of secondary sexual characteristics by 13 years in females and 14 years in males

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34
Q

If there is delayed puberty in males and females what are they at risk of

A

Osteoporosis due to decrease bone mass

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35
Q

Which ethnic group can present with precocious puberty

A

African-Caribbean

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36
Q

What are the 2 ways in which precocious puberty can present

A

Concordant

Discordant

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37
Q

What does concordant mean

A

Puberty follow the normal sequence of events in order

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38
Q

What does discordant mean

A

Sequence of events is random e.g pubic hair but small testis

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39
Q

What is the likely cause of concordant precocious puberty

A

Central gonadotropin activation

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40
Q

What is the likely cause of discordant precocious puberty

A

Peripheral sec hormone production

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41
Q

In central precocious puberty what happen

A

1) early activation of GNRH in the hypothalamus
2) LH/FSH release is stimulated
3) this leads to gonadal sex hormone production

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42
Q

What happens in peripheral precocious puberty

A

1) GNRH secretion is silent
2) there are no LH/FSH release
3) there is however an increase in gonadal sex steroids due to a problem at the gonads, adrenal glands or a secreting tumour

43
Q

What is adrenarche

A

The onset of adrenal androgen production not in the gonads that reflects maturation of the zona reticularis in the adrenal glands

44
Q

Describe the process that occurs during adrenal gland maturation

A

1) foetal zone of adrenal gland produces many adrenal androgen precursors
2) the zona glomerulusa and zona fasciculata form- no androgen forms
3) in mid late childhood zona reticularis forms so adrenal androgen is produced
4) the zona reticularis completely forms in the early adolescence which results in increase of androgen i.e DHEA

45
Q

What are the clinical features of Adenarche

A

Growth acceleration
Pubic hair/ axillary growth
Mild acne
Body odour

46
Q

The the process of adenarche independent to central puberty regulation

A

Yes but adenarche occurs within the onset of central puberty

47
Q

What so premature adenarche

A

The onsent of androgen secretion from adrenal glands before 8 years in females and 9 years in males

48
Q

If someone presents with adrenarche what do we need to exclude

A

Precocious puberty
Enzyme defects
Virilizing tumours that secrete androgen

49
Q

What is the diagnostic test to differentiate between central and peripheral precocious puberty

A

GNRH (LHRH) stimulation test test

50
Q

How does a GNRH test work

A

1) you inject 100mcg GNRH analogue

2) measure LH/FSH at 30 and 60 mins

51
Q

If the patient has a central precocious puberty what would the results be after a GNRH test

A

1) an increase in LH and FSH

2) higher LH than FSH

52
Q

If a patient has peripheral precocious puberty what would be the results after a GNRH Test

A

LH and FSH will remain flat

53
Q

What are the causes of central precocious puberty

A
  • idiopathic precocious puberty
  • CNS tumours
  • CNS disorders
  • psychosocial
  • secondary central precocious puberty i.e CAH
54
Q

What are the causes of peripheral precocious puberty

A
  • increased androgen secretion i.e CAH due to 21 hydroxylase deficiency
  • gonadotropin secreting tumours
  • ovarian cyst
  • Oestrogen secreting neoplasm
  • hypothyroidism
55
Q

What are the consequences of precocious puberty

A
  • psychological symptoms: adolescent behaviour, altered self image
  • growth: growth will finish early so you will have a short stature
  • metabolic: glucose intolerance, diabetes, cardiovascular complications
56
Q

What is the treatment of central precocious puberty

A

Long acting GNRH analogues

57
Q

How does long acting GNRH analogues work

A

Down regulate GNRH receptors so GNRH cannot cause the release of LH/FSH

58
Q

What is the definition of delayed puberty

A

Absence of secondary sexual characteristic by 13 years in girls and 14 years in boys or first period after 15 years in girls

59
Q

What are the 2 types of gonadal failure

A

Primary gonadal failure

Secondary gonadal failure

60
Q

What is the primary gonadal failure due to

A

Problem at gonads

61
Q

What is secondary gonadal failure due to

A

Problem at higher centres

62
Q

What happens to the LH/FSH levels in primary gonadal failure

A

Increase as they try to stimulate the gonads and do not have a negative feedback

63
Q

In secondary gonadal failure what are the levels of LH/FSH like

A

Low due to a problem at the higher centres

64
Q

What are the levels of gonadoropins like in primary gonadal failure

A

Hypergonadotrophic i.e LH/FSH

Hypogonadism i.e sex steroids

65
Q

What are the level of gonadotropin in secondary gonadal failure like

A

Hypogonadroptrophins i.e LH and FSH

Hypogonadism i.e sex steroids

66
Q

In central hypogonadism i.e secondary gonadal failure what can the HPG axis be

A

Intact

Impaired

67
Q

If there is intact HPG axis in secondary gonadal failure what do we need to check for

A

other chronic diseases such as hypothyroidism that is affecting the HPG axis to become activated

68
Q

What do we need to look for if there is an impaired HPG axis in secondary gonadal failure

A
  • Tumours in the hypothalamus that have destroyed gonadotrophs
  • Trauma to the head
  • Congenital anomalies
69
Q

What are the primary gonadal failure causes in males

A
  • Bilateral testicular damage: cyptochidism, torsion, haemochromatosis
  • syndromes associated with cryptochidism
70
Q

What are the primary gonadal failure causes in females

A

Disorders of sex development

Toxic damage

71
Q

What are the primary gonadal failure causes in both sexes

A

Turners syndrome
Klinefelters syndrome
Chemotherapy

72
Q

What is the first line investigation of gonadal failure

A

Full blood count
Karyotype for turners or klinefelters
Basal LH, FSHm oestradiol, testosterone
Bone age

73
Q

If the test results show high LH, FSH and low oestradiol and testosterone what type of gonadal failure does this indicate

A

Primary gonadal failure

74
Q

What is the second line investigation for gonadal failure

A

GNRH test
HCG stimulation test- males
Pelvis USS- females
Ovarian antibodies

75
Q

What is the treatment for delayed puberty in males

A

Replace testosterone

76
Q

What is the treatment for delayed puberty in female

A

Replaces oestrogen

77
Q

When we treat delayed puberty with testosterone/ oestrogen what do we need to do to the levels

A

Titrate it very slowly to mimic the natural puberty development

78
Q

What is the definition of ambiguous genitalia

A

Appearance of external genitalia that is ambiguous when sex assignment is not possible at birth

79
Q

What are the 3 ways to define sex development

A

Chromosomal sex
Gonadal sex
Phenotype sex

80
Q

What is sex determination by

A

Chromosomal sex to gonadal sex

81
Q

What is sex differentiation by

A

Gonadal sex to phenotype sex

82
Q

Which gene on the Y chromosome determine male sex development into the testicles

A

SRY gene

83
Q

What cells are in the testes

A

Leydig cells

Sertoli cells

84
Q

What hormone does the Sertoli cells produce during embryological development

A

Anti mullerian hormone (AMH)

85
Q

What does AMH cause

A

Regression of mullerian/female structures

86
Q

What hormone does the leydig cells produce

A

Testosterone s

87
Q

What structure in the embryo does testosterone lead to

A

Wolffian structures

88
Q

In Sertoli cells what is testosterone converted to

A

DHEA

89
Q

Which enzyme converts the testosterone to DHEA

A

5 alpha reductase enzyme

90
Q

What structures from the Müllerian duct is formed

A

Ovary
Fallopian tubes
Uterus
Proximal 1/3rd of vagina

91
Q

What structure does the wolffian duct form in males

A

Testicles
Epididymis
Vas deferens
Seminal vesicle

92
Q

What are the important external genitalia in the embyro

A

Genital tubercle
Genital swelling
Urethral folks and grove

93
Q

In females what does the genital tubercle give rise to

A

Clitoris

94
Q

In males what does the genital tubercle give rise to

A

Glans of penis

95
Q

In females what does the urethral fold give rise to

A

Labia minora

96
Q

In males what does the urethral folds give rise to

A

Corpus spngiosum

97
Q

Which hormone influences the development of the EXTERNAL genitalia

A

Dihydrotestosterone produced by the testicles

98
Q

What are the 3 main subgroups of disorders of sex development

A

1) chromosomal DSD
2) DSD 46 XY
4) DSD 46 XX

99
Q

What does chromosomal DSD involve

A

Turners syndrome

Klinefelters syndrome

100
Q

What does DSD XY involve

A

Disorders of testicular development

Disorders of synthesis of androgen

101
Q

What does DSD 46 XY involve

A

Disorders of ovarian development

Excess production of androgens

102
Q

Explain what occurs in 5 alpha reductase deficiency

A

1) testesterone is bound to SHBG and becomes free and enters the cell
2) testosterone is converted to DHT by 5 alpha reductase
3) DHT binds to androgen receptors
4) androgen receptors travel to the nucleus and activate specific response elements in the genome to activate protein expression and process
5) in 5 alpha reductase deficiency these processes cannot take place for external genitalia development

103
Q

What is androgen insensitivity syndrome

A

When there is a defect in the Andorgen receptor (AR) so DHT cannot bind or travel to the nucleus to activate genes

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