203 - Puberty Flashcards by Lucy Knox

Puberty is characterised by 4 changes - they are:

Secondary sexual characteristics
Acceleration of somatic growth
Advancement of bone maturation
Behavioural + psychological changes

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What is the difference between puberty and adolescence?

Puberty = physical changes
Adolescence = psychological and nerological

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What factors influence the onset of puberty?

Genetics - when parents did
Nutritional status
Exercise
Chronic inflammatory conditions
Environment (abusive environment - early start)

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When is the normal range of onset of puberty in boys and girls?

Girls - 8-13.75

Boys - 9-13.25

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What is consonance?

The sequence of puberty

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What activated + controls puberty?

Hypothalamic-pituitary-gonadal axis

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What are the 3 consonant stages in male puberty?

1) testes growth >4mls
2) Penile growth + pubic hair
3) Growth spurt - late in puberty

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What are the 3 consonant stages in female puberty?

1) breast development + fat deposition around hips + uterus + vagina increase in size
2) Growth spurt
3) Menarche

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Why do boys generally end up taller than girls?

Boys have their growth spurt later in puberty (testes vol = 10-12mls), so have 2 more years of childhood growth = 10cm extra.
Boy’s growth spurt is usually 28cm, whereas girls is 25cm.

So boys have 10 + 3 = 13cm extra growth than girls

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What stimulates breasts to develop?

Begin after 1 yr of pulsatile LH + FSH

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What controls development of pubic and auxiliary hair in girls?

Adrenal androgens - so not always at same time.

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Describe the hypo-pit-gonadal axis

Hypothalamus produces GnRH (pulsatile)
This stimulates the anterior pituitary to produce LH and FSH

Girls: LH acts on gonads (ovaries) - oestrogen and progesterone produced, FSH acts on ovaries - Ova produced

Boys - LH + FSH act on gonads. LH acts on leydig cells which produce testosterone

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What is Adrenarche?

Adrenal hormones begin to be released, eg. DHEA
Cause virilization, pubic and auxiliary hair growth in girls
Can begin 1 yr before puberty

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What is gonadarche?

Puberty onset controlled by the hypo-pit-gonadal axis

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How does growth end?

Fusion of the epiphyseal plate of bone

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What causes the fusion of the epiphyseal plate?

Oestrogen levels (girls have more - stop growth earlier)

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Is a delay in puberty more common in boys or girls?

10 x more in boys

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What defines a delay in puberty in boys?

Failure of testicular growth > 4mls by 14yrs

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What defines a delay in puberty in girls?

Absence of breast development by 13.5yrs

OR when puberty is incomplete - menstruation hasn’t occurred within 3 yrs of breast development

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What is the cause of the majority of boys with delayed puberty?

Constitutional delay - 80%

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What is usually the cause of girls with delayed puberty?

Pathology - destruction of axis / lack of gonadal response

What investigations are done in delayed puberty?

Hormone levels (FSH, LH, Oestrogen, Testosterone, adrenal hormones)
Pelvis US
Bone age
Karyotype
CT/MRI of cranium

What do you X ray to asses bone age?

L hand and Wrist

What treatment can be given to a boy with maturational delay?

Give testosterone supplements until natural puberty kicks in

What are the two main types of delayed puberty?

Primary gonadal failure | Central failure

What would the hormone profile look of someone with primary gonadal failure?

High FSH, High LH

What conditions may cause primary gonadal failure?

``` Turners (XO), Klinefelters (XXY) Autoimmune Enzyme deficiencies Androgen insufficiency Chemo/Radiotherapy Bilateral, unconnected, cryptoorchidysm ```

What is AIS - causes delayed puberty?

Androgen insensitivity syndrome - genital tissue insensitive to androgens - so despite testes forming and producing androgens, they aren't detected, so the genitals develop as female. X-linked recessive 1/20,000

What treatment can be given for AIS : androgen insensitivity syndrome?

Counselling (genetically man, phenotypically female, blind ending vagina) Gonadectomy Vaginal dilators? HRT to stop osteoporosis

What hormone profile would you expect to see in a central failure delayed puberty?

Low FSH, Low LH

What may cause a central failure delayed puberty?

``` Constitutional Eating disorders Excessive exercise Hypothyroid Intracranial tumour Pan hypopituitarism GH/GnRH deficiency PCOS Chronic illness ```

What is precocious puberty?

Onset of secondary sexual characteristics early

Under what age is it considered precocious puberty?

Girls - under 8 or menarche under 9 | Boys - under 9

What impact does precocious puberty have?

Reduced height Fertility + menopause age - ovarian reserve? Psychological issues

What symptoms might you see in precocious puberty?

Sex steroids cause - greasy skin/hair, mood changes, deep voice, growth spurt, pubic hair in boys The aetiology might be evident - tumour cause - headaches, vomiting, visual issues?

What are the 2 types of precocious puberty?

Central/true/gonadotrophin dependant Peripheral/gonadotrophin independant

What are the features of central precocious puberty?

puberty is consonant but early, hypothal is activated | more common in girls

What can cause central precocious puberty?

``` idiopathic secondary to tumours cerebral palsy hydrocephelus trauma sex abuse adoption ```

What are the features on peripheral precocious puberty?

May be non consonant | Sexual characteristics due to abnormal secretion of sex steroids - independent of hypo-pit-gonadal control

What causes are there for peripheral precocious puberty?

- Genetic - McCune Albright synd., testotoxicosis - Precocious breast development - Thelarche, hypothyroidism, ovarian cysts - Virilisation - Adrenarche, CAH, Cushings - Gonadotrophin releasing tumour - Exogenous steroids

What is McCune Albright syndrome?

A rare hereditary condition, triad of effects: - Polyostotic fibrous dysplasia. - Café au lait skin pigmentation. - Autonomous endocrine hyperfunction -> precocious puberty, hyperthyroid..

What is Thelarche?

Isolated breast development, in absence of other symptoms (no growth spurt or sexual precocity)

Do you need to investigate Thelarche? What is the treatment?

No - can be normal | No treatment, just follow up.

What would an LHRH test show in Thelarche?

Pronounced FSH, Low LH

What is exaggerated adrenarche?

'adrendal puberty' - adrenal androgens secreted early | Age 6-8

What does exaggerated adrenarche cause?

Early pubic + auxillary hair, body odour, mild acne

What investigations could you do in exaggerated adrenarche?

Hormone levels - would show: | - High DHEAs + High Androstenedione + high adrenal hormones

What investigations might you do for a child with precocious puberty?

``` Auxology (measurements) Parental heights Hormone levels TFT Bone age Pelvic U/S in girls ```

What hormone profile would you expect in central precocious puberty?

High LH, FSH and Oestradiol | LHRH response - LH dominant

What hormone profile would you expect in peripheral precocious puberty?

No LH or FSH High oestradiol No LHRH response

In any precocious puberty, what would you find when measuring bone age and on pelvic US (girls)?

Bone age advanced by around 2 yrs Increase in ovary and uterus size Endometrial stripe present

What is the management of a central precocious puberty?

GnRH analogue - binds for longer than normal GnRH, which causes a -ve feedback which inhibits LH/FSH Take until 11/12, then periods begin a year later