Disorders of sexual development Flashcards

1
Q

Describe the embryology of the uterus and the vagina

A

Begins at 3/40 until trimester 2
Derived from the mullerian ducts, urogenital sinus & vaginal plate
closely associated with development of the urinary system
the internal female reproductive tract (tubes, uterus, upper 1/3 of vagina) is formed from the fusion of the mullerian ducts when there is an absence of AMH

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2
Q

What are the 3 categories of Mullerian duct abnormalities?

A
  • lateral fusion abnormalities
  • vertical fusion abnormalities
  • agenesis
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3
Q

Give 4 examples of lateral fusion abnormalities of the mullerian duct?

A

Septate/arcuate
Bicornuate
Unicornuate
Uterine didelphys

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4
Q

What is a septate uterus?

A
  • uterus appears as a single organ but has a midline septum that is either partial or complete
  • arcuate uterus has only a small septate indentation present
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5
Q

What is a bicornuate uterus?

A

Single chamber vagina and cervix with complete or partial septate uterus and two uterine bodies

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6
Q

what is a uni-cornuate uterus?

A

When there is destruction of one of the mullerian ducts during the embryonic period, this abnormality is often associated with a missing kidney or uterer on ipsilateral side

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7
Q

What is uterine didelphys?

A

Complete duplication of the vagina, cervix and uterus

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8
Q

Give 4 examples of vertical fusion abnormalities of the mullerian duct

A
  • transverse vaginal septum
  • absent cervix
  • cervical stenosis
  • cervical incompetence
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9
Q

What are the obstetric implications of mullerian duct abnormalities?

A
  • fertility issues - (agenesis = cannot get pregnant)
  • miscarriage - increased risk, resection of septum may improve pregnancy rates
  • increased risk of APH
  • malpresentation
  • increased risk of CS due to incoordinate contractions
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10
Q

What determines the male phenotype?

A

SRY gene on Y c’some makes SRY protein which stimulates germ cells and testes to form
Presence of testosterone (from leydig cells) stimulates the Wolffian duct development (vas deferens, epididymis, seminal vesicles)
Presence of AMH (from Sertoli cells) prevent Mullerian duct development
Testosterone is converted to DHT by alpha reductase
DHT stimulates the male external genitalia via androgen receptor

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11
Q

What determines female phenotype?

A

Lack of Y chromosome means DAX-1 stimulates gonads to become ovaries
Lack of AMH means that mullerian duct develops
Lack of testosterone results in regression of Wolffian duct
Lack of testosterone, DHT, alpha reductase means the external female genitalia form

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12
Q

What are the 5 conditions associated with Karyotype XY but female phenotype?

A
  • androgen insensitivity syndrome
  • 5alpha reductase deficiency
  • true gonadal dysgenesis (swyer syndrome)
  • AMH deficiency
  • Abnormal androgen synthesis
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13
Q

What are the 5 main management steps for a XY karyotype, female phenotype?

A
  • MDT input, tertiary centre
  • psychologica support
  • physical development and maintenance - estrogen replacement
  • removal of gonads
  • Fertility
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14
Q

What are the symptoms someone with uterine didelphyis might present with?

A
  • outlet obstruction
  • tampon failure
  • sexual dysfunction
  • possible reduced fertility if obstructing
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15
Q

What extra investigations does someone need once uterine didelphys diagnosed?

A
  • renal USS

- dual smears

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16
Q

What are the fertility implications of someone with uterus didelphys

A

No different to general population

17
Q

What are some pre pregnancy surgical options that can be offered for this woman?

A
  • vaginoscopic resection of vaginal septum

- consider metro-pasty (surgical re-unification of the 2 cavities)

18
Q

List causes of hypergonadotrophic hypogonadism

A
  • ovarian dysfunction - premature ovarian insufficiency
  • 46XY disorders - pure gonadal dysgenesis (streak ovaries), Androgen insensitivity syndrome, CAH, 5alpha reductase deficiency
  • Turner syndrome
19
Q

how can you differentiate between XY CAIS and MRKH?

A
  • Karyotype - XY = CAIS, XX = MRKH

- serum free testosterone - normal to high range for CAIS, normal female range in MRKH

20
Q

explain the pathophysiology that causes CAIS phenotype?

A
  • normal androgen production from functioning testes
  • insensitivity to androgens
  • AMH still secreted from Sertoli cells–> regression of mullerian structures
  • Pubic hair is scant due to undervirilisation
  • default to female phenotype