Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MRCOG Part 2 > Sex Development Disorders and Precocious Puberty > Flashcards

Sex Development Disorders and Precocious Puberty Flashcards

1
Q

What is the inheritance of Congenital Adrenal Hyperplasia?

A

Autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the most frequent enzyme deficiency in Congenital Adrenal Hyperplasia and what proportion of cases does it constitute?

A

21-hydroxylase deficiency

>90% of cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the function of 21-hydroxylase?

A
  • Catalyzes the conversion of 17-hydroxyprogesterone to 11-deoxycortisol, a precursor of cortisol
  • Catalyzes the conversion of progesterone to deoxycorticosterone, a precursor of aldosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does a lack of 21-hydroxylase explain the phenotype?

A
  • Excess cortisol precursors - diverted into sex hormone synthesis, ie excess androgens
  • Aldosterone deficiency - salt wasting (75%)
  • Postnatal virilization, precocious puberty and rapid somatic growth (ie short stature) if inadequately treated

NB spectrum of the above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many births are detected with classic 21-hydroxylase deficiency?

A

1 in 16,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do the female and male genitalia look like in CAH?

A

Female:
Ambiguous - large clitoris, common urogenital sinus, partially fused labia majora but normal uterus, fallopian tubes, ovaries. No Wolffian duct.

Male:
Usually subtle hyperpigmentation and penile enlargement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the fertility rates in women with CAH?

A

80% simple virilizing disease

60% salt wasting disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is classic CAH diagnosed?

A

Elevated 17-hydroxyprogesterone

ACTH stimulation test (high dose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the treatment of CAH?

A

Glucocorticoids (hydrocortisone)
Fludrocortisone if salt wasting type
Surgical correction of ambiguous genitalia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

At what age is precocious puberty defined?

A

Devlopment of secondary sex characteristics < age 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the incidence of precocious puberty?

A

1:5000-10,000

F:M 10:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the biochemical mechanism of puberty?

A
  • Increased pulsatile GnRH
  • Increased LH and FSH during sleep, then 24 hrs
  • Ovarian follicles -> oestrogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is adrenarche and when is its onset?

A

Androgen-dependent signs of puberty (pubic/axillary hair, greasy hair, skin, etc)
Precedes gonadarche
Begins by 6-8 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How long after thelarche is menarche and what is the median age of menarche in the UK?

A

Usually occurs within 2-3 years

Median age - 13

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 3 classifications of premature sexual development?

A
  1. Central, true - gonadotrophin-dependent
  2. Peripheral, pseudo - gonadotrophin-independent
  3. Isolated variants - precocious pubarche, thelarche or menarche
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the causes of central precocious puberty?

A

NB always isosexual

  1. Idiopathic (75%)
  2. CNS pathology/lesion (Harmatomas, tumours, congenital e.g. hydrocephalus, acquired e.g. post-irradiation, trauma, infection, meningitis)
  3. Secondary to peripheral precocious puberty
17
Q

What are the causes of peripheral precocious puberty?

A
  1. Ovarian
    - Oestrogenic e.g. granulosa tumour, cyst
    - Androgenic e.g. Sertoli-Leydig cell tumour, arrhenoblastoma (contrasexual)
  2. Adrenal
    - CAH (contrasexual)
    - Cushing syndrome
    - Neoplasm
  3. Exogenous sex hormones
  4. McCune-Albright syndrome
  5. Severe long-standing hypothyroidism
18
Q

What is the growth pattern in precocious puberty?

A

Initial tall stature and accelerated growth

Then get premature fusion of epiphyses and end up with compromised final height

19
Q

How is Central precocious puberty diagnosed?

A

LH and FSH measured sequentially after GnRH analogue - LH>FSH ratio >1

20
Q

What is the treatment of central precocious puberty?

A

Depends on brain lesion - often conservative or GnRH analogues dependent on age of onset.

21
Q

What is McCune-Albright syndrome and what is its treatment?

A

Caused by activating mutations of GNAS1 gene
Polyostotic fibrous dysplasia (bone cysts)
Cafe au lait spots
Peripheral precocious puberty
May see raised prolactin levels in some - pituitary adenomas associated

Rx: Suppression of gonadal steroidogenesis with aromatase inhibitors

22
Q

How are androgen-producing adrenal tumours diagnosed biochemically?

A

Raised serum DHEAS

May see very elevated urinary 17-ketosteroid levels

23
Q

What is the phenotype of Mayer-Rokitansky-Kuster-Hauser syndrome and why does it happen?

A
  • Congenital absence upper 2/3 vagina (caudal part)
  • Absent/rudimentary uterus (mid part)
  • Normal secondary sex characteristics
  • Ovaries absent/hypoplastic in 10%
  • Often associated renal abnormalities (up to 40%) - 12% absent kidney
  • Skeletal abnormalities (12-20%) incl Klippel-Fiel anomaly
  • Auditory malformations 10-25%
  • 46XX

Agenesis/hypoplasia of Mullerian (paramesonephric duct)
(Fuse 12th week)

24
Q

What are the eponymous surgical procedures recommended for MRKH syndrome?

A

Vecchieti - dilating ‘olive’ suspended intraperitoneally and gradual traction to create neovagina. Removed and maintained by dilators/regular SI

Davydov - neovagina from woman’s own peritoneal lining - postop mould and dilators for 6/52

25
Q

What is the inheritance of androgen insensitivity syndrome?

And the karyotype/phenotype of CAIS?

A

X linked recessive - mutation in AR gene on Xq11-13
Karyotype - 46XY
Phenotype - External female genitalia with male testes; no fallopian tubes/uterus/proximal vagina (as normal AMH), no pubic/axillary hair

26
Q

How is CAIS differentiated from 5-alpha reductase deficiency?

A

CAIS/PAIS have normal production of testosterone and conversion to dihydrotestosterone (DHT)
NB 5-ARD is autosomal recessive

27
Q

What is the incidence of AIS?

A

1 in 20,400

28
Q

In which sex devlopment disorder should gonadectomy be performed to reduce the risk of malignancy?

A

Complete Androgen Insensitivity Syndrome

Risk 0-22% of developing gonadoblastoma

29
Q

From which embryological layers does the urogenital system develop?

A

Intermediate mesothelium of the peritoneal cavity and the endoderm of the urogenital sinus

30
Q

At what gestation do primordial germ cells form?

A

By week 4

Migrate to developing ovary by week 6 and differentiate into oogonia

31
Q

What is the incidence of MRKH syndrome?

A

1 in 5000 female births

32
Q

What is the incidence of transverse vaginal septum?

A

1 in 30,000-50,000

33
Q

What is the biochemical profile in CAH?

A
  • Insufficient cortisol
  • Stimulates CRH (hypothalamic)
  • Chronically elevated ACTH
  • Stimulates adrenal gland - hyperplastic

MRCOG Part 2 (97 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions