Pubertal development

Question 1

What is precocious puberty?

Answer 1

Onset of puberty before 8 in girls and before 9 in boys.

Question 2

What scale is used to stage puberty?

Answer 2

The Tanner staging.

Question 3

How is delayed puberty defined?

Answer 3

Puberty is considered delayed if it hasnt started by 13 in girls and 14 in boys.

Question 4

How can you subclassify delayed puberty?

Answer 4

Delayed puberty can be either due to:

Hypogonadotrophic hypogonadism.

• There is a central defect, i.e. in the hypothalamus or pituitary

Hypergonadotrophic hypogonadism

• Caused by gonadal failure

Question 5

What are possible causes of hypogonadotrophic hypogonadism?

Answer 5

• Can be constitutional, but exclude other causes
• Anorexia nervosa
• Excessive exercise
• Chronic illness (diabetes, renal failure)
• Pituitary tumours
• Kalmans Syndrome

Question 6

What are possible causes of hypergonadotrophic hypogonadism?

Answer 6

This is caused by gonadal failure, with high levels of LH/FHS.

Causes include:

• Turner (45XO)
• Gonadal Dysgenesis
• Premature Ovarian failure
• Autoimmune/radiaton/metabolic disorder that destructs the ovary

Question 7

What is Kallmann Syndrome?

How is it treated?

Answer 7

Kallmann Syndrome describes a group of genetic defects where there is no GnRH produced, therefore leading to primary amenorrhoea and delayed puberty. They also have anosmia.

This is managed with hormone replacement therapy. This can consist of either sex hormone replacement (osetrogen, progesterone; testosterone), gonadotrophins (LH/FSH) or pulsatile GnRH analogues.

Question 8

What is Turner Syndrome?

What are its clinical features?

Outline its management.

Answer 8

45XO, i.e. the absence of a second X chromosome.

It is the most common chromosomal abnormality in females.

There is underdevelopment of the ovaries (i.e. hypergonadotrophic hypogonadism). (“streak gonads”)

Clincal features:

• Short statue
• Webbed neck
• Wide spaced nipples
• Wide carrying angle
• Delayed puberty
• Associated with:
  
  • Aortic Coarctation
  • IBD
  • Deafness

Management:

• If detected in childhood: induce growth and puberty
• If detected in adulthood: induce puberty
• Pregnancy only possible with donated ovum
• Psychological Support

Question 9

Name 3 conditions in which a person with 46XY does not develop male genitalia.

Answer 9

1. 46XY Gonadal dysgenesis
   
   • Male gonads don’t develop despite Y chromosome
   • Cause not known, but can be due to mutations in SRY gene
2. Complete androgen insensitivity syndrome
   
   • Inability of the androgen receptor to respond to androgen stimulation
   • Testes form normally and produce anti-Mullerian hormone in-utero, therfore patients have no uterus
   • External genitalia, however, do not virilise, therefore stay female
   • Often present with primary amenorrhoea in puberty
3. 5-Alpha-Reductase Deficiency: In this condition, the foetus has XY karyotype and testes that produce testosterone. However, the foetus is unable to convert the testosterone into dihydrotestosterone in the periphery to virilise the external genitalia, and so the presentation is with ambiguous genitalia. There can also be increasing virilisation at puberty due to increasing androgens.

Question 10

Name a condition in which a patient with 46XX might not develop female genitalia.

Answer 10

Congenital Adrenal Hyperplasia (CAH)

• enzyme deficiency in the corticosteroid synthesis.
• This leads to a build up of andorgen precursors, and subsequently androgen production
• External genitalia are virilised in many cases