Paediatric endocrinology

Question 1

Klinefelter’s syndrome : Definition

Answer 1

• Male with an additional X chromosome
• 47 XXY genotype

Question 2

Klinefelter’s syndrome : Pathophysiology

Answer 2

Error in meiosis leads to defective sperm carrying extra X chromosome which in turn - fertilises a normal egg leading to 47XY X
Extra X chromosome causes
* Issues with testicular development
* Hormonal imbalances : Inhibits testosterone and increases oestrogen levels

Thus leading to;
1.Infertility : lack of seminiferous tube development
2. Hypogonadism : Low testosterone release, causes testicular atrophy, delayed puberty and lack of secondary male sexual characteristics
3. High oestrogen : Gynaecomastia

Question 3

Klinefelter’s syndrome : Clinical features

Answer 3

1. K - Tall Stature (Kink in the Height)
2. L - Long Limbs (Lengthy Limbs)
3. I - Infertility (Inability to make Infants)
4. N - No Beard - lack of 2nd sexual characteristics
5. E - Extra X chromosome (Extra chromosome, X-tra features)
6. F - Firm Testes (Firm and Small Testes)
7. E - Estrogen dominance (Enlarged breasts, Elevation of estrogen - increased risk of breast ca
8. L - earning difficulty and Language delays)

Question 4

Kallmann syndome : Definition

Answer 4

• Kallmann syndrome is a X linked recessive genetic disorder that primarily affects the hypothalamus and the olfactory system,
• Combination of hypogonadotropic hypogonadism (resulting in delayed or absent puberty) and anosmia (loss of the sense of smell).

Question 5

Kallman’s syndrome : Pathophysiology

Answer 5

1 . X-linked recessive trait

2 . Defect in development
* Failure of migration of GnRH (Gonadotropin releasing hormone) neurones
* From Olfactory placode to Hypothalamus

3 . No GnRH neurone in hypothalamus
* No Gonadotropins release

4 . Ofactory development is disruption
* Anosmia

Question 6

Kallman’s syndrome : Clinical features

Answer 6

1. Hypogonadism - Cryptorchidism
2. Hypogonadotrophins : Sex hormone results are low
3. Delayed puberty
4. Anosmia

Question 7

Androgen insensitivity syndrome : Definition

Answer 7

X-linked recessive condition due to end-organ resistance to testosterone causing genotypically male children (46XY) to have a female phenotype.

Question 8

Androgen insensitivity syndrome : Clinical features

Answer 8

1. Primary amenorrhoea
2. Groin swelling : 2nd to bilateral undescended testes
3. Breast development : excess testosterone is converted to estradiol

Question 9

Androgen insensitivity syndrome : Management

Answer 9

1. Increased risk of testicular cancer : Bilateral Orchidectomy
2. Raised Child as female

Question 10

Congential hypothyroidism : Definition

Answer 10

• Thyroid hormone deficiency present AT birth.
• If not treated early - associated with irreversible neurological problems and poor growth

Question 11

Congential hypothyroidism : Diagnosis

Answer 11

UK Newborn screening programme

Question 12

Congential hypothyroidism : Clinical features

Answer 12

1. No clinical manifestations at birth : partial maternal thyroxine hormone transfer
2. Sx develop over 6 weeks; Early manifestation
   * Lethargy, hypotonia
   * Large fontanelle
   * Feeding difficulties
   * Prolonged jaundice
   * Constipation
   * Hypothermia