L33 Steroid disorders

Question 1

When is thehypothalamus-pituitary-adrenal axis active in humans?

Answer 1

since in utero

Question 2

ACTH from the feral pituitary gland acts on ____________ of the foetal adrenal glands to release ______________ to the foetal liver.

Answer 2

foetal zone (FZ) 
DHEAS (DHEA sulphate)

Question 3

What is the action of DHEAS?

Answer 3

increases oestrogen in placenta by placental sulphatase

Question 4

Why would placental sulphates deficiency cause a delayed onset of labour?

Answer 4

No placental sulphate = no estrogen;

E2 promotes uterine contractility, unopposed progesterone (P4) blocks contractility without E2

Question 5

Other than delayed onset of labour, list 2 clinical manifestations of placental sulphates deficiency.

Answer 5

1. X-linked ichthyosis: dry and scaly skin

2. Low urine oestrogen level (indicated placental insufficiency)

Question 6

Differential diagnosis of placental sulphates deficiency?

Answer 6

Anencephaly - absence of major portion of brain, skull, cap that occurs during embryonic development > foetal pituitary fails to secrete ACTH > low DHEAS

Question 7

List the 3 possible ethology of testicular feminisation syndrome.

Answer 7

1. Androgen insensitivity syndrome
2. 17alpha-hydroxylase deficiency (CAH - congenital adrenal hyperplasia)
3. 5alpha-reductase deficiency

Question 8

What is testicular feminisation syndrome.

Answer 8

Phenotypical female in genetic male (XY)

Question 9

Characteristics of testicular feminisation syndrome due to 17alpha-hydroxylase deficiency? (2)

Answer 9

1. reduced androgen production
2. associated with HT
   - because aldosterone production is not inhibited

Question 10

Characteristics of testicular feminisation syndrome due to5alpha-reductase deficiency ? (2)

Answer 10

1. Undescended testis, external genitalia may present as male/female/ambiguous
2. Often raised as girls, apparent during puberty:
   - primary amenorrhea, virilisation, masculinisation
   - due to large amount of testosterone during puberty

Question 11

PP: 16/F primary amenorrhea. PE revealed a female with well developed breasts, but lacking axillary and pubic hair.
She had a blind ending introitus. Her BP was normal.

High LH, Male testosterone levels.

Diagnosis? (1) Brief description.
Karyotype? (2)
Precautionary measures required?

Answer 11

1. Diagnosis:
   - Androgen insensitivity syndrome due to androgen receptor defect

• normal BP excludes 17alpha-hydroxylase deficiency

2. XY male
3. Testes should be removed to prevent neoplastic transformation because of excessive stimulation from raised gonadotrophin and also because of high temperature at the abdomen.

Question 12

Respiratory distress syndrome is the absence of _________________ in premature infants (<32 weeks).

_______________ in amniotic fluid is checked for assessing the maturity of the lungs.

Answer 12

surfactant;

Lecithin-sphingomyelin ratio (L:S)

Question 13

What Lecithin-sphingomyelin ratio (L:S) ratio indicates high risk of RDS?

What do they represent respectively?

Answer 13

<1.5

Lecithin: phospholipid component of surfactant
Sphingomyelin: constant in amniotic fluid.

Question 14

Chemical castration, aberrant sexual behaviour and androgen-dependent Ca prostate can be treated with _____________, MOA?

Answer 14

Cyproterone acetate;

androgen receptor antagonist

Question 15

What is clomiphene and its clinical use?

Answer 15

• inhibits oestrogen receptors in hypothalamus and pituitary > stimulates FSH secretion;
  for ovulation induction

Question 16

What is mifepristone (RU486) and clinical uses x2?

Answer 16

• Progesterone antagonist
  For
• emergency contraception
• abortion

Question 17

What is tamoxifen what clinical uses?

Answer 17

SERM
- selective estrogen receptor modulator

for estrogen receptors and treat CA breast