Hypersecretion of APG

Question 1

What is hyperpituitarism?

Answer 1

symptoms associated with xs production of adenohypophysis hormones

Question 2

What is the main cause for hyperpituitarism?

Answer 2

Usually due to isolated pituitary tutors (but tutors can also be ectopic)

Question 3

What is bitemporal hemianopia?

Answer 3

Compression of the optic chiasm- you cannot see temporal aspects. The optic chiasm, fibres from the nasal (medial) retinae cross. Light from the outer (temporal) aspects of the visual fields strikes the nasal aspect of the retina. Hence compression of these crossing fibres at the optic chiasm means that there is loss of vision from the outer temporal visual fields.

Question 4

What does excess ACTH (corticotrophin) cause?

Answer 4

Cushing’s disease

Question 5

What does excess TSH (thryotropin) cause?

Answer 5

Thryotoxicosis

Question 6

What does excess LH/FSH (gonadotrophin) cause?

Answer 6

Precocious puberty in children

Question 7

What does excess prolactin cause?

Answer 7

Hyperprolactinaemia

Question 8

What does excess GH cause?

Answer 8

Gigantism, acromegaly

Question 9

What is hyperprolactinaemia?

Answer 9

High levels of prolactin

Question 10

When would you have high prolactin?

Answer 10

Physiologically, it is normal to have high prolactin when women are pregnant or breast feeding.
Pathological reasons for high prolactin- prolactinoma- most common functioning pituitary tumour.

Question 11

What is GnRH pulsitality?

Answer 11

In puberty, GnRH pulses become more frequent. Prolactin stops this so GnRH cannot produce LH and FSH.
High prolactin suppresses GnRH pulsatility.

Question 12

What is the presentation of hyperprolactinaemia in females?

Answer 12

galactorrhea (milk production)
Secondary ammenorrhoea (or oligomenorrhoea)
Loss of libido
Infertility

Question 13

What is the presentation of hyperprolactinaemia in men?

Answer 13

Galactorrhea- uncommon (since steroid appropriate steroids background usually inadequate- there isn’t enough oestrogen in men to produce milk normally)
Loss of libido
Erectile dysfunction
Infertility

Question 14

What is the inhibitory hormone of prolactin?

Answer 14

Dopamine (sourced from hypothalamic dopaminergic neurones)

Question 15

What is the mechanism behind dopamine inhibiting prolactin secretion?

Answer 15

D2 receptors are present on lactotrophs. Dopamine from hypothalamus binds to these receptors and inhibits the prolactin secretion.

Question 16

How can you manage excess prolactin secretion?

Answer 16

You can manage excess prolactin secretion with a D2 receptor agonist. They bind to the D2 receptors and prolactin cannot be produced.

Question 17

What is prolactinoma?

Answer 17

the only pituitary tumour where you can manage it medically as opposed to surgically- i.e. just reducing prolactin secretion and therefore reducing the tumour size.

Question 18

What drugs can be used to treat prolactinomas?

Answer 18

Bromocriptine and cabergoline

Question 19

What are the side effects of the drugs that treat prolactinomas (Bromocriptine and cabergoline)

Answer 19

nausea and vomiting, postural hypotension, dyskinesias, depression and impulse control disorder (pathological gambling and hypersexuality).

Question 20

What does XS GH result in childhood?

Answer 20

Gigantism

Question 21

What does XS GH result in adulthood?

Answer 21

Acromegaly