Hypersecretion of APG Flashcards
What is hyperpituitarism?
symptoms associated with xs production of adenohypophysis hormones
What is the main cause for hyperpituitarism?
Usually due to isolated pituitary tutors (but tutors can also be ectopic)
What is bitemporal hemianopia?
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.
What does excess ACTH (corticotrophin) cause?
Cushing’s disease
What does excess TSH (thryotropin) cause?
Thryotoxicosis
What does excess LH/FSH (gonadotrophin) cause?
Precocious puberty in children
What does excess prolactin cause?
Hyperprolactinaemia
What does excess GH cause?
Gigantism, acromegaly
What is hyperprolactinaemia?
High levels of prolactin
When would you have high prolactin?
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.
What is GnRH pulsitality?
In puberty, GnRH pulses become more frequent. Prolactin stops this so GnRH cannot produce LH and FSH.
High prolactin suppresses GnRH pulsatility.
What is the presentation of hyperprolactinaemia in females?
galactorrhea (milk production)
Secondary ammenorrhoea (or oligomenorrhoea)
Loss of libido
Infertility
What is the presentation of hyperprolactinaemia in men?
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
What is the inhibitory hormone of prolactin?
Dopamine (sourced from hypothalamic dopaminergic neurones)
What is the mechanism behind dopamine inhibiting prolactin secretion?
D2 receptors are present on lactotrophs. Dopamine from hypothalamus binds to these receptors and inhibits the prolactin secretion.
How can you manage excess prolactin secretion?
You can manage excess prolactin secretion with a D2 receptor agonist. They bind to the D2 receptors and prolactin cannot be produced.
What is prolactinoma?
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.
What drugs can be used to treat prolactinomas?
Bromocriptine and cabergoline
What are the side effects of the drugs that treat prolactinomas (Bromocriptine and cabergoline)
nausea and vomiting, postural hypotension, dyskinesias, depression and impulse control disorder (pathological gambling and hypersexuality).
What does XS GH result in childhood?
Gigantism
What does XS GH result in adulthood?
Acromegaly
