Pituitary Disorders Flashcards
What structures can be affected by pituitary mass lesions?
Cranial nerves III, IV, V1, V2, VI, carotid artery, optic chiasm
Which hormones are released from the anterior pituitary?
FSH, LH, TSH, GH, ACTH, prolactin
What hormone stimulates FSH and LH release?
GnRH
What hormone stimulates TSH release?
TRH
What hormone stimulates GH release?
GRF
What hormone inhibits GH release?
Somatostatin
What hormone stimulates ACTH release?
CRF
What hormone inhibits prolactin release?
Dopamine
What is produced by the posterior pituitary?
ADH and oxytocin
What is the management of non functioning pituitary adenomas?
Only treat if mass effect (headache, visual changes, reduced hormone function) Options: 1. Surgery 2. Radiotherapy 3. Surgery followed by radiotherapy 4. Temozolamide
What are the signs and symptoms of hypopituitarism?
ACTH: hypotension, weight loss, fatigue TSH: cold intolerance, fatigue FSH/LH: loss of menses, loss of libido Prolactin: no lactation GH: fatigue ADH: central DI
What investigations should be ordered to diagnose hypopituitarism?
TSH T3 T4 8am cortisol +/- short synacthen FSH, LH and oestradiol/testosterone IGF-1 +/- GH stimulation test Urine/serum Na and osmo +/- water deprivation test/hypertonic saline infusion test
What 8am cortisol level clearly indicates deficiency?
<100
What is involved in a hypertonic saline infusion test?
Give hypertonic saline until Na > 150mmol/L
Measure copeptin level in blood
If copeptin doesn’t rise > 4.9 indicates partial or total central DI
What is copeptin?
C terminal segment of arginine vasopressin prohormone
What is the treatment for hypopituitarism?
Hydrocortisone and thyroxine (most important) OCP/HRT in women Fertility treatment if required Testosterone for men Growth hormone injections Desmopressin
What is the usual dose of hydrocortisone?
10mg/m2 which usually equates to 20-30mg split into divided doses 2/3rd in AM 1/3rd in PM
What is the result of GH excess?
Acromegaly in adults
Gigantism in children
What is the most common hyperfunctioning pituitary lesion?
Prolactinoma
What is the result of a lesion in the pituitary stalk?
Increase in prolactin with loss of other pituitary hormones
What causes prolactin level increase?
Stress, oestrogen, medications (antipsychotics), tumour
Usually not more than 2-4x upper limit unless tumour
How does hyperprolactinaemia cause hypogonadism?
Inhibits pulsatile gonadotropin release
What is the treatment for prolactinoma?
Dopamine-2 receptor agonists e.g. cabergoline
If not effective/tolerated then surgery/radiotherapy
What is the treatment for acromegaly?
Transphenoidal resection
Long acting somatostatin analogue (octreotide)
GH receptor antagonist (pegvisomant)
Dopamine agonists if co secrete prolactin
Radiotherapy if failed surgery
