Acromegaly/Prolactinoma Flashcards
GH hormone causing amenorrhea and galactorrhea?
these are prolactin effects
1 GH acts on JAK STAT receptors
-same as PRL
so can cross activate
2 also - GH adenoma may release some PRL
3 and - acromegalic tumor - push on pituitary stalk - block dopamine - no PRL inhibition
inhibition of PRL
dopamine
TRH
stimulates PRL secretion
PRL
blocks LH at ovary and testes
positive tinel sign
of median nerve
-myxedema - GAG infiltrates
bony overgrowth and synovial thickening
- in acromegaly
HA worse with coughing, nausea, worse upon arising
marker for mass effect in brain
acanthosis nigricans
and skin tags
seen in epidermis overgrowth - IGF-1 effect (acromegaly)
increased head size
acromegaly
possibly cowdens
why order calcium in GH adenoma
suspected MEN
-may have parathyroid involvement as well**
serum GH 2 hours post 75g glucose
glucose should suppress GH level
if not - acromegaly**
inability to suppress GH to less than 1 ng/mL
why T4, TSH, and cortisol measured in GH adenoma
may compress other cell types
GH effects on glucose
1 produces lipolysis
- leads to increased gluconeogenesis
- increased conversion of lactate and glycerol to glucose
2 FFA block glucose uptake by muscle and fat cell
GH is slow acting counter regulatory hormone like cortisol
microadenoma with somatotroph mutation
cause of acromegaly
-mutation of alpha subunit of GTP-binding protein resulting in stimulatory Gs subunit
with increased cAMP producing GH secretion
causes of acromegaly
microadenoma
macroadenoma
ectopic GH - lung
acromegaly associations
1 - MEN 1
2 - carney complex
3 - mucune albright syndrome
3 Ps, hypercalcemia, peptic ulcer, hypoglycemia
MEN 1
complcation of GH adenoma
mass effects
additional hormone production
interfere with other hormones
dopamine agonist
bromocryptine
primary tx for acromegaly
surgery
radiation
also -dopamine agonst - suppress somatotrophs - bromocryptine
octreotide
pegvisomant
somatostatin
inhibit GH release
octreotide
somatostatin analog
inhibit GH release
pegvisomat
GH receptor antagonist
acromegaly, pituitary hyperplasia, mediastinal mass
oat cell carcinoma of lung - secreting GHRH
before surgery for GH adenoma
GHRH assay
-to see if ectopic production of GHRH
like oat cell carcinoma
goals of tx for acromegaly
GH levels under 1ng/dL
glucose suppressed GH under 0.4ng/dL
dopamine
activates G-i to decrease cAMP
decreased PRL secretion
hirsutism
with prolactinoma
decreased estrogen - decreased sex hormone binding globulin - increased free testosterone and DHEAS**
leading to hirsutism and acne
increased PRL
to decreased GnRH - to decreased LH - to decreased estrogen
resulting in osteoporosis and amenorrhea
hypothyroid and PRL??
can lead to increased prolactin levels
hypothyroid - has high TRH
TRH - stimulates prolactin release from pituitary
kidney disease and PRL
decreased excretion and increased blood levels
verapamil
can lead to hyperprolactinemia
metoclopromide
can lead to hyperprolactinemia
type IV RTA
with diabetes
hyporeninemic hypoaldosteronism
dump sodium - retain K
each 2Na - lose K and H
hyperchloremic acidosis**
Cl and HCO3
cancel each other out
Cl elevated 15
should see bicab down 15
normal calcium in hyperPRL
helps exclude MEN-1
PRL >200
prolactinoma
20-100 - another cause
male hyperPRL
loss of libido
impotence
bitemporal hemianopsia
tx of hyperPRL
bromocryptine
surgery
radiation
postpartum cardiomyopathy
mediated by cathepsin D-cleaved prolactin
irreversible dysfunction in heart occurs
