Pituitary Disorders Flashcards
Pit Adenomas can be part of which hereditary ds
Multiple Endocrine Neoplasia - MEN I : 3 Ps: pit ad, parathyroid hyperplasia, pancreatic
Most pituitary adenomas are what type
Microadenomas < 1 cm
Which is the most common type of Pit Ad secretory or non secretory?
Secretory
Prolactinomas are most common
High prolactin level can be due to
!Pit stalk (infindibulum) compression
!Physiologic stiumuli: suckling, chest wall trauma
! Hormonal : pregs, estrogen therapy, hypothyroidism
! Drugs: psych meds, cimetidine, verapamil, opiates
! Renal or liver failure
Renal or liver failure can cause
high prolactin
Posterior pituitary secretes which Hs
ADH (vasopressin)
Oxytosin
Both are MADE by Hypothalamus!
PP does not PRODUCE any hormones, just secretes it
what are the sx of nonsecretory adenomas?
asx usually
Dx by accident on imaging
Pit adenomas
asx = common
Sx: pit H dysfx
Mass effect sx:
HA, Nausea, lethargy, altered mind, cranial nerve palsies, visual field defects, compression - part or complete hypopituitarism
what visual defect is common in pit adenomas?
no peripheral vision = “temporal hemianopsia”?
refer to optomology and endo
Med therapy for Pit Adenomas
Dopamine agonists = supress Prolactin release:
bromocriptine and cabergoline
tx excess hormone secretion
reduce tumor size
Do Surgery for pit adenomas if
- secretory: GH (growth h), ACTH, TSH
- large, non fx’l tumors: mass effect, visual compromise
- potl complications (of surgery?): D Insipidus, Hupopituitarism
what tx after surgery if tumor remains?
radiotherapy
potl complication: hypopituitarism
Excess GH
GH secreting pit adenoma
results in gigantism or acromegaly
Gigantism
kids, prior to closure of epiphysis
excess growth of long bones
very rare
Acromegaly
enlargement/thickening and elongation of hand, feet, jaw, internal organs
does NOT affect long bones (vs gigantism does)
onset in 30s
dx’d in 50s
etiology of acromegaly
Macroadenoma is most common >1 cm
often ass with prolactin (PRL) secretion
risks of acromegaly
DM, HTN, CAD !!!
OVERT HF !!! at Dx in 10%
increased mortality due to CVD if untreated
Sx
CVD, CAD, DM
deep boice
acne
radiographic findings in acromegaly
skull: enlarged sella, thickened skull
hands/feet: tufting (unreveling) of terminal phalanges
Dx studies for GH excess
!! Random GH not accurate as levels fluctuate (pulsatile in acrom)
1) Random serum IGF-1 (hepatic):
if normal for age, rules out acromegaly
if elevated 5x, likely GH secreting adenoma (not truly Diagnostic)
2) 75 gm 1 hr glucose tolerance test (GTT)
shows failure of GH to suppress
3) PRL prolactin
GH-secreting tumors often co-secrete PRL
4) MRI - imaging test of choice BUT must do biochem studies BEFORE doing imagins
Which is the imaging test of choice for GH excess?
MRI but
must do biochem studies before do imaging!
Tx of GH excess
combo surg, meds, radio transsphenoidal microsurgery, Dopamin to decr PRL bromocriptine,mcabergolide, GH rec antag expensive SOMATOSTATIN analogs: (decrease GH) octreotide/lanreotide decrease GH sectons, injections - radiation
Tx of excess GH
Dopamine agonist: bromocriptine cabergolide GH receptor antagonist Pegvisomant injection blocks hepatic IGF-1 production
Radiation
GH deficiency in kids
pit dwarfism:
fail to grow
Causes: congenital, tumor (craniopharyngioma), severe brain injury
Often co-occurs with deficiences of other pit hormones
look at the pit dwarfism ss
slide 37
Pit dwarfism dx tests
PE + hand x-ray to determine BONE AGE ????????
!!! IGF-1 below nl for age and gender supports dx
!!! GH stimulation test: insulin-induced hypoglycemia ASK??????????
measure other hormones
MRI of head
GH is pulsatile, not helpful for Dx
GH deficiency in adults sx
reduced E depressed mood emotional lability diminished libido decrease muscle mass, strength increased abdominal adiposity decreased exercise capacity
Tx for GH deficiency
SC injection
SE:
HA, fluid retention, m and joint aches, slipped capital femoral epiphysis (peds)
Diabietes Insipidus (DI)
Insipid = tastless
polydipsia, polyuria and DILUTE URINE (vs hunger in DM)
DI has a problem with which hormone?
ADH
secreted in response to osmoreceptors and baroreceptors in the carotids, atria and aorta
cental DI is
deficincy of ADH , can’t secrete
nephrologic DI
resistance of kidney to ADH, can’t bind ADH
often due to lithium use
which med often contributes to nephro DI
lithium
What is the serium osmolality in DI?
It is normal (285-295)
What is the urine osmolality and spesific gravity SG in DI?
Urine OSM < 300 (low)
Plasma OSM >287 (high but normal)
Urine Spec Gravity <1.005
urine volume, osm, etc in DI vs normal
Normal urine volume: 800-2000 ml.day DI: >3 L /day
Serum OSM: 285-295 DI: >287
thirst at 290 mOsm no thirst mech in DI
Urins Osm 50-1200 normal DI: < 300
Urine SG: 1.010-1.030 DI: <1.005
Is ADH high or low in central DI
ADH is low bc unable to produce.secrete ADH
Is ADH high or low in nephro DI?
ADH is high bc brain can produce it but kid can’t respond to it
When does central DI happen most
after head trauma or neurosurgery
in adulthood
responds to desmopressin (DDAVP)
When is nephro DI most commone
Lithium!!! Childhood Chronic renal fail hypercalcemia, hypokalemia No response to DDAVP (desmopressin)
DI SS
???????? intense thirst fluid intake up to 20L per day Ice water craving Large volume polyuria Enuresis (bed wetting) HyperNa why ??????????, dehydration possible
See slide 47 for DI pic
ok
Dx studies for DI
?????? 24 hour urine to measure volume
serum electrolytes and glucose to ro osmotic diureces??
!!! SIMULTANEOUS URINE and serum OSMOLALITY!!!
must do SIMULTANEOUSLY - call lab
urine osm - low 287 (normal but high)
-urine SG <1.005
DI dx
?????? water deprivation and vasopressin challenge?
?if central - double urine osmolality
? if nephro - little or no elevation in urine osm
MRI of pituitary
DI tx
???????Mild: adequate hydration Central DI: Desmopressin acetate (DDAVP) Nephro DI: Indomethacin, with or without HCTZ (thiazide?) DDAVP or Amiloride (k sparing but causes hypothyroid?) use with Lithium
Panhypopituitarism
deficient in GH (HYPOGLYCEMIA, short), ADH (polyuria -> polydipsia, hyperNa, dehydration, lethargy), LH/FSH: low estrogen, delayed puberty, amenorrhea,. TSH (Low T4: fatigue, constipation, cold intolerance bradycardia), ACTH (low cortisol: HYPOglycemia, vomiting, malaise)
how to dx panhypopit
S S, provocative tests, MRI last
ACTH deficiecy in panhypopit
1) ACTH stimulation test can be neg or pos:
if adrenal gland is functional -> positive test
if not _> negative
2) tx with Hydrocortisone or Prednisone
3) GIVE above before Thyroid hormone to lower risk of cortisol insufficientcy due to increased metabolism with thyroid meds
Which type of pit adenomas have to be removed surgically
1) secretory : GH, ACTH, TSH (goiter)
2) Large non-fx’al tumors that have mass effect and/or visual compromise
3) complications of surgery are: DI, hypopituitarism
if you don’t want to surgically remove pit adenoma, what medical tx to use
Dopamine agonists: bromocriptine and cabergoline ( to tx excess hormone secretion and reduce tumor size)
when to use radiation to tx pit adenomas
following surgery if residual tumor remains
ACTHn def in pan pt should carry what?
hydrocortisone vial and syringe
med alert tag
Pan tx:
if TSH def: Levothyroxine
if Gonadotropin def: estrogen, progest, OCP, test
if ADH def: DDAVP (intranasal, oral or sublingual)
GH def in PAn
tx with GH
Tx of high prolactin in PAN
Stalk effect: compression of pit stalk decreases dopamine
Dopamine inhibits prolactin - so give dopamin?
