Hypopituitarism/Diabetes Insipidus Flashcards
weak, lethargic, cold, loss of libido, full body hair loss, arthralgias, decreased muscle mass, central obesity, wrinkling of skin, hyperpigmentation, hepatosplenomegaly
hypopituitarism
queen annes sign
loss of outer third of eyebrows
-alopecia
loss of TSH - in hypopituitarism
wrinkling of skin
loss of gonadotropins in hypopituitarism
also hair loss
loss of sex hair
loss of ACTH - hypopituitarism
order of loss of hormones in hypopituitarism
1 - GH
2 - GN
3 - TSH
4 - ACTH
sheehans
cause of anterior pituitary falure
carotid aneurysm including SAH
cause of anterior pituitary failure
assays for anterior pituitary function
PRL GH/IGF-1 TSH/T4 testosterone, estradiol, FSH, LH ACTH, Cortisol, DHEA
assume GH low
if 3 other pituitary hormones low
and/or low IGF-1
GH stimulation test
glucagon insulin induced hypoglycemia arginine GHRH carbidopa/levodopa exercise
GH < 5 - positive test
PRL
may be high or low with assay for anterior pituitary
low T4 without TSH elevation
TSH deficiency
low 8AM total testosterone 2x with non-elevated LH
GN deficiency - male
low estradiol with non-elevated FSH
GN deficiency - female
8AM cortisol <3microg/dL
cortisol deficiency
ACTH stimulation test
draw serum in 45 minutes - cortisol <18 - adrenal insufficiency
low BP and sodium in hypopituitarism?
low T4 and cortisol
-decreased CO
increased ADH - retain fluid - hyponatremia
also - cortisol inhibit CRH and ADH - leads to more ADH release if deficient
cortisol - also for epinephrine production - no cortisol - low BP
fast elevation of blood sugar
epi and glucagon
slow elevation of blood sugar
cortisol and GH
counterregulatory hormones
prevent glucose from dropping too low
epi, glucagon, cortisol, GH
not there in hypopituitarism
so diabetic - reduce insulin to avoid hypoglycemia
lab confirms hypopituitarism - what next?
pituitary MRI with and without contrast
order of hormone replacement in hypopituitarism
1 - hydrocortisone**
2 - thyroxine
3 - testosterone
4 - GH
replacement of cortisol causing polyuria in hypopituitarism
unmask true panhypopituitarism
-cortisol increases GFR
unmasked ADH deficiency**
-from posterior pituitary
hemochromatosis
iron overload
hyperpigmentation
arthralgias
diabetes
hepatomegaly
cause of anterior pituitary failure
empty sella
filled with CSF
craving ice water
diabetes insipidus
high uric acid
DI
low uric acid
PP - psychogenic polydipsia
polyuria
DI and DM
cortisol excess
psychogenic polydipsia
increased serum sodium
DI
-renal loss of water
decreased serum sodium
PP
-problem - water ingestion - dilute out sodium
V1 receptors
uric acid secretion
ADH present - serum uric acid low
-but - no ADH - DI - get high uric acid**
Uosm/Posm <1
only in complete central and renal DI
only corrects in central DI after DDAVP test (vasopressin)
central and partial central DI
respond to DDAVP test
no ADH present
central DI
pituitary stalk thickening
autoimmune
sarcoid
histiocytosis X
tx for DI
desmopressin acetate
suicide risk**
HCTZ
lithium
partially knocks out ADH receptor
central vs. nephrogenic DI
> 10% change in Uosm after DDAVP is central
CDI vs. PCDI
CDI - no ADH
CNDI vs. PNDI
PNDI - urine osm 300-500
CNDI - urine osm <300
normal Uosm
800-1200
gene mutations in vasopressin receptors
V2 - x linked in males
aquaporin - auto dom or rec
