Pituitary Flashcards
most common form of primary endocrine hyperfunction
neoplasia!!
*except thyroid
pituitary embryologic origin
Rathkes pouch
posterior pituitary histo
axonal neurons supportive pituicytes (neuroglial cells)
anterior pituitary histo
acidophils (GH, prolactin)
basophils (TSH, LH/FSH, ACTH)
chromophobe
mass effect of pituitary lesions
increased ICP resulting in: headaches N/V HTN bradycardia resp depression papilledema bilateral temporal hemianopsia pituitary apoplexy (hemorrhage)
types of pituitary adenomas
non-functional - cause mass effect
functional - cause hormone excess
most common functional pituitary adenoma
lactotroph adenoma/prolactinoma
prolactinoma presentation in females
menstrual irregularities galactorrhea diminished libido infertility mass effect
prolactinoma presentation in males
decreased libido
decreased sperm count
mass effect
classification of prolactinomas
sparsely granulated - most common
densely granulated - rare
histo progression of prolactinomas
stromal hyalinization with psammoma bodies
dense calcifications = pituitary stone
prolactinoma tx
dopamine agonists - bromocriptine, cabergoline
surgery
causes of hyperprolactinemia in absence of adenoma
pregnancy lactation loss of dopamine (damage or drugs) renal failure hypothyroidism
somatotroph adenoma presentation
gigantism (children)
acromegaly (adults)
features of acromegaly
enlargement of face and hands protruding jaw enlarged nose thickened lips joint pain/limited mobility enlarged viscera cardio complications shorten lifespan
acromegaly diagnostic testing
get serum IGF-1
if elevated, oral glucose tolerance test for GH response (glucose should inhibit GH release)
corticotroph adenoma
causes hypercortisolism and Cushing syndrome
Cushing syndrome
hypercortisolism resulting in: obesity DM hirsutism adrenal hyperplasia moon face buffalo hump
Cushing disease
increased secretion of pituitary ACTH secondary to adenoma
results in hypercortisolism
causes of Cushing syndrome
exogenous cortisol (glucocorticoid administration)
small cell carcinoma
pancreatic CA
neural tumors
Cushing syndrome diagnostic testing
check ACTH level:
if low –> get CT/MRI of abdomen
if high –> get MRI of brain
dexamethasone suppression test
diagnostic test to determine corticotroph adenoma vs ectopic tumor vs adrenal hyperplasia
pituitary adenoma response to dexamethasone suppression test
elevated urine/serum cortisol
elevated corticotropin
low dose dexamethasone does not suppress
high dose dexamethasone DOES suppress
ectopic corticotropin response to dexamethasone suppression test
elevated urine/serum cortisol
elevated corticotropin
low does dexamethasone does not suppress
high dose dexamethasone does not suppress
adrenal tumor/hyperplasia response to dexamethasone suppression test
elevated urine/serum cortisol
suppressed corticotropin
low does dexamethasone does not suppress
high dose dexamethasone does not suppress
hypercortisolism tx
somatostatin analogs
bromocriptine
surgical excision
typical presentation of gonadotroph adenoma
mass effect!
also called “silent” or “null cell” adenomas
which transcription factor is associated with most functioning pituitary adenomas?
PIT-1
which transcription factor is associated with corticotroph adenoma?
TPIT
which somatic gene mutation is associated with most pituitary adenomas?
GNAS
*cAMP driven cell proliferation
which somatic gene mutation is associated with corticotroph adenomas
USP8
*EGFR upregulation
which familial gene mutation predisposes individuals to pituitary adenomas?
AIP (FIPA)
rathke’s cleft cyst
cystic mass derived from Rathke’s pouch
can expand and compress normal pituitary
can rupture and cause inflammation/infection
adolescent craniopharyngioma
most often adamantinomatous
growth retardation and hypopituitarism
adult craniopharyngioma
papillary
increased ICP and hypopituitarism
etiology of craniopharyngioma
derived from Rathke’s pouch remnants
histo of craniopharyngioma
squamous epithelium
“wet” keratin
calcified cyst
primary empty sella syndrome
CSF leaks into the sella and compresses the pituitary
secondary empty sella syndrome
pituitary expands and infarcts within the sell, leaving an empty space
common causes of hypopituitarism
tumors (craniopharyngioma, rathke’s cyst, gliomas)
empty sell syndrome
sheehan syndrome
pathophysiology of sheehan syndrome
pituitary enlarges during pregnancy which makes it susceptible to compression, ischemia and avascular necrosis
what predisposes pregnant women to sheehan syndrome?
small sella turcica
autoimmunity
coagulation abnormalities
severe postpartum hemorrhage
diabetes insipidus
ADH deficiency
central vs nephrogenic
presentation of DI
increased serum osmolality/hypernatremia
dilute, excessive urine
polyuria
how do you determine central vs nephrogenic DI?
administer desmopressin
does the kidney respond?
yes - central
no - renal
SIADH causes
small cell carcinoma of the lung
TBI/subarachnoid hemorrhage
drugs (SSRIs)
SIADH presentation
decreased serum osmolality/hyponatremia concentrated urine (hypernaturia) AMS muscle weakness seizures
when does thirst present, DI or SIADH?
BOTH
DI - legit need to replace fluids
SIADH - effect of ADH on brain results in inappropriate thirst
