disorders of the hypothalamus and pituitary axis Flashcards
CRH
corticotrophin- releasing hormone
GHIH
growth hormone inhibiting hormone
PIH
prolactin inhibiting hormone
MSHIH
melanocyte-stimulating homrone inhibiting hromone
GnRH
gonadotropin releasing homrone
TRH
thyrotophin releasing hormone
ACTH
adrenocorticostopic hormone
TSH
thyroid stimulating hormone
GH
growth hormone
PRL
prolactin
TSH
follicule-stimulating hormone
LH
leuteinizing hormone
MSH
melanocyte stimulating hormone
ADH
antidiuretic hormone
what are products of the anterior pituitary
ACTH
TSH
GH
PRL
FSH
LH
MSH
What are the products of the posterior pituitary
ADH
oxytocin
what is hypopituitarism
low functioning pituitary - either problem with the hypothalaus upstream or pituitary gland itself
what are casues of hypopituitarism
primarily due to hypothalamus or pituitary lesions - pituitary adenoma
can be inherited
damage from trauma, infection, vascular disorder
infiltrative disorders (hemochromatosis, sarcoidosis, amyloidosis)
what is pituitary adenoma
average age 30-40; mostly benign; can be functioning or non-functioning
prolactin-secreting adenomas (prolactinomas) m/c**
what is the presentation of hypopituitarism
headaches or visual changes (mass effect)
non-specific: fatigue, dizziness, hypotension, confusion, cognitive dysfunction, sexual dysfunction, polydipsia, cold intolerance
What is the typical order of hormone disruption with hypopituitarism
GH -> FSH/LH -> TSH -> ACTH
what is seen with GH deficiency
short stature, micropenis, central obesity, hyperlipidemia, reduced muscle/bone mass, CV dysfunction
What is seen with Gonatotropin deficiency
FSH and LH deficiency
hypogonadism and infertility, impaired/absent puberty, sexual dysfunction, loss of male secondary sex characteristics
what is seen with TSH deficiency
hypothyroidism
what is seen iwth ACTH deficiency
adrenal insufficiency
what is seen with prolactin deficiency
impaired or absent lactation
what is the workup of hypopituitarism
eval of hormone levels or downstream effects:
eval of GH levels - stimulation testing
adrenal deficiency testing (low serum cortison, ACTH, DHEA, ACTH with cosynotropin stimulation)
MRI of hypothalamus/pituitary to assess for mass
what is the treatment for hypopituitarism
resection of tumor/mass
dopamine agonist first line for prolactinomas (bromocriptine or cabergoline)
radiation last line
lifetime hormone replacement therapy
What is the prognosis for hypopituitarism
increased mortality risk overall - especially women who are younger
mortality risk due to risk for adrenal crisis
risk for local invasion of some pituitary tumors
if due to radiation, risk for other intracranial neoplasms or stroke
what is the first line treatment for prolactinomas
dopamine agonists
bromocriptine or cabergoline
what is the glucocorticoid replacement
oral hydrocortisone 10-20mg in AM and 5-15mg in afternoon
titrate to patient
watch for neutropenia/lymphopenia
Stress dosing PRN during physical illness
who is not to taken hGH
during pregnancy or while using oral estrogen therapy
What are pituitary adenomas
benign tumors arising from any one of the pituitary cell types
makeup about 15% of intracranial neoplasms
most common cause of hypo- and hyperpituitarism in adults
what are the classifications of pituitary adenomas
micro-(<1cm diameter) verus macroadenomas (>1cm diameter - mass effect - hypopiutitarism)
functioning (secretion of hormone - hyperpituitatarism) vs non-functioning
what are the different types of presentation of pituitary adenomas
symptoms related to mass effect (HA, visual changes)
symptoms related to pituitary hormone imbalance
- hyperfunctioning from tumor secretion
-hypofunctioning due to mass effect/destruction
what different origin of tumors are there
Acidophils - growth hormone and prolactin
Basophile - gonadotrophs, ACTH and TSH
what is the test of choice for pituitary adenomas
MRI with gadolinium
adjunctive CT if suspected bony invasion or to look for calcifications
what is the workup for pituitary adenomas
MRI
secondary hormone dysfunction workup
what is the treatment of incidental pituitary adenoma tumors
no homrone secretion and small size - monitoring with annual MRI
what is the treatment for macroadenomas (pituitary adenomas)
resection due to risk of infiltration, mass effect
transsphenoidal approach preferred
+/- adjunctive radiation
what is the treatment of functional tumors (pituitary adenomas)
medical therapys available - somatostatin and dopamine inhibit
prolactinomas - dopamine agonists
acromegaly - somatostatin analogues, GH receptor antagonists
TSH secretion - somatostatin analogues +/- dopamine agonist
ACTH secretion - +/- somatostatin anaolgues
What is hyperprolacinemia
most common pituitary hormone hypersecretion syndrome
many different causes: physiologic, pharmacologic, pathologic
prolactin secreting pituitary tumor (prolactinomas): W>M, 30-40 yo
what is the presentation of hyperprolactinemias in males
infertility
decreased libido
erectile dysfunction
gynecomastia
decreased muscle/bone mass
decreased facial/body hair
depression
hot flashes
what is the presentation of hyperprolactinemias in females
amenorrhea
oligomenorrhea
infertility
vaginal dryness
irritability
anxiety/depression
what are miscellaneous presentations of hyperprolactinemias
acromegaly
HA
visual disturbances
other pituitary deficiencies
what is the workup for hyperprolactinemia
prolactin level
eval underling cause: pregnancy, hypothyroidism, CKD, cirrhosis, hyperparathyroidism
evaluate hypogonadism
Pituitary MRI
what is the treatment for hyperprolactinemia
stop medications known to increase PRL levels
correct hypothyroidism with thyroxine
oral contraceptive or estrogen replacement to treat infertility
increased surveillance during pregnancy
dopamine therapy
resection
radiation
chemotherapy
what is the treatment for large prolactinomas or symptomatic prolactinomas
dopamine agonists (carbergoline best tolerated)
What is gigantism
excessive growth in childhood, prior to physeal closure (impacts long bones)
what is acromegaly
excessive growth AFTER physeal closure (no long bone involvement)
What are physical symptoms of gigantism and acromegaly
tall stature
delayed puberty
enlargement of hands, feet and digits
soft, doughy handshake
moist handshake
prominent underbite
enlargement of skull
excessive sweating
tooth space widens
enlarged forehead
enlarged tongue, nose and lips
what are other associated symptoms with gigantism and acromegaly
CTS
arthritis
HA
DM
HTN
HD
deepening of voice
spinal stenosis
skin changes
colon polyps
hypogonadism
secondary hypothyroidism
OSA
how do you work up acromegaly/gigantism
random serum IGF-1 (elevated)
100g glucose drink, measure GH 60 min later - normal r/o acro
prolactin level
glucose
LFTs, BUN, creatinine
serum calcium
Free T4 and TSH
imaging: MRI - skull radiographs/hand and foot xr
what is the treatment of choice for acromegaly/gigantism
transsphenoidal resection
if remission not achieved with surgery - radiation or add adjunctive medcations
What is achondroplasia
dwarfism
autosomal dominant: fibroblast growth factor receptor 3 (FGFR3) gene
what are features of achondroplasia
disproportionate short statues, long bone shortening, large head, delayed motor development, normal cognition, short finger/toes, exaggerated lumbar lordosis, kyphocoliosis, prominent forehead, underdeveloped maxilla, genu varum, normal torso size
what is the workup of achrondoplasia
diagnosis mainly clinical
support with imaging
confirm with genetic testing (+ FGFR3 mutation)
how do you manage achondroplasia
manage complications: recurrent otitis media, OSA, obesity, spinal stenosis, narrowing foramen magnum)
PT for motor delays/genu varus
adaptation for ADLs
plot growth
weight management
? limb lengthening
? GH administration
What is diabetes insipidus
deficiency in ADH (vasopressin) - posterior piutitary
loss of renal H20 reabsoprtion
results in compensatory polyuria
central D1 1/3 of cases
nephrogenic types also exist
what is the presentation of diabetes insipidus
intense thirst(2-20L daily)
craving for icewater
polyuria
enuresis
symptoms worsened by corticosteroids
what is the workup of diabetes insipidus
primarily clinical
associated findings: 24h urine collection with less than 2L / 24 hours r/o DI
+/- hyperuricemia (redcued renal clearance)
Vasopression (ADH) challenge test
MRI of pituitary and hypothalamus to r/o mass
what is the treatment of DI
mild - no specific treatment, maintain fluid intake
avoid aggravating factors (corticosteroids)
pharmacologic treatment of choice: DDAVP (Desmopressin)
What is SIADH
syndrome of inappropriate antidiuretic hormone
opposite of DI
inappropriate release of ADH from posterior pituitary
what are the causes of SIADH
central - structural (CNS), psychiatric, pharmacologic (iatrogenic), metabolic issues
lungs - infection, mechanical, tumors (ectopic/paraneoplastic)
what is the presentation of SIADH
decreased fluid output, even with adequate or increased intake
fluid overload -> edema, elevated BP, hyponatremia
what should the workup for SIADH show
serum hyponatremia, hypoosmolality and urine osmolality about 100mosmol/kg
urine sodium concentration above 20 mEq/L
absence of heart, kidney or liver disease
normal thyroid and adrenal functon
low BUN and hypouricemia
