pituitary and hypothalamic disorders Flashcards
Anterior pituitary disorders?
- adenomas
- prolactinomas
- acromegaly
- gigantism
- panhypopituitarism
- cushing’s disease
Posterior pituitary disorders?
- SIADH
- Diabetes insipidus
What are the 2 main causes of pituitary gland disorders?
- hyperactivity
- hypoactivity
6 regulatory hormones of the hypothalamus?
- thyrotropin releasing hormone (TRH)
- gonadotropin releasing hormone (GnRH)
- corticotropin releasing hormone (CRH)
- growth hormone releasing hormone (GHRH)
- growth hormone inhibitory hormone (somatostatin)
- prolactin inhibiting hormone (PIH)
Major hormones of the anterior pituitary?
- FSH
- LH
- ACTH
- TSH
- Prolactin
- GH
FLAT PeG
Hormones of the posterior pituitary?
- ADH
- oxytocin
(both manufactured in the hypothalamus)
What holds the pituitary gland?
- the sella turcica
Presentations of pituitary tumors?
- hormonal abnormalities
- neuro sxs: HA, visual field impairment
- incidental finding on MRI obtained for another reason (incidentaloma)
What is an adenoma?
-a benign tumor of glandular tissue
Difference b/t microadenom and macroadenoma?
- microadenoma: tumor less than 10 mm in diameter, more common than macroadenomas (prolactinoma)
- macroadenoma: larger than 10 mm in diameter, may cause mass effect
etiologies of hyperprolactinemia?
- adenoma: most common cause of sellar region masses - prolactinoma is the most common type of pituitary adenoma
- trauma
- meds: SSRI’s, antipsychotics, cocaine, alpha methyldopa
- hypothyroidism
Why would a a prolactinoma lead to bitemporal hemianopsia?
- because it may cause compression of the optic chiasm
What is a prolactinoma a tumor of?
- the anterior pituitary
- secretes prolactin
What will happen if there is damage to the pituitary stalk?
- signals from the hypothalamus won’t be transmitted to pituitary
- so prolactin levels then increase unchecked
What meds that increase serotonin might lead to increased prolactin levels?
- antidepressants
- antipsychotics
- alpha methyldopa (aldomet -> antihypertensive)
- serotonin is a prolactin releasing factor
What may hypothyroidism cause?
- increased prolactin levels
- TRH from hypothalamus stimulates the release of TSH and prolactin
What kind of adenomas are more common in men? women?
- microadenomas more common in women ( 1 cm in size
- prolactin blocks gonadotropins FSH and LH
What sxs of prolactinoma will women present with?
- amenorrhea, galactorrhea and infertility (b/c of blocked secretion of FSH and LH)
What sxs of prolactinoma will men present with?
- decreased libido, gynecomastia, erectile dysfunction, infertility, bitemporal hemianopsia, headache, sxs due to decreased testosterone and mass effect from the tumor
What is the best lab test for dx of hyperprolactinemia? other tests?
- prolactin level: best initial test
- additional tests to rule out causes of secondary hyperprolactinemia (TSH, Beta-HCG, CMP, LH, FSH, serum estradiol (women), serum free and total testosterone (men)
- MRI to confirm dx
Rx Tx of hyperprolactinemia?
- cabergoline (best tolerated)
- Bromocriptine
Other tx options for hyperprolactinemia?
- transsphenoidal pituitary surgery for large sx tumors
- radiation therapy in some
- chemo with Temozolomide if no response to meds or radiation and if not a surgical candidate
What is acromegaly?
- anterior pituitary characterized by enlargement, thickening and broadening of bones - particularly extremities
What are the causes of acromegaly?
- hypersecreton of GH after fusio of epiphysis with shaft of bone
- adenomatous tumor of anterior pituitary involving acidophilic cells
signs and sxs of acromegaly?
- striking features are protrusion of:
supraorbital ridges, broadening of nose, thickening of lips, thickening and wrinkles formation on forehead, lower jaw (prognathism) - face with these features: referred to as acromegalic or gorilla face
- kyphosis: enlargement of hands and feet with bowing spine
- scalp is thickened and thrown into folds
- overgrowth of body hair
- visceral organs are enlarged
- thyroid, parathyroid and adrenal glands show hyperactivity
- hyperglycemia and glycosuria
- HA, HTN
- visual disturbance - bitemporal hemianopia
What is always the cause of acromegaly?
- pituitary tumor which causes an excess GH secretion
- most frequently occurs in ages 20-40
- may also be associated with tumors of pancreas or parathyroid glands
More signs and sxs of acromegaly?
- skeletal changes
- coarsening of facial features: jaw protrusion, prominent brow
- enlargement of hands and feet
- deepening of voice
- carpal tunnel syndrome
- CHF
- amenorrhea
- HAs
- visual field loss
- weakness
- organ enlargement
Why do acromegalics die at such a young age?
- because they suffer end-organ effects from HTN and abnormal glucose metabolism. 50% die