Pituitary

Question 1

What is the relationship between dopamine and prolactin?

Answer 1

Dopamine inhibits prolactin synthesis and release from the anterior pituitary

Question 2

What hormone release from the hypothalamus decreases the release of growth hormone from the anterior pituitary?

Answer 2

Somatostatin

Question 3

List the three cell types found in the adenohypophysis (anterior pituitary)

Answer 3

Acidophils - stains red
Basophils- stains blue
Chromophobes- stains clear

All three grow together, and clusters are separated by a reticulin network

Question 4

List the cell types present in the neurohypophysis

Answer 4

The neurohypophysis resembles neural tissue- it has glial cells, nerve fibers, nerve endings, and intra-axonal neurosecretory granules

Question 5

What is the most common cause of hyperpituitarism?

Answer 5

Functional anterior pituitary adenoma

Functional indicates they are actively secreting hormone

Question 6

Differentiate micro vs macroadenomas

Answer 6

microadenoma: <1cm
macroadenoma: >1cm

Question 7

Which is the most common kind of pituitary adenoma?

Answer 7

Lactrotrophs- secretes Prolactin

Question 8

What is the second and third most common hormones secreted from pituitary adenomas?

Answer 8

2- GH

3- ACTH

Question 9

What are the classic mass effect symptoms caused by pituitary adenomas?

Answer 9

Bitemporal hemianopsia (with macroadenoma)

…also headaches

Question 10

Do functional or non-function adenomas tend to be larger upon presentation?

Answer 10

Non-functional, because the only symptoms are caused by mass-effect

Question 11

MEN 1 includes neoplasms of what three structures?

Answer 11

parathyroid, pancreas, and pituitary

Question 12

Are pituitary adenomas familial or sporadic?

Answer 12

95% sporadic

5% familial

Question 13

What is the role of GNAS1 in many pituitary adenomas?

Answer 13

GNAS1 gene mutations –> constitutive activation of Gs protein –> unchecked cellular proliferation (ultimately through cAMP)

Question 14

How do females present with a prolactinoma?

Answer 14

Galactorrhea
Infertility and amenorrhea (prolactin inhibits LH surge)

Women present earlier because they realize they’re no longer menstruating regularly

Question 15

How do males present with a prolactinoma?

Answer 15

Infertility and impotence

Question 16

Name two drugs that are used to treat prolactinomas

Answer 16

Dopamine agonists: bromocriptine and cabergoline

Question 17

How are macroadenomas of the pituitary treated?

Answer 17

Surgical resection

Question 18

What cell type is responsible for the production of growth hormone?

Answer 18

Somatotrophs

Question 19

Persistent GH stimulation in the liver leads to over-production of what?

Answer 19

Insulin-like growth factor 1 (IGF-1)

Question 20

Contrast the effects of a GH producing pituitary adenoma in prepubertal vs post-puberty patients

Answer 20

Pre-puberty –> gigantism

Post-puberty–> acromegaly

Question 21

List three ways we diagnose GH adenoas

Answer 21

Increased IGF-1 serum levels
Increased GH serum levels
Lack of GH suppression by oral glucose

Question 22

List two treatments for GH adenomas

Answer 22

1) surgical resection

2) Somatostatin analogs

Question 23

Name two specific somatostatin analogs

Answer 23

Octreotide

Lantreotide

Question 24

Corticotrophs produce which hormone?

Answer 24

ACTH

Question 25

What is cushings disease?

Answer 25

Hypercortisolism via pituitary adenoma

Question 26

Along with symptoms of hypercortisolism, what other unique skin finding is seen with excess ACTH production?

Answer 26

Hyperpigmentation POMC --> ACTH and melanocyte stimulating hormone

Question 27

What is Nelson syndrome?

Answer 27

Removal of adrenal gland in presence of corticotroph adenoma --> rapidly progressing mass (no more feedback from adrenal glands --> Mass effect and hyperpigmentation, but no excess cortisol

Question 28

List 4 potential causes of hypopituitarism

Answer 28

1) Nonfunctional pituitary adenoma 2) Ischemic injury 3) Surgery, radiation 4) Inflammatory conditions

Question 29

What is a pituitary apoplexy?

Answer 29

Acute hemorrhage into an adenoma -If ACTH is eliminated --> lack of cortisol and hypotensive emergency

Question 30

What causes Sheehan syndrome?

Answer 30

Post partum necrosis of the anterior pituitary (posterior pituitary has some collateral circulation) The anterior pituitary is particularly sensitive to ischemic damage, and so is vulnerable following a postpartum hypotensive state

Question 31

What is the initial clinical clue as to Sheehan syndrome?

Answer 31

Lack of lactation (due to lack of prolactin)

Question 32

Is Sheehan syndrome dangerous?

Answer 32

Yes- there can be a life-threatening lack of secondary adrenal insufficiency

Question 33

What can cause primary empty sella syndrome?

Answer 33

Increased CSF pressure causes pituitary atrophy

Question 34

ADH deficiency leads to __________

Answer 34

Central diabetes insipidus

Question 35

Excess ADH secretion is called ________--

Answer 35

SIADH

Question 36

What is desmopressin?

Answer 36

Synthetic ADH analog

Question 37

How does central diabetes insipidus respond to desmopressin?

Answer 37

It does respond

Question 38

What is nephrogenic diabetes insipidus?

Answer 38

Renal tubules are unresponsive to ADH - does not respond to desmopressin

Question 39

Do patients with central diabetes insipidus have hypo or hypernatremia?

Answer 39

HYPERnatremia (they are dehydrated due to free water loss)

Question 40

Do people with SIADH have hypo or hypernatremia?

Answer 40

They usually have euvolemic hyponatremia They dilute out their Na+, but generally are not fluid overloaded Total body water increases, blood volume remains nearly normal (clinically euvolemic)

Question 41

What is the most common paraneoplastic cause of SIADH?

Answer 41

Small cell carcinoma of the lung

Question 42

List a few drugs that can cause SIADH

Answer 42

SSRIs, carbamazepine, chlorpromazine, cyclophosphamide

Question 43

What does Rathke's pouch develop into?

Answer 43

The anterior pituitary

Question 44

What are the tumors that can arise from Rathke's pouch?

Answer 44

Craniopharyngioma

Question 45

Where do craniopharyngiomas occur?

Answer 45

Suprasellar

Question 46

Are craniopharyngiomas benign or malignant?

Answer 46

THey are benign, but tend to recur after resection

Question 47

What is a Rathke cleft cyst? Why are they important?

Answer 47

Developmental failure of Rathke's pouch obliteration They're important because their growth may compromise the pituitary gland