ENDO- Pituitary

Question 1

What is origin of the anterior pituitary

Answer 1

comes from the upper palate, back of throat

Question 2

What is development of the posterior pituitary

Answer 2

neuron in origin

Question 3

Why is the location of the pituitary is an issue

Answer 3

close to the optic chiasm and can cause issue when enlarged;
near cavernous area (vessels, etc) so it can make it inoperable

Question 4

How is the anatomy of the posterior pituitary

Answer 4

direct connection from the brain to the posterior pituitary via neurons

Question 5

What is the anatomy of the anterior pituitary

Answer 5

anterior can still function if the stalk is cut because it is signaled through blood vessels

Question 6

What is the thyroid axis

Answer 6

Hypothalamus -> TRH -> Pituitary -> TSH -> Thyroid -> T4

Question 7

What is the adrenal axis

Answer 7

Hypothalamus -> CRH -> Pituitary -> ACTH -> Adrenal Gland -> Cortisol

Question 8

What is the release pattern of cortisol

Answer 8

circadian rhythm, usually peaked in the morning

Question 9

Wha is the growth hormone axis

Answer 9

1] Excititory: Hypothalamus -> GHRH -> Pituitary -> GH -> Liver cell -> IGF;

2] Inhibitory: Hypothalamus -> somatostatin -> Pituitary -> inhibits GH release

Question 10

Describe the Male & Female Gonadotropin axis

Answer 10

Hypothalamus -> GnRH -> Pituitary -> LH, FSH -> Testes/Ovaries ->

Organs- Inhibin (negatively feedbacks on pituitary) and

testosterone/estrogen (negatively feedbacks on hypothalamus)

Question 11

Describe the female Gonadotropin axis just before ovulation

Answer 11

Hypothalamus -> GnRH -> Pituitary -> LH, FSH -> ovaries -> Inhibin (negatively feedbacks on pituitary) and
estrogen (POSITIVELY feedbacks on hypothalamus)

Question 12

Describe the prolactin axis

Answer 12

Hypothalamus -> dopamine and neural stimuli inhibits -> Pituitary -> Prolactin -> mammary gland

Question 13

What are the hallmarks of pituitary dysfunction

Answer 13

1] Wrong hormone at the wrong time,
2] Inappropriate hormone release given the expected milieu
3] Lack of expected hormone

Question 14

what happens when Low blood volume or high osmolarity of the blood?

Answer 14

hypothalamus- posterior pituitary - ADH to act on the kidneys. RETAIN NA, thus water

Question 15

What happens if posterior pituitary tract is destroyed

Answer 15

unable to release ADH in response

Question 16

What is elevated cortisol from any source?

Answer 16

Cushing Dz., rare
Central/Pituitary from elevated pituitary ACTH

S/S
1] thin skin/purple striae,
2] supraclavicular fat pads,
3] proximal muscle weakness

Question 17

What diagnostic tools are used for Cushing’s Syndrome

Answer 17

1] Screen 24 hr urine free cortisol and/ or

2] late night salivary cortisol

Question 18

What is next step if elevated cortisol of 24 hr urine free cortisol test?

Answer 18

1] use low dose dex, to suppression pituitary

2] check ACTH at the same time

Question 19

What if ACTH low and low dose dex suppression is inadequate/ doesn’t dec cortisol?

Answer 19

then= adrenal Cushing’s,
LOW ACTH mean pit not release like it should
if ACTH normal or high, then pituitary or ectopic

Question 20

How would you differentiate between pituitary or ectopic Cushing’s syndrome?

Answer 20

use HIGH dose dex suppression to differentiate pituitary vs. ectopic;
suppression = cushing’s syndrome;
no suppression=is ectopic

Question 21

How do you get a late night salivary cortisol sample

Answer 21

Saliva sample at 11 pm to 12 midnight

Cortisol circadian

Question 22

How is the dexamethasone suppression test

Answer 22

increases cortisol levels to see if negative feedback to ACTH

Dex is a steroid, that less invasive on body

Question 23

What is the next step in management of Cushing’s Disease?

Answer 23

1] Image what is necessary, pituitary vs. adrenal

2] Consider vein sampling to lateralize mass

Question 24

What are the treatments of Cushing’s?

Answer 24

1] surgery,
2] radiation, preferable gamma knife,
3] medications that decrease the synthesis of cortisol

Question 25

Describe the special consideration for large masses

Answer 25

evaluation for loss of other pituitary functions is appropriate

Question 26

Describe gigantism

Answer 26

excess GH is before closure of epiphyses, long bone growth

Question 27

Describe acromegly

Answer 27

excess GH is after closure of epiphyses; circumferential bone growth (widened, rather than longer)

Question 28

What lab value is used to confirm gigantism or acromegly

Answer 28

IGF-1 796 (nl 90-450 ng/mL), because growth hormones comes out in pulses

Question 29

What are the treatments for gigantism or Acromegaly

Answer 29

1] generally surgery, 2] radiation, preferable gamma knife, 3] medications decrease GH release or block its binding to the receptor

Question 30

Describe the characteristics of Acromegaly

Answer 30

``` 1] Rare, 2] Insidious Onset, 3] coarse features. 4] Enlarged tongue, 5] Deep voice, 6] Large joints in hands, 7] old pictures to make a diagnosis ```

Question 31

What are the cause of hyperprolactinemia

Answer 31

1] MC is pregnancy which is normal, 2] prolactinoma

Question 32

What inhibits the production of prolactin?

Answer 32

Dopamine Agonist therapy for hyperprolactinemia

Question 33

List the Dopamine Agonists

Answer 33

1] bromocriptine (long-term safety in pregnancy), | 2] cabergoline (longer acting)

Question 34

What should follow dopamine Agonist therapy

Answer 34

MRI to check for shrinkage of mass

Question 35

What are possible causes of non-hormone function tumors?

Answer 35

1] pure non-functioning, 2] meningioma, 3] cancer

Question 36

Describe the treatment of Panhypopituitarism

Answer 36

1] first remove or shrink the mass, 2] All the hormones need to be replaced: Steroids first for the adrenal insufficiency, 3] After 2 days, thyroid and testosterone therapy

Question 37

Describe the characteristics of diabetes insipidus

Answer 37

Lots of low osmolarity urine and hypernateremia | ADH not responding

Question 38

What tests should be done to confirm diabetes insipidus

Answer 38

1] Water deprivation | 2] Vasopressin (ADH will cause retention challenge 5mcg SQ x one

Question 39

Describe the Vasopressin challenge

Answer 39

DI is central(HP ant)-if urine osm increases by >50% then the kidneys are responding (ADH will make osmol HIGH) DI is nephrogenic; if urine osm does not change, then the kidneys are NOT responding vasopressin ADH

Question 40

Describe the incidence of diabetes insipidus

Answer 40

1] Rare, Can be seen isolated. | 2] rarely associated with anterior pituitary function loss

Question 41

why water deprivation is necessary in diabetes inspidus patients?

Answer 41

People who complain of polyuria/polydipsia usually have normal sodiums. They just drink a lot of water to keep up.

Question 42

What are exteremely rare endocrine masses?

Answer 42

1] gonadotrope (FSH/LH) secreting masses, | 2] TSH secreting masses leading to incr free T4, 3isolated pituitary TSH loss without loss of other axes

Question 43

how to determine what pituitary disorder is going on

Answer 43

1] Determine if low or high levels, 2] Is it endorgan or pituitary, 3] If theres a mass is it making something?, 4] Is mass blocking the release of something else?

Question 44

Should A normal TSH with a low free T4 be of concern?

Answer 44

very suspicious for pituitary disease and rarely occurs alone. Work it up.