Bod: Endocrinology: Pituitary Disorders

Front 1

Adenohypophysis = ?

Back 1

Anterior pituitary

Front 2

Neurohypophysis = ?

Back 2

Posterior pituitary

Front 3

What nuclei in the hypothalamus supply the nerves that terminate in the posterior pituitary?

Back 3

The supraoptic nuclei and the paraventricular nuclei.

Front 4

What are the hormones released from the anterior pituitary?

Back 4

FSH
LH
ACTH
TSH

Prolactin
Endorphins
GH

Front 5

What are the hypothalamic hormones that control the release of prolactin?

Back 5

Dopamine (-)
TRH (+)
PRFs (+)

Front 6

What are the hypothalamic hormones that control the release of hormones from somatotrophs?

Back 6

Somatotrophs release GH

GHRH (+)
Somatostatin (-)

Front 7

What are the hypothalamic hormones that control the release of hormones from corticotrophs?

Back 7

Corticotrophs secrete ACTH

CRH (+)
Vasopressin (augments CRH)

Front 8

What are the hypothalamic hormones that control the release of hormones from thyrotrophs?

Back 8

Thyrotrophs secrete TSH

TRH (+)
Somatostatin (-)

Front 9

What are the hypothalamic hormones that control the release of hormones from gonadotrophs?

Back 9

Gonadotrophs release FSH, LH

GnRH (+)

Front 10

Compression of the optic nerve at the optic chiasm can cause what kind of optic defect?

Back 10

Bitemporal hemianopia

Front 11

What is the most common tumor of the sella tursica?

Back 11

Pituitary adenoma. 10%-20% of intercranial tumors.

Front 12

What is the most common type of pituitary adenoma?

Back 12

Prolactinoma (prolactin cell adenoma) (20-30%)

Front 13

What is the presentation of a prolactinoma?

Back 13

Galactorrhea (F>M)
PRL high so FSH, LH low
Usually diagnosed as a microadenoma (<1) in females because of associated amenorrhea.

Front 14

What is the "stalk effect?"

Back 14

The state where decreased dopamine causes a loosening of regulatory control on prolactin, causing levels to rise. (Usually less than 100 ug/L)

Front 15

Prolactinoma: treatment

Back 15

Oral dopamine receptor (type 2) agonists to suppress PRL synth and sec. 80-90% of pts are responsive.

- Bromocriptine (Parlodel): Daily

- Carbergoline (Dostinex): Long-acting, once or twice weekly. Tolerated better than bromocriptine

AE with both: nasal stuffiness, dry mouth, insomnia, vertigo, rare: psychiatric symptoms.

Front 16

Growth hormone adenoma: presentation

Back 16

Acromegaly (adults)
Gigantism (children)
Insidious onset

- Everything gets thicker and bigger.
- Proximal muscle weakness
- HTN
- Diabetes mellitus

Note that 25% of GH adenomas also sec PRL.

Front 17

What is prognathism?

Back 17

Thickening of the soft tissues of the face and lip.

Front 18

What are the tests used to screen for a growth hormone adenoma?

Back 18

- Insulin-like Growth Factor (IGF-1) level will be high.

- To confirm, do a glucose suppression test. Failure to reduce GH with glucose is a positive test.

Front 19

What is the treatment for a GH adenoma?

Back 19

1. Surgical resection.

2. Somatostatin analogues (via SSTR2 and SSTR5 receptors on GH sec cells)
- Octreotide acetate (Sandostatin): SC injection

3. GH receptor antagonists: decrease IGF-1 levels, have no effect on tumor size.

- Pegvisomant (Somavert)

Front 20

What is it called when high cortisol levels are caused by a pituitary adenoma?

Back 20

Cushing's DISEASE

Front 21

ACTH adenoma: presentation

Back 21

F>M
All effects of increased cortisol
Increased ACTH = hyperpigmentation

Front 22

Cushing's disease: diagnostic tests

Back 22

1. High 24 hr urine for cortisol
2. High overnight dexamethasone suppression test
3. High two day (low dose) dexamethasone suppression test
4. NORMAL two day (high dose) dexamethasone suppression test. (Normal because tumor cells are suppressable at high glucocorticoid doses - note that ectopic ACTH tumors will not be suppressed).

Front 23

ACTH producing adenoma: treatment

Back 23

- Surgical resection then followup for AI
- Pituitary irradiation (15% effective)
- Oral meds have no effect on tumor size (ketoconazole, metyrapone, mitotane)

Front 24

What are two types of rare pituitary tumors (among the functional tumors)?

Back 24

- Gonadotropin producting adenomas
- TSH producing adenomas

Front 25

"Most common non-glial tumor in pediatric age group; also occurs in adults."

Back 25

Craniopharyngeoma

Front 26

Lymphocytic hypophysitis: attributes

Back 26

- Affects young women in late pregnancy or postpartum
- Probably an autoimmune element
- Associated with other autoimmune disorders (Hashimoto's, Addison's)
- Clinical presentation due to hypopituitarism

Front 27

Lymphocytic hypophysitis: treatment

Back 27

Surgical hypophysectomy
Corticosteroids may also be effective

Front 28

Two very basic etiologies of hypopituitarism?

Back 28

1. Mass effect
2. Loss of hypothalamic input

Front 29

What is the observed pattern of acquired pit hormone deficiency?

Back 29

GH --> FSH/LH --> TSH --> ACTH

Front 30

Loss of PRL: clinical presentation

Back 30

none!

Front 31

What is wrong in secondary adrenal insufficiency?

Back 31

There is a loss of ACTH

Front 32

Hypopituitarism with loss of ACTH: diagnosis

Back 32

- Inappropriately low ACTH in the setting of low AM cortisol.

- Inadequate cortisol response to ACTH stimulation test

Front 33

Hypopituitarism with loss of ACTH: treatment

Back 33

Glucocorticoid replacement with hydrocortisone up to 30 mg daily, divided into 2-3 doses. Use lowest dose possible to prevent cushingoid effects.

Front 34

Hypopituitarism with loss of ACTH: hyperpigmentation

Back 34

Should see NONE because there is no overproduction of ACTH.

Front 35

Hypopituitarism with loss of GH: attributes, diagnosis, treatment

Back 35

- Everything small in children
- 1/3 of children have familial form
- IGF-1 levels low, but not a sensitive screen
- Inappropriate GH response to stimulation tests.
- Treat with injectable GH (Humatrope)

Front 36

Hypopituitarism with loss of FSH/LH: attributes, treatment

Back 36

Inherited disorders such as Kallmann syndrome (XXY) can cause Isolated Hypogonadotropic Hypogonadism (IHH)

- Acquired forms present with extreme weight loss, stree, high PRL, idiopathic.

- Will see low to normal FSH/LH in the setting of low estradiol/testosterone

- Treatment: males - testosterone replacement, females - premenopausal: cyclic estrogen and progesterone (OCP)

Front 37

Hypopituitarism with loss of TSH: diagnosis

Back 37

Central hypothyroidism
- Pituitary hypothyroidism: low or inap. normal TSH in the setting of low free T4

- Hthal hypothyroidism: a lack of TRH. May have normal or slightly high TSH ?

Front 38

What is a pituitary apoplexy?

Back 38

A sudden bleed into pituitary - a neurosurgical emergency.

Front 39

Sheehan's syndrome

Back 39

A massive pituitary infarction occurring in postpartum period.

- Shock or hemorrhage causes loss of blood supply to pituitary.

- Etiology: vasospasm of preportal arterioles, enlargement of gland during pregnancy makes more susceptible to ischemia

Front 40

What is a "remote" pituitary infarction?

Back 40

When the anterior pituitary is replaced by a fibrous scar.

Front 41

What are the two hormones released by the posterior pituitary?

Back 41

ADH (Vasopressin)
Oxytocin

Front 42

Oxytocin

Back 42

Milk letdown during nursing, uterine contraction during labor.

Front 43

What is notable about the volume state of a person with SIADH?

What other two diseases have similar presentations?

Back 43

They are euvolemic. There is not enough volume overload to see edema.

Other causes of euvolemic hyponatremia are hypothyroidism and adrenal insufficiency.

Front 44

Rapid correction of SIADH with hypertonic saline can cause what?

Back 44

Central pontine myelinolysis

Front 45

Treatment of chronic SIADH?

Back 45

Demeclocycline (decreases ADH effect on kidney)

Fludrocortisone (increases Na resorption), monitor for HTN, hypokalemia

Front 46

Diabetes insipidus: clinical presentation

Back 46

- Polyuria (up to 18 L/day), patients emphasize nocturia

- Dilute urine (100-150 mOsm, specific gravity is <1.005)

- High serum osmolarity, hypernatremia. Patient can't match water intake to make urine losses.

Front 47

Diabetes insipidus: diagnostic tests

Back 47

Water deprivation test:
1. Diagnosis of DI. Dilute urine in the setting of 4-6 hours of water restriction.

2. Determination of type of DI. Administer ADH. No response = nephrogenic DI. Reponse = Central DI.

Front 48

Central diabetes insipidus: treatment

Back 48

Desmopressin

Front 49

Nephrogenic diabetes insipidus: treatment

Back 49

- Low solute diet
- Thiazide diuretic
- K sparing diuretic
- NSAIDs (prostaglandins antagonize ADH at the kidney, so NSAIDS up --> prostaglandins down --> ADH sensitivity up).