Hypothalamus & Pituitary Disorders

Question 1

Embryological origin of anterior pituitary

Answer 1

Ectodermal derivative from Rathke’s pouch

Question 2

Embryological origin of posterior pituitary

Answer 2

Downgrowth from primitive neural tissue

Question 3

Anterior pituitary hormones

Answer 3

Acidophilic: GH, prolactin (ASP)
Basophilic: ACTH, TSH, FSH, LH (BFLAT)

Question 4

___ inhibits prolactin release.
___ stimulates prolactin release.

Answer 4

Dopamine.
TRH.

Question 5

What is the most powerful stimuli for prolactin release?

Answer 5

Suckling; also inhibits dopaminergic neurons

Question 6

Estrogen ___ sensitivity to TRH

Answer 6

increases

Question 7

Kallmann Syndrome is due to

Answer 7

Failure of differentiation or migration GnRH neurons in olfactory mucosa

Question 8

In Kallmann Syndrome, what does low GnRH hormone cause?

Answer 8

Low FSH & LH → lack of sexual maturity & absence of secondary sexual characteristics

Question 9

Cause of pituitary apoplexy

Answer 9

Hemorrhage into pituitary gland (usually d/t pituitary adenoma)

Question 10

Pituitary apoplexy presents with

Answer 10

Excruciating headache, diplopia

Question 11

Pituitary change during pregnancy

Answer 11

↑ lactotrophs (acidophilic) and ↑ pituitary size

Question 12

Pathogenesis of Sheehan syndrome

Answer 12

Pituitary hyperplasia, hypotension in peripartal period, low pressure of hypophyseal portal system → pituitary ischemia & necrosis

Question 13

Pathogenesis of Empty Sella Syndrome

Answer 13

Arachnoid herniation and CSF compression of pituitary → shrinks

Question 14

Clinical features of CSF

Answer 14

CSH rhinorrhea, headache, hypopituitarism

Question 15

Where is ADH synthesized

Answer 15

Supraoptic nucleus of hypothalamus

Question 16

Mechanism of ADH

Answer 16

Aquaporin insertion on tubular side; water reabsorption

Question 17

Four types of diabetes insipidus

Answer 17

Central, Nephrogenic, Physiogenic (polydipsia), Gestational

Question 18

Psychogenic vs Central vs Nephrogenic diabetes insipidus

Answer 18

Psychogenic: Increased water intake
Central: ADH deficiency
Nephrogenic: Kidney unresponsive to ADH

Question 19

Etiology of lithium in diabetes insipidus

Answer 19

Nephrogenic d/t ENaC channel

Question 20

Water deprivation test results on psychogenic vs central vs nephrogenic diabetes inspidus

Answer 20

Psychogenic: ↓ volume, ↑ osmolality
Central: ↑ urine osmolality after ADH
Nephrogenic: no change to urine osmolality after ADH

Question 21

How to treat central vs nephrogenic diabetes insipidus

Answer 21

Central: DDAVP
Nephrogenic: Thiazide-increased absorption in PCT

Question 22

SIADH symptoms

Answer 22

oliguria, free water resorption, hyponatremia, cerebral edema

Question 23

Causes of SIADH

Answer 23

Small CC of lung, head trauma, or drugs (antiepileptics, painkillers, anticancer drugs)

Question 24

Pathopysiology of SIADH

Answer 24

↑ ADH ↑ aquaporins, dilutes sodium, ↓ aldosterone, hyponatremia

Question 25

Mass effects of pituitary adenomas

Answer 25

Optic chiasm compression (bitemporal hemianopsia - loss of outer half of vision), headache, hypopituitarism

Question 26

How to distinguish adenomas from non-neoplastic tissue

Answer 26

cellular monomorphism and absence of reticulin network

Question 27

Prolactinoma presentation in females vs males

Answer 27

Females: galactorrhea, amenorrhea Males: ↓ libido, gynecomastia, headache

Question 28

Prolactinoma treatment

Answer 28

dopamine agonists (bromocriptine, cabergoline)

Question 29

Stalk effect

Answer 29

Mass in suprasellar compartment ↑ prolactin

Question 30

Growth hormone secreting adenomas in children vs adults

Answer 30

Children: gigantism - ↑ linear bone growth (epiphyses not fused) Adults: acromegaly - sausage shaped fingers, visceral organ growth, cardiac failure, enlarged tongue (sleep apnea)

Question 31

Lab results for GH adenoma

Answer 31

↑ ↑ IGF 1 (somatomedin C)

Question 32

OGTT results in healthy vs acromegaly

Answer 32

Healthy: glucose ↓ GH (negative feedback) Acromegaly: glucose doesn't suppress GH

Question 33

Laron Syndrome defect

Answer 33

Growth hormone receptor AR defect

Question 34

Laron syndrome presentation

Answer 34

short stature d/t extreme GH resistance

Question 35

Laron syndrome labs

Answer 35

↑ serum GH, ↓ IGF-1

Question 36

Corticotroph adenoma pathogenesis

Answer 36

ACTH causes Cushing syndrome & hyperpigmentation (MSH same precursos as ACTH)

Question 37

Nelsons syndrome pathogenesis

Answer 37

↑ ACTH, MSH d/t large aggressive tumors after bilateral adrenal removal (no negative feedback)

Question 38

Craniopharyngioma etiology

Answer 38

Arises from remnants of Rathke's pouch in children/young adults

Question 39

Craniopharyngioma presentation

Answer 39

Supratentorial mass that compresses optic chiasm → bilateral hemianopsia

Question 40

Gross and microscopic appearance of craniopharyngioma

Answer 40

Gross: Cystic, reddish-gray mass with dark motor oil fluid Microscopy: palisading squamous epithelium, wet keratin, dystrophic calcification