Pituitary Pathophysiology

Question 1

What are hormonal consequences of pituitary and hypothalamic diseases?

Answer 1

Hypersecretion: only pituitary adenomas
Hyposecretion: Any disease of pituitary/hypothalamus for anterior pituitary hormones

Hyposecretion of vasopressin can only be caused by disease of hypothalamus or infundibulum

Question 2

What are signs of GH deficiency? (3)

Answer 2

Short stature prior to epiphyseal closure
Decreased muscle/increased fat mass
Decreased BMD

Question 3

GH Replacement: What is it approved for and what is its effect

Answer 3

Approved for short stature.

Effects: growth, increase in BMD

Question 4

Which adenomas involve peptide hormones? What is noticeable effect?

Answer 4

Adenomas involving somatotrophs, lactotrophs, corticotrophs.

Effect: people “look funny”

Question 5

Which adenomas involve glycoprotein hormones? Are they recognizable?

Answer 5

Ones involving gonadotrophs, thyrotrophs

Only recognizable once they are much larger

Question 6

Somatotroph Adenomas: Presenation

Answer 6

Acromegaly (huge facial features, big hands) and gigantism

Question 7

Somatotroph Adenomas: Diagnosis via chemical confirmation (2)

Answer 7

Lack of suppression of Gh in response to oral glucose load

Elevated IGF-1

Question 8

Somatotroph Adenomas: Dx via pathologic confirmation

Answer 8

Histologic appearance of pituitary adenoma

IHC staining

Question 9

Consequences of Somatotroph Adenomas (7)

Answer 9

Arthritis (OA), cancer (esp colon cancer), CVD, DM, Neuropathy (carpal tunnel), sleep apnea, death

Question 10

Somatotroph Adenomas: Pharma Options (3) and other options (2)

Answer 10

Pharmacologic: DA agonists (cabergoline), SS analogs (octreotine), GH receptor antagonists (pegvisomant)
Surgical
Radiation

Question 11

How does pegvisomant antagonize GH receptor?

Answer 11

Dimerizes GHR

Question 12

Lactotroph adenomas: Clinical Syndromes
Premenopausal women? (2)
Postmenopausal women? (1)
Men? (3)

Answer 12

Premenopausal: amenorrhea and galactorrhea
Postmenopausal: neurological syndromes
Men: Decreased libido, fertility, potency

Question 13

Causes of hyperprolactinemia: Physiologic (4) and pathologic (6)

Answer 13

Phys: Pregnancy, nursing, exercise, stress
Path: lactotroph adenomas, DA receptor antagonist, catecholamine inhibitor, H2 antagonists, estrogens, opiates

Question 14

Treatment of lactotroph adenomas

Answer 14

Dopamine agonists: cabergoline, bromocriptine

Question 15

Px of Corticotroph Adenomas (2)

Answer 15

Cushing’s syndrome, neurological symptoms

Question 16

Thyrotroph Adenoma Presentation (2)

Answer 16

(Hyperthyroidism): A-fib and CHF

Question 17

Thyrotroph Adenoma Treatment and Effect

Answer 17

SS Analogs (octreotide): reduces T4 and TSH…also decreases adenoma size

Question 18

Gonadotroph Adenomas: Clinical Px (3)

Answer 18

Neurological symptoms: visual field impairment and headaches
Incidental finding on MRI
Hormonal abnormality: Premature puberty in boys, ovarian hyperstimulation

Question 19

Lab values in Gonadotroph Adenomas:

Answer 19

Elevated FSH, alpha subunit, estradiol

Low LH

Question 20

What do you see on US in women with gonadotroph adenomas?

Answer 20

Big ol ovaries (due to hyperstimulation)