EXAM #1: HYPOPITUITARISM

Question 1

What inhibits prolactin secretion from the anterior pituitary?

Answer 1

Dopamine, which TONICALLY inhibits prolactin release

*Thus, anything that disrupts dopamine can cause prolactin INCREASE

Question 2

What is hypopituitarism?

Answer 2

Decreased secretion of anterior and/or posterior pituitary hormones

Question 3

What is the definition of panhypopituitarism?

Answer 3

Decreased secretion of all pituitary hormones

Question 4

Describe the basic etiology of hypopituitarism.

Answer 4

There are three basic causes of hypopituitarism:

1) Pituitary disease (most common)
2) Hypothalamic disease
3) Idiopathic causes

Question 5

What can cause the insidious onset of panhypopituitarism?

Answer 5

Radiation exposure leading to panhypopituitarism months-years s/p

Question 6

What is pituitary apoplexy? What are the symptoms of this condition?

Answer 6

• Patient with pituitary tumor
• Tumor hemorrhages suddenly

*Sx include sudden onset excruciating headache and diplopia

Question 7

In terms of clinically describing hypopituitarism, what does secondary mean?

Answer 7

Problem is in the pituitary gland or hypothalamus, NOT the target gland itself (primary)

*E.g. when referring to the thyroid; defect in TRH or TSH is secondary hypothyroidism vs. T4 which would be primary

Question 8

What is the physiologic consequence of ACTH deficiency (hormone)?

Answer 8

Cortisol deficiency

Question 9

What are the signs and symptoms of ACTH deficiency?

Answer 9

Sx=

• Weakness/fatigue
• Anorexia
• Abdominal pain
• Weight loss

Signs=

• Postural hypotension/ reflex tachycardia
• Vascular collapse
• Pallor
• Hypoglycemia

Question 10

What labs clue you into secondary ACTH deficiency?

Answer 10

Simultaneously low ACTH and cortisol

Question 11

What is missing from secondary ACTH deficiency vs. primary?

Answer 11

1) Hyperpigmentation
2) Aldosterone deficiency

*I.e. no salt wasting, no hyperkalemia

Question 12

How is adrenal insufficiency diagnosed?

Answer 12

1) Morning cortisol
2) Cortrosyn stimulation test
3) Measure ACTH

Cortisol, 18= normal

Question 13

What tests can be used to provoke a high ACTH level?

Answer 13

1) Metyrapone
2) Insulin induced hypoglycemia

*If these are positive; secondary

Question 14

How is adrenal insufficiency treated?

Answer 14

Hydrocortisone (15-30mg daily)

Note that the patient will need higher doses during times of stress/illness (This is called “stress-dosing”)

Question 15

How is secondary hypothyroid diagnosed?

Answer 15

1) Low T4 (primary)

2) Low TSH (should be high–secondary)

Question 16

How is hypothyroid treated?

Answer 16

L-thyroxine

*Goal is to maintain normal T4 and a sense of well-being NOT TSH measurements

Question 17

If a patient has hypothyroid, what do you need to check first before starting treatment?

Answer 17

Adrenal function

Question 18

What are the symptoms of gonadotropin deficiency?

Answer 18

1) Infertility
2) Irregular periods (female)
3) Osteopenia/perosis

Question 19

How is secondary gonadotropin deficiency diagnosed?

Answer 19

Low:

1) Estradiol or testosterone
2) Low LH/FSH

Question 20

How is gonadotropin deficiency treated in men?

Answer 20

1) Testosterone replacement if NOT seeking fertility
2) IF seeking fertility
- LH/FSH for pituitary disease
- GnRH for hypothalamic

Question 21

How is gonadotropin deficiency treated in women?

Answer 21

1) Estrogen-progestin replacement
2) IF seeking fertility
- LH/FSH for pituitary disease
- GnRH for hypothalamic

Question 22

What is the mainstay of GH deficiency diagnosis?

Answer 22

IGF-1 levels

Question 23

What is the likelihood of deficiencies in panhypopotuitarism?

Answer 23

1) GH
2) LH/FSH
3) TSH
4) ACTH

Question 24

How is GH deficiency treated?

Answer 24

Recombinant GH

*Goal of therapy is to maintain IGF-1 level and sense of well-being

Question 25

What is the treatment for prolactin deficiency?

Answer 25

None–no treatment available

Question 26

What are the to stimuli that induce vasopressin release?

Answer 26

1) Increases in plasma osmolality

2) Decreased plasma volume

Question 27

Where are V1 receptors located?

Answer 27

Vasculature

Question 28

Where are V2 receptors located?

Answer 28

Renal tubules

Question 29

What happens when vasopressin binds V2 receptors?

Answer 29

1) Synthesis of aquaporins
2) Aquaporins are inserted into collecting duct membrane

Thus, there is reabsorption of solute free water

Question 30

What is central diabetes insipidus (DI)?

Answer 30

Deficiency of vasopressin due to posterior pituitary problem

Question 31

How is central DI diagnosed?

Answer 31

1) Hypotonic polyuria
2) Hypernatremia
3) Loss of pituitary bright spot on MRI

Question 32

How is central DI treated?

Answer 32

Mild= ingest enough water to keep-up

Severe= Desmopressin (ddAVP) synthetic vasopressin analogue

Question 33

What will high prolactin cause?

Answer 33

Low FSH/LH i.e. low estrogen/testosterone?

Question 34

What is a prolactin level less than 100 most associated with?

Answer 34

Pituitary stalk compresion