EXAM #1: HYPOPITUITARISM Flashcards Preview

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Flashcards in EXAM #1: HYPOPITUITARISM Deck (34):
1

What inhibits prolactin secretion from the anterior pituitary?

Dopamine, which TONICALLY inhibits prolactin release

*Thus, anything that disrupts dopamine can cause prolactin INCREASE

2

What is hypopituitarism?

Decreased secretion of anterior and/or posterior pituitary hormones

3

What is the definition of panhypopituitarism?

Decreased secretion of all pituitary hormones

4

Describe the basic etiology of hypopituitarism.

There are three basic causes of hypopituitarism:
1) Pituitary disease (most common)
2) Hypothalamic disease
3) Idiopathic causes

5

What can cause the insidious onset of panhypopituitarism?

Radiation exposure leading to panhypopituitarism months-years s/p

6

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

- Patient with pituitary tumor
- Tumor hemorrhages suddenly

*Sx include sudden onset excruciating headache and diplopia

7

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

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

8

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

Cortisol deficiency

9

What are the signs and symptoms of ACTH deficiency?

Sx=
- Weakness/fatigue
- Anorexia
- Abdominal pain
- Weight loss

Signs=
- Postural hypotension/ reflex tachycardia
- Vascular collapse
- Pallor
- Hypoglycemia

10

What labs clue you into secondary ACTH deficiency?

Simultaneously low ACTH and cortisol

11

What is missing from secondary ACTH deficiency vs. primary?

1) Hyperpigmentation
2) Aldosterone deficiency

*I.e. no salt wasting, no hyperkalemia

12

How is adrenal insufficiency diagnosed?

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

Cortisol, 18= normal

13

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

1) Metyrapone
2) Insulin induced hypoglycemia

*If these are positive; secondary

14

How is adrenal insufficiency treated?

Hydrocortisone (15-30mg daily)

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

15

How is secondary hypothyroid diagnosed?

1) Low T4 (primary)
2) Low TSH (should be high--secondary)

16

How is hypothyroid treated?

L-thyroxine

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

17

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

Adrenal function

18

What are the symptoms of gonadotropin deficiency?

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

19

How is secondary gonadotropin deficiency diagnosed?

Low:
1) Estradiol or testosterone
2) Low LH/FSH

20

How is gonadotropin deficiency treated in men?

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

21

How is gonadotropin deficiency treated in women?

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

22

What is the mainstay of GH deficiency diagnosis?

IGF-1 levels

23

What is the likelihood of deficiencies in panhypopotuitarism?

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

24

How is GH deficiency treated?

Recombinant GH

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

25

What is the treatment for prolactin deficiency?

None--no treatment available

26

What are the to stimuli that induce vasopressin release?

1) Increases in plasma osmolality
2) Decreased plasma volume

27

Where are V1 receptors located?

Vasculature

28

Where are V2 receptors located?

Renal tubules

29

What happens when vasopressin binds V2 receptors?

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

Thus, there is reabsorption of solute free water

30

What is central diabetes insipidus (DI)?

Deficiency of vasopressin due to posterior pituitary problem

31

How is central DI diagnosed?

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

32

How is central DI treated?

Mild= ingest enough water to keep-up

Severe= Desmopressin (ddAVP) synthetic vasopressin analogue

33

What will high prolactin cause?

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

34

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

Pituitary stalk compresion