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Flashcards in Disorders of Ant. Pituitary (Fisher) Deck (59):
1

What is monotropic hypopituitarism?

isolated deficiency of GH, LH/FSH, ACTH or TSH

2

What is polytropic hypopituitarism?

deficiency of GH, LH/FSH, ACTH and TSH in various combinations

3

What is panhypopituitarism?

anterior and posterior pituitary failure

4

What is the sequence of hormonal deficiencies following pituitary destruction?

Gonadotropic + GH → PRL + TSH → ACTH

5

Loss of ___% of the pituitary results in moderate effects.
Loss of ___% of the pituitary results in severe effects.

65-75%

90%

6

What 4 types of tumors cause hypopituitarism?

1. Hypothalamic
2. Pituitary
3. Parasellar
4. Metastatic

7

What do hypothalamic tumors cause?

secondary hypopituitarism

8

How do parasellar tumors cause hypopituitarism?

--may directly compress median eminence or stalk
--may invade hypothalamus or pituitary

9

What are 2 causes of Vascular Infarction which cause hypopituitarism?

Sheehan’s Syndrome
Pituitary apoplexy

10

What is Sheehan’s Syndrome?

Intra- or post-partum pituitary necrosis due to severe blood loss → shock

11

What is pituitary apoplexy?

intrapituitary hemorrhage caused by tumor compression of vessel walls + redistribution of blood flow
(this results in hypoxic injury, damage to capillary integrity + extravasation of blood from capillaries into tumor)

12

What are possible outcomes of pituitary apoplexy?

Tumor +/- normal tissue may be completely destroyed, which leads to autocure +/- hypopituitarism

13

What can occur if bleeding extends superiorly in pituitary apoplexy?

subarachnoid hemorrhage

14

Sarcoidosis, tuberculosis and post-meningitic fibrosis cause destruction of:

median eminence

15

Encephalitis can (occasionally) destroy:

hypothalamic nuclei

16

What types of infiltration may directly damage pituitary cells?

Amyloidosis
hemochromotosis

17

How can head trauma cause hypopituitarism?

damage to median eminence or stalk

18

When does idiopathic hypopituitarism occur, and what causes it?

pre-puberty

genetic defects in transcription factors needed for differentiation of anterior pituitary cells

19

What causes autoimmune hypopituitarism?

chronic inflammation causes pituitary cell destruction from lymphoid infiltrate

20

What causes primary Empty Sella hypopituitarism?

defect in diaphragm sella, which allows CSF pressure to enlarge sella

21

What causes Secondary Empty Sella hypopituitarism?

mass (e.g. adenoma) which has been removed by operation, radiation or infarction

22

What are the hormonal effects of deficient TSH?

↓ T3/T4

23

What are the hormonal effects of deficient ACTH?

↓ Cortisol
↓ androgens

24

What are the hormonal effects of deficient LH/FSH?

↓ T
↓estradiol/progesterone (females)

25

What are the hormonal effects of deficient GH?

↓ somatomedin-C (IgF1)

26

What is the clinical consequence of deficient TSH?

hypothyroidism

27

What is the clinical consequence of deficient ACTH?

Hypoadrenalism

28

What is the clinical consequence of deficient LH/FSH?

Hypogonadism

29

What is the clinical consequence of deficient GH?

Growth failure

30

What is the clinical consequence of deficient PRL?

Failed lactation

31

What are 5 general causes of hypothalamic disorders?

i. Infiltrative Disorders
ii. Mass lesions
iii. Radiation
iv. Infection
v. Trauma

32

What are the results of pituitary stalk section?

--DI
--pituitary hormone deficiency except PL (↑ due to loss of tonic inhibition by dopamine)

33

What 3 conditions result from hypothalamic lesions, and cause hyperpituitarism?

i. Precocious puberty
ii. Acromegaly
iii. Cushing’s Syndrome

34

What conditions do prolactinomas cause?

amenorrhea/galactorrhea (women)
impotence/↓libido (men)

35

What are the hormonal effects of prolactinomas?

↓GnRH
↓LH/FSH
↓T (men)
↓estradiol/progesterone (women)
↑adrenal androgens

36

What conditions do GH adenomas cause?

acromegaly (adults)
gigantism (children)

37

What conditions do ACTH adenomas cause?

Cushing’s disease
Nelson’s syndrome

38

What conditions do mixed GH-PRL cell adenoma cause?

acromegaly
hyperprolactinemia

39

What conditions do gonadotropin cell adenomas cause?

hypogonadism
visual impairment (when large enough due to compression of optic chiasm)

40

What conditions do TSH adenomas cause?

--hyperthyroidism
--thyrotoxicosis
--acromegaly or hyperprolactinemia (1/3 of cases)

41

How do TSH adenomas respond to TRH? TSH?

TRH = no response
TSH = no suppression

42

What suppresses TSH adenomas?

glucocorticoids

43

What is elevated in 85% of patients with TSH adenomas?

alpha subunits

44

What conditions does pituitary hyperplasia cause?

i. Cushing’s disease
ii. Hyperprolactinemia

45

What types of ectopic tumors cause Cushing's?

1. ACTH-secreting lung carcinoma
2. CRH-Secreting bronchial adenoma or carcinoids

46

What type of ectopic tumors causes acromegaly?

GHRH-secreting pancreatic islet tumor or carcinoids
(due to secondary GH cell hyperplasia)

47

What hormone increases when GH levels increase?

IgF1

48

What results from increased levels of IgF1?

1. ↑ growth of cartilaginous bones (resulting in prognathism; splaying of teeth; large nose, nasal sinuses, hands/feet)
2. ↑ soft tissue mass (resulting in thickened skin + subQ tissue, skin tags)
3. sweat gland hypertrophy (↑ sweating)

49

What results from increased levels of ↑GH and ↑IgF1

1. Visceral enlargement (liver, spleen, kidney)
2. Insulin resistance (glu intolerance or DM)

50

What results from increased levels of ↑GH and ↑PRL

1. Galactorhhea
2. Hypogonadiam (infertility)
3. Acromegaly

51

What hormones are elevated in and cause Cushing's?

ACTH
Cortisol
Adrenal Androgen

52

What are the effects of increased ACTH in Cushing's?

1. Bilateral adrenal hyperplasia with increased plasma cortisol and adrenal androgen
2. Loss of diurnal rhythm of ACTH and cortisol
3. Increased urinary cortisol

53

What are the effects of increased cortisol in Cushing's?

Salt retention
Insulin resistance
↑ fat deposits
↓ skin collagen
Proximal myopathy
Cerebral effects

54

What are the effects of increased adrenal androgens in Cushing's?

↓LH/FSH

↑ hair growth + sebum production

↓ libido

55

Signs/Symptoms of Cushing's?

obesity
HTN
glu intolerance
menstrual irregularity
hirsutism
striae
dorsal fat pad (hump)

56

Most common cause of Cushing’s syndrome?

exogenous glucocorticoid ingestion

57

How is Cushing's diagnosed?

dexamethasone suppression tests, which evaluate ACTH secretion in response to potent synthetic glucocorticoid

(nml = negative feedback)

58

When diagnosing Cushing's, what can low doses of drug distinguish between?

Cushing’s syndrome versus normal hypothalamus/pituitary/adrenal function

59

When diagnosing Cushing's, what can high doses of drug distinguish between?

Cushing’s disease versus Ectopic ACTH Syndrome and adrenal tumors