Disorders of Ant. Pituitary (Fisher)

Question 1

What is monotropic hypopituitarism?

Answer 1

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

Question 2

What is polytropic hypopituitarism?

Answer 2

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

Question 3

What is panhypopituitarism?

Answer 3

anterior and posterior pituitary failure

Question 4

What is the sequence of hormonal deficiencies following pituitary destruction?

Answer 4

Gonadotropic + GH → PRL + TSH → ACTH

Question 5

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

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

Answer 5

65-75%

90%

Question 6

What 4 types of tumors cause hypopituitarism?

Answer 6

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

Question 7

What do hypothalamic tumors cause?

Answer 7

secondary hypopituitarism

Question 8

How do parasellar tumors cause hypopituitarism?

Answer 8

• -may directly compress median eminence or stalk

- -may invade hypothalamus or pituitary

Question 9

What are 2 causes of Vascular Infarction which cause hypopituitarism?

Answer 9

Sheehan’s Syndrome

Pituitary apoplexy

Question 10

What is Sheehan’s Syndrome?

Answer 10

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

Question 11

What is pituitary apoplexy?

Answer 11

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)

Question 12

What are possible outcomes of pituitary apoplexy?

Answer 12

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

Question 13

What can occur if bleeding extends superiorly in pituitary apoplexy?

Answer 13

subarachnoid hemorrhage

Question 14

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

Answer 14

median eminence

Question 15

Encephalitis can (occasionally) destroy:

Answer 15

hypothalamic nuclei

Question 16

What types of infiltration may directly damage pituitary cells?

Answer 16

Amyloidosis

hemochromotosis

Question 17

How can head trauma cause hypopituitarism?

Answer 17

damage to median eminence or stalk

Question 18

When does idiopathic hypopituitarism occur, and what causes it?

Answer 18

pre-puberty

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

Question 19

What causes autoimmune hypopituitarism?

Answer 19

chronic inflammation causes pituitary cell destruction from lymphoid infiltrate

Question 20

What causes primary Empty Sella hypopituitarism?

Answer 20

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

Question 21

What causes Secondary Empty Sella hypopituitarism?

Answer 21

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

Question 22

What are the hormonal effects of deficient TSH?

Answer 22

↓ T3/T4

Question 23

What are the hormonal effects of deficient ACTH?

Answer 23

↓ Cortisol

↓ androgens

Question 24

What are the hormonal effects of deficient LH/FSH?

Answer 24

↓ T

↓estradiol/progesterone (females)

Question 25

What are the hormonal effects of deficient GH?

Answer 25

↓ somatomedin-C (IgF1)

Question 26

What is the clinical consequence of deficient TSH?

Answer 26

hypothyroidism

Question 27

What is the clinical consequence of deficient ACTH?

Answer 27

Hypoadrenalism

Question 28

What is the clinical consequence of deficient LH/FSH?

Answer 28

Hypogonadism

Question 29

What is the clinical consequence of deficient GH?

Answer 29

Growth failure

Question 30

What is the clinical consequence of deficient PRL?

Answer 30

Failed lactation

Question 31

What are 5 general causes of hypothalamic disorders?

Answer 31

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

Question 32

What are the results of pituitary stalk section?

Answer 32

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

Question 33

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

Answer 33

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

Question 34

What conditions do prolactinomas cause?

Answer 34

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

Question 35

What are the hormonal effects of prolactinomas?

Answer 35

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

Question 36

What conditions do GH adenomas cause?

Answer 36

acromegaly (adults) | gigantism (children)

Question 37

What conditions do ACTH adenomas cause?

Answer 37

Cushing’s disease | Nelson’s syndrome

Question 38

What conditions do mixed GH-PRL cell adenoma cause?

Answer 38

acromegaly | hyperprolactinemia

Question 39

What conditions do gonadotropin cell adenomas cause?

Answer 39

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

Question 40

What conditions do TSH adenomas cause?

Answer 40

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

Question 41

How do TSH adenomas respond to TRH? TSH?

Answer 41

``` TRH = no response TSH = no suppression ```

Question 42

What suppresses TSH adenomas?

Answer 42

glucocorticoids

Question 43

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

Answer 43

alpha subunits

Question 44

What conditions does pituitary hyperplasia cause?

Answer 44

i. Cushing’s disease | ii. Hyperprolactinemia

Question 45

What types of ectopic tumors cause Cushing's?

Answer 45

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

Question 46

What type of ectopic tumors causes acromegaly?

Answer 46

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

Question 47

What hormone increases when GH levels increase?

Answer 47

IgF1

Question 48

What results from increased levels of IgF1?

Answer 48

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)

Question 49

What results from increased levels of ↑GH and ↑IgF1

Answer 49

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

Question 50

What results from increased levels of ↑GH and ↑PRL

Answer 50

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

Question 51

What hormones are elevated in and cause Cushing's?

Answer 51

ACTH Cortisol Adrenal Androgen

Question 52

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

Answer 52

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

Question 53

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

Answer 53

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

Question 54

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

Answer 54

↓LH/FSH ↑ hair growth + sebum production ↓ libido

Question 55

Signs/Symptoms of Cushing's?

Answer 55

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

Question 56

Most common cause of Cushing’s syndrome?

Answer 56

exogenous glucocorticoid ingestion

Question 57

How is Cushing's diagnosed?

Answer 57

dexamethasone suppression tests, which evaluate ACTH secretion in response to potent synthetic glucocorticoid (nml = negative feedback)

Question 58

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

Answer 58

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

Question 59

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

Answer 59

Cushing’s disease versus Ectopic ACTH Syndrome and adrenal tumors