Hypoadrenocortism

Question 1

What two hormones are stored in the posterior pituitary gland?

Answer 1

ADH (vasopressin) and oxytocin

Question 2

General function of ADH?

Answer 2

promotes reabsorption of water in collecting duct of kidneys

Question 3

General function of oxytocin?

Answer 3

stimulates contractions of uterus in childbirth and contraction of mammary glands in breast for lactation

Question 4

where is ADH made?

Answer 4

the supraoptic nucleus of the hypothalamus

Question 5

where is oxytocin made?

Answer 5

the paraventricular nucleus of the hypothalamus

Question 6

Which is FALSE regarding mineralocorticoids (aldosterone)?
A) promotes Na, Cl and water reabsorption
B) promotes K secretion
C) deficiency results in hypernatremia, hypochloremia, and hypokalemia
D) major regulators of aldosterone secretion are plasma K levels and the RAS

Answer 6

C - deficiency results in hyponatremia, hypochloremia and hyperkalemia

Question 7

Describe ADH (antidiuretic hormone, vasopressin)

Answer 7

decreases urine production, sweating, and increases BP

released if animal is dehydrated, inhibited if animal is over hydrated

Question 8

Describe aldosterone

Answer 8

hormone that affects Na reabsorption
released when blood is diluted and low in volume
causes sodium absorption to fix concentration
works on DCT and collecting duct

Question 9

Which tissue is not directly acted on by ADH/vasopressin?
A) kidney
B) arterioles
C) liver
D) sweat glands

Answer 9

C - liver

Question 10

What part of the adrenal gland produces aldosterone?
A) zona fasciculata
B) zona glomerulosa
C) zona reticularis
D) adrenal medulla

Answer 10

B - zona glomerulosa

Question 11

What is “typical” hypoadrenocorticism?

Answer 11

deficient in mineralocorticoids and glucocorticoids due immune mediated adrenal gland destruction

Question 12

Signalment of hypoadrenocorticism?

Answer 12

dogs, young to middle aged, females > males

Question 13

3 major signs of addisonian crisis?

Answer 13

collapse, bradycardia, melena

Question 14

Clinical signs of Addison’s?

Answer 14

anorexia, lethargy, fasting, hypoglycaemia

Question 15

What is atypical Addison’s? What are 2 causes?

Answer 15

low glucocorticoids only

1. pituitary lesion, not enough ACTH (but ACTH not needed for aldosterone release)
2. early in typical before it has progressed to typical

Question 16

A client calls you because she accidentally threw out her dog’s medicine. The dog was on a long term plan involving glucocorticoids. The owner thinks the dog doesn’t want to pay to continue the glucocorticoid treatment. Why is this a bad idea?

Answer 16

Sudden stoppage of glucocorticoid treatment causes iatrogenic Addison’s because the atrophied adrenals have not had enough time to respond. When stopping steroid use, must wean off slow

Question 17

What would you expect to see if you gave an Addison’s patient an ACTH stimulation test?

Answer 17

flat line

Question 18

What kind of supportive care should you give a patient with Addison’s?

Answer 18

heat, IV with saline fluids, emergency hyperkalemia treatment (calcium gluconate), insulin with dextrose, bicarbonate because will likely see metabolic acidosis

Question 19

What is ideal treatment for acute Addisonian crisis?

Answer 19

restore blood volume rapidly (0.9% NaCl IV)
address life threatening hyperkalemia: shock dose fluids then insulin/glucose, calcium gluconate or bicarb if necessary
give glucocorticoids: dexamethasone
give mineralocorticoids: DOCP/fludricortisone

Question 20

Two strategies for maintenance therapy of Addison’s

Answer 20

Percorten (DOCP) - injectable, slow release of mineralocorticoid, Q25d, no glucocorticoid activity
Florinef (fludrocortisone) - oral, daily, some glucocorticoid activity

Question 21

T/F: glucocorticoids for maintenance are required by all Addison’s patients

Answer 21

False

Question 22

T/F: hypoadrenocorticism is common in cats

Answer 22

false, rare