Endocrinology - Hypoadrenocorticism Flashcards Preview

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Flashcards in Endocrinology - Hypoadrenocorticism Deck (67)
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1
Q

What are the regions of the adrenal cortex?

A

Zona glomerulosa, zona fasciculata, and zona reticularis

2
Q

What does the zona glomerulosa secrete?

A

mineralocorticoids - think salt

3
Q

What does the zona fasiculata secrete?

A

glucocorticoids - think sugar

4
Q

What does the adrenal medulla secrete?

A

catecholamines

5
Q

What does a deficiency in aldosterone (mineralcorticoid) result in?

A

Hypoadrenocorticism (Addison’s disease)

6
Q

What does an excess of cortisol (glucocorticoid) result in?

A

Hyperadrenocorticism (Cushing’s)

7
Q

What does a deficiency in cortisol (glucocorticoid) result in?

A

Hypoadrenocorticism (Addison’s disease)

8
Q

What stimulates the production and release of glucocorticoids from the adrenal cortex?

A

ACTH

9
Q

What provides negative feedback on the pituitary gland to stop secreting ACTH?

A

Cortisol

10
Q

What provides negative feedback on the hypothalamus to stop secretion of CRH?

A

ACTH and cortisol

11
Q

What are the actions of glucocorticoids?

A

Antagonize the effects of insulin, stimulate appetite, maintain normal blood pressure/vascular tone, and maintain normal GI perfusion, motility, and mucosal integrity

12
Q

If there is a deficiency in glucocorticoids, what is the consequence of the decreased antagonistic effect on insulin?

A

hypoglycemia

13
Q

If there is a deficiency in glucocorticoids, what is the consequence of decreased appetite stimulation?

A

anorexia

14
Q

If there is a deficiency in glucocorticoids, what is the consequence of decreased BP/vascular tone maintenance?

A

hypotension

15
Q

If there is a deficiency in glucocorticoids, what are the consequences of altered maintenance in GI perfusion, motility, and mucosal integrity?

A

Vomiting, diarrhea, and weight loss

16
Q

What is aldosterone secreted in response to?

A

Hyponatremia, hypotension, hypovolemia, hyperkalemia, and ACTH (minor role)

17
Q

What chemical stimulates aldosterone secretion and from where is aldosterone secreted?

A

Angiotensin; aldosterone is secreted from the adrenal glands

18
Q

How does aldosterone correct a drop in ECF/Na/BP?

A

It stimulates renal sodium conservation so that water is passively reabsorbed with sodium and the net result is an increase in ECF volume

19
Q

How does aldosterone correct hyperkalemia?

A

It stimulates renal potassium excretion which results in blood K levels to decrease

20
Q

What are the actions of aldosterone?

A

Renal excretion of potasisum, renal conservation of sodium, and renal excretion of hydrogen ions

21
Q

If there is a deficiency in aldosterone, how is renal excretion of potassium effected?

A

hyperkalemia

22
Q

If there is a deficiency in aldosterone, how is renal conservation of sodium effected?

A

Hyponatremia (+PU/PD)

23
Q

If there is a deficiency in aldosterone, how is renal excretion of hydrogen ions effected?

A

Metabolic acidosis

24
Q

What are the two forms of hypoadrenocorticism?

A

Primary and secondary

25
Q

What is affected in primary hypoadrenocorticism?

A

the adrenal gland

26
Q

What is affected in secondary hypoadrenocorticism?

A

the pituitary gland

27
Q

Is primary or secondary hypoadrenocorticism more common?

A

primary

28
Q

What physiologically causes primary hypoadrenocorticism?

A

There is a loss of functional adrenal cortical tissue - 85-90% loss before CS

29
Q

What physiologically causes secondary hypoadrenocorticism?

A

Loss of ACTH stimulation to the adrenal gland

30
Q

What are the two main etiologies of primary hypoadrenocorticism?

A

Immune-mediated disease and idiopathic atrophy and fibrosis

There are many other causes - basically anything that can injure the adrenal gland in any way can be a cause

31
Q

Typically, are males or females more prone to getting primary hypoadrenocorticism?

A

Females

32
Q

Typically, what breed of dogs are more prone to getting primary hypoadrenocorticism?

A

Mixed medium to larger breed dogs

33
Q

Typically, at what age is primary hypoadrenocorticism diagnosed?

A

at a younger age

34
Q

What breed of dogs possibly have a genetic predisposition to acquiring primary hypoadrenocorticism?

A

Standard poodle, portugese water dog, Nova Scotia duck tolling retriever, and Bearded collies

35
Q

Hypoadrenocorticism has no pathognomonic signs which is why it is known as the ______ _______.

A

great imitator

36
Q

What PE exam findings are consistent with hypoadrenocorticism?

A

Dehydration, bradycardia, poor peripheral pulse quality, melena/hematochezia, hypothermia, and abdominal pain (rare)

37
Q

What CBC findings are consistent with hypoadrenocorticism?

A

Lack of a stress leukogram, eosinophilia, and lymphocytosis

38
Q

What chemistry findings are consistent with hypoadrenocorticism?

A

Hypoglycemia, hyperkalemia, hyponatremia, metabolic acidosis, azotemia, hypocholesterolemia, hypoalbuminemia, and hypercalcemia

39
Q

What does a stress leukogram look like?

A
Segs
Monocytes
Increased
Lymphocytes
Eosinophils
Decreased
40
Q

What is a classic finding (chemistry) in cases of hypoadrenocorticism?

A

Combined hyponatremia and hyperkalemia as the result of aldosterone deficiency

41
Q

How is hypoadrenocorticism diagnosed?

A

ACTH stimulation test

42
Q

What is the procedure for a ACTH stimulation test?

A

Collect baseline serum cortisol, then administer ACTH, and then collect a second serum cortisol sample an hour after cortisol administration

43
Q

What will the result of ACTH stimulation test be in a healthy dog? An addisonian dog?

A

In a healthy dog, the post cortisol level should be elevated. In an addisonian dog, the cortisol level will remain the same.

44
Q

What does the ACTH stimulation test test for?

A

adrenal reserve

45
Q

What will an exaggerated cortisol increase after ACTH indicate?

A

Hyperadrenocorticism (Cushing’s)

46
Q

What basal cortisol level helps rule out hypoadrenocorticism?

A

a level of >2.0 micrograms/dl

47
Q

What can interfere with an ACTH stimulation test?

A

Exogenously administered steroids because they can suppress normal adrenal glands or cross-react and be measured as cortisol

48
Q

How is hypoadrenocorticism treated?

A

Hormone replacement therapy - Glucocorticoids or mineralcorticoids

49
Q

When using glucocorticoid replacement therapy for hypoadrenocorticism treatment, what should you inform the clients about?

A

Make sure they know the clinical signs associated with deficiency and excess glucocorticoids

50
Q

What are the injectable forms of mineralcorticoid hormone replacement?

A

Percortin or Zycortal

51
Q

What is the oral form of mineralcorticoid hormone replacement?

A

Florinef

52
Q

When should you recheck a patient after starting treatment for hypoadrenocorticism?

A

10-14 days and 25-28 days

53
Q

What should be done at the 10-14 day recheck in an Addisonian patient?

A

Weight, physical exam, renal panel, and electrolyte levels

54
Q

What should be done at the 25-28 day recheck in an Addisonian patient?

A

Weight, physcial exam, renal panel, electrolyte levels - redose DOCP

55
Q

When adjusting mineralcorticoids at recheck appointments, what dose should you adjust to?

A

The lowest dose or the longest interval that keeps electrolytes normal

56
Q

When adjusting prednisone at recheck appointments, what dose should you adjust to?

A

you want to adjust it to as needed based on clinical response

57
Q

What is an Addisonian crisis?

A

Severe, acute manifestation of hypoadrenocorticism

58
Q

What clinical manifestations are associated with an Addisonian crisis?

A

Hypotension, hypovolemia, electrolyte imbalances, hypoglycemia, and severe GI signs

59
Q

What is the most important treatment for patients in an Addisonian crisis?

A

IV fluids

60
Q

What other treatments should be done in patients with Addisonian crisis?

A

Dextrose if the patient is hypoglycemic, emergency management of hyperkalemia, symptomatic supportive care, and address any complicaitons

61
Q

In patients in Addisonian crisis, when is glucocorticoid replacement given?

A

Ideally once the ATCH stimulation test is complete

62
Q

When is it indicated to use dexamethasone in patients in Addisonian crisis/

A

It should be used if glucocorticoids must be given prior to completion of ACTH stimulation test

63
Q

What is the prognosis for patients with hypoadrenocorticism?

A

Excellent with committed owners but it can be expensive

64
Q

What is ‘atypical’ Addison’s disease?

A

Glucocorticoid deficiency only with normal electrolytes and mineralcorticoid levels

65
Q

What clinical signs are associated with atypical addisonian disease?

A

GI signs and decreased appetitie

66
Q

How is atypical addisonian disease diagnosed?

A

ACTH stimulation test and normal electrolyte levels

67
Q

What is the therapy of choice for atypical addisonian disease?

A

glucocorticoid replacement

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