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Flashcards in Cushings/Addisons Deck (104):
1

What does the cortex of the adrenal gland do

Produces the glucocorticoid cortisol and aldosterone

2

What does the cortex of the adrenal gland do

Produces the glucocorticoid cortisol and aldosterone

3

What does the medulla of the adrenal gland do

Secretes as epinephrine or adrenaline

4

What is the function of aldosterone

Aldosterone acts on renal tubes to preserve and reabsorb Sodium and excrete Potassium

5

What are the 3 types of cushion's disease

1. Pituitary tumor
2. Adrenal gland tumor
3. Iatrogenic

6

Why does a pituitary tumor cause cushings disease

Pituitary tumor (adenoma) produces excess ACTH  overstimulates the adrenal gland  xs cortisol

7

What does the hypothalamus produce

Corticotropin releasing factor

8

What does the corticotropin releasing factor do to the pituitary gland

Causes the pituitary to release ACTH.

9

What is ACTH

Adrenocorticotropic hormone

10

What does ACTH do in the body

Causes adrenal growth and secretion.

11

What does the adrenal gland produce

Cortisol (glucocorticoid)

12

What effect does cortisol have on the body

Inhibits CRF and ACTH by means of negative feedback

13

What are the hormones released by the Anterior pituitary gland

Thyroid, adrenal, ovary, teste

14

What are the hormone released by Posterior pituitary

Oxytocin, vasopressin (ADH)

15

What does a brain or pituitary tumor do

Causes excess ACTH --> Secondary bilateral adrenal hyperplasia --> excess cortisol

16

What does the adrenal gland tumor do

Other adrenal will become hypoplastic and unilateral,

17

What are the 3 types of excess cortisol hyperadrenocorticism

1. Brain or pituitary tumor
2. Adrenal gland tumor
3. Iactrogenic

18

Describe pituitary dependant cushings disease

Up to 90% of all Cushing's cases in dogs fall into this category.
It is slow growing cancer called an adenoma ( pituitary).
This causes secretion of excess ACTH.
The adrenal glands respond to this excess ACTH by enlarging and secreting excess cortisol.

19

Describe non-pituitary dependent cushings disease

In up to 15% of Cushing's there is an actual tumor of one of the adrenal glands (sometimes both are involved). It enlarges and secretes excess cortisol in the bloodstream.
The benign version of this tumor occurs 50% of the time, and is called an adenoma.
The malignant version, which occurs the other 50% or the time, is called an adenocarcinoma. It can spread from the adrenal gland to the liver, lung, kidney, and lymph nodes.

20

Describe iatrogenic cushings disease

Long term use of supplemental cortisone, in oral, injectable, or even topical form, might cause an animal to have the symptoms of Cushing's disease.
i.e. Long term use of Drug prednisone. will cause the adrenal glands to shrink in size. This is because the negative feedback loop tells the brain there is plenty of cortisol in the bloodstream, so the pituitary secretes less ACTH.

21

What does Iatrogenic hyperadrenocorticism

exogenous excess cortisone atrophied adrenal glands

Sudden withdrawal results in Addisonian crisis

22

What are the clinical signs of cushings disease

Polyphagia- excess appetite.
Polyuria/polydypsia (PU/PD)-
Pot bellied abdomen.

Thin skin and usually symmetrical hair loss along the trunk. The hair might grow in lighter in color or even be hyperpigmented. Secondary skin infections are common.
Other symptoms could include lethargy, muscle wasting, poor appetite, weakness, and behavioral changes. 

23

Describe the signalment of cushings diease

Cushing's tends to be a problem that affects older dogs, usually greater than 10 years of age. The disease tends to have a slow and gradual onset, so the early symptoms are easily missed.

24

What are the breed dispositions of cushings disease

Yorkshire Terrier
Poodle
Beagle
Boston Terrier
Boxer
Dachshund

25

How do you diagnose cushings

CBC might show an increased WBC and an eosinopenia ( cortisol)
BIOCHEM
******elevated alkaline phosphatase (Alk Phos) ****
maybe elevation Cholesterol
Urinalysis
Low sp .gravity often

26

What does the urine cortisol/creatinine ratio show

is a screening test for Cushing's disease;
a positive test here does NOT confirm Cushing's syndrome but a negative test DOES rule it out.
If there is a high ratio - a relatively high amount of cortisol being excreted - further testing is in order.
Ideally for this test the urine sample is collected at home so that cortisol secreted in response to the stress of visiting the vet's office does not interfere with results.

27

Specific diagnostic tests for cushings

ACTH Stimulation test

Low Dose Dexamethasone Suppression Test (LDDS) 

High Dose Dexamethasone Suppression Test (HDDS)

28

How do you treat a pituitary tumor

give drugs that will partially destroy or prevent the adreanal gland from secreting excess cortisone
Mitotane (o,p'-DDD) Lysodren,
L-Deprenyl (anipryl)
Ketaconazole

29

How do you treat an adrenal tumor

can do surgery or use above drugs

30

What is Hypoadrenocorticism
 or Addison’s dse

Cortisone and a mineralocorticoid deficiency (aldosterone)
Atrophy of adrenal cortex
Results in decrease of glucocorticoids (cortisone) and mineralocorticoids (aldosterone)

31

What are the clinical signs of addison disease

32

What are the clinical signs of addison disease

33

What does the medulla of the adrenal gland do

Secretes as epinephrine or adrenaline

34

What is the function of aldosterone

Aldosterone acts on renal tubes to preserve and reabsorb Sodium and excrete Potassium

35

What are the 3 types of cushion's disease

1. Pituitary tumor
2. Adrenal gland tumor
3. Iatrogenic

36

Why does a pituitary tumor cause cushings disease

Pituitary tumor (adenoma) produces excess ACTH  overstimulates the adrenal gland  xs cortisol

37

What does the hypothalamus produce

Corticotropin releasing factor

38

What does the corticotropin releasing factor do to the pituitary gland

Causes the pituitary to release ACTH.

39

What is ACTH

Adrenocorticotropic hormone

40

What does ACTH do in the body

Causes adrenal growth and secretion.

41

What does the adrenal gland produce

Cortisol (glucocorticoid)

42

What effect does cortisol have on the body

Inhibits CRF and ACTH by means of negative feedback

43

What are the hormones released by the Anterior pituitary gland

Thyroid, adrenal, ovary, teste

44

What are the hormone released by Posterior pituitary

Oxytocin, vasopressin (ADH)

45

What does a brain or pituitary tumor do

Causes excess ACTH --> Secondary bilateral adrenal hyperplasia --> excess cortisol

46

What does the adrenal gland tumor do

Other adrenal will become hypoplastic and unilateral,

47

What are the 3 types of excess cortisol hyperadrenocorticism

1. Brain or pituitary tumor
2. Adrenal gland tumor
3. Iactrogenic

48

Describe pituitary dependant cushings disease

Up to 90% of all Cushing's cases in dogs fall into this category.
It is slow growing cancer called an adenoma ( pituitary).
This causes secretion of excess ACTH.
The adrenal glands respond to this excess ACTH by enlarging and secreting excess cortisol.

49

Describe non-pituitary dependent cushings disease

In up to 15% of Cushing's there is an actual tumor of one of the adrenal glands (sometimes both are involved). It enlarges and secretes excess cortisol in the bloodstream.
The benign version of this tumor occurs 50% of the time, and is called an adenoma.
The malignant version, which occurs the other 50% or the time, is called an adenocarcinoma. It can spread from the adrenal gland to the liver, lung, kidney, and lymph nodes.

50

Describe iatrogenic cushings disease

Long term use of supplemental cortisone, in oral, injectable, or even topical form, might cause an animal to have the symptoms of Cushing's disease.
i.e. Long term use of Drug prednisone. will cause the adrenal glands to shrink in size. This is because the negative feedback loop tells the brain there is plenty of cortisol in the bloodstream, so the pituitary secretes less ACTH.

51

What does hypothyroidism do

inadequate active thyroid hormone
most common hormone imbalance of the dog. 
In Dogs:
T3 is the active form
T4 is the inactive form
When T4 is absorbed into tissue cells, it is converted into T3

52

What are the clinical signs of cushings disease

Polyphagia- excess appetite.
Polyuria/polydypsia (PU/PD)-
Pot bellied abdomen.

Thin skin and usually symmetrical hair loss along the trunk. The hair might grow in lighter in color or even be hyperpigmented. Secondary skin infections are common.
Other symptoms could include lethargy, muscle wasting, poor appetite, weakness, and behavioral changes. 

53

Describe the signalment of cushings diease

Cushing's tends to be a problem that affects older dogs, usually greater than 10 years of age. The disease tends to have a slow and gradual onset, so the early symptoms are easily missed.

54

What are the breed dispositions of cushings disease

Yorkshire Terrier
Poodle
Beagle
Boston Terrier
Boxer
Dachshund

55

How do you diagnose cushings

CBC might show an increased WBC and an eosinopenia ( cortisol)
BIOCHEM
******elevated alkaline phosphatase (Alk Phos) ****
maybe elevation Cholesterol
Urinalysis
Low sp .gravity often

56

What does the urine cortisol/creatinine ratio show

is a screening test for Cushing's disease;
a positive test here does NOT confirm Cushing's syndrome but a negative test DOES rule it out.
If there is a high ratio - a relatively high amount of cortisol being excreted - further testing is in order.
Ideally for this test the urine sample is collected at home so that cortisol secreted in response to the stress of visiting the vet's office does not interfere with results.

57

Specific diagnostic tests for cushings

ACTH Stimulation test

Low Dose Dexamethasone Suppression Test (LDDS) 

High Dose Dexamethasone Suppression Test (HDDS)

58

How do you treat a pituitary tumor

give drugs that will partially destroy or prevent the adreanal gland from secreting excess cortisone
Mitotane (o,p'-DDD) Lysodren,
L-Deprenyl (anipryl)
Ketaconazole

59

How do you treat an adrenal tumor

can do surgery or use above drugs

60

What is Hypoadrenocorticism
 or Addison’s dse

Cortisone and a mineralocorticoid deficiency (aldosterone)
Atrophy of adrenal cortex
Results in decrease of glucocorticoids (cortisone) and mineralocorticoids (aldosterone)

61

What is the free T4

Most of the circulating T4 is carried by blood proteins and is not available for tissue absorption;
the portion that is not carried by proteins (the so-called “free T4”)
free T4 is the portion that is able to enter tissues for activation

62

What are the clinical signs of addison disease

63

What is an addison crisis

Medical Emergency—
Presents with sudden weakness, vomiting, diarrhea
Low Na- causes a drastic drop in Blood pressure
High K - heart problems
Hypovolumemic – symptoms of shock

64

How do you treat an addison crisis

Crisis- fluids– Normal Saline
Replace Na (do not want K)

Cortisone- prednisone or dexamethasone

65

What is the treatment for addisons

Percoten V - monthly injections,

Florinef- tablets

66

How do you diagnose addison disease

Pre treatment Blood work: electrolyte imbalance
Na:K -- less than 27:1
Often pre renal increase in BUN CREAT
High BUN in absence of Kidney dse

67

How do you confirm the diagnosis of addison disease

ACTH stimulation test to confirm addisons

68

What is an ACTH sim test used for

used To dx Addison's or Cushing’s
Evaluates the degree of adrenal response to exogenous ACTH

69

What hyperplastic adrenal gland do

Exaggerated response indicates cushings

70

What does a hypo plastic adrenal gland do

Diminished response indicates addisons

71

What is Low dose dexamethasone Suppression test

Replaces the ACTH test - to diagnose cushings

72

What is High dose Dex. Suppression test

helps to distinguish if it’s a pituitary or adrenal tumor

73

What dexamethasone suppression test is used for cats

use only in the high dose test

74

What is the LDDST Protocol

Patient fasted before collection.
i) Collect blood into a plain or SST for a baseline cortisol
ii) Administer 0.01 mg/kg off dexamethasone IV

iii) Collect post-dexamethasone blood into a plain or SST at both 4 hours and 8 hours post-dexamethasone administration

75

What are the results of LDDST

In the normal animal blood cortisol level will drop after a tiny dose of dexamethasone is given
If there is a pituitary tumor, it will not turn off its stimulatory message and it ignores the dexamethasone. There is No drop in cortisol level is seen at the end of eight hours
Adrenal tumor will not suppress either

76

How does the low dose/high dose work

Normally dexamethasone  suppress ACTH decreased cortisol
Pituitary tumor does not suppress to a low dose dex, but will suppress to a high dose dex– ( results in lower cortisol levels)
Adrenal gland tumor pumps out cortisol regardless of ACTH  NO Suppression by large dose dex
High dose dex suppression test will distinguish between the adrenal and pituitary cause of cushing’s

77

Why can't we measure ACTH

Very labile protein– requires special handling for sample—and immediate freezing of the plasma

78

What does a pituitary tumor cause

HIGH ACTH

79

What does an adrenal tumor

LOW ACTH

80

What does the thyroid gland produces

T4 Thyroxine
T3 Tri-iodothyronine

81

What do T3 and T4

These hormones regulate metabolism of all tissues and organs

82

What does hypothyroidism do

inadequate active thyroid hormone
most common hormone imbalance of the dog. 
In Dogs:
T3 is the active form
T4 is the inactive form
When T4 is absorbed into tissue cells, it is converted into T3

83

What causes hypothyroidism

immune-mediated destruction of the thyroid gland,
natural atrophy of the gland,
dietary iodine deficiency, (Goiter)
a congenital problem

84

What are the breeds predisposed to hypothyroidism

the Doberman pinscher,
the Golden retriever,
the Irish Setter,
the Great Dane,
the Dachshund,
the Boxer

85

What are the clinical signs of hypothyroidism

Weight gain without an increase in appetite
Lethargy and lack of desire to exercise
Cold intolerance (gets cold easily)
Dry, dull hair with excessive shedding and flaking
Very thin to nearly bald hair coat
Increased dark pigmentation in the skin
Increased susceptibility and occurrence of skin and ear infections
Failure to re-grow hair after clipping or shaving
High blood cholesterol
Slow heart rate

86

What is hypothyroidism

biochemistry panel might show an elevated cholesterol ( 75% of time)

CBC mild non responsive anemia

May see target cells due to cholesterol deposits on RBC membrane

87

What is the physiology of hypothyroidism

(Hypothalmus)  TRF  pituitary (TSH) - thyroid gland  T3 +T4 (triiodothyronine and thyroxine)

All of the T4 is produced by thyroid
T4 can be converted to converted to T3 at the tissue level
Most T4 + T3 in blood is protein bound
fT4 freeT4 enters the cell and is converted to T3

88

Describe the Pituitary gland

pituitary gland --. TSH
When T4 levels are dropping, the pituitary gland sends out TSH--stimulates the thyroid gland to make and release more T4.

You expect to have a high TSH in a hypothyroid dog

89

What is the total T4 screening test

Often part of a geriatric profile

90

What is the free T4 by equilibrium dialysis

Can be a more specific test

91

Do we ever do TSH and T4 together

Yes

92

What is the free T4

Most of the circulating T4 is carried by blood proteins and is not available for tissue absorption;
the portion that is not carried by proteins (the so-called “free T4”)
free T4 is the portion that is able to enter tissues for activation

93

What is Euthyroid sick

Many chronic illnesses will cause an animal to have a low T4 and he is not hypothyroid

94

What is the TSH response test

Many diseases and drugs can suppress T4 levels-- this test is more sensitive

95

How do you do the TSH response test

Draw Pre-test blood sample
– give TSH
Draw post-test blood samples 4-6 hrs later
Normal dogs or euthryoid sick dogs should show increased T4
Hypothyroid dog shows no increase

96

What are the two other hypothyroid tests

TRH- thyrotropin –Releasing Hormone Response test

Triiodothyronine Suppression test

97

Monitoring thyroid treatment

Monitoring with T4
Monitoring with +/- TSH level

98

How do you know if diagnosis correct

to repeat test:
thyroid hormone supplementation must be discontinued at least 2 months for blood testing to be valid

99

What is hyperthyroidism

Caused by benign tumor (adenoma) on the thyroid gland excess of amounts of T3 and T4.

These adenomas are not under the control of TSH

100

What are the clinical signs of hyperthyroidism

Weight loss
Excess appetite (polyphagia)
Decreased appetite (anorexia)
Nervousness , vocalization
Muscle weakness
Vomiting (emesis)
Diarrhea
Excess drinking and urinating (polyuria and polydipsia)
Poor hair coat
High heart rate (tachycardia) ( 200-300bpm) - gallop rhythm
Labored breathing (dyspnea)

101

What are the secondary complications of hyperthyroidism

thyrotoxic cardiomyopathy

Hypertension (high blood pressure)
If left untreated there are significant complications that can develop. Blindness can occur due to retinal detachment from high blood pressure.
Long term kidney damage and non-stop diarrhea might also be consequences, along with heart failure and death.

102

What are the elevated enzymes in a biochem panel

Elevated liver enzymes on biochem panel- ALT AST

103

How do you diagnose hyperthyroidism

Routine geriatric biochemistry

Total T4 is very elevated

Sometimes if T4 is normal and Hyperthyroidism is suspected the free T4 by equilibrium dialysis will be done

104

What are the 4 treatment hyperthyroidism

Radioactive Iodine

Tapazole (Methimazole) - monitor T4 levels

Surgery (thyroidectomy)

Y/D diet from Hills ( has no iodine)- monitor T4 levels