Hypoadrenocorticism

Question 1

Where are mineralocorticoids (aldosterone) secreted from?

Answer 1

Zona glomerulosa

Question 2

Where are glucocorticoids (cortisol) secreted from?

Answer 2

Zona fasciculata

Question 3

What is primary hypoadrenocorticism due to?

Answer 3

Destruction/ infiltration of adrenal cortices

Question 4

How much of both glands must be destroyed before signs are apparent?

Answer 4

90%

Question 5

What is the most common cause of primary HOC?

Answer 5

Immune mediated destruction

Question 6

What is secondary HOC due to and what does it cause?

Answer 6

Lack of ACTH production
Very uncommon
Aldosterone production is unaffected
Signs reflect lack of cortisol

Question 7

What can cause iatrogenic HOC?

Answer 7

Abrupt withdrawal of exogenous steroids
Therapy for HC with trilostane or mitotane

Question 8

What are signs of cortisol deficiency?

Answer 8

Anorexia, vomiting, diarrhea, lethargy, depression, weight loss, abdominal pain

Question 9

What does aldosterone do?

Answer 9

Increase blood volume, grabs salt and water

Question 10

What are signs of aldosterone deficiency?

Answer 10

Weakness, hypotension, dehydration, pre-renal azotemia, cardiac consequences of hyperkalemia (bradycardia, irregular beats, sinus arrest)

Question 11

What is the common signalment for HOC?

Answer 11

young, female, breed predisposition (portuguese water dog, standard poodle, west highland terrier)
ANY DOG
Rare in cats

Question 12

What are the chief complaints for HOC?

Answer 12

ADR
Commonly suggests GI disease
The great pretender
Signs may be triggered by a stressful event
Most patients appear to have GI or renal disease

Question 13

What causes most dramatic signs?

Answer 13

Lack of aldosterone

Question 14

What are common CBC findings in patients with HOC?

Answer 14

anemia is common, lack of stress leukogram, eosinophilia is a classic marker for HOC

Question 15

Always consider HOC in a sick dog with eosinophils greater than

Answer 15

500

Question 16

What chem findings are common in patients with HOC?

Answer 16

Low sodium
High potassium
High phosphate
Low chloride
High calcium

Question 17

What sodium:potassium ratio is suggestive of HOC?

Answer 17

<1:27

Question 18

What chemistry changes will you see in a dog with lack of cortisol?

Answer 18

Hypoglycemia
Hypocholesterolemia
Hypoalbuminemia

Question 19

What chemistry changes will you see in a dog with lack of aldosterone?

Answer 19

Azotemia
Electrolyte changes

Question 20

What would you expect to see in a UA in a HOC patient?

Answer 20

Low urine specific gravity

Question 21

What additional changes might be seen on radiographs?

Answer 21

Microcardia
Pulmonary hypoperfusion
Megaesophagus

Question 22

What ultrasonic change might be seen on ultrasound?

Answer 22

Small adrenal glands (<3.7 mm)

Question 23

When should you consider HOC as a differential?

Answer 23

Patient has waxing and waning non-specific illness with anorexia and lethargy
Episodes of disease seem to be triggered by stressful events
Any patient with GI disease
Any patient with azotemia
Any patient with hyponatremia or hyperkalemia
Any patient with hypoglycemia

Question 24

What baseline cortisol is highly suggestive of HOC?

Answer 24

<2 mcg/dl

Question 25

When running an ACTH stim test, what post acth stim cortisol confirms HOC?

Answer 25

< 3 mcg/dl

Question 26

Dogs with primary HOC will have very low ____ and very high ____.

Answer 26

Very low cortisol
Very high ACTH

Question 27

What fluids does the NAVLE want for patients in an Addisonian crisis?

Answer 27

0.9% NaCl unless sodium is <130 mmol/L

Question 28

What are ways to manage hyperkalemia?

Answer 28

Bolus dextrose, beta agonists (Terbutaline, Albuterol), calcium gluconate (need ECG monitoring), insulin (LAST OPTION)

Question 29

What is a fast aldosterone replacement used to bridge before giving DOCP?

Answer 29

Fludocortisone

Question 30

What should be used for glucocorticoid replacement?

Answer 30

Prednisone (0.5-1 mg/kg/day)/prednisolone (0.3 mg/kg/day)
Taper down to lowest effective dose over 4 weeks

Question 31

What should be used for mineralocorticoid replacement?

Answer 31

DOCP SQ every 25 days
Not necessary unless serum electrolytes are abnormal

Question 32

When should patients be rechecked when given DOCP?

Answer 32

Day 12 and 25