Hypoadrenocorticism

Question 1

What are the parts of the adrenal gland?

Answer 1

Outer - zona glomerulosa - mineralocorticoids
Middle - zona fasiculata - glucocorticoid
Inner - zona reticularis - glucocorticoid

Question 2

What is the pathway for cortisol production

Answer 2

Hypothalamus releases CRH
Pituitary releases ACTH
Adrenal - cortisol

Question 3

What types of hypoadrenocorticism are there?

Answer 3

Primary
most common = immune mediated destruction of the adrenals
mitotane/ trilostane therarpy

Secondary
Due to pituitary disease or rapid withdrawl of steroids

Question 4

What is the common signalment of an addisons case?

Answer 4

F>M
young to middle aged
Any bredd possible, more common in poodles, bearded collies, WHWTs, spaniels

Question 5

What are the main c/s of hypoadrenocorticism?

Answer 5

Lethargy (most)
Dehydration (few)
GI signs (most)
GI bleeding (few)
Trembling (few)

Question 6

How does an acute case present?

Answer 6

Collapse
Hypovolaemia/ bradycardia
V/D/ abdo pain

Question 7

How does a chronic case present?

Answer 7

Waxing/ waning
Often responds to IVFT
Chronic GI signs
Bradycardia
PUPD
Mego oesophagus?

Question 8

What happens when there are low mineralocorticoids?

Answer 8

Low Na and Cl
High K
Hypovolaemia/ poor perfusion
Loss of Na in urine -> PUPD

Question 9

What happens where there are low glucocorticoids?

Answer 9

Inappetence
Abnormal GI mucosal barrier
Susceptible to stress
Anaemia
Hypoglycaemia

Question 10

What may you seen on haematology with hypoadrenocorticism?

Answer 10

In acute - high PCV
In chronic - mild non regenerative anaemia
Lack of stress leukogram

Question 11

What may you see on biochemistry with hypoadrenocorticism?

Answer 11

In ?90% cases - Low Na and Cl with high K
Azoataemia (urea> crea) in 90%
some have high Ca
Mild hypoglycaemia in few

Question 12

What may you see with USG?

Answer 12

Low

Question 13

What may you see on rads with hypoadrenocorticism?

Answer 13

Evidence of hypoperfusion

Could possibly see oesophagus changes

Question 14

What is the rule out test for hypoadrenocorticism?

Answer 14

Basal cortisol - >55 nearly definitely not

If still think it may be then still do ACTH stim

Question 15

What are the aims of treatment in an acute crisis?

Answer 15

Restore fluids
Correct lytes
Replace glucocorticoids
Mineralocorticoids can be addressed once rest is done

Question 16

Outline IVFT in an acute crisis

Answer 16

Ideally saline
10-30ml/kg/hr for 2-3 hours
Then 2-3xm
Add dextrose if hypoglycaemic
Supp K may be needed once normal
May need to give Ca gluconate if K+ v high

Question 17

What is the initial steroid of choice in a crisis?

Answer 17

dexamethasone 0.1-0.2mg/kg IV SID

Question 18

What is hydrocortisone sodium succinate?

Answer 18

has both glucocorticoid and mineralocorticoid activity
use reduces hospital stay
may cause too rapid an increase in Na - care

Question 19

How do you monitor an acute patient?

Answer 19

HR, BP, demeanour, lytes ideally QID, glucose, PCV

Question 20

What is the treatment for chronic management?

Answer 20

DOCP - zycortal

Prednisolone 0.1-0.2mg/kg

Question 21

how do you monitor zycortal?

Answer 21

Check lytes day 10 to see if dose is high enough, and day 28 to check lasts long enough
2 months of all being in wnl, that is the maintenance dose.
then monitor q3-6m, consider also checking renal and haem
Adjust by 10-20% a time if needed

Question 22

How do you monitor the use of glucocorticoids

Answer 22

clinical signs

Question 23

How much do you increase the dose for in times of stress?

Answer 23

2-4x

Question 24

Outline the use of fludrocortisone

Answer 24

Pred not needed as has both actions
CASCADE
Monitor Na and K pre pill and 4-6hr post pill

Question 25

What is true atypical addisons?

Answer 25

Lytes normal
Cortisol low on stim, aldosterone wnl

if aldosterone low but lytes normal, then this is typical primary adidsons, with unknown mechanism causing lytes to be fine. In this case, either tx for normal hypoadrenocorticism, or just treat with preds and monitor lytes q3