Hypoadrenocorticism Flashcards
What are the parts of the adrenal gland?
Outer - zona glomerulosa - mineralocorticoids
Middle - zona fasiculata - glucocorticoid
Inner - zona reticularis - glucocorticoid
What is the pathway for cortisol production
Hypothalamus releases CRH
Pituitary releases ACTH
Adrenal - cortisol
What types of hypoadrenocorticism are there?
Primary
most common = immune mediated destruction of the adrenals
mitotane/ trilostane therarpy
Secondary
Due to pituitary disease or rapid withdrawl of steroids
What is the common signalment of an addisons case?
F>M
young to middle aged
Any bredd possible, more common in poodles, bearded collies, WHWTs, spaniels
What are the main c/s of hypoadrenocorticism?
Lethargy (most) Dehydration (few) GI signs (most) GI bleeding (few) Trembling (few)
How does an acute case present?
Collapse
Hypovolaemia/ bradycardia
V/D/ abdo pain
How does a chronic case present?
Waxing/ waning Often responds to IVFT Chronic GI signs Bradycardia PUPD Mego oesophagus?
What happens when there are low mineralocorticoids?
Low Na and Cl
High K
Hypovolaemia/ poor perfusion
Loss of Na in urine -> PUPD
What happens where there are low glucocorticoids?
Inappetence Abnormal GI mucosal barrier Susceptible to stress Anaemia Hypoglycaemia
What may you seen on haematology with hypoadrenocorticism?
In acute - high PCV
In chronic - mild non regenerative anaemia
Lack of stress leukogram
What may you see on biochemistry with hypoadrenocorticism?
In ?90% cases - Low Na and Cl with high K
Azoataemia (urea> crea) in 90%
some have high Ca
Mild hypoglycaemia in few
What may you see with USG?
Low
What may you see on rads with hypoadrenocorticism?
Evidence of hypoperfusion
Could possibly see oesophagus changes
What is the rule out test for hypoadrenocorticism?
Basal cortisol - >55 nearly definitely not
If still think it may be then still do ACTH stim
What are the aims of treatment in an acute crisis?
Restore fluids
Correct lytes
Replace glucocorticoids
Mineralocorticoids can be addressed once rest is done
Outline IVFT in an acute crisis
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
What is the initial steroid of choice in a crisis?
dexamethasone 0.1-0.2mg/kg IV SID
What is hydrocortisone sodium succinate?
has both glucocorticoid and mineralocorticoid activity
use reduces hospital stay
may cause too rapid an increase in Na - care
How do you monitor an acute patient?
HR, BP, demeanour, lytes ideally QID, glucose, PCV
What is the treatment for chronic management?
DOCP - zycortal
Prednisolone 0.1-0.2mg/kg
how do you monitor zycortal?
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
How do you monitor the use of glucocorticoids
clinical signs
How much do you increase the dose for in times of stress?
2-4x
Outline the use of fludrocortisone
Pred not needed as has both actions
CASCADE
Monitor Na and K pre pill and 4-6hr post pill
What is true atypical addisons?
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
