Hypoadrenocorticism

Question 1

Define CIRCI

Answer 1

= critical illness-related corticosteroid insufficiency

Question 2

What is CIRCI?

Answer 2

• relates to management of ‘pressor resistant septic shock’

Question 3

Why do you get adrenal haemorrhage with hypoadrenocorticism?

Answer 3

Adrenal haemorrhage d/t increased ACTH

Question 4

2 forms of hypoadrenocorticism

Answer 4

• TYPICAL where’re reduced capacity to produce cortisol and aldosterone
• ATYPICAL where a proportion of cases have no electrolyte abnormalities

Question 5

Breeds - hypoadrenocorticism

Answer 5

• standard poodles
• bearded collies
• leonburgers
• NSDT retrievers

Question 6

Clinical pictures of hypoadrenocorticism

Answer 6

2 broad categories:

1. ) acutely collapsed severely compromised patient
2. ) variable subtle, unwell animal, has a waxing and waning presence

Question 7

CS - acute hypoadrenocorticism

Answer 7

• NON-SPECIFIC
• waxing and waning
• lethargy, depression, under responsive
• reduced enthusiasm to exercise
• weakness
  
  • inappetance
• vomiting and or diarrhoea
• Melena (structural secondary gut disease)
• heart rate usually unaffected though occasionally bradycardic (

Question 8

Clinical pathology suggestive of hypoadrenocorticism

Answer 8

• mild to moderate anaemia (non regenerative and or regenerative)
• hypoproteinaemia (or normoproteinaemic in hypovolaemic patient)
• eosinophilia and/or lymphocytosis or lack of a stress leukogram
• hyponatraemia and or hyperkalaemia (some people talk about a ratio between these two. If Na/K is

Question 9

Clinical pathology - hypoadrenocorticism (typical form)

Answer 9

Absence of stress leukogram and either hyponatraemia or hyperkalaemia or both (decreased Na:K ratio)

Question 10

Desvribe clinical pathology of atypical hypoadrenocorticism

Answer 10

Absence of a stress leukogram and normal Na and K levels.

Question 11

What can over diagnosis of hypoadrenocorticism lead to?

Answer 11

• exacerbation of already compromised organs
• protracted period of administration of inappropriate medicines with adverse effects
• once on these meds it is very difficult to investigate things further

Question 12

Dx - hypoadrenocorticism

Answer 12

• ACTH stimulation test with demonstration of subnormal levels of cortisol before and after ACTH as well as confidence at no prior glucocorticoid therapy could be interfering with test results
• basal cortisol measurement will give an indication but not definitive answer (if >30mmol then hypoadrenocorticism is unlikely but this is not definitive)

Question 13

Treating acute presentation of hypoadrenocorticism

Answer 13

• supportive fluids (not too much as particularly fluid sensitive). 0.9% NaCl, absolutely no more than 7-8ml/kg/hour.
• hormone suuplementation: PN administration, similar degrees of GC and MC activity. Use hydrocortisone sodium succinate.
• when hydrocortisone is infused IV at 0.5mg/kg/h the amount of cortisol present in circulation provides adequate amounts of GC and MC for seriously stressed dogs

Question 14

Outline hydrocortisone as tx of hypoadrenocorticism

Answer 14

• PN route
• 0.5mg/kg/h IV infusion
• equal GC and MC bioactivity
• short half-life
• simple, physiological
• effective

Question 15

Tx - chronic hypoadrenocorticism

Answer 15

• ** fludrocortisone (GC and MC) OR:
• deoxycorricosterone pivalate (USA only)
• 50% cases need GC supplementation (cortisone acetate or prednisolone)
• diet (add salt)

Question 16

Chronic clinical picture - tx principles

Answer 16

• subacute patient with varyingly severe CS featuring # o fdifferent body systems, including:
• GIT (structural gut dz, IBD biopsies)
• NMS (weakness, lethargy)
• indicators of renal dysfunction (azotaemia and inaapropriately dilute urine
• TX: = appropriately balanced GC and MC activity

Question 17

What is the correct GC dose for chronic hypoadrenocorticism ?

Answer 17

• normal adrenal production in dog (0.2mg/kg/24hr cortisol)

- prednisolone has 5 times GC activity of cortisol

Question 18

With fluorinef (= fludrocortisone), do you need a GC?

Answer 18

• 10-15microg/kg/24 hours
• 15x GC potency of cortisol so theoretically almost enough GC for general maintenance
• supplement with least potent GC (cortisone acetate, 0.5mg/kg/12h for 5 days then 0.5mg/kg/24 hr)

Question 19

What if dog has no indications of an electrolyte problem?

Answer 19

Perform aldosterone extimates on ACTH test samples BUT cost and assay considerations. Usually tx with GC only.

Question 20

Monitoring hypoadrenocorticism efficacy

Answer 20

• clinical response paramount
• GC activity evaluated by leukogram
• MC activity evaluated by Na and K levels
• don’t do ACTH stim test or basal ACTH test to evaluate

Question 21

Pathophysiology - hypoadrenocorticism

Answer 21

• results in marked adrenolysis
• often I-M
• destruction results in diminished adrenocortical reserve: reduced capacity to produce cortisol and aldosterone, may or may not be clinically signficant, proportion of cases have no electrolyte abnormalities

Question 22

T/F: confirm dx of hypoadrenocorticism with an ACTH stim test BEFORE use of cross-reacting GCs

Answer 22

True (otherwise test interference)

Question 23

T/F: once stable, minimise GC excess by using cortisone in small dogs

Answer 23

True