Likelihood of Addison's in 2 nights?

RE: Likelihood of Addison's in 2 nights?

Andrew Kent — Thu, 14 Jan 2016 10:04:44 GMT

[quote user="Anthony Dennison"]

[quote user="Robin Grimmer"]

[quote user="Andrew Kent"]

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

[/quote]

So, turning this around, if you get an isolated normal cortisol presumably this rules hypoadrenocorticism out? - without having to do a full ACTH stim test, as suggested by Anthony D.

[/quote]

That's what I was told by Idexx when I was wondering whether I might have an early Addisonian dog (lethargy and weakness that only ever responded to steroids, and rapidly responded).

I guess it's the same as a urine cortisol:creatinine ratio being able to rule out hyperadrenocorticism with a low result.

[/quote]

Absolutely, a few people have looked at this over the last couple of years, 99-100% of dogs with hypoadrenocorticism will have a basal cortisol less than 55 nmol/L. So as a screening test in dogs with relatively low clinical suspicion of disease it can be a good option, and with the current expense of synthetic ACTH preparations is definitely a useful tool.

[quote user="Glen McIntosh"]So while I agree that low baseline cortisol can be a normal finding, and therefore non diagnostic for addisons in the "normal" animal, most of the animals we are testing for addisons aren't "normal", and so in those cases I would be taking that result fairly seriously and using it to direct treatment and doing an acth stim test asap.[/quote]

I agree with the theory but, interestingly, since I have been running a lot of basal cortisols I find a low level in a surprising number of 'sick' dogs, the theory with many of those dogs is that you can get adrenal exhaustion in sick dogs which might lower basal levels (the significance of that is unclear). So I do think you have to be carful with over-interpreting a low level.

It also depends on what you class as low - if you use <20 nmol/L (so below the readable range of most assays) then the number of normal dogs with that will be low (about 10% in the Bristol study). If you use 55 nmol/L then about 40% of those dogs will be normal.

This is the Bristol basal cortisol study if anybody is interested, its in JVIM so open access:

http://onlinelibrary.wiley.com/doi/10.1111/jvim.12415/abstract

Andy

RE: Likelihood of Addison's in 2 nights?

Anthony Dennison — Thu, 14 Jan 2016 09:28:49 GMT

[quote user="Robin Grimmer"]

[quote user="Andrew Kent"]

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

[/quote]

So, turning this around, if you get an isolated normal cortisol presumably this rules hypoadrenocorticism out? - without having to do a full ACTH stim test, as suggested by Anthony D.

[/quote]

That's what I was told by Idexx when I was wondering whether I might have an early Addisonian dog (lethargy and weakness that only ever responded to steroids, and rapidly responded).

I guess it's the same as a urine cortisol:creatinine ratio being able to rule out hyperadrenocorticism with a low result.

RE: Likelihood of Addison's in 2 nights?

Anthony Dennison — Thu, 14 Jan 2016 09:26:39 GMT

[quote user="Andrew Kent"]

The reason for doing a stim is that ACTH secretion (and therefore cortisol) is pulsatile with 6-12 daily peaks in most dogs (people have a defined diurnal rhythm but that has not been identified in dogs).

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

[/quote]

Thanks Andy, I will remember that for the future!

RE: Likelihood of Addison's in 2 nights?

Glen McIntosh — Thu, 14 Jan 2016 09:10:22 GMT

[quote user="Robin Grimmer"]

[quote user="Andrew Kent"]

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

[/quote]

So, turning this around, if you get an isolated normal cortisol presumably this rules hypoadrenocorticism out? - without having to do a full ACTH stim test, as suggested by Anthony D.

[/quote]

I think this is true.

Also, most of the animals that we suspect have addisons will be far from normal, usually vomiting and diarrhoea, often very sick and often collapsed/in shock. So a low baseline cortisol level would be unexpected and somewhat abnormal in these cases (unless it was actually addisons and therefore would make us very suspicious for addisons if not providing a definitive diagnosis). Whereas a normal or (more commonly) an elevated baseline cortisol would be the expected/normal finding in a sick animal with the type of presenting symptoms that would make us suspicious for addisons in the first place, and would definitively rule out addisons.

So while I agree that low baseline cortisol can be a normal finding, and therefore non diagnostic for addisons in the "normal" animal, most of the animals we are testing for addisons aren't "normal", and so in those cases I would be taking that result fairly seriously and using it to direct treatment and doing an acth stim test asap.

RE: Likelihood of Addison's in 2 nights?

Robin Grimmer — Thu, 14 Jan 2016 00:20:58 GMT

[quote user="Andrew Kent"]

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

[/quote]

So, turning this around, if you get an isolated normal cortisol presumably this rules hypoadrenocorticism out? - without having to do a full ACTH stim test, as suggested by Anthony D.

RE: Likelihood of Addison's in 2 nights?

Kate Richardson — Wed, 13 Jan 2016 23:31:02 GMT

i guess we may never know

just interesting musing

RE: Likelihood of Addison's in 2 nights?

Andrew Kent — Wed, 13 Jan 2016 23:05:47 GMT

So detecting an isolated low cortisol isn't pathological and indeed is not that abnormal.

However I don't think we really know what happens to dogs with hypoadrenocorticism before hand because they are never identified and (at least to my knowledge) nobody has been able to follow the natural evolution of the disease.

Andy

RE: Likelihood of Addison's in 2 nights?

Kate Richardson — Wed, 13 Jan 2016 22:37:04 GMT

[quote user="ruths"]I see what you are saying but it's the lack of cortisol that causes the problems in addisons. So by definition, a normal cortisol rules addisons out...[/quote]

would a dog 'developing' addisons have the ability to respond adequately in a 'natural' stress situation? Do they produce acth at normal levels? Can they have a lack of inate acth? Or would you expect inate acth to be high a bit like tsh in hypothyroid dogs?

RE: Likelihood of Addison's in 2 nights?

Kate Richardson — Wed, 13 Jan 2016 22:32:24 GMT

Good on you for following it up by the way, I would imagine if just working in emergency only, it is easy to lose perspective on 'what is normal/common' in the same way as you would in general day to day practice where you get to follow things up, as you are always potentially expecting to deal with the weird!

RE: Likelihood of Addison's in 2 nights?

ruths — Wed, 13 Jan 2016 22:29:25 GMT

[quote user="Kate Richardson"]

is it possible the dog with low baseline cortisol is an early addisons ie I assume it is a progressive condition? They are usually diagnosed later on in the disease process when baseline and post acth stim cortisols are both low but this is often after several episodes of unexplained illness- how do we know what the cortisol pattern is earlier on? But I presume they don't go from normal function to no function overnight (unless bilateral adrenalectomy)

also if dog has been ill recently as it had, it seems odd baseline cortisol would be low?

do they plan to do a follow up acth stim/electrolytes in the future? (dont expect you to know the answer to that Silvia Maldonado ) but I think that's what I would do

another question silvia- does your emergency clinic stock cortisol testing? i would presume it would be a necessity for these scenarios. If they don't have it available in clinic, why not?

[/quote]

I see what you are saying but it's the lack of cortisol that causes the problems in addisons. So by definition, a normal cortisol rules addisons out...

I think!

RE: Likelihood of Addison's in 2 nights?

Silvia Maldonado — Wed, 13 Jan 2016 22:21:17 GMT

It may be :

Cortisol pre ACTH 22.6 Low nmol/L 25.0 - 125.0

ACTH Stimulation Test *Cortisol post ACTH 287.0 nmol/L 125.0 - 520.0

No advice from Idexx about it (neither checking in X month's time, or what to do next)

I don't think we have cortisol testing, coz other Cushing/Addison cases have been sent to external lab, but I'll ask

RE: Likelihood of Addison's in 2 nights?

Kate Richardson — Wed, 13 Jan 2016 22:08:41 GMT

also if dog has been ill recently as it had, it seems odd baseline cortisol would be low?

do they plan to do a follow up acth stim/electrolytes in the future? (dont expect you to know the answer to that Silvia Maldonado ) but I think that's what I would do

another question silvia- does your emergency clinic stock cortisol testing? i would presume it would be a necessity for these scenarios. If they don't have it available in clinic, why not?

RE: Likelihood of Addison's in 2 nights?

Silvia Maldonado — Wed, 13 Jan 2016 21:52:37 GMT

[quote user="Andrew Kent"]

Hi Silvia,

Hypoadrenocorticism more commonly causes hypercalcaemia, when I see high potassium with low calcium I wonder first about contamination with an EDTA sample which will do just that.

Are you filling the EDTA tubes first? Or is it possible that the analysis was run on an EDTA sample?

Usually it causes quite a profound hyperK and hypoCa so it would be useful to see the figures if possible?

Andy

[/quote]Triple checking tubes from now on! Exactly, it didn't make sense high K and low Ca. One of the dog had a bradychardia that considerably improved after fluids, but it was also the dog I thought anaemic, and his clinical findings, after a PCV of 48%, were more consistent with shock (MM pale pink, CRT long, but bradychardia!). This is the one I was told the prednisolone levels were low, but the ACTH stimulation test ruled out Addison.

RE: Likelihood of Addison's in 2 nights?

Silvia Maldonado — Wed, 13 Jan 2016 21:41:44 GMT

Hi, again, all. Thanks for the replies. I will recheck the blood tubes I used, just in case. The istat and biochemistry machines have not been changed recently, and I'm familiarized with both. One of the dog had a "comprenhensive profile" (the one we checked the BUN) twice in a week, by two different vets. The other one, only istat elytes. I would feel like a "Mrs Bean" if after so many months in this hospital, I got them wrong. On the other hand, we didn't have any similar abnormal results in any other patients I had that week (OOH, week on, week off)

As far as I know, one of the dogs, Hamish, case 1, had the ACTH stimulation test. The prednisolone baseline was low (22nmol/l in a normal range of 25-125), but after the ACTH the levels were normal. No Addison, and plan is monitoring at home, no diagnostic so far.

The other case, Ted, no news (the cons of the OOH and transferring the cases back to their vets, I miss diagnostics and progresses)

RE: Likelihood of Addison's in 2 nights?

Martin Atkinson — Tue, 12 Jan 2016 10:52:13 GMT

[quote user="Nicola Lawlor"] I second the comment above to check which tubes being filled first t[/quote]Silvia hasn't given absolute levels but my experience with samples contaminated from the EDTA tube is that potassium levels are so high that you smell a rat immediately. A Na:K ratio of 27 doesn't smell too bad and is pretty borderline but I did have one dog that had an Addisonian crisis at that figure so we always tried to keep it above 30.

RE: Likelihood of Addison's in 2 nights?

Nicola Lawlor — Mon, 11 Jan 2016 22:08:43 GMT

My first thought would be to check the lab machines with control samples and check that reliable results are being obtained. I second the comment above to check which tubes being filled first too.

RE: Likelihood of Addison's in 2 nights?

Andrew Kent — Mon, 11 Jan 2016 16:21:25 GMT

Hi Silvia,

Hypoadrenocorticism more commonly causes hypercalcaemia, when I see high potassium with low calcium I wonder first about contamination with an EDTA sample which will do just that.

Are you filling the EDTA tubes first? Or is it possible that the analysis was run on an EDTA sample?

Usually it causes quite a profound hyperK and hypoCa so it would be useful to see the figures if possible?

Andy

RE: Likelihood of Addison's in 2 nights?

Anthony Dennison — Mon, 11 Jan 2016 16:07:04 GMT

[quote user="Martin Atkinson"]

[quote user="Silvia Maldonado"]Any thoughts?[/quote]You need ACTH stimulation tests.

[/quote]

Or just a baseline cortisol - if it's having an Addisonian crisis you'll know without having to use any precious synacthen.

RE: Likelihood of Addison's in 2 nights?

Martin Atkinson — Mon, 11 Jan 2016 16:02:52 GMT

[quote user="Silvia Maldonado"]Any thoughts?[/quote]You need ACTH stimulation tests.