RE: Time off preds before ACTH stim test

Anthony Todd — Fri, 05 Mar 2021 09:47:07 GMT

I just wonder whether the accepted dose rate and regime of illogial daily dosage leading to rising blood levels may influence this?

RE: Time off preds before ACTH stim test

Beats — Thu, 04 Mar 2021 19:23:33 GMT

[quote userid="8991" url="~/001/veterinary-clinical/small-animal/medicine/f/discussions/29700/time-off-preds-before-acth-stim-test"]Lab said 4-6 weeks which seems too long. [/quote]

I think it probably depends how long has been on steroids for (and what dose)

If only 6 months old can't be very long on them i would think, and if being treated for suspected addisons with preds (I'm not sure if that is what you are saying) then dose likely to be low.

If been on 0.2mg/kg daily or less of pred for a month or less, then i'd think that ACTH likely to rule out addisons (assuming doesn't have addisons) after 2 weeks. I guess?

2 aspects:

1) pred cross-reacts with cortisol in assay (I believe), I'm sure 3 days off sufficient to be sure this doesn't occur. [could, in theory, cause falsely ELEVATED cortisol level in dog sampled while on preds?]

2) pred use may have led to adrenal insufficiency - I suspect 2 weeks off preds would suffice in this case, but if the cortisol response was still poor at that then I guess it would be a clinical judgement as to whether to wait another 2-4 weeks and test again or assume addisonian dependent on how dog was doing.

Checking electrolytes while off preds would seem reasonable if unsure - if not hyperkalemic etc then can probably wait an extra week or two to be bit more sure re what sounds like an unusal presentation for an addisons. Of course there are other steroid responsive cases and ultimately if does poorly off preds and great back on them again then I guess at least you know what to do with the dog treatment-wise in the short term.

RE: Time off preds before ACTH stim test

Clive Ansell — Thu, 04 Mar 2021 09:58:18 GMT

Have in my head about a month?

Maybe run the ACTH Stim and see what you get? - normal result excludes Addison's. could always be repeated if inconclusive.

Electrolytes?

Aldosterone assay? from memory I think both cortisol and aldosterone can be measured with an ACTH stim test.