Cushing's no longer due to Mitotane

[Boomersmom]

Hello, I'm new to this site. I had a question about my dog, Boomer, and thought you guys would know.

Just a quick history of Boomer. He's an 8 year old toy poodle who's been diagnosed with Cushing's for about 3 years.

We've been handling his cortisol levels well with Mitotane (Lysodren) and his regular ACTH tests. He just had one done a little over 2 weeks ago and for the first time his cortisol levels were low. The vet suggested to stop his Mitotane and to give him prednisone for 2 weeks, stop 2 day before retesting him again with ACTH test. So we did and it again came back low. The vet said that long term use of Mitotane can sometimes permanently damage his adrenal gland and reverse him into Addison's disease.

Other then having low levels of cortisol, Boomer has been acting and felling fine. He's active, eating well, has increase his drinking and peeping but I'm guessing it's probably do to the prednisone. He's already decrease it some.

The vet said to keep and eye on him, making sure he doesn't show signs of his levels dropping too low. I have some prednisone on hand just in case. But she said that in some sort of way, this is actually a good thing. She wants to see him again in 3-4 months and retest to make sure things are ok.

I'm curious if anyone else has gone through this before. It just seems too good to be true. I've heard how dangerous Addsion's can be, though the vet said that's is more true on dogs with acute Addison's, not with the ones brought on due to meds.

[Harley PoMMom]

Hi and welcome to you and Boomer from me and my boy Harley.

We have many members here that are using or have used Lysodren/Mitotane as the treatment med. for their pup and I am sure they will be along to give their opinion/advice and support.


The vet said that long term use of Mitotane can sometimes permanently damage his adrenal gland and reverse him into Addison's disease.


This can happen if the dose of Mitotane/Lysodren is too high. That is why owner observation and the ACTH stim tests are very important.

Could you post Boomer's last ACTH stim test and any previous stim tests here. The more we know about your precious boy the better our feedback will be.

Did your vet check Boomer's electrolyte levels too?

I am so glad you found this forum and we will help you in any way we can.

Love and hugs,
Lori

[Boomersmom]

Thank you for the welcome.

I only have the test results of his first testing and I don't really understand them. It's a type of spread sheet with all the variables of the test result.

He's been going in for his ACTH test since his first diagnose and almost every 6 month after wards. His levels came high twice in the past (most recent was a year ago) where I had to reload his med and return after 4 weeks to have his levels come into the normal range. This is the first time they came in low.

I say almost every 6 month because his last test that was supposed to happen in June wasn't done. He went in for a check up and since he's been doing so well the vet allowed us to wait and test him for his 6 month visit. We've been financially strained due to the economy and my husband being in real estates and thought he'd be ok to wait till now.

As for electrolyte levels, this is new to me. The vet never mentioned that they had to be checked.

His symptoms were increase thirst, and urination, hair loss in the torso area and skin sores. Also increase appetite was very noticeable. After he started his meds all the symptoms disappeared except for hair loss which improved after his last loading of the med. That was a year ago, and his mitotane dose had increased. I was shocked when we got his results back this time as being low. He's been acting like a puppy with so much energy.

[Harley PoMMom]

There are two types or degrees of Addison's - one is what is called Atypical Addison's which is when just cortisol production is affected and the other is more typical Addison's where the production of both cortisol and aldosterone are affected. Atypical Addison's is treated with just prednisone (or some other artifical glucocorticoid like dexamethasone or cortisone). Full Addison's is treated by replacing both the missing cortisol and the missing aldosterone.

Aldosterone is what balances electrolytes and the mineral/water balance in the body.

Typically a vet checks cortisol production and electrolyte levels in a pup when an Addison crisis is suspected.

Electrolyte levels are checked from a blood draw, the test may be called a Chemistry test.

For the ACTH test, we are looking for the pre/baseline number and the post number.

Love and hugs,
Lori