Hi Randy - I'm sorry you're going through so much right now. I know *exactly* what you're going thru and have been thru as my Wylie has Atyp Cushings. (and, thanks to Lj for PMing me about your kiddo)
First off...something easy...Cushings dogs (atyp or typ) are very, very prone to skin infections, especially when they're pre-diagnosis. This is bc their immune system is suppressed and a few other things. Since you mentioned she is itching - ask your vet to do a quick skin smear while you're there - he should be able to see on the slide whether there is excess bacteria present. Lots of Cush dogs get Pyoderma. A great antibiotic to treat it is Simplicef - once a day, for 3-4 weeks.
On the Melatonin: Wylie takes 3mg BID too - and he never shows tiredness on it. Even if your kiddo shows some tiredness at first, it usually goes away. Most dogs have a very easy time taking it.
We too sent our bloods to U of Tenn, they're wonderful. We started out giving melatonin and flax lignans right away. And then retested in about 3 mths. No change. So, we now have Wylie on Lysodren and Melatonin; and he is hypothyroid - so he takes meds for that too. Oh, btw, they did test Reese's thryoid, right? Many cush dogs have hypothyroid.
I can tell you, it can take a full year to get the meds titrated correctly. I know how scary that is! You feel very confused, and it's a big learning curve. Believe me though, you will get her there. The way it will prob work for you is: give the melatonin, do ACTH after 3-4 mths; if effective, great. If not, add lignans...wait 3mths...test again. If not effective, move to more aggressive meds and repeat. And you go like this until the right combo is found. Granted, cush drugs (the aggressive ones) are not great to read about...they're pretty major drugs. However, most cush owners find something that works so well, w/ very little side effect. Wylie does simply amazing on his Lysodren. He takes it MWF.....fyi, most atyp cush dogs don't have to take the aggressive meds EVERY day, which is nice. Whereas some typicals do have to take them every day (which can be a little tougher, in terms of side effects).
As far as understanding the numbers....you will get there. It takes time and a lottttt of reading, believe me. But eventually, it all clicks much better in your mind. To me, it looks like you have a very good understanding of everything already.
Yes, sometimes high cortisol levels/Cushings can be due to a tumor in the adrenals or in the pituitary. Did they ultrasound her adrenals, btw? A cushings Vet may want to do this, just to see if there have been any structural changes. But like Wylie, your Reese's issues stem from an intermediate sex steroid/hormone. Wylie's main one that is high is progresterone, but his estradiol is slightly elevated too. Btw, Wylie was only about 4 when it was diagnosed (he's now 7).
I've already typed a lot...I don't want to overwhelm you. Here are some sites that I found helpful. You've already been given the yahoo Cushings group - and that's an AMAZING site for reference documents.
Overview, basic:
Cushings
No-posting forum that contains good reference info:
Important Information and Resources - Canine Cushing's Forums
Good journal article, including Dr. Jack Oliver (RIP
) from UofTenn:
Newer tests shed light on causes, treatment of adrenal disorders - DVM
Know that w/ treatment, some of Reese's symptoms will subside. Some cush dogs look like totally different dogs after effective treatment is started. Her hunger will normalize at least a little, if not a lot. And I'd imagine you'd eventually see a major change in energy. Wylie didn't have the pot belly, which is so common in cush. He had polydipsia/polyuria, recurrent skin/ear issues, hair loss, 'aged' look to face, muscle wasting in hind legs. All of that is much better now.
Hang in there, and just know that you'll feel better about this diagnosis as time goes on.