Barbara,
You sound like you have good reason to be concerned about your daughter. Everything that you described---an eighty pound weight gain in one year, nausea and stomach upset, corroborating test results---would seem to point to the notion that she is grossly oversuppressed. However, 8 trips to the ER in 9months (I assume because of adrenal crises??) would indicate undersuppression. Something does not seem to quite add up. Here are a few thoughts:
As a start, the amount of medication that you mentioned your daughter is getting---0.175 mg--actually does sound very low. My 7 yo. son is also on dex, almost certainly physically smaller than your daughter, and his dose is more than double what your daughter is getting (right now, he is getting the equiv. of 0.40 mg).....significant, considering that dex is very potent, to begin with. Yet he has never suffered any ill effects, whatsover, and he is not even a salt-waster. (I would be reluctant to attribute this simply to innate differences in each child, especially with the problems that you've faced.) First, is it possible that we are not truly comparing "apples to apples?"
Dex does come in different potencies. Is it possible that the stuff your daughter is getting is more highly concentrated than what my son takes, therefore giving her much more replacement cortisol than she really needs? My son takes a dilute elixir---concentration 0.5 mg/5ML. In what form---pill or liquid--is your daughter getting her dex and are you certain of the unit of measure?
Also, how was your daughter's dex dose determined, when she was switched from the HC? If her doctor tried to equate the amount of HC she was getting (when she was considered to be in good control) to an equivalent amount of dex, it is quite possible that her dose was miscalculated because an incorrect conversion factor was used----a very common mistake, even with the most experienced doctors, as we found out, ourselves,firsthand. When my son was temporarily switched from dex to HC, his dose was erroneously halved. When changing from HC to dex, the tendency is to end up with the opposite problem--- double, or even triple, the amount of dex than is actually required, resulting in gross oversuppression, as appears to be the case with your daughter (at least on first impression).
Here is another thought, this having to do with the seeming contradiction between your daughter's symptoms of oversuppression and those 8 trips to the ER---what puzzled me when I first read your post: If you are sure of your daughter's dose (extremely low, in my opinion, as I mentioned earlier), maybe what is happening is that you are being caught in a vicious cycle between under- and oversuppression. That is, the 0.175 mg dose that your daughter gets daily is not nearly enough; is causing severe undersuppression; and sending her into crisis and to the hospital on on regular basis. Once she gets to the ER, however, she is almost certainly being given a big dose of steroids to boost her up (perhaps you've also been giving her solu-cortef shots on top of that, prior to going to the hospital?) Eight trips to the hospital in 9 months means that she has been injected with mega-doses of steroids, now, on a regular basis. Perhaps, that is what is causing the clear signs of steroid excess and why her bloodtests keep showing oversuppressed, even though her dose is so low.
It definitely sounds like there is a big problem with your daughter's medication regimen. Gaining eighty pounds in one year is certainly not normal, but then, neither is a trip to the ER every month. It is easy to say that the problem is the dex....and leave it at that. But, in my opinion, you might want to look a bit more carefully at not just the medication, but how it is being managed. As I mentioned, you sound possibly caught in a vicious cycle and, if it were me, I would certainly question my ped. endo about why my child has "yo-yo" ed between oversuppression and crisis in the last year.
P. S. The article that Martha mentioned about dex treamtent in CAH children is still up on this MB. Look for the thread "Dexamethasone vs. Hydrocortisone" started by Jenni on Feb. 7...I think it's currently on page 4 or 5.