My Wylie has what is sort of the opposite of Addison's - he has Cushing's (atypical Cushing's, to be specific). Atypical Cushing's means one of the intermediary steroids (androstendione, estradiol, progesterone, 17-OH progesterone or aldosterone) is out of whack, causing the excess of that hormone, and often excess cortisol as well. Any disease involving the adrenals is tough to diagnose, manage, and treat - and I'm finding that so true, but we're getting there. Wylie has a very good internist, and that helps a lot.
I wish you all the luck w/ your baby.