AndrewSo many questions run through your head in the period just after your child has been diagnosed. You may find it useful to make a list of your questions and keep adding to it so that your next visit with the endocrinologist will be more productive and reassuring.
A 'problem' with hydrocortisone replacement therapy is that your child should be so well while taking it, that you subconsciously question the need for the medication and worry about side effects.
This treatment is only about 50 years old, so studies don't extend into very old age, but there seems to be no evidence of any great problems. Consider how much more refined the tests and treatment have become over the last 50 years, and try to relax. There are many problems associated with a CAH patient not taking the hydrocortisone replacement therapy.
Andrew