Blanche writes:

For starters, don't publish personal/medical information like this
in a public newsgroup. Nothing ever goes away, everything can be
discovered many years later.

Good general advice, but it should not be limited to medical information.
Everything you write tends to linger forever on the Net. Just your style and
attitude can influence people who might google for your name. Don't write
anything you wouldn't want to see on the front page of the New York Times.

If you must publish like this, use an anonymous remailer to
avoid obvious references.

That might be overkill for many cases. Some USENET providers already obfuscate
the source of posts as a matter of policy, and unless you are doing something
highly illegal, that degree of anonymity is sufficient to work around casual
fishing expeditions by others.