Actually AETNA is a huge insurance company and they do employ nurses. I used to do case management - in house and I loved it.
This sort of work is more desk work, lots of phone calls talking to docs and patients (or their families), negotiating lengths of stays, assisting with discharge planning, etc.... it's not as hands on but there is a level of job satisfaction.
I have been thinking of returning to case management. Can you post the contact information? I would love to see if they need a representative in my neck of the woods.
Thanks and good luck.