I did this for 17 years and loved it a lot/hated it some, pretty much like any job. I loved the autonomy (I was in the field, not stuck in a cubicle or a desk doing telephonic), getting out and about to meet new people, and learning an entirely new field of nursing that, eventually, led to my present work. And at one point I was making so much reimbursement for my mileage that it was more than my car payment. Bonus!
I got a little tired of obnoxious IWs (injured workers) but, as in hospital care, the vast majority of your patients are not obnoxious. Contrary to all the stereotypes about work comp, 95% of the claimants really did get hurt at work, really do want to get better, and really do return to work (RTW), and are grateful for your assistance in getting them appropriate, timely care.
Of the remaining 5%, more than half really did get hurt at work, and really will complete treatment, and RTW with your shoe firmly placed against their upper backs.
The last small percentage are the out-and-out frauds who find themselves in the newspaper exposes of comp fraud as they collect thousands of dollars in indemnity for work injury in Minnesota while running a salvage business in the Florida Keys . But even those guys make up for much of the aggravation in entertainment value. Every WC CM can tell you hilarious stories of IWs who thought they could game the system but alas for them, came up against a smart NCM (nurse case manager) who had a well-developed BS filter (and I don't mean "bachelor's of science") and could name this tune in two notes.
Most companies won't hire if you don't already have the CCM or the RN-BC credential for case management, but some will, and will even help you get your certification (it takes two years). I think everybody should learn an entirely new field every few decades, it keeps you sharp.
TPA = "third-party administrator," a company that administers claims, pays benefits and the other bills, hires case managers, etc. for insurance carriers that don't want to have claims departments themselves. My first WC CM job was with a TPA and I did files from more than 25 different carriers.
Since WC is very regulated, the process was all pretty much the same for all of them, and our company had a particular monthly report format we used for all of them, so there was not that much difference. A few had "special handling instructions," meaning they required that we always do thus-and-such in case of XYZ, or use a particular wording, or bill no more than $X for a monthly report, or paid only 1/2 mileage, or whatever.