What consideration does the HIPPA laws have for email correspondence between a patient and care provider.

From the facts you have set out it is unclear whether a violation of Hippa has occurred, because we don't know who the third party is, what relationship that third party has with your and/or the therapist, and/or why that third party would be forwarding the email in question to an other therapist. We also don't know whether the email discloses confidences you related to your therapist during treatment, or merely addresses a disagreement over fees, etc. While I certainly understand your outrage at the email having been forwarded by someone in whom you placed your trust, I also wonder whether you have been harmed in some redressable way, or if you are simply angry and hurt and looking for a way to lash out at your former therapist. If you strongly feel you have been wronged and wish to pursue action, my advice is to contact an attorney with experience dealing with hippa issues and set up a consultation to discuss your options.