Breach of confidentiality, like all medical malpractice suits, need an injury in order for legal consequences to befall the doctor. This isn't to say that a breach of confidentiality doesn't exist when there is no injury, its that the patient won't collect money if an injury can't be shown.
By injury, I mean any type of loss. In prior cases involving breach of confidentiality, the patient may have lost their job when the doctor gave the information to an employer or their privacy and safety if the doctor gave the information to a stalker.
Also be sure that the breach doesn't meet any of the exceptions: public safety, health insurance, interest of science, freedom of speech and similar defenses. If an exception is met, then the doctor cannot be held liable even if the breach can be proven and injury did result.
(removed)