Health care practitioners have a code of ethics to which they must adhere. Because of the Hippocratic Oath, and the underlying power of their state and national licenses, they are held to a high ethical standard in their medical practice. Patients place their trust in physicians, and thus physicians are bound by this trust. Doctor-patient relationships by nature have open confidential communication as its foundation. In this context ethical principles must be strictly adhered to.
Over the past several decades, medical technology and a growing impersonal aspect to patient care vis a vis managed care (or what some would call, "mill care") has reduced the intimate nature of that doctor-patient relationship. While ethical requirements have not changed, the reduction in personal involvement, and consequently the trust that grows from longstanding interpersonal relationships has resulted in a situation where more and more patients are less reluctant to sue their physicians with whom they may have not been able to establish committed relationships.
At the same time, within this growing impersonal context, doctors have sometimes forgotten their ethical obligations. Also, as medical technology has advanced new ethical questions have been raised.
A couple, Jack and Jill, are engaged to be married. In a pre-marital blood test Jack is tested for HIV, which surprisingly turns out positive. Jack's physician informs his fiance that his test is positive without obtaining permission from Jack. Jill's fiance is understandably upset and calls off the engagement. Soon afterwards, they break up. Jack is distraught and subsequently loses his job. A month later, all positive HIV samples are randomly subjected to a second level confirmation study, and Jack's sample tests negative. Investigation into the discrepancy revealed that his blood sample was confused with another person's sample. Jack is informed but it is too late. His fiance has changed her phone number and address, and his employer has already filled his position.
This unauthorized disclosure of private information by Jack's physician violated Jack's right to privacy and caused life-changing damage. Jack promptly hired an attorney and his physician was sued.
What this shows is that medical information is confidential. All information about a patient in effect belongs only to the patient, and the physician is only the keeper of that information. Thus, the physician has an ethical duty to safeguard this information and not reveal it to any third party without the written consent of its owner, the patient. The only exception to this rule is in litigation when a patient files a lawsuit and de facto waives his confidentiality rights with regard to the parties involved in the litigation.
This is one example of an ethical breach by a physician. There are many more including developing intimate physical relations with patients, patient abandonment because of age or terminal nature of disease, issues around ability to pay and socioeconomic status, and more. All of these can result in malpractice litigation.