Rule 1001 There is no privilege under this article as to a communication relevant to an issue of breach, by the physician or by the patient, of a duty arising o…

When a doctor or patient is accused of breaking a responsibility they had to each other, the normal doctor-patient privacy protections do not apply.

For example, if a patient sues a doctor for malpractice, or if a doctor has a legal dispute with a patient over unpaid bills, either side can use medical communications as evidence. The privacy rule that normally keeps those conversations secret gets set aside when the dispute is about something the doctor or patient was supposed to do (or not do) as part of their medical relationship.