I would march myself into the office and proceed in a CALM, firm manner and ask to speak to the Dr. in person and privately for just 5 minutes. If they ask, tell them you want him to be aware that a long time patient was treated rudely by discussing a personal matter in a public place and causing great distress. To me public discussions border on illegal, just like bill collectors who harrass or discuss a bill with someone other than the bill owner is illegal now. Let them know you will sit and wait until he can speak to you personally, privately. Review the incident explaining the pain this caused and explaining you do not want anyone else to suffer this embarrassment in his office. Hopefully he will get it and give his staff some sensitivity training. He needs to be aware of how his office staff treats his patients.