When a psychiatrist was called to the home of a 12-year-old patient who was very distressed, he found her barricaded inside her room.
She refused to come out, saying she didn't trust doctors, including him.
He told her to look him up on the website,iWantGreatCare, on her smartphone.
The site was set up to allow patients to rate their doctors, and his teenage patients had recorded their comments about his care.
Seeing what her peers had written finally persuaded her to let him in.
It illustrates the power of the internet to empower patients and change the future shape of the doctor-patient relationship, says Neil Bacon, the doctor behind the website.
He has a vision of creating a "TripAdvisor" for health, where the collective voice of consumers, not the powers of the traditional healthcare regulators, become the new health watchdogs.
Dr Bacon - a kidney specialist - is one of the new breed of business-savvy doctors, who some have dubbed doctorpreneurs.
"It's the voice of the patient that is going to shine a new light and provide transparency for quality across health and social care," he says.
The site, which incensed some doctors when it launched in 2008, has recently joined forces with HIV/Aids charity, The Terrence Higgins Trust.
HIV positive people can be extremely anxious about choosing GPs and dentists as they are concerned about stigma and confidentiality, says Garry Brough of The Terrence Higgins Trust.
He wants individuals with HIV to work together to create recommendations for gold standards of HIV care, creating "a national database of high quality services for HIV that have been peer recommended".
The idea of patient power on the web is being tried out elsewhere in Europe.
In the Netherlands, Lucien Engelen, director of the Radboud REshape & Innovation Center at Radboud University Nijmegen medical centre, is researching how new technologies can improve healthcare provision.
One project for young cancer patients is a secure online community called AYA4 (all the information you have asked for), where they can talk about their health problems and send medical questions direct to an oncologist.
Dr Engelen says patients and their families are experts in a disease, as well as their doctors.
"Roles are not only shifting but they are flipping around," he explains. "There's more to be said about a disease than from the medical expert only."
He says in an era of democratisation of the media and the first Facebook generation, medicine is slowly starting to catch up with industries like travel and music, which have been revolutionised by the internet.
"It takes a little longer but it will have exactly the same impact and maybe even more. Once it creates mass, it will have some kind of value," he adds.