My mother is my role model and my inspiration for what I do every day. She was diagnosed with breast cancer when she was in her forties, and fought it courageously for seven years until she passed away in 2010.

There are so many stories I can tell about my mother and her battle with cancer. Let me start with just one. Whenever she’d go to her oncologist, she would go armed with a list of symptoms. To his credit, the oncologist was always good about giving her a working diagnosis that made sense of her symptoms. Still, though, she often called me to complain that she didn’t understand the diagnosis and how her symptoms could possibly be attributed to it. For example, she went to her doctor once because her stomach was hurting. He thought it was due to constipation caused by her “medications,” and asked her to take some stool softeners. She couldn’t understand why—if her “medications” were the cause of her problems, why was he telling her to take more of them?

I knew that what her doctor meant was that he suspected her abdominal pain was due to constipation, which was caused by the pain medications she was on—but either he didn’t explain this to her, or she didn’t understand what he said. “So why didn’t you ask the doctor about it?” I would ask.

She never had an answer to this, and it took me a long time to see her perspective—the patient’s perspective—about why she was so reticent. Asking her doctor questions just wasn’t something she thought she could do, and no amount of cajoling on my part could get her to change her mind. That didn’t mean she would eventually agree with the doctor; actually, she often disagreed, and often didn’t follow his treatment recommendations. Throughout the entire time she was ill, I didn’t understand the logic, and attributed her reticence to her having come of age in China. However, I didn’t quite understand, because she was a schoolteacher in some of the roughest parts of Los Angeles and never had trouble standing up for her students. So why couldn’t she advocate for herself when she needed it the most?

As a doctor, now, I see that my mother was hardly alone: many patients are genuinely afraid to challenge their doctors. And I don’t mean challenge the doctor as in pick a fight with them, but even to ask basic questions. When I talk to patients about their diagnosis, they tend to nod and agree with almost anything I say. Sometimes, they’ll ask a question or two; very infrequently does someone actually stop me and say, “Hmm, that doesn’t sound quite right.”

In speaking with patient advocates about this, it seems that patients think they would be rude or presumptuous to question a diagnosis, especially since they think they know so little. It’s quite the opposite: doctors should wantour patients to ask questions and help us perform a final reality check! In my practice, I’ve taken to asking patients specifically if they think the diagnosis I had in mind makes sense to them, because it encourages them to bring up any concerns or questions. Not infrequently, these questions lead to a real breakthrough and really change their diagnosis and management.

My mother is my inspiration for writing because she had gone through many misdiagnoses: initially a missed diagnosis of cancer and then multiple other misses along the way, including, eventually, a missed diagnosis of pneumonia that led to her death. There is nothing I can do bring her back now, but she always believed that one person can make a difference. I want to make a difference to my patients and encourage all of you to make a difference in your healthcare. Speak up the moment you have a question, the moment you don’t understand something the doctor said. Don’t let more time—and more opportunity for misunderstanding—pass by. The work that you do will revolutionize your interactions with your doctor, and potentially change how your doctor interacts with future patients as well.

Leana Wen is an emergency physician who blogs at The Doctor is Listening. She is the co-author of When Doctors Don’t Listen: How to Prevent Misdiagnosis and Unnecessary Tests.  She can also be reached on Twitter @drleanawen.