The doctor told me that I had a middle ear infection. That seemed like a reasonable conclusion, because I had fluid in my middle ear. When I didn't get better after months of treatments, he decided to slice my eardrum open and suction out the fluid. As he was tidying up afterwards, he told me that all the fluid was gone and no more would appear.

That night, though, I kept waking up every half-hour or so, each time because the pillow had a new wet spot on it. The cottonball in my ear had become saturated and fluid had overflowed onto the pillow. Each time, I threw the soggy cotton ball onto a mat beside my bed and inserted a dry one.

In the morning, there were 13 discarded cotton balls on the mat. Over the next several days, fluid continued to drain and finally stopped. I saw the doctor several days later and described my experience.

He said, "Oh, that's ridiculous! That didn't happen!"

He said that I was cured. But a week later, I was back in his office with more fluid in my ear. About a month after that, he sliced my eardrum open again, suctioned out all the fluid, and tried to install a little drainage tube, but it wouldn't stay in place. He stepped away to prepare for a second try, and when he came back, he said in astonishment, "There's more fluid in your ear!"

Within a few minutes, he had scheduled me for brain surgery. It turns out that brain fluid was leaking into my ear because there were a couple of holes in places where there shouldn't have been.

If he'd succeeded in installing the drainage tube, he would have opened a quasi-permanent direct channel from the outside air to the inside of my brain. I almost certainly would have gotten a brain infection and probably would have died. In fact, I was lucky that I didn't die between the first time he sliced open my eardrum and the second time.

If I had died, it would have been his assumptions that killed me. After the first procedure, when my facts and his assumptions didn't match, the doctor chose to throw away the facts and hang on to his assumptions.

According to Dr. Robert M. Wachter at the University of California, people are misdiagnosed on average about 10 percent of the time. Dr. Peter Pronovost at Johns Hopkins University has concluded that mistakes in diagnosis kill 40,000 - 80,000 hospitalized patients a year.

If you are misdiagnosed, you may receive the perfect treatment for a disease you don't have. The U.S. health care system recognizes 68,064 different diagnoses, so it's not always easy for doctors to tell which one belongs to you.

What can you do to increase the odds that you'll get an accurate diagnosis? Keep a careful record of your symptoms. Each time a symptom you're worried about appears, write down:

  • The date, the day of the week, and the time 
  • A clear and detailed description of the symptom: where exactly in the body it is and what it feels or looks like  
  • How long it lasts 
  • What you were doing when the symptom arose - eating, sleeping, hiking, sitting at your computer, etc.  
  • What, if anything, seemed to make it better  
  • What, if anything, seemed to make it worse

Keep a copy of these notes and give one to your doctor. Having written notes helps in three ways.

  • First, you won't forget to mention important points.
  • Second, your doctor can see the order in which symptoms appeared, which can be an important clue.
  • Third, your doctor may take your report of a problem more seriously.

Once treatment starts, it's important to continue to track your symptoms, for two reasons.

First, this record will help you understand if the treatment is working for you or not. If you have exactly the same symptoms - once the treatment has had a chance to work - as you did before you started the treatment, it's reasonable to discuss with your doctor whether the treatment is working for you or not.

Second, if you develop any new symptoms, a careful written record can help determine if they are a side effect of the treatment.

If it doesn't seem as if the treatment is working, one possible reason is that the diagnosis is wrong. Dr. Jerome Groopman at the Harvard Medical School suggests three questions to ask to try to determine if you've been misdiagnosed:

  1. What else could it be? 
  2. Is there anything that doesn't fit? 
  3. Is it possible that I have more than one problem?

By taking the above steps, you can improve your chances of being treated for the condition you actually have.