Misdiagnosed: What to do When Your Doctor Doesn't Know

If Hopper's story sounds familiar to you, you're not alone: Twenty-five million Americans suffer from rare illnesses, many of which go undiagnosed for years, according to statistics compiled by the National Institutes of Health (NIH). A study published by the Mayo Clinic found that the true cause of illness had been either missed or misdiagnosed in roughly 20 percent of patients who underwent autopsies after dying in the intensive care unit. An analysis of diagnostic errors published in The Journal of the American Medical Association suggested that approximately 10 percent of all hospital deaths involve a major diagnostic error. Not surprisingly, the cost is high: Legal-claim payouts alone for diagnostic errors account for more than $2.5 billion a year, a recent analysis by Johns Hopkins Hospital in Baltimore shows.

But the financial cost pales in comparison with the emotional and physical toll. Patients who go for years without a diagnosis often are "medical disasters," says William Gahl, M.D., Ph.D., director of the NIH's Undiagnosed Diseases Program, which was launched in May 2008 to study some of the most difficult-to-diagnose medical cases. "They may be given diagnoses based on spurious test results that lead to treatments that are inappropriate or even harmful," he says. "And living for years without a diagnosis can accrue all sorts of complications. People come to us having had unnecessary surgeries, and compression fractures and osteoporosis from taking steroid medications."

The problem is complex. Not only do many illnesses mimic others, but physicians sometimes lack the time or expertise to arrive at a definitive diagnosis. This can occur particularly when a patient has a rare disorder or a common illness with an unusual symptom, says Lisa Sanders, M.D., a Yale University School of Medicine professor who writes the Diagnosis column in The New York Times Magazine. The good news is that patients can do a lot to help their doctors reach the right diagnosis sooner.

Next: Why diagnoses are missed. >>