Deaths By “Wrong Diagnosis” Exceed 40,000/Year

Misdiagnosis: Serious Mistakes More Common than Drug Errors

Imagine going to the emergency room with a severe headache and being told you’re having a migraine, but actually it turns out to be a brain aneurysm… or experiencing dizziness that’s diagnosed as a minor inner ear problem, only to discover later — too much later to treat it — that you’ve had a stroke.

Horror stories like these are more common than you may think. According to Johns Hopkins patient safety experts, misdiagnosis accounts for 40,000 to 80,000 hospital deaths per year. Lawsuits for diagnostic errors (defined as a diagnosis that is missed, wrong or delayed) are nearly twice as common as claims for medication errors. While health experts have focused on drug-prescribing errors, wrong-site surgeries and hospital-acquired infections in their overall effort to reduce medical errors, in fact, diagnostic errors are probably more common and at least as dangerous. Research shows 14% of physician errors that caused adverse events were diagnostic versus 9% for those that were drug-related.

ROOM FOR IMPROVEMENT

David E. Newman-Toker, MD, PhD, assistant professor of neurology and otolaryngology-head and neck surgery, at Johns Hopkins University School of Medicine, lead author of the commentary (published in the March 11, 2009, issue of the Journal of the American Medical Association) emphasized that “the process of getting diagnoses correct is not an exact science, it’s quite challenging.” He added, “But we’re not performing as well as we could be. There’s room for improvement.”

First, to put the problem in perspective, not every error leads to harm. Some misdiagnoses are caught and corrected, others are inconsequential, and there are some cases in which a poor outcome couldn’t have been prevented anyway. Still it is important to recognize that diagnostic errors are a major source of preventable harm. Dr. Newman-Toker told me his passion for preventing misdiagnosis was triggered during his medical training, when he witnessed serious consequences of missed neurologic conditions that should not have occurred — for instance, one woman suffered permanent paralysis that could have been prevented had doctors realized she’d suffered a stroke.

STROKE MISDIAGNOSIS: A PUBLIC HEALTH PROBLEM

Indeed, misdiagnoses can cause permanent disability. The leading cause of major disability in the United States is stroke and Dr. Newman-Toker said it is one of the most important and most frequent conditions that is misdiagnosed. This, he says, is “a major public health problem.”

A recent systematic review conducted by Dr. Newman-Toker and colleagues found that an average of 9% of strokes are initially missed by ER doctors and staff and the odds of misdiagnosis increase at least five-fold when symptoms are mild or transient. Errors are also more likely when symptoms are less specific for stroke — for example, numbness of the hand may be misattributed to carpal tunnel syndrome. Key findings: A patient whose chief complaint involves weakness (especially on one side of the body, which is a classic stroke symptom) has a 4% chance of having his/her stroke misdiagnosed… but if the chief complaint is dizziness, which is more often caused by benign conditions other than stroke, the likelihood of stroke misdiagnosis rises to 35% — and to nearly 50% if dizziness is the only symptom.

REDUCING ERRORS

The researchers say that diagnostic errors for stroke, along with many other problems, could potentially be reduced with a variety of simple tools and strategies. Checklists can help physicians connect symptoms with particular conditions that are obscure and difficult to diagnose… computer programs can help calculate an individual’s risk for a certain disease… X-rays and CT scans can be confirmed with “second looks” by a different physician to reduce errors of misinterpretation… and patients with unusual symptoms can be rapidly directed to diagnostic experts.

Also important is the need for physicians to be educated and re-educated in use of available technology. For instance, researchers found that 28% of patients arriving at the ER complaining of dizziness were given a CT scan, while only 2% got an MRI. This is unsurprising given that most ER physicians recognize dizziness as a symptom of stroke and most hospitals have CT scans readily available to the ER — but the problem is, CT scans don’t detect the kind of strokes that usually cause dizziness. These “ischemic” strokes (caused by blood clots in the brain rather than bleeding) may not be visible on a CT till a few days after symptoms begin, particularly when the stroke occurs in the back part of the brain, which is where balance is controlled. A normal CT scan result, therefore, can give false reassurance that all’s well. MRI is clearly the better choice for detecting new ischemic strokes in patients with dizziness.

AVOIDING MISDIAGNOSIS

Obviously it’s the responsibility of the hospital and physician to take necessary steps to implement procedures and best practices that will minimize misdiagnosis… and Dr. Newman-Toker told me he hopes the Journal of the American Medical Association commentary serves as a strong nudge in that direction. However, I asked if he could also offer some advice to patients and family members on what we can do to reduce the odds of misdiagnosis. He offered these recommendations:

• Make sure that you clearly and effectively communicate all of your symptoms — and ask your doctor to repeat them to you. It may be a good idea to bring along a close friend/family member aware of the problem for help in remembering details you forget. A doctor who hasn’t heard your symptoms correctly cannot accurately diagnose them.

• Ask your doctor to explain the reasoning he/she used to arrive at the diagnosis. According to Dr. Newman-Toker, a physician who can articulate the logic is more likely to have gone through the correct steps to arrive at a diagnosis.

• Ask your doctor how certain he/she is about the diagnosis and whether there are other problems that could be causing your symptoms. This step reinforces the need to rule out other possibilities, particularly dangerous ones that can mimic more benign problems.

• If you sense that a diagnosis is incorrect, trust your instinct and seek a second opinion, especially if symptoms persist, get worse or increase in frequency.

If it turns out that you have been misdiagnosed, make sure you report the error to your physician and hospital. Many misdiagnosed patients go on to seek care somewhere else and don’t let the doctor who arrived at the wrong conclusion know about the error — but in fact, this is a disservice to the doctor and the community, as it removes the opportunity to learn from the experience and increases the likelihood it will happen again. Not all misdiagnoses represent substandard medical care but some certainly do — in the case of egregious errors or those of negligence, contact your state medical board.