Posted by Bill Sandweg on 09 December 2019.

I have written often about misdiagnosis.  See here and here, for example.  It is a frequent subject because it is the most common form of medical malpractice.  Some new research suggests that the most damaging misdiagnoses occur in a relatively small number of settings and disproportionately involve only a few disease types.

While almost everyone agrees misdiagnosis is a huge problem that causes many injuries and deaths, they disagree over the magnitude of the problem.  Estimates vary from 40,000 injuries and deaths per year due to misdiagnosis to 4,000,000.  That is a pretty big range.  Research and statistics suggest the actual number of injuries and deaths is much closer to 4,000,000 than 40,000.

The new research into misdiagnosis appears in a recent issue of the peer-reviewed medical journal Diagnosis.  The authors are teams out of Johns Hopkins University School of Medicine and CRICO, a major national medical malpractice insurance company.  The researchers used 10 years of closed malpractice claims files for their source material.  They hope the results will lead to better training in how to avoid the most common diagnostic errors.

The leading cause by far of serious injuries and death due to misdiagnosis was what are called clinical judgment failures.  These accounted for almost 85% of all of the misdiagnosis claims.  Clinical judgment failure is what doctors call it when a doctor makes a mistake in doing things like failing or delaying in ordering tests, failing to put everything together to make sure all important information has been considered, misinterpreting test results, failing to consider all possible causes for the patient’s problems, and failing to get a timely consultation.

The researchers also discovered that most serious injuries and deaths due to misdiagnosis were almost all in what are called “The Big Three”: (1) vascular events, such as stroke; (2) infections, such as sepsis; and (3) cancer.

The diagnostic errors involving vascular events and infections almost always occurred in an emergency department or urgent care setting or during an inpatient hospital admission.  By contrast, the errors in cancer diagnosis almost always occurred over the course of a number of office or outpatient visits, where there was lots of opportunity for the doctor or staff to miss things.

All of this leads the researchers to conclude that many lives could be saved by improving decision making in just a few relatively high-risk conditions in just a few clinical settings.

The bottom line here is that doctors don’t know as much as you might think.  Even when they are very knowledgeable, which is often, they are subject to the same type of mistakes in thinking as the rest of us.  They often fixate on the first condition that comes to their mind, instead of making a mental list of all the possible illnesses or conditions that match the given information.  As I have heard malpractice defense lawyers tell juries many times, “When you hear hoofbeats, you think horses, not zebras.”  The problem, of course, is that sometimes the patient has that unusual “zebra” illness or condition and reasonably expects the doctor to figure it out.  Your chance of being misdiagnosed goes way up, if you have an unusual presentation or an unusual condition.

Ask for second opinions.  Use the internet to educate yourself so you can have a better idea of what questions to ask your doctor.  If the doctor orders medication and it does not appear to be working, don’t assume that it is the fault of the medication.  It may be the doctor was mistaken about what is wrong with you.  Be polite but aggressive in pushing to get the best diagnosis.  Ask whether this could be anything else.  Ask whether the diagnosis accounts for all of your symptoms and test results.  Ask whether there are any other tests which might be useful.  Be especially careful, if you think your condition may be one of the Big Three.

Do all these things and you will have improved your chances of getting an accurate diagnosis.