When the hoofbeats are zebras

An analysis by Johns Hopkins researchers claims that a third of all deaths in the US annually are due to medical errors.  This finding not only calls for better reporting of such errors, but also for better medical training to prevent them.  But death is not the only outcome of medical errors—instead, unnecessary patient suffering can result.

Anyone who binge-watches the TV show Discovery Life: Mystery Diagnosis will soon detect a pattern, one that demonstrates the need for improvements in medical training.  A typical show might have a young woman suddenly taken violently ill with an apparent stomach flu.  But instead of getting better, she continues feeling nauseated and weak. She has to drop out of college.  At home she develops a myriad of symptoms—such as night sweats, sore throat, swollen glands, and difficulty reading and speaking.  She visits a doctor, who tells her she has strep throat.  Despite antibiotics, she doesn’t get better, then goes to an internist, who tells her she should see a psychiatrist.  This continues on for several more scenes—sometimes several years in the life of the ill person whose story is being told—as one after another wrong diagnosis is made.  The mistaken doctors are always played by actors, as no doctor who gave the incorrect diagnosis would like to be identified.  Finally a smart doctor figures out what is wrong, and is identified by name and appears on the show.  The grateful young woman now has a diagnosis, and sometimes a treatment, often leading to a happy ending.

{mosads}Such could be a show made to describe Laura Hillenbrand’s journey to a diagnosis of chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis, as described in her vivid, and often shocking, New Yorker article.  But while she eventually did receive the correct diagnosis, she didn’t get a happy ending.  For there is no effective treatment for most victims of the disease, and she remains ill and rarely able to leave her house.  

As a researcher who surveys CFS patients who volunteer as experimental subjects, I have learned that a long journey to be diagnosed with chronic fatigue syndrome is not unusual.   In fact, it is common for individuals with symptoms of CFS to go through multiple years of misdiagnoses, most seeing an average of 4-6 doctors or more, often being told they have a psychiatric disorder, before they find a doctor who has learned enough about CFS to identify the disease.  The Centers for Disease Control estimates that fewer than 20% of Americans who have CFS have been diagnosed.  Part of the blame for this problem lies in medical training, in which students are told the famous adage: “If you hear hoofbeats, think horses, not zebras.” In other words, if symptoms appear to fit a common disease, then that is the best diagnosis.  This idea, when not applied properly, is the origin of many of the errors chronicled by the Mystery Diagnosis TV show.  Because though some diseases are less common than others, that doesn’t mean they don’t exist—every rare disease has its victims.  Another lesson from the show’s episodes: advocating for yourself can save your life.  A striking number of the patients or their caregivers came to a suspected diagnosis or consulted a knowledgeable physician through researching their own symptoms on the web or in the library.

Standard blood tests are given to someone who arrives complaining of long-lasting fatigue, malaise, and muscle pain. But no abnormalities are seen in such tests of patients with CFS.  This leads to the favorite diagnosis of doctors who don’t want to spend time dealing with a patient with unexplained symptoms: depression.  Indeed, some CFS patients do become depressed—after being ill for years, losing their jobs, being maligned by friends and family, and repeatedly being told that there is nothing physically wrong with them.  But not all CFS patients become depressed, and even those who have psychological problems also have a physical illness of unknown origin.  More sophisticated tests, ones more often found in research labs rather than medical testing labs, have revealed immunological and neurological abnormalities in CFS patients.  But these are difficult to translate into a simple, easily administered test.

Why is a diagnosis important, given that there is no effective treatment for most CFS victims that can restore their prior functioning?  Because recommended therapies for misdiagnosed illnesses often can do harm, increasing the severity of CFS.  Inappropriate drugs or lifestyle changes—such as types of exercise harmful to people with CFS—can causes patients to become worse, sometimes with long-term detrimental effects.

Improved training of physicians about CFS is needed if patients are not going to continue being unwilling characters in real-life episodes of Mystery Diagnosis.  A 2010 survey of medical textbooks revealed that only 40% even mentioned CFS. Until recently, little has been done to dispel early and stubbornly persistent notions of the psychological basis of the illness.  Fortunately, the National Institute of Medicine undertook a year-long study of the scientific literature, and concluded that that CFS is a “serious, chronic, complex, and systemic disease that frequently and dramatically limits the activities of affected patients.”  The report provided a simple set of diagnostic criteria that could be applied by a physician in general practice or any speciality to determine whether a patient should be diagnosed with CFS.  A Clinican’s Guide the Institute produced should reduce the time to diagnosis—and help knowledgeable patients advocate for themselves.


Maureen Hanson is Professor of Molecular Biology and Genetics at Cornell University and conducts NIH-supported research on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. She is with The OpEd Project’s Public Voices Fellowship at Cornell.

See all Hill.TV See all Video

Most Popular

Load more


See all Video