The possibility of zebras in primary care

It is critical for physicians to share unusual patient diagnoses that present to clinic with routine type symptoms.  In a hospital setting, these are cases for discussion and debate at Grand Rounds.  In a primary care setting, we do case reviews when we can with informal sharing for the purpose of teaching and learning.  The bottom line, whether in a formal academic setting, or an informal setting around the lunch table: clinicians need to always be thinking of the possibility of a zebra hiding in camouflage among the many ponies in the primary care setting.

After twenty two years working as a physician in college health and seeing two or three extraordinary cases every year, suddenly I’ve seen three “once in a career” patients in the last three months.

Several weeks ago I saw an otherwise healthy student with an unusual rash and history of nightsweats for two weeks.  The well circumscribed large erythematous lesions matched photos I looked up of erythema marginatum which can occur with rheumatic fever from Group A strep infection.  The student had never had a sore throat but did have a positive rapid strep test that day as well as a markedly elevated streptozyme and sed rate, and met other clinical criteria of rheumatic fever.  The infectious disease consultants agreed.   Thankfully the student was diagnosed and treated early enough that echocardiogram was normal.  The rash and sweats disappeared within 48 hours on Penicillin VK.  This is believed to be the only case of rheumatic fever in our state this year.

Last week I saw an otherwise healthy student with a history of a pet rat having bitten an index finger a week before.  The bite healed without intervention but the student was feeling generally unwell with headache, nausea, fever, chills and muscle and joint aches, as well as a new macular rash of discrete erythematous lesions on palms and soles, extending to the dorsum of the feet.  All symptoms appeared classic for rat bite fever, a rare infection by Streptobacillus moniliformis with a 25% mortality rate if left untreated.  Blood cultures remain negative but must be kept at least three weeks for this particular bacteria. The patient has finished a week of IV antibiotics while remaining in school and all symptoms have improved.  There are apparently very few cases in the U.S. annually but since it is not reportable, the incidence is unclear.

Also last week an otherwise healthy student was hospitalized in septic shock after being seen twice in emergency rooms while home over Thanksgiving break–fever, sore throat, nausea, muscle aches that appeared viral to the evaluating clinicians.  The student came back to school still sick,  went to the local emergency room when feeling so lightheaded that walking was difficult, ended up in ICU on a ventilator due to incipient respiratory failure.  It took several days of touch and go clinical management for the diagnosis to become clear:  Lemierre’s Syndrome — septic thromboembolism to the lungs that results from a gram negative infection in the throat and causes deep pharyngeal abscesses, with a jugular vein that becomes infected with septic emboli.  The student was initially placed empirically on three antibiotics by the infectious disease specialist so was being appropriately treated even before the diagnosis was obvious, and will likely be on IV antibiotics at home for up to eight weeks due to the persistence of the emboli.  Lemierre’s is something that is reported two or three times a year in young adults nationally and carries a significant mortality rate.

These three patients have survived these devastating infections.  I’m very humbled by the fact that presentation of routine symptoms in a young adult primary care population should never leave the clinician complacent about what the potential cause might be.

The zebra just might be hiding in the bushes, right in the middle of a herd of horses.

Emily Gibson is a family physician who blogs at Barnstorming.

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  • http://makethislookawesome.blogspot.com/ PamC

    We tell doctors, when you hear hoof beats, think horses not zebras. But when it’s not a horse, and it’s not a zebra, have a little humility and faith of heart. You just may be hearing a unicorn. http://makethislookawesome.blogspot.com/2011/12/i-met-another-unicorn.html

  • Anonymous

    Your zebras don’t appear to be zebras, because they were simply classic presentations of rare diseases. Unusually colored horses, perhaps, but not zebras. A zebra is ANY disease with an ATYPICAL presentation that leads you astray. The Anonymous Doc has one on his blog right now — a man presenting with chest pain who turned out to have a kidney infection. Take a look at it!

    • Anonymous

      Maybe I was trained in a different era (the late 1970s/early 1980s) when we used the aphorism –”"When you hear hoofbeats, don’t expect to see a zebra”  to keep newly trained health care professionals from immediately leaping to an unexpected or unusual diagnosis when presented with common symptoms.  The differential diagnosis process used on the TV show “House” spends considerable time dwelling on “zebra” type cases. 

      I use “zebra” here to emphasize the camouflage aspect of not always easily seeing the stripes that accompany the hoofbeats–we are so conditioned to expect the expected, not the unexpected that it takes a trained eye to keep looking for the zebra stripes when the hoofbeats are everywhere.

      Then there is the aphorism “If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck” which also was used frequently in my medical training.   I think I like the zebra analogy better…

      Emily Gibson M.D.

    • http://expatdoctormom.com/ Expat Doctor Mom

      Dear Natsera

      Yes, you make a good point. 

      It is all in the presentation however…

  • http://twitter.com/AfternoonNapper Afternoon Napper

    It was my primary care doc who first hit on my renal artery stenosis. He’d had one other patient during his career who had it—that patient and I shared symptoms. I’m thankful for those docs who are willing to look beyond the obvious and consider the possibilities. 

    • Anonymous

      yes, you are right–once we’ve seen an unusual case (or learn of one from a colleague which is why I am sharing these cases) we never forget it.  We will always be looking for it again.

      Emily Gibson

  • Anonymous

    Dr. Robert Centor (of the Centor Criteria and http://www.medrants.com blog) has written me to say that Lemierre’s Syndrome is, in fact, more common than I cited in my blog–possibly an incidence range of 1/70,000 adolescent/young adult patients annually.  On the College Health Listserv of 2000 + members where I shared this posting last week, there were at least six cases of Lemierre Syndrome that had been diagnosed in the last year.  Most of us on the listserv had heard of Lemierre Syndrome but had never seen it: I’ve cared for over 250,000 college students over two decades and this was the first case in my clinic population.  Since we use the Centor Criteria for making our decision about treatment, I don’t think that is due to overuse of empiric antibiotics.

    So in Dr. Centor’s wise words to me:
    “Lemierre syndrome thus represents a zebra that is just common enough for
    everyone to know, but rare enough for us to have insufficient data.”

    Emily Gibson, M.D.

  • http://twitter.com/SarahWW Sarah Wells

    Young adults should get the antibiotics.  It’s not overuse; stricter criteria for doling them out has led to an uptick in cases.

  • Anonymous

    Thank God for you and other Primary Care Physicians who hear hoof beats and actually LOOK to see what is causing them instead of making assumptions about common things being common.  Not an easy accomplishment in 15 minute increments.   I will be forever grateful for the PCP who sorted through all my common symptoms and discovered my rare disease in time to save my life.  

  • http://expatdoctormom.com/ Expat Doctor Mom

    meaning your presentation. 

  • Tracy Krulik

    Interestingly, when my doctor figured out that I had a rare neuroendocrine tumor on my pancreas after nine years of all my doctors missing the diagnosis, he started looking a little too closely for zebras. He ordered a number of unnecessary tests for both my husband and me when we came to him with problems, and we soon realized that we needed to find another doctor. My doctor it seemed was so afraid of making another mistake that he became overly cautious. It’s now four years later, and I wonder from time to time if he’s still torturing his patients with too many tests. What’s worse? Missing the common diagnosis or becoming an alarmist and putting patients through expensive and possibly unnecessary tests? It always comes down to finding the balance between art and science. 

  • Art Papier

    One of the myths that the TV show House promotes is the idea that the doctor can memorize all of medicine and deliver back that knowledge to each patient’s encounter perfectly and without error.  Common sense tells us that it is impossible for even the specialists to memorize everything there is to know and to use that knowledge to problem solve accurately for each unique patient every 20 minutes.  When i attended medical school in the dark ages of the 80′s there were no online tools or mobile devices to aide cognition.  Now at the point of care, on the desktop or in the pocket there are excellent tools to aide decision-making for clinicians.  I notice that my residents use these tools all the time.  I have seen physicians in their 70′s use these tools, but unfortunately there are many physicians that never use references as they work.  Are the physicians that never reference a medical textbook or computerized reference that much “smarter” than the ones that do?  Are they expert diagnosticians that can diagnose like House MD?  The answer is NO and if you never see your doctor checking a dose or diagnostic possibilities he or she is just not taking advantage of tools that will enhance their practice of medicine.  These tools are not just about zebras.  In our work in diagnostic decision support we are focused on variants of common diseases as well as assisting rare disease diagnosis.    Common things do happen commonly, and variants of common diagnoses happen more frequently than rare diagnoses.   Assisting diagnosis, particularly in the new era of asking our primary care doctors to work harder with less time means we need to do more to train primary care residents in the diagnostic process, and train them in the modern tools that can assist diagnosis.   We need to train our students in decision-making and model for them excellent information seeking behavior and open problem-solving and communication with the patient.  Would we idolize and respect a pilot who insisted on memorizing all the routes and ignored the cockpit computerized guidance systems?  That is the House model of aviation and medicine.  
    Art Papier MD
    CMIO
    http://www.visualdx.com

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