Wednesday, August 16, 2017

Wisdom Wednesday: When You Hear Hoof Beats, Don’t Look for Zebras


Many years ago an MD I worked with gave me this answer when I inquired about the possibility of some exotic disease in a common patient. The exact quote was “Oh Bill, when you hear hoof beats, don’t look for zebras, it’s usually horses.”

My response was that during college I lived along the Hillsborough River in Tampa. Every morning, driving to class at USF, I passed Bush Gardens and saw lots of zebras.

Zebras do occur in everyday practice. They just don’t occur every day. However, as a primary care physician, it is my responsibility to see the tell-tale ‘stripes’ and act accordingly.

The patient that comes in with acute low back pain is almost always a horse. But if she has a history of breast cancer or he has a history of prostate cancer, they might be a zebra. Metastasis from breast or prostate loves bone, especially the low back. I am responsible for picking up on that stripe even if the patient doesn’t give me the history. That’s because it’s my responsibility to ask.

I don’t have to diagnose the cancer or treat it, but I have to make the appropriate referral. I may decide to run further testing to make a more educated referral or even co-treat. What I cannot do is delay proper diagnosis or medical treatment.

Diagnosing zebras is also an issue. If I, or any other physician, suspect a particular disease, you cannot tell the patient they have that disease without running the appropriate diagnostic testing. You tell them that you suspect a possible pathology. If pressed, you give them a differential that includes a few possible disease processes.



Recently, I had a new patient that was told by her neurologist, within 10 minutes of consultation, that she had MS. She may have MS but we probably won’t know for sure for a least three months. In the meantime, she is living under the assumption that she has this disease.

I have another patient who was told she had HIV/AIDS. She had not been sexually active for three years and had no other history of potential exposure. I suggested repeating the testing. Two weeks after revealing her diagnosis to her family and friends, the repeat lab work ruled out HIV/AIDS. She was obviously relieved but what about that needless suffering under a faulty diagnosis?

Last week, I had a new patient with previous diagnosis of GERD (gastroesophageal reflux disease). The treatment had not been very effective and she sought alternative care in my office. I found evidence of GERD and the post-nasal drip that was aggravating her esophagus. However, I also found evidence of cardiac insufficiency (that’s a zebra). I treated the GERD and post-nasal drip but referred her back to her PCP recommending a cardiac work-up. Three days after seeing me she had two cardiac stints implanted for several coronary artery blockage.

The symptoms of GERD and angina are very similar, much like the hoof beats of horses and zebras. You have to look for both. In fact, you have to suspect both. I would much rather error on the side of caution than have a patient suffer permanent damage or death because I assumed their symptoms were commonplace.

The Bottom Line:
When you hear hoof beats, you better be on the lookout for zebras. Yes, they are exotic but not extinct. If I’m looking for them, then the patient, hopefully, can rest at ease, knowing that I have a watchful eye.

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