Lyme: Zebra or Horse?

A new patient waited in exam room one. I fumbled into the room juggling the new chart and my requisite morning coffee. We introduced ourselves. Her serious demeanor dissolved into an ambivalent, nervous smile as I settled in my chair. She found me through a Lyme forum on the net. Several months of symptoms troubled her. Admittedly the symptoms were not severe, but they had persisted for several months. She had sought answers from her primary doctor, her ENT and a neurologist. No one had an answer. She googled her symptoms and did her cyber research. The same diagnoses kept popping up: Lyme and MS. The neurologist at her behest had ordered a second Lyme test- the definitive one- the Western blot. A phone call reassured her that it DEFINITELY was not Lyme- the test proved this. She wasn't convinced. She found me.

Now I was supposed to settle the matter. Always healthy in the past, this attractive young mother of 4 was now saddled with- dizzy spells, tingling in her fingers, tremors, a loss of balance and mild joint pains. She had no real fatigue or cognitive issues. Nonetheless the symptoms were bothersome. After much research and ambivalent contemplation she made a decision- she sat on the exam table across from me.

As always I asked questions, probing her history and related symptoms. I did my exam, the careful neurological exam which has become the cornerstone of my Lyme disease evaluation. I look for subtleties that would be called "WNL" in most exams. This means within normal limits- As interns we claimed it meant "We Never Look." As usual, I found various abnormalities. There was evidence of: cranial nerve dysfunction, upper motor neuron disease, peripheral neuropathy and a subtle tremor suggesting mild Parkinsonian features. I ordered the usually battery of tests to help confirm the diagnosis I suspected at this point.

She didn't know anything about Lyme she said. In reality she was already steeped in the world of Lyme land, with its own language and complex iconoclastic paradigms.

She asked THE question. "Do I always diagnose Lyme disease in patients like her. Do the labs always point me in that direction?"

She had already been to three doctors. I had spent over 20 years considering all the other diagnoses, the usual suspects, until I wandered down the rabbit hole into Lyme land. Here's the odd twist. As a physician I was taught that one must consider common disorders first when making a diagnosis. If a patient had a cough it was likely due to bronchitis, asthma or pneumonia. It probably wasn't Wegeners granulomatosis. Odd ball diagnosis were called Zebras. This came from the oft told metaphor: If you hear hoof beats in Central Park think Horses- not Zebras.

As far as the rest of the Medical world is concerned the diagnosis of Lyme disease as an explanation for her symptoms would clearly constitute a Zebra. And now, in the new reality I inhabit, any diagnosis other than Lyme (think common first) could only be categorized as a Zebra.