Putting the Answer Before the Question

Throughout history, doctors have revered knowledge. So how can knowledge blind us to the truth? Easy. After a few years of practice, most doctors deal capably with a host of diagnoses. They are familiar foes.

Yet sometimes symptoms don’t add up, and we still see the same old foes. That’s when knowledge short-circuits wisdom.

This is a story about my own knowledge and short-circuited thinking. Some years ago, I mistook a diagnosis and clung to it like a dog to a bone--until my patient solved her own case and set me straight.

True, along the way she neglected to tell me an important fact. But I also neglected to ask her an important question because I had already made up my mind about what she had.

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Amy Ward, a teacher in her 50s, had always hoped to explore the world. After nursing her husband through terminal cancer, she was ready. And so she left for the jungles of South America where, as a vegetarian, she ate tropical fruits and greens to her heart’s content.

But soon after returning home, Amy’s calves and thighs began to ache, and fiery hives broke out on her shins. With no more home remedies left to try, she decided to see her internist. He ordered lab tests.

That’s when I was called. Amy’s blood contained massive numbers of cells called eosinophils. Eosinophils are usually seen with allergies, but they also skyrocket in response to certain parasites.

I immediately sketched an infectious disease scenario to explain Amy’s eosinophils. She didn’t have allergies, I reasoned, therefore she must have parasites. Specifically, tiny worms transmitted by tropical produce. Worm eggs are smaller than dust motes yet surprisingly hardy. Once expelled from humans and animals, they survive for weeks in soil. From there they can attach to fresh fruits and vegetables, the same foods Amy loved.

My theory also fit Amy’s aching muscles and red-hot rash. These symptoms, I figured, must be due to migrating larvae now hatched from eggs. Biologically, the interval between Amy’s South American trip and her symptoms--four to six weeks--fit perfectly.

But despite my conviction, weeks passed and test after test failed to prove my theory.

Meanwhile, Amy was getting worse. In fact, some days her legs were so painful and swollen she could hardly walk. Finally, I admitted her to the hospital for one more test--a muscle biopsy to look for larvae and other abnormalities--and then put her on an experimental drug used to treat parasites. Later that week, my pager went off. It was Amy. What now, I worried. As I picked up the phone, I could have kicked myself for delaying treatment so long.

Thank God, there was Amy’s voice, sunny as always, accompanied by the rustle of her morning newspaper. I’ve got the answer! she greeted me exultantly. Did you know I’ve been calming my nerves with L-tryptophan from the health food store ever since my husband died? And now they’ve found it causes symptoms just like mine. In the last few months, I’ve gone through tons of that stuff.

First came doubt, then chagrin. But, after reading the article for myself, my deepest feeling was relief. The amino acid tryptophan, manufactured impurely, had just been reported as the cause of a nationwide outbreak of muscle disease and eosinophilia. So much for parasites. At last, Amy’s case made sense.

Over years of practicing medicine, from time to time all doctors revise diagnoses. In 20 years of medical practice, I have reconsidered diagnoses many times, based on input from lab tests, patients and other doctors. But rarely, I suspect, from a newspaper story.

Amy’s case sticks with me because of the newspaper story. The headline showed me my own blindness, right there in black and white.

Not that I could have predicted the truth about tryptophan. After all, medicine isn’t about gazing into crystal balls, but slowly and methodically gathering data. This time I was lucky: The data broke just when I needed it.

Looking back, what I regret most in Amy’s case was my mistaken belief--minus proof--that she had an exotic infectious disease. Why did I hold that belief? Probably because I specialize in exotic infectious diseases.

My other regret is neglecting to ask--not about Amy’s eating habits during her vacation--but self-treatment from the neighborhood health food store. Of course, this was 10 years ago, when only a handful of patients were dabbling in herbs and dietary supplements. Today, I would be even more remiss.

It seems it has always been true. In medicine, new knowledge is so close, if only we ask the right question.

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Claire Panosian Dunavan is an internist and infectious diseases specialist practicing in Los Angeles. Reader comments are welcome at: drclairep@aol.com.

* The Doctor Files runs the fourth Monday of every month in Health.