Testing, 1, 2, 3
Although tests are extremely important, they should be used along with critical thinking -- not in place of it, say experts. They should be used judiciously and never as a substitute for a thorough history and physical examination, Dr. Katz advises.
"Whenever you order a test, ask yourself, 'What's my differential diagnosis? How will I act differently based on the results?'" He suggests ordering tests in "reasonable sequence" rather than "all up front," not only to contain costs but also to look at findings in a stepwise fashion. This increases the likelihood that important data won't be overlooked.
Experts regard "active listening" as the most critical component of successful diagnosis.
Lesley Ann Fein, MD, MPH, a rheumatologist and infectious disease specialist in West Caldwell, New Jersey, often sees patients with complicated conditions, who have been to previous physicians without obtaining a satisfactory diagnosis.
"Patients need to tell their story all the way from the beginning. I allow open-ended narration and also engage in pointed questioning. I ask myself, what variables might be linked? What doesn't belong? I follow the leads while my mind is simultaneously going through the differential diagnosis, narrowing it down. The answer may lie deep in their medical history, in the remote past, in some 'trivial' detail no one ever questioned before," says Dr. Fein.
Listening and Looking for Subtleties
Dr. Fein acknowledges that the history she takes is time-consuming, with appointments lasting a minimum of 3 hours. "I don't participate with insurance plans because I don't want the time constraints," she says. Dr. Fein adds that she asks patients to bring all their diagnostic tests, no matter how old. "The most ancient test might contain the most important information," she says.
But even in time-pressured settings, "you can listen for clues," says Dr. Groopman. "Attune your ear to nuances, and deviations from the typical presentation will jump out at you."
Daniel Pranson, MD, a pediatrician in Chicago with a reputation as a top-notch diagnostician, described an instance of finding the less obvious diagnosis. A toddler presented with slight fever and rhinorrhea, and he suggested a decongestant. Two days later, the mother returned saying, "He's not acting like himself." Dr. Pranson accurately suspected meningitis.
What made Dr. Pranson jump to the zebra instead of the horse?
"I'm no genius, and I wasn't the class valedictorian," says Dr. Pranson. "I try to stay current with the literature, but more important, I look at subtleties. And I regard a mother's return visit as a red flag, which I trust. Parents can sense when something isn't right with their child. This motivated me to look more carefully under the surface presentation."
Conclusion
Even the best doctor and diagnostician will make a mistake or miss something on occasion. "The real issue is whether you've learned from your mistakes -- and from the mistakes of your colleagues," Dr. Groopman says.
He adds that integrating a strong knowledge base with regular examination of your thinking patterns will enable you to continue honing your diagnostic skills.
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Cite this: Are You a Great Diagnostician? - Medscape - Mar 27, 2013.
