Blog | Thursday, May 9, 2019

Fictional detectives as diagnostic models

Like most internists, I love a good mystery novel, TV show, or movie. Mention Sherlock Holmes and internists smile. When Dr. Mark Shapiro wanted to complement Dr. Gurpreet Dhaliwal for his diagnostic expertise, he labelled their podcast discussion ”Gurpreet Dhaliwal, The Sherlock Holmes of Medicine.”

Studying fictional detectives helps me understand some basic principles of diagnostic excellence. A common trope in detective novels is the misdiagnosis. Someone has been falsely accused or even convicted of a heinous crime. Superficially, the evidence points to the accused, but the fictional detective has an uncomfortable feeling because of something in the case that does not fit.

In the BBC series “Sherlock,” Season 1, Episode 2, Sherlock states, “You have a solution that you like, but you are choosing to ignore anything that you see that doesn't comply with it.”

It's that uncomfortable feeling you get about a patient's diagnosis. Many years ago I described this as reading the textbook description of the patient's diagnosis and finding that it does not fit. When that happens, the patient is not wrong, rather you are reading on the wrong page.

When this happens, we need more data, or as Sherlock said in the Adventure of the Copper Beeches, “Data! Data! Data!” he cried impatiently. “I can't make bricks without clay.”

Sometimes the data comes from questioning the patient again. When stumped go back to the bedside. Or as Agatha Christie wrote for Hercule Poirot, “It often seems to me that's all detective work is, wiping out your false starts and beginning again. Yes, it is very true, that. And it is just what some people will not do. They conceive a certain theory, and everything has to fit into that theory. If one little fact will not fit it, they throw it aside. But it is always the facts that will not fit in that are significant.”

When the diagnosis does not make sense, start over. Michael Connelly's great character Harry Bosch said, “I've learned over the years that sometimes if you ask the same question more than once you get different responses.” And this really happens at the bedside.

These wonderful, entertaining detectives give us permission to be skeptical of accusing a particular disease as the cause of the patient's illness. We owe our patients a dispassionate, dogged approach to the truth of their diagnosis. We have great role models from whom we can all learn.

And remember the wisdom of Dashiell Hammett in “The Thin Man”, “The problem with putting two and two together is that sometimes you get four, and sometimes you get twenty-two.”

db is the nickname for Robert M. Centor, MD, MACP. db stands both for Dr. Bob and da boss. He is an academic general internist at the University of Alabama School of Medicine, and the former Regional Dean for the Huntsville Regional Medical Campus of UASOM. He still makes inpatient rounds regularly at the Birmingham VA and Huntsville Hospital. His current titles are Professor-Emeritus and Chair-Emeritus of the ACP Board of Regents. This post originally appeared at his blog, db's Medical Rants.