The Calculus of Pain
By David L. Katz, MD; Chief Medical Officer of the Community Pain Center
My wife and I have 5 children, and as they’ve grown up and become more independent, it has become ever more complicated, and ever less common, to get all 7 of us together. Like all families, we have an almost limitless capacity to drive one another crazy–but we all really love one another. So those occasions to convene the whole tribe are precious to us all.
We had just such an occasion planned last spring for Family Weekend at the University of Florida, where one of our daughters recently completed her freshman year. We were starting from Connecticut, New York, and Massachusetts–and the plan was to converge on Gainesville. But out of the 6 of us with tickets, only 5 got on their planes. My daughter living in Boston didn’t make the trip, because at the last minute, she was afflicted with abdominal pain, nausea, and vomiting pretty much out of the blue. So out of the blue she stayed, stuck in bed. She described the episode to me, and in a young healthy person, it sounded like a trivial, if ill-timed, bout of gastroenteritis–perhaps food poisoning. I thought nothing more of it. We missed her in Florida, but she promptly recovered–and life resumed its customary cadences for us all.
“When you hear hoof beats, think horse not zebra.”
Until several weeks ago, when my daughter called me from Boston. My wife is far more the family concierge than I; all reports of routine comings and goings tend to come to her. When I get a direct call, it is almost invariably of the “please send money, Dad” or “does this need stitches?” variety. This was, predictably, one of those. My daughter was having another bout virtually identical to the first. And that changed the calculus entirely. In medical school, we are taught that “when you hear hoof beats, think horse not zebra.”
The “zebra” represents the unlikely, rare, or exotic diagnosis. In a place where horses are common and zebras rare, any given hoof beat is far more likely to be that of a horse. The more prosaic version of the same insight is: “most people have what most people have.” We could take this further, and explore Bayes’ theorem–but we won’t. In a healthy, young adult without any known chronic gastrointestinal ailment, a single bout of the GI duress described is overwhelmingly likely to be some form of gastroenteritis, a condition that occurs nearly 180 million times a year in the U.S. But the likelihood that two, virtually identical episodes from independent causes would occur within a few months in a person who otherwise had no such episode in years–is vanishingly less probable. It could happen if there is a source of food poisoning, but then others should be getting sick too. None of my daughter’s friends or co-workers had any similar ailment.
The recurrence invited the application of another bit of conventional wisdom codified into medical education, called Occam’s razor. This basically stipulates that 14 different symptoms in a given person at a given time are far more likely due to a single cause that accounts for them all than 14 different conditions that happened to spring up simultaneously. Closely related is that recurrent bouts of any given syndrome are likely connected by a common cause, rather than independent mimics.
So this second bout evoked a very different response from me. My daughter arranged a trip down from Boston to Connecticut, and I ordered blood work and an abdominal ultrasound. As I expected it would, the abdominal ultrasound showed gallstones. The rest proceeded predictably, and my daughter had her gall bladder removed–a laparoscopic cholecystectomy–several days ago at Griffin Hospital in Derby, CT, where she received surgical expertise from Dr. Lee Soto, and wonderfully compassionate care from the staff. She is recovering nicely–although she did have to avoid the pool, and sit out the traditional Katz Family Independence Day volleyball game. As anyone who has ever played volleyball with her can attest–not that big a loss.
On the other hand, she was supposed to work during the holiday weekend, and stay in Boston. Although surgery was the excuse for this visit, it was a visit just the same–and since the other four of our kids were all gathered for the holiday, we got our clan together after all. Better late than never.
…recurrent bouts of any given syndrome are likely connected by a common cause, rather than independent mimics.
The generalizable message here is that the calculus of pain, or any given symptom, changes with context. Common things are common–and the most common explanation is the most probable. But if you have recurrences of abdominal pain, or chest pain, or headaches, or breathlessness–then an underlying condition that can account for those recurrences is far more likely than a series of unfortunate and unrelated events. Seek medical care accordingly. No need to think zebra each time you hear hoof beats, but you sure don’t want to ignore an imminent stampede of zebras while looking around for your horse. Sometimes even a very improbable diagnosis is correct. As Sherlock Holmes said, when you have eliminated the impossible, whatever is left–however improbable–must be the truth.
In this case, the calculus of one episode was gastroenteritis. The calculus of a recurrence was stones, or calculi, in the gall bladder–a fairly common condition in its own right, although a bit unusual in a 25-year-old. The perpetrators are now in a specimen jar, and all is well. On the occasion of Independence Day, it is perhaps timely to note that in matters medical, we are each our own first line of medical defense. Calculate accordingly.