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Four years ago, I was driving home from work when I began to experience mild chest pain.  It was located slightly to the right of my sternum and felt like a muscle strain.  My chest was slightly tender when I pressed on it, but so slightly that I felt unsure with every other palpation if it actually was.  When I turned in my car seat, it hurt more as well.  I thought it was one of those mysterious minor pains we all get every so often.

I’d recently suffered from an internal hemorrhage—a complication of an appendectomy—that had required a re-operation a day later, and had planned to call my doctor as I drove home to discuss some follow up labs.  He told me my results were normal when I called, to which I responded offhandedly and incongruently, “Well, that’s good, because I’m having a little chest pain.”

“Since when?” he asked.

“Just now.  About five minutes.”

There was silence.

Surprised by his hesitation, I asked, “Why?  What are you thinking?”

“I don’t know,” he answered.  “Maybe a PE.”

“PE” stands for pulmonary embolism, a potentially life-threatening condition in which a blood clot forms, typically in one of the deep veins of the legs, and then breaks off, travels through the right side of the heart, and lands in the lungs.  If large enough, or if multiple PEs shower the lungs at once, it can be fatal.  PEs usually occur in the context of risk factors:  recent surgery, obesity, airplane travel of greater than four hours duration, and trauma, just to name a few.

That I could have had one hadn’t even occurred to me.  Which was strange, I thought, given that I’d had recent surgery—twice—the second of which was in response to a form of trauma (the internal bleeding), and had just returned from a round-trip airplane flight, each lasting exactly four hours, from Mexico.  PE, as a resident had once taught me, “is the devil”—meaning, it can present in almost any way it wants:  with chest pain (or not), shortness of breath (or not), the coughing up of blood (or not), a rapid pulse (or not).  You made the diagnosis by retaining a high index of suspicion when risk factors were present.

All this is to say that any kind of chest pain in the context of my recent medical history should have immediately triggered the possibility of a PE in my mind.  It should have done so in a  third year medical student’s mind.  But it hadn’t even entered mine at all.

“It’s definitely tender,” I told my doctor.

“Maybe…” he mused, meaning that maybe the cause was only musculoskeletal as I’d originally supposed.

I continued driving to my wife’s work to pick her up.  “What do you think I should do?” I asked him, determined not to play at being my own doctor.

“Well,” he said reluctantly, “we could just watch you overnight.  If it’s still there in the morning, we could scan you then…”

I liked that idea very much, even though I knew the pain from a PE often faded once the inflammation it kicked up had settled down.  Nevertheless, we quickly agreed on that plan and hung up.

A minute later, however, he called me back.  “I’m not going to be able to sleep if we don’t scan you tonight,” he said.

“Really?” I said.  I’d almost reached my wife’s work and was more than a little reluctant to drive all the way back to the hospital.  “I’m turning in my seat now and it’s clearly making it worse,” I argued.

“Alex,” he said, “so what?”

I stopped.  “Okay,” I said.  “I’ll come back.”

So I picked up my wife and together we drove back to the hospital.  There I had a PE-protocol CT scan and walked back to the waiting area where my wife waited.  I felt chipper and unconcerned.

That is, until I saw the expression on the radiology resident’s face as he approached us a few minutes later.  “You actually have a moderate-sized PE in your right lung,” he said uncomfortably.

“You’re kidding,” was all I could think to say.  He shook his head and walked me over to the ER where I was placed on an IV blood thinner.  As I lay on the ER gurney, terrified, I wondered why I’d not even thought that I might have a PE, as well as why my doctor (who happened to be a close personal friend) had tried to ignore the possibility himself once he’d thought of it.

The answer at which I arrived has to do with the way our minds work and a particular cognitive bias I’ve described before.  Disconfirmation bias means simply we ignore facts that support ideas we don’t want to believe.  I clearly had a good reason not to want to believe I had a PE.  What shocked me, however, was how unconsciously this bias worked, preventing me from even having the thought that I might.  My doctor friend struggled with the same bias, the strength of his desire not to hand me a bad diagnosis leading him to act as if it was less likely than it actually was, something I’ve written about in previous post, When Doctors Don’t Know What’s Wrong.  Neither of us wanted me to have what I ended up having.

I’ve seen this kind of behavior in my own patients as long as I’ve been a doctor (I once had a veteran take a nine-hour bus ride with crushing substernal chest pain to come to a university hospital rather than his local ER).  The ability to deny a symptom’s significance is as strong in some people as the tendency to read too much into it is in others.  Studies suggest that the risk of dying from a heart attack is greatest in the first thirty minutes after symptoms appear.  By that time, however, most of my patients are just getting around to thinking about calling a relative to ask them if they think it’s likely to be anything serious.

The point, then, is simply this:  we’re cognitively predisposed, most of us, to believe we’re okay.  The moment even minor symptoms flare, most of us begin explaining them away, not because they’re necessarily unimportant, but because we don’t want them to be.  This cognitive distortion is actually quite useful in that it protects us from suffering overwhelming anxiety in response to the daily inexplicable aches and pains many of us experience.  But when it obscures our judgment and prevents us from acting quickly to preserve our health, it’s quite clearly a liability.  It very well may not be possible to entirely free ourselves from this bias, and certainly in most situations we probably don’t want to.  But whenever we find ourselves automatically dismissing an unusual symptom, we should stop and ask ourselves:  are we sure it’s really nothing?

If you’re like me, the context in which you find yourself when such symptoms occur will have an enormous impact on what you decide to do about them.  Had I not been on my way home when my chest pain struck, for instance, I’m certain I wouldn’t have resisted getting it evaluated as much as I initially did.  (The prospect of getting to an ER from where we are and potentially having to wait hours even to be seen can be enormously off-putting.)  That such small considerations can loom large in our mind when we’re debating whether or not to seek help should be something of which we remain wary.  I see no other way to minimize the bias that, if we’re not careful, could mean the difference between life and death.  Otherwise, when it comes to our own health, sometimes we’re the last people to whom we should listen.

Next Week:  Funerals