Not all medical expertise is created equal
How this accidental lesson helped me be a better doctor
A diagnosis, in a sense, is a story - a story that involves certain kinds of questions, such as, who are the major players, how might they interact, and what plot twists does your doctor foresee? Ancient physicians had less information about the physical world. Correspondingly, their stories had less physical basis: air going to the penis to cause erections, and imbalanced humors causing everything else, for example. As we learned more about the physical world through direct observation of human and animal bodies, dissection and microscopes, and more, we incorporated that knowledge into our understanding. Our theories became better at prediction. Our treatments became more effective. Always, however, our explanations remain approximations of reality. As such, there are likely some things that I say to my patients that future doctors will raise their eyebrows about, like the way we raise our eyebrows about Galen's pneumatic erections.
Each generation unlearns some things that have been known for a very long time. Part of the fun of medicine is to learn which of the things that everyone knows are actually not true. The canonical example of this for my generation is "gastric ulcers are caused by stress." This is a very appealing idea because stress can increase acid secretion, which can lead to heartburn-type symptoms, which can be confused with an ulcer. Once the technology was developed to put a camera into a patient's stomach and directly visualize its lining, an observant doctor could notice that the story was not playing out as expected. At the present time, we think that gastric ulcers are caused by infection with the bacteria h. Pylori, not stress. The observant scientists who figured this out won the Nobel prize for it.
My med school attempted to be pedagogically advanced by having us do a couple of research papers in addition to the usual multiple-choice tests. They gave us a patient case for which we had to figure out the diagnosis and explain the standard treatment. One of these papers was on contrast-induced nephropathy - an unfortunate complication of medical procedures in CT scans and cardiac catheterizations that involve the dye used to show blood vessels. The dye can be bad for the kidneys and cause (usually) temporary kidney failure, sometimes bad enough to require temporary dialysis.
Since I wrote my research paper, better techniques have been developed to allow us to give smaller amounts of dye. This has reduced the frequency of contrast-induced nephropathy, but it remains a problem. I have seen several cases of it among my patients over the years.
I remember well that I lost points on that research paper for being unable to explain the rationale for the standard treatment. At the time, it was felt that the best treatment was to give the patient IV fluids and lasix simultaneously. Lasix is a medication that tricks the kidneys into making more urine than they think they need to. It makes people pee more. The IV fluids give them something to pee.
The explanation for this treatment never made sense to me. Because of this, I could not regurgitate it for the paper and cannot remember it now. I only recall that it was a complicated cascade involving sodium channels, sodium/potassium ion exchangers, and ion gradients, and I can't remember what else. Evidently, most of my classmates were able to regurgitate the explanation because my score was in the lower half of the class on this paper.
A literature search was a required part of the research paper, but it was not central. Because I was having such a hard time understanding the material, I did a deeper literature search than was expected, hoping to find an explanation that I could understand. The more articles I read explaining how the IV fluid/lasix treatment worked, the more confused I became. There was even one small clinical trial that studied this exact question. It found that IV fluid and lasix were associated with worse outcomes. The professor wrote "yikes!" in the margin next to where I reported this finding. Despite this, I didn't get back any of the points I had lost for my inability to explain why the treatment was supposed to work.
It turns out that I deserve those lost points back. The standard treatment has been changed. It is now felt better to give IV fluids and let the kidneys make the amount of urine they feel is best. No more lasix. In fact, just three years after I submitted that paper, when I was in residency, my kidney attending told us that there was no reason to ever give IV fluids and a diuretic to a patient simultaneously except to enrich the IV fluid manufacturer. He declared this with the same level of authority and certainty that our kidney professor had told us the exact opposite three years previously.
I was able to easily decide which of these contradictory authorities to believe because my professor in med school was a PhD scientist who had never given IV fluids or lasix to a patient in his life, whereas my residency attending had been a nephrologist for thirty years and had given a lakeful of IV fluids over his career. I follow the rule: Those who talk should do and only those who do should talk. For this kind of thing, the expertise that comes from having done the thing in question matters more than expertise with the theory. Galen had obviously observed erections but never had dissected a human to see the theorized connection between the lungs and the penis. He told the best story he could construct with the knowledge he had, but as more knowledge became available, his story fell apart.
The internet has changed what it means to be an expert. Expertise can be said to have two components: knowledge and experience - know-what and know-how. The internet has made knowledge available to all, but experience is still only available from doing something for a while. My patients will sometimes google their symptoms and tell me their diagnosis. When they do this, well over half the time I find they are at least partially right with respect to the knowledge portion of the issue. On the other hand, Dr. Google usually exaggerates the severity of their condition and gives them a treatment plan that is unlikely to be appropriate for their situation. Routinely, when patients have first consulted Dr. Google, I have to tell them that they are unlikely to die from their symptoms even though they have the correct diagnosis, especially if the home remedies are working. Despite this, I have found Dr Google to be a positive development. It can be helpful that the person has already accepted their diagnosis, and all I have to do is confirm and answer questions.
Sometimes I hear other doctors disparage Dr Google. The proliferation of mugs that say, "Do not confuse your Google search with my medical degree" corroborates this. I can imagine that it would be frustrating for some doctors to have a patient believe Dr. Google rather than them. I can understand why they might respond to this in a way that would cause the patient to go to their cousin's doctor and complain.
I like to think that I would use the patient's preference for Dr Google's expertise as an opportunity to examine my own way of working. What might I be doing to cause the patient to devalue my experience? One common complaint with doctors is that they do not take the patient's experience into account–that doctors devalue the patient’s experience. The patient is the expert in their life. If a doctor disregards this expertise, sometimes people reciprocally disregard the doctor's expertise. Even if the patient doesn't get the facts right, their personal experience with their own life would still be true. The reciprocal thing is true for the doctor's experience: even if we learn that a long-cherished theory is wrong, such as the theory behind why the IV fluid needed to be chased with lasix in order to work, what we did still worked.
There are countless examples in medicine of things we know whose opposites were known with the same certainty ten years earlier. Remember Donald Rumsfield and his unknown unknowns? In the exam room, I often find myself trying to thread my way between known unknowns (things we know that we don't know) without stumbling on an unknown known (things we think we know that we do not know). Remembering that there are unknown knowns helps me stay humble when I'm sure that I know the best course
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The patient is the expert in their life.
Wonderful acknowledgment
Great article
Thank you