Or perhaps a more apt title would be “Not Knowing that we Don’t Know in Medicine”. A colleague and I gave a lecture last week on EBM in the context of how do we know what to do in medicine. We pointed out that there are 4 general ways that we know what we know in medicine: authority, clinical experience, pathophysiological rationale, and systematic investigation. I serendipitously read an article late last week in a great new series in JAMA called JAMA Diagnostic Test Interpretation.  I thought about all the times I used ammonia levels incorrectly and all the times my colleagues and residents used ammonia incorrectly. Why? Was I too lazy to evaluate the literature in this area? Admittedly I hadn’t but it didn’t even occur to me to do so because during my training my senior residents and attendings told me to check ammonia levels in patients who we suspected had hepatic encephalopathy as it “would help make the diagnosis”. 20 years later an epiphany has made me realize I have been doing the wrong thing for all these years. I didn’t know jack about the limitations of ammonia in chronic liver disease.

Why did I trust authority? Was it because John Mellencamp sang “I fought authority and authority always wins” so I didn’t question what I was told to do?  I wonder how many other things like this I do with no idea that I am doing it all wrong. Likely a fair amount. The hard part is there isn’t time to go back and review literature on everything we do. Even if I only reviewed the information in a preappraised resource like Dynamed or UpToDate I wouldn’t have enough time as I can barely find time to keep up with newer things without having to go through all the things I “KNOW” already.

I hope articles like this simple review in JAMA will help educate us all. I hope other journals follow JAMA’s lead and make distilled evidence summaries that we can quickly digest to improve the cost-effective care that we provide. I hope each of us will occasionally, maybe just once a month, question how we “KNOW” something and if we can’t give a good enough answer that we will take the time to  find that answer. We likely will be surprised by how much we don’t know in medicine.