Monday, January 30, 2017

Chronic Pain: Do We Even Know What We Don't Know?

My wife is currently training to become a yoga instructor.  Our conversations have begun to revolve around concepts like "being present" and "finding my center."  I'm a somewhat reluctant participant in such conversations and even though I understand all of the individual words being used, I admit the concepts are largely lost on me.  One thing that has resonated with me, though, is the humility that one can derive by recognizing what one does not know.  We can start to develop more rational and realistic responses to life's problems when we step back and question the basis of our views.

Two studies caught my attention recently and reminded me of this important principle.  In the swirl of debate and conjecture surrounding contemporary approaches to pain management, I think it's critical for us to distinguish what we know and what we don't know.

First, from the joint efforts of radiology service provider Spreemo and the Hospital for Special Surgery (HSS), we learned that objective diagnoses for low back pain aren't as straightforward as one might think.  A single patient was sent to 10 different centers to get an MRI of the lower back.  Of the 49 distinct objective findings identified across the 10 centers, not a single finding was identified by all 10 centers.  The study points to a potential diagnostic error rate of up to 43%.  

Next, from the Proceedings of the National Academy of Sciences, we learned that opioids might actually prolong neuropathic pain.  The paper titled "Morphine paradoxically prolongs neuropathic pain in rats by amplifying spinal NLRP3 inflammasome activation" is a technical piece, to say the least and I won't claim to have comprehended all of it.  But here's a snippet from the conclusion of the paper that I did understand (mostly):

In summary, the mechanisms underlying the transition from acute to chronic pain are poorly understood. We discovered that a short course of morphine administered upon expression of neuropathic pain remarkably doubled the duration of CCI-allodynia. This process was dependent upon dorsal spinal microglial reactivity and NLRP3 inflammasomes. These findings comport with prior demonstrations that repeated immune challenges induce a transition from acute to chronic pain, which may also underpin pain comorbidities. An evaluation of the long-term consequences of opioid treatment for chronic pain will identify whether this phenomenon manifests clinically.

It's really astounding to think about how much we don't know when it comes to chronic pain.  For all the time we spend debating the use of opioids for the treatment of low back pain, it's both frightening and illuminating to realize we get the diagnosis wrong almost 50% of the time and the drugs we use to treat it might actually make it worse.  

Long way to go...

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1 comment:

  1. This also makes me wonder about how far we have to go in terms of treating chronic pain patients that have co-morbid psychiatric disorder. If we're getting the diagnosis wrong 50% of the time, I can only imagine how much worse the rate much more difficult it must be treating such patients.