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10 Articles in Volume 17, Issue #10
A Guest Editorial on Counterfeit Pain Medication: The Other Epidemic
A Model to Incorporate Functional Medicine into Chronic Pain Care
Chronic Pain and Substance-Related Disorders
Getting at the Root of Opioid-Induced Constipation (OIC) with an Osteopathic Approach
Inside FDA's Guidance on Generic Abuse-Deterrent Opioids
Neural Pathway Pain — A Call for More Accurate Diagnoses
Pain Care in a Natural Disaster
Pharmacological Interventions in Sport-Related Concussion
The Internet of Medical Things
What Type of Withdrawal Symptoms from Tramadol Might a Patient Experience?

Neural Pathway Pain — A Call for More Accurate Diagnoses

In the treatment of chronic pain, the author argues that a patient’s physical and emotional history may play a more significant role in long-term outcomes than expected.
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I gave a lecture on chronic pain at the Academy of Integrative Pain Management’s 2017 annual meeting in San Diego. At the beginning, I asked the audience whether they thought pain care providers needed better treatments for chronic pain or better diagnoses of the causes of chronic pain. “Better treatments” was the unanimous response, and the following explains why I have come to the opposite conclusion. (Read about a January 2018 training opportunity with the authors at the end of this article.)

Current Conceptions of Chronic Pain

The most widely accepted behavioral intervention model to treat chronic pain relies on the perspective that all pain is the same. If “pain is pain,” treatments may be designed to reduce the pain, or to help patients cope with the pain. This practice seems to blur the line between the two major causes of chronic pain:

  • inflammatory pain due to ongoing physical injury, tumor, fracture (ie, nociceptive pain), or due to nerve damage (ie, neuropathic pain)
  • brain-induced pain (ie, neural pathway, centralized, psychophysiologic, or psychosomatic pain).

When physicians fail to make this distinction, they may be viewing chronic pain as a static, non-reversible process, for which the etiology does not matter.

Structural Distinctions

This lack of distinction may have significant consequences. The most common reason that patients visit physicians is due to neck or back pain,1-2 and the causes are almost always attributed to some kind of physical injury or degeneration.

For example, physicians typically rely on MRI scans to indicate the cause of the neck or back pain. When MRIs reveal fractures, tumors, inflammatory conditions, or severely herniated discs with evidence of nerve damage, a structural disorder is highly likely. Yet, MRIs of pain-free 30-year-olds show degenerative disc disease in 50% of patients, and bulging discs in 40% of patients.3 Those statistics reach levels of 80% and 60%, respectively, in pain-free 50-year-olds, and are even higher in older patients.3 The vast majority of adults, therefore, have abnormal MRIs, suggesting that these “abnormalities” do not necessarily cause pain. Despite this, many clinicians continue to point to minor structural findings as the cause of chronic neck or back pain.

Treatments for neck or back pain commonly include surgery, injections, and/or opioid medications. However, there are no studies demonstrating that surgery for axial back pain is superior to nonsurgical interventions.4 Meta-analyses of injection therapies show no clear benefit over placebo injections.5 Widespread opioid use for pain has been termed a national epidemic. Moreover, suggesting to a patient that the back may be irreversibly damaged may generate increased fear and anticipation of pain, thereby activating increased actual pain and disability.

Another misconception about chronic pain is that brain-generated pain is rare. Studies show that approximately 85% of patients with chronic neck or back pain do not have a clearly identifiable, structural cause for their pain.6 Of the millions of individuals experiencing tension and migraine headaches, only about 5% have an identifiable structural cause. Very few people with irritable bowel syndrome, fibromyalgia, and many chronic pelvic pain syndromes have tissue damage to account for their pain.7 These data suggest that the majority of patients presenting with chronic pain do not necessarily have a structural cause.

Brain Distinctions

As pain management evolves, practitioners are turning to mechanisms in the brain to explain chronic pain.8 Imaging from MRI and functional MRI studies (fMRI) identify clear changes in the brains of individuals with chronic pain.9-10 However, brain-generated pain is often conceived to be static and irreversible.

This conceptualization does not account for the dynamic nature of brain-generated pain. Emerging research on brain function may explain how our brains generate internal experiences, including pain.11 There is a “danger/alarm” mechanism that elicits pain when danger is sensed, either in the form of physical injury or emotional threat. The parts of the brain activated by emotionally upsetting events are identical to those activated by physical injury, thus demonstrating the mechanism by which emotional pain may lead to physical pain.12

We now know that children who suffer from the consequences of parental divorce, drug abuse, neglect, or outright abuse have much higher rates of chronic pain (and other difficulties) later in life.13 The experience of growing up feeling “unsafe” sensitizes the danger/alarm mechanism that may then be triggered later in life through stressful life events or physical injuries, such as a car accident or a surgical procedure. In these situations, the brain may construct pain as a protective mechanism. Specifically, the brain activates neural circuits or pathways of pain that create real pain in the absence of tissue damage. These pathways are, however, reversible due to the brain’s neuroplasticity.

Identifying Neural Pathway Pain in the Clinical Setting

Physicians may apply this evolving understanding of pain in their clinical practice by identifying patients who have brain-generated or neural pathway pain. After ruling out significant structural disorders, physicians may use clinical evidence to rule in neural pathway pain. Following are some guidelines that may help to link a patient’s symptoms to neural pathways:

Last updated on: December 7, 2017
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Pharmacological Interventions in Sport-Related Concussion
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