Neuropathic Pain & Wind-Up Phenomenon

Managing Difficult Pain Cases: Neuropathic Pain & Wind-Up Phenomenon – WSAVA2013 – VIN – 2013

I was looking for information on the “pain wind-up” phenomenon and found this veterinary paper that explains it well – and without any special fuss about opioids, treating them the same as any other pain-relieving medication. What a refreshing change!

And with animals, there are no “biopsychosocial” factors to blame for increasing pain, so vets take it seriously and don’t just discount it as an attitude problem.

The options for analgesia are ever increasing as our understanding of pain physiology improves.

Yet for humans, there is still little understanding of chronic pain and few new treatments significantly different from the old. 

Choosing the correct analgesic therapy requires an understanding of both the pharmacokinetics of a wide range of drugs, as well as the levels or type of pain associated with various conditions.

Yet for humans, they’ve established standard limits on what’s sometimes the only effective treatment for our pain, without any concern for the wide variety in people and situations.

The basic principles of current pain management include 

  • preemptive (preventative) analgesia,
  • multimodal (using different classes of drugs simultaneously to interrupt the pain pathway at various points) and
  • appropriate follow-up analgesia (postop and take home).

It seems we’d be better off if they did “treat us like dogs.”

Wind-up phenomenon is a very important, newly understood concept in pain management.

Maybe for animals, but I haven’t heard about it in humans for the last decade as all attention turned to the evils of opioids, counting milligrams, and ignoring anything else.

The vast majority of patients experiencing acute pain can be managed with conventional analgesics, such as NSAIDs, opioids and local anesthetics, but patients whose pain is unmanaged or who present in preexisting pain states may require additional therapy.

Many patients stop responding to common analgesic drugs due to spinal cord wind-up.

The central nervous system adapts adversely to repetitive pain impulses after prolonged stimulation of nociceptors.

This can cause a profound effect to the nervous system’s architecture, thereby altering pain processing.

When spinal neurons are subjected to repeat or high-intensity nociceptive impulses, they become progressively and increasingly excitable even after the stimulus is removed.

This condition is known as central sensitization or windup phenomenon and leads to nonresponsive or chronic intractable pain.

Wind-up is the culmination of two distinct phases of change in the nervous system.

  1. First, pain-transmitting nerve fiber threshold is reset. This resetting results in hyperalgesia, where less and less stimulation is required to initiate pain.
  2. In the second phase, nerve fibers that normally carry non painful information are recruited and become part of the pain-transmission process. This phase is termed allodynia and results in normally harmless sensations being interpreted as pain.

Preemptive analgesics, prevention of spinal cord wind-up and administration of adequate analgesia early in the pain process are key in preventing long-term, chronic pain states

The presence of hyperalgesia and allodynia collectively is considered wind-up phenomenon.

3 thoughts on “Neuropathic Pain & Wind-Up Phenomenon

  1. canarensis

    Unfortunately, there’s a huge push to stop prescribing opioids in the veterinary setting….all those millions of people injuring their pets just to get opioids, dontcha know (I have yet to find anything like documentation of ONE SINGLE CASE of this, yet it’s taken as gospel). Here in Oregon, they’ve formed yet another task force to ban opioids in the veterinary setting (of course).

    What does puzzle & intrigue me lately is a comment I found (without citations) that recent research shows that dogs lack the mu1 receptor & therefore cannot get any analgesic effects from tramadol, which is one of the main go-to pain meds for dogs. My dog has been on it for years for his back pain & it seems to work. I’m left wondering if i’ve been imagining his back pain, or have succumbed to a delusion that the pain med is actually helping him (placebo effect by proxy??) & that his apparent improved mood & ease of movement are also delusions. I’m still trying to get my hands on the original veterinary paper

    Liked by 1 person

    Reply
    1. Zyp Czyk Post author

      Interesting question about whether opioids work on dogs. These days, it seems life itself is a delusion – and it requires a placebo effect (it’s going to be a great day!) just to get out of bed in the morning to face another round of disappointment in our fellow humans.

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      Reply
  2. Pingback: hEDS Deficit in Pain Control Mechanisms | EDS and Chronic Pain News & Info

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