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Published: September 21, 2020

Understanding Pain Sources and How They are Perceived in Your Brain

[vc_row][vc_column width="1/1"][vc_column_text]By: Dr. Corey Finan BSc., DC, CCSP, RMT, ART

I can’t tell you how many patients come into my office complaining of nerve pain, or a pinched nerve feeling, but it is a lot!  Most of the time it turns out they are having nociceptive pain (pain from a nociceptor activation, which is basically a pain fiber in their soft tissue that sends a signal back to the brain that we call “pain”).  Studies estimate that of the thousands of patients that suffer from chronic pain, 20% of them have neuropathic pain.  That leaves the other 80% to be of nociceptive origin.  Unlike nociceptive pain, neuropathic pain does not respond to anti-inflammatories or opioid medications as they are unable address the underlying mechanisms of the neuropathic pain.  To add insult to injury, the underlying mechanisms of neuropathic pain are often vague and hard to determine.

To understand each pain source better, let’s identify each of them.

Nociceptive pain is:

  • Generally the result of damage or degeneration of the soft tissues of the body (or in the case of a fracture, the hard tissues of the body as well).
  • Clear, proportionate mechanical/anatomical nature to aggravating and easing factors.
  • Pain occurring, and in proportion to, movement/postural dysfunction, and/or trauma.
  • Pain localized to the area of injury/dysfunction (with or without some somatic referral).
  • Usually rapidly resolving or resolving in accordance with expected tissue healing/pathology recovery times.
  • Responsive to simple analgesics / NSAIDs.
  • Usually intermittent and sharp with movement/mechanical provocation; may be a more constant dull ache or throb at rest.
  • Pain in association with other symptoms of inflammation (i.e. swelling, redness, heat).
  • Pain of recent onset.

Neuropathic pain is:

  • In neuropathic pain, tissue damage directly affects the nervous system.
  • Pain variously described as burning, shooting, sharp, aching or electric-shock-like.
  • History of nerve injury, pathology or mechanical compromise.
  • Pain in association with other neurological symptoms (e.g. pins and needles, numbness, weakness).
  • Pain referred in a dermatomal (specific nerve root pattern) or cutaneous (to the skin) distribution.
  • Less responsive to simple analgesic/NSAIDs and/or more responsive to anti-epileptic (e.g. Neurontin, Lyrica)/anti-depression (e.g. Amitriptyline) medication.
  • Pain of high severity and irritability (i.e. easily provoked, taking longer to settle).
  • Mechanical pattern to aggravating and easing factors involving activities/postures associated with movement, loading or compression of neural tissue.
  • Pain in association with other dysesthesias (e.g. crawling, electrical, heaviness).
  • Reports of spontaneous (i.e. stimulus-independent) pain and/or paroxysmal pain (i.e. sudden recurrences and intensification of pain).

As you can see the two are VERY different from one another.  Most people who come in to our clinic, and really any walk-in clinic will be typically presenting with nociceptive pain.  Neuropathic pain leads people to believe something drastic is going on with them, and they seek emergency medical attention.  Once they go through the battery of tests that show their pain is neurogenic and not something worse, they will come in for care.  Both types of pain can be treated conservatively, and both respond well to care.  Nociceptive pain can be further broken down by the tissue that is causing the pain.  Muscle pain is different than tendon pain, which is different than ligament pain and bone pain is different as well.  Muscle pain is often achy if it is tight or fatigued (overused), while ligament pain is very sharp.  Tendon pain can be a combination of sharp and achy depending on the reason it is sore.  Bone pain is often described as a “deep achy pain”.  Some nociceptive pain can be a sort of phantom pain, where the pain is felt in one part of the body (say along the outside of the knee or lower leg), but is generated by a trigger point in the hip.  Working on the knee and lower leg WILL NOT help this type of pain, ONLY working on the trigger point in the hip will resolve the leg pain.

This raises another important point in understanding pain, and that is understanding the timing of the pain.

When does it hurt?

Neurogenic / Neuropathic pain is generally a constant pain (the nerve fiber is constantly irritated, thus sending off constant pain signals to the brain), while nociceptive pain often comes and goes.  Sometimes the pain is present at rest, consistent with tightness in the muscles that when not being used, and therefore lacking blood flow and warmth will tighten.  This tightening leads to a pulling of the tendon where it attaches to the bone.  This will lead to an achy sensation at the tendon-bone interface.  This is a common presentation of patellofemoral syndrome, where the quadriceps gets tight through activity, but while using it, it becomes more pliable and does not cause pain.  Once activity is complete, blood flow through the muscle diminishes, and the muscle begins to tighten (shorten), causing a pull at the tendon-bone interface again, leading to that achy pain down at the knee cap, or at the tibial tuberosity where the patellar tendon attaches.  This is basically what patellofemoral syndrome is.

The emotional side of pain...

Most people think pain is simply a physiological phenomenon.  It is however a multi-factorial collection of several ongoing processes including, but not limited to, contextual, psychological, and socio-cultural factors.  What this means for the average pain sufferer is that not all pain is the same person-to-person.  A stubbed toe for you may feel like a 2 out of 10 achy pain, while for another person it could feel like an 8 out of 10 excruciating pain.  This interpretation of the pain level often has an emotional component to it, and may be influenced by emotional scars from childhood, or other experiences in your life.  We all know people who have an unexplained fear of things such as spiders, snakes, thunderstorms, etc., these people have been primed emotionally to fear such things because of prior experiences or hearing about tragedies involving whatever it is they fear.  This is an emotional tag placed on the object they fear.  They associate whatever they are afraid of with something bad that could happen to them (a spider bite, getting struck by lightening, etc.), and so they have a heightened sense of fear around those things.  The same can work with pain.  People have an eversion to pain.  I’ve been working on patient’s dry needling them, and they burst into tears, not due to pain from the treatment, but rather from the fear of the needles.  When I ask them if it is painful they deny that it is, and they often cannot explain why they are crying.  They just are afraid of the needle damaging them.  They are almost paralyzed with fear, while another person can carry on a conversation with me as if we were sitting having coffee instead of me inserting dry needles into them.  Our experiences in life shape how we perceive things, and it is no different with pain.  Perception of pain is really what we are looking at here, not just pain.

So, what is the takeaway?

There are many faces to pain.  We all suffer from pain at one point in our life, usually we get over the pain, sometimes it lingers.  No matter what the cause, pain is usually and end stage of damage to tissues, and is the body’s “smoke detector” telling us there is a fire.  We can use the pain to guide our activities and avoid doing further damage to the tissue, or we can take pain meds to decrease the pain.  This is like taking the batteries out of the smoke detector in order to stop the alarm going off.  However, the fire is still there.  Naturally, it is important for everyone to find their comfort level, and do what you feel is important for yourself.

If you are unsure what is causing your pain, it is important to seek out professional advice from a musculoskeletal specialist to get a proper assessment and figure out exactly where the pain is coming from, and the most effective way to treat your particular pain.

At AST we are experts in musculoskeletal pain, and can take care of any pain you present with, be it acute, chronic, of unknown origin, and unrelenting.  We are here to help, and happy to do so.

If you are in pain and want to get an accurate diagnosis and treatment plan to help, please call to book in today.

*This blog is not intended to officially establish a physician-patient relationship, to replace the services of a trained physician, naturopathic doctor, physical therapist or chiropractor or otherwise to be a substitute for professional medical advice, diagnosis, or treatment.  [/vc_column_text][/vc_column][/vc_row]

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