Pain is an unavoidable part of human life. On the negative side, pain can be a source agony. On the flip side, pain can be an alarm signal and motivator to make a necessary change and do something different. Having a better understanding of something we all have to live with is of importance.
Let’s start with the definition developed by the International Association for the Study of Pain (IASP). “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage” (emphasis added). Of major significance here is that there does NOT have to be physical or pathologic damage for there to be pain. This is why pain specialist say “pain lives in the brain”. It is why someone can have a gun shot wound in a situation of duress and not even feel it and why people feel pain in an area long after healing has occurred. This is why pain can appear very mysterious and when it becomes chronic can be difficult to resolve.
Two general categories of pain are acute and chronic. Acute is time limited while chronic persists for more than 3-6 months which is often long after the needed time for healing. From these 2 general categories the IASP delineates over 30 different “types” of pain. For our purpose I will address 2 general categories: nociceptive and non-nociceptive.
Nociceptive pain results from signals being sent to the brain from specialized nerve endings in the body tissues. When they reach a significant level the brain interprets it as pain. Nociceptive pain can in general be divided into the categories of somatic and visceral as the source of the signals.
Non-nociceptive pain is generated in the brain without signals originating from the specialized nerve endings in the tissues. The 2 general types of Non-nociceptive pain are Neuropathic and Sympathetic. Neuropathic is where there is damage to the nerves or they become hypersensitized and start producing signals on their own. Sympathetic is where the central nervous system becomes over active which in the literature is referred to as “central windup”. The nervous system starts interpreting normal signals as noxious ones leading to pain perception in the brain and a downward spiral in the body.
[to get a fuller description of the symptoms for the different types of pain – Pain Characteristics Description below]
Why is this all so important? Because pain then does not necessarily mean that there is something pathologically wrong at the site of pain. The nervous system can generate pain as an alarm to get your attention when a threshold of threat/stress is reached. As said in Z-Health, pain is an action signal to do something different. And the nervous system often uses old “pain pathways” so it does not have to create new ones. The problem then is figuring out what the nervous system wants us to pay attention to.
Reducing the threat level can often resolve pain. This can be accomplished by rehabilitating and optimizing the Visual, Vestibular/Balance, and Proprioceptive (body senses) systems all of which can contribute to the threat/stress level when not working well. This is why I use both the techniques of Muscle Activation Techniques which addresses the neuro-muscular system and those of Z-Health which has assessments for all three systems.
To learn more about Pain, I recommend the book “Explain Pain” by David Butler and Lorimer Moseley. It is a great laypersons explanation of the topic.
Source – Usually known as musculoskeletal pain, this pain typically arises from the skin, muscle, joints, bones, ligaments, fascia, etc.
Receptors Activated – Heat, cold, vibration, stretch (muscles), inflammation (e.g. cuts and sprains which cause tissue disruption), and oxygen starvation (ischemic muscle cramps).
Characteristics – This type of pain is often sharp, well defined, and can often be reproduced by touching or moving the area or tissue that is nociceptively active.
Source – This pain arises from the internal organs of the main body cavities – thorax (heart and lungs), abdomen (liver, kidneys, spleen and bowels), pelvis (bladder, uterus, and ovaries).
Receptors Activated – Specific receptors (nociceptors) for stretch, inflammation, and oxygen starvation (ischemia).
Characteristics – Visceral pain is often poorly defined, and may feel like a vague deep ache, can be continuous (liver, kidney), or colicky (hollow organ).
Source – This pain arises from within the nervous system itself: either from the peripheral or central nervous system. It can have a number of different causes including:
1 Nerve degeneration due to disease, stroke, brain injury, or ischemia.
2 Nerve pressure or impingement such as carpal tunnel syndrome.
3 Nerve inflammation created by the inflammatory soup surrounding aninjured tissue (e.g. disk).
4 Nerve infection from a virus such as varicella (shingles).
Receptors Activated – In this case, there are no specific receptors. Rather than the cascade of events associated with acute nociceptive action, there are electrically unstable nerves firing in an inappropriate, random, and disordered fashion.
Characteristics – This type of pain is often described as stabbing, shooting, burning, electrical, and hypersensitive. It is also often associated with signs of nerve dysfunction such as hypersensitivity (touch, vibration, hot and cold), tingling, numbness, and weakness.
Source – Among the worst, and most confusing forms of pain, sympathetic pain is due to an over-active sympathetic nervous system. It occurs more commonly after fractures and soft tissue injuries of the arms and legs and may lead to Complex Regional Pain Syndrome (CRPS) which is the new term for Reflex Sympathetic Dystrophy (RSD).
Receptors Activated – This pain is non-nociceptive in nature so there are no specific pain receptors activated.
Characteristics – The most common characteristic of this type of pain is what is termed allodynia, which is an extreme hypersensitivity to light touch and temperature. Additionally, you will often see signs of an overactive sympathetic nervous system reaction which may include: sweating, nausea, vertigo, pale skin, trembling, elevated heart rate, etc.