Among the advances and scientific knowledge that brought about the twentieth century, there is the detailed description of the physiological mechanisms that allow us to feel pain. From there, the latter was defined taking into account various elements.
For example, depending on your specific cause and your background, pain has been divided into three main types: neuropathic, nociceptive and psychogenic. In this article, we will see what are the main characteristics of these types, as well as the differences between neuropathic pain and nociceptive pain.
Types of pain and their characteristics
According to the International Association for Pain Studies, “Pain is an unpleasant sensory and emotional experience with actual or potential tissue damage or described in terms of such damage” (1994).
Depending on their functions and location, this sensory and emotional experience can be classified as: nociceptive pain, neuropathic pain, or psychogenic pain.
1. Nociceptive pain
Also known as somatic pain, nociceptive pain is defined as a normal body response to an offending stimulus, And its purpose is to prevent further damage. It is adaptive pain, which is called nociceptive precisely because its main function is to perceive, alert and protect the body from a harmful stimulus. An example would be removing our hand when we started to feel a hot object.
That kind of pain it is understood as an alert mechanism, An alarm signal or an adaptive response to real or apparent harmful stimuli. The latter, harmful stimuli, are transmitted through messages also called “nociceptive messages”. They start at the periphery and advance to the dorsal shaft of the spinal cord, then to different structures that allow it to reach the thalamus and cortex (considered the higher centers of pain).
Likewise, nociceptive pain receptors can be found on the skin, muscles, joints or the vise. For the same it is a pain well localized and that the person can write without other difficulty. A persistent experience of nociceptive pain may also result in local sympathetic effects, muscle contractions and changes in posture.
2. Neuropathic pain
For its part, neuropathic pain is no longer considered an adaptive response and is characterized by changes in the physiology of the response. This type of pain results from chronic injuries or alterations in the peripheral or central nerve pathways. It develops in the face of a harmful stimulus, but can also do without it. For their description, people often use unusual terms, such as represents a new experience that is difficult to describe.
It can occur in the following forms, which at the same time are part of a hypersensitivity to pain called hyperpathy:
- Dysesthesia: Basal sensation of pain, burning or burning.
- Hyperalgesia: As an excessive or exaggerated response.
- Allodynia: By perceiving any stimulus as painful.
Additionally, neuropathic pain can be divided into the following types depending on the specific location:
2.1 Pain of central origin
This can be the case, for example, of a heart attack or multiple sclerosis. Its location is in the central nervous system and it is usually pain more resistant to treatment.
2.2. Peripheral pain
In this case, it is pain that has a generally favorable response to treatment and originates from areas of the peripheral nervous system. Over time, this type of neuropathic pain can develop not only as peripheral but central pain, through a process called precisely “centralization” and it is characterized by plastic changes in the posterior stem of the spinal cord.
3. Psychogenic pain
Psychogenic pain is the psychological experience (eg, Anxiety or depression) described in terms of tissue damage. This description can be made in both verbal and behavioral terms, regardless of whether tissue damage has existed or not. It is an experience of pain that it has its genesis in a psychological state, And which is not localizable in the organic structures of the nervous system.
Differences between neuropathic pain and nociceptive pain
Once the general characteristics of the different types of pain have been described, we can explain and summarize some of the differences between nociceptive and neuropathic pain. We follow Dagnino (1994) in the following five points.
1. The stimulus
In case of nociceptive pain, the stimulus causing the pain is obvious and easily located both by the person experiencing it and by the specialist. In the case of neuropathic pain, there is no obvious stimulus.
2. The location
Related to the above, the place where pain occurs is easily located by the person experiencing it, so it easily describes it. For its part, neuropathic pain is usually diffuse in the location.
3. Description and its characteristics
The experience reported by people with nociceptive pain is often similar. On the other hand, the experience reported by people with neuropathic pain is difficult to report, it seems to be unusual and different pain, so it is more difficult to explain and may vary from person to person.
4. The narcotic response
The differences in responses to drug treatment in the two cases are also different. While in nociceptive pain an effective effect has been reported, in the case of neuropathic pain partial relief has been reported.
5. The response to placebos
Unlike the above, neuropathic pain generally responds better to placebo treatments, and nociceptive pain responds almost ineffective. According to Dagnino (1994), the figures are effective at 60% in the first case and 20 to 30% in the second.
- ChangePain (2018) How is chronic pain defined? Accessed August 9, 2018. Available at http://www.change-pain.org/grt-change-pain-portal/change_pain_home/chronic_pain/insight/definition/es_ES/324800317.jsp.
- Cruciani, RA, Nieto, MJ (2006). Pathophysiology and treatment of neuropathic pain: the most recent advances. Journal of the Spanish Society of Pain. 5: 312-327.
- Perena, MJ, Perena, MF, Rodrigo-Royo, MD, et al. (2000). Neuroanatomy of Pain. Journal of the Spanish Society of Pain (7) II: 5-10.
- Dagnino, J. (1994). Definitions and classifications of pain. Bulletin of the School of Medicine. Catholic University of Chile. 23 (3). Accessed August 9, 2018.Available at http://www.arsmedica.cl/index.php/MED/
- IASP (1994). Part III: (pages 209-214). Classification of Chronic Pain, second edition, IASP Task Force on Taxonomy, edited by H. Merskey and N. Bogduk, ISAP Press, Seattle, 1994. http://www.iasp-pain.org.