The 5 differences between nociceptive pain and neuropathic pain

Two types of experiences based on displeasure but which can be distinguished from each other.

Among the advances and scientific knowledge brought about by the 20th century is the detailed description of the physiological mechanisms that allow us to experience pain. physiological mechanisms that allow us to experience pain.. From there, the latter has been defined taking into account different elements.

For example, according to its cause and specific course, 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 of Pain Studies, "pain is an unpleasant sensory and emotional experience with actual or potential tissue damage or described in terms of such damage" (1994).

According to its functions and location, such sensory and emotional experience can be classified in the following ways: nociceptive pain, neuropathic pain or psychogenic pain.

Nociceptive pain

Also known as somatic pain, nociceptive pain is defined as a normal response of the organism to an offensive stimulus, and its aim is to prevent damage.and its objective is to prevent further damage. It is an 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 to withdraw the hand when we begin to feel a hot object.

This type of pain is understood as an alert mechanismThe latter, the noxious stimuli, are transmitted through messages also known as "nociceptive messages". The latter, the noxious stimuli, are transmitted through messages that are also known as "nociceptive messages". They start in the periphery and advance to the dorsal horn of the medulla, and then to different structures that allow them to reach the thalamus and the cortex (considered the superior centers of pain).

In the same way, nociceptive pain receptors can be found in the skin, muscles, joints or veins. It is therefore a well localized pain that the person can write down without much difficulty. A persistent experience of nociceptive pain can also provoke a series of local sympathetic effects, contractions of the muscles and joints or the veins. local sympathetic effects, muscle contractions and postural changes..

2. Neuropathic pain

Neuropathic pain is pain that 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 lesions or alterations in peripheral or central nerve pathways. It develops in response to a noxious stimulus, but can also occur without the stimulus. For its description, people often use unusual terms, since it represents a new and difficult to describe experience. represents a new and difficult to describe experience.

It can present itself through the following forms, which at the same time are part of a hypersensitivity to pain known as hyperpathia:

• DysesthesiaDysesthesia: basal sensation of pain, burning or burning.
• Hyperalgesiaas an excessive or exaggerated response.
• Allodyniathrough perceiving any stimulus as painful.

In addition, neuropathic pain can be divided into the following types according to the specific localization:

2.1.Pain of central origin

This may be the case, for example, of a Cardiovascular accident or multiple sclerosis. Its localization is in the central nervous system and is usually more resistant to treatment..

2.2. Pain of peripheral origin

This is pain that generally responds favorably to treatment and originates in areas of the peripheral nervous system. Over time, this type of neuropathic pain can develop not only as peripheral pain but also as central pain, through a process called "centralization", which is characterized by plastic changes in the peripheral nervous system. characterized by plastic changes in the posterior horn of the spinal cord..

3. Psychogenic pain

Psychogenic pain is the psychological experience (e.g. anxiety or depression) described in terms of tissue damage. Such a description can be made in both verbal and behavioral terms, whether or not tissue damage has occurred. It is an experience of pain that has its genesis in a psychological stateand which cannot be located in the organic structures of the nervous system.

Differences between neuropathic pain and nociceptive pain

Having described the general characteristics of the different types of pain, we can explain and summarize some differences between nociceptive and neuropathic pain. We follow Dagnino (1994) in the following five points.

1. The stimulus

In the case of nociceptive pain, the stimulus that provokes the pain is evident and easily locatable by both the person experiencing it and the specialist. In the case of neuropathic pain, there is no obvious stimulus.

2. The location

Related to the above, the place where the pain occurs is easily located by the person experiencing it, and therefore easily described. On the other hand, neuropathic pain is generally of diffuse localization..

3. The 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 an unusual and different pain, so it is more difficult to explain it. is more difficult to explain and may vary from person to person.

4. Narcotic response

The differences in the responses to pharmacological treatment in the two cases are also different. Whereas in nociceptive pain an effective effect has been reported, in the case of neuropathic pain partial relief has been reported..

5. Response to placebos

Contrary to the above, neuropathic pain usually responds better to placebo treatments, and nociceptive pain responds practically ineffectively. According to Dagnino (1994) the figures are 60% efficiency in the first case, and 20-30% in the second.

Bibliographic references:

• ChangePain (2018) How is chronic pain defined? Retrieved August 09, 2018. Available at http://www.change-pain.org/grt-change-pain-portal/change_pain_home/chronic_pain/insight/definition/es_ES/324800317.jsp.
• Cruciani, R.A., Nieto, M.J. (2006). Pathophysiology and treatment of neuropathic pain: most recent advances. Journal of the Spanish Pain Society. 5: 312-327.
• Perena, M.J., Perena, M.F., Rodrigo-Royo, M.D., et al. (2000). Neuroanatomy of pain. Revista de la Sociedad Española del dolor (7)II: 5-10.
• Dagnino, J. (1994). Definitions and classifications of pain. Bulletin of the School of Medicine. Catholic University of Chile. 23(3). Retrieved August 09, 2018. Available at http://www.arsmedica.cl/index.php/MED/
• IASP (1994). Part III: (pp 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.