Hyperpathia, Hyperalgesia, and Hypersensitivity

Hypersensitivity can be part of a chronic neck or back pain problem.
Hypersensitivity can be part of a chronic neck or back pain problem. Cath Riley/Ikon Images/Getty Images

Hyperpathia and Hypersensitivity to Pain

The word hyperpathia describes an exaggerated reaction to stimuli that normally cause pain. Such stimuli include touch, vibration, pinpricks, heat, cold, and pressure.

Hyperpathia lowers your pain threshold, increasing your sensitivity to things you physically feel. It is similar to hyperalgesia, with the addition that the feeling of pain continues even after the stimulus that causes it has been removed.

Scientists are just beginning to study the underlying mechanisms of hypersensitivity and augmented pain responses.

Related: What is Nocioceptive Pain?

To Understand Hyperpathia, Look to Hyperalgesia

To understand hyperpathia, it's probably a good idea to start with hyperalgesia, as more research has been focused here.

Hyperalgesia is one of the predominant types of neuropathic (i.e., nerve) pain symptoms. Jensen, et. al, in their study, "Allodynia and hyperalgesia in neuropathic pain: clinical manifestations and mechanisms," published in the September 2014 issue of The Lancet say that between 15% and 50% of patients with neuropathic pain experience hyperalgesia.

While pain intensity and pain relief are important qualities to measure, understand and track, they  probably don't fully describe the experience of exaggerated nerve pain responses like hyperalgesia and hyperpathia. This is because chronic nerve pain is complex in nature.

Jensen, et. al. say that including hyperalgesia in studies may help scientists get a better overall understanding of nerve pain in general.

Hyperalgesia is classified into subtypes that relate to the type of stimuli causing the response. These include the stimuli mentioned above, in other words, thermal sensations, pressure, touch and more.

Each subtype has its own way of working (called mechanism.)

Hypersensitivity can be generated and/or continued in two possible ways: Peripheral sensitization and/or central changes. Peripheral sensitization is caused by extra excitability and/or a reduced pain threshold in nerve endings at your skin, and in your muscles, joints and/or organs. Changes in your central nervous system is characterized by excitability of cells in your central nervous system.

Related: Allodynia

Does Your Psychology Affect Your Back Pain Levels?

If you’ve been traumatized psychologically your risk for a chronic back problem may be increased - even if you don’t have PTSD. (Scientists have found an association between PTSD and chronic back pain risk.) That said, pain specialists are unclear about the role that psychological trauma plays in nonspecific chronic low back pain.

To fill in some of the information gaps, Tesarz, et. al conducted a study involving 180 of participants with and without psychological trauma and with and without chronic back pain.

The study, entitled "Distinct quantitative sensory testing profiles in nonspecific chronic back pain subjects with and without psychological trauma," was published in the April 2015 issue of Pain.

The researchers divided the participants into 3 comparison groups and asked the question: Do specific alterations in pain perception accompany psychological trauma?

In this case, psychological trauma was determined by means of an assessment given to the study participants. The assessment asked the participants about their anxiety and depression, and more.

The researchers concluded that people with hyperalgesia who also experienced psychological trauma had lower pain thresholds in general - in both painful areas (i.e., their backs) and non-painful areas such as their hands. Study participants who had not experienced psychological trauma but who did have hyperalgesia also had lower pain thresholds, but only in the painful areas (again, their backs.)

The authors suggest that the difference between patients with psychological trauma and those without it may be due to increased processing activity on the part of the central nervous system.

Sources:

Curatolo, M., Arendt-Nielsen, L. Central hypersensitivity in chronic musculoskeletal pain. Phys Med Rehabil Clin N Am. May 2015

Jensen, Troels, S., DMS, Finnerup, Nanna, B., DMSc. Allodynia and hyperalgesia in neuropathic pain: clinical manifestations and mechanisms The Lancet. Sept 2014. http://www.thelancet.com/journals/laneur/article/PIIS1474-4422%2814%2970102-4/abstract

Tesarz, Jonasa,; Gerhardt, Andreasa; Leisner, Sabinea; Janke, Susannea; Treede, Rolf-Detlefb; Eich, Wolfganga Distinct quantitative sensory testing profiles in nonspecific chronic back pain subjects with and without psychological trauma. Pain. April 2015

Woolf, C. Pain hypersensitivity. Pain. The Wellcome Trust. Accessed. Sept 2015. http://www.wellcome.ac.uk/en/pain/microsite/science4.html

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