Editing Pain (section)

== Classification ==
In many cases, pain fits into one or a combination of three categories:<ref>{{Cite web|url=https://www.ninds.nih.gov/health-information/disorders/pain|title=Pain &#124; National Institute of Neurological Disorders and Stroke|website=www.ninds.nih.gov|access-date=12 March 2025|archive-date=4 March 2025|archive-url=https://web.archive.org/web/20250304174721/https://www.ninds.nih.gov/health-information/disorders/pain|url-status=live}}</ref>

* Nociceptive pain (caused by [[inflamed]] or damaged tissue that activates pain sensors called [[nociceptors]]).<ref name="Treede-2015">{{Cite journal|last1=Treede|first1=Rolf-Detlef|last2=Rief|first2=Winfried|last3=Barke|first3=Antonia|last4=Aziz|first4=Qasim|last5=Bennett|first5=Michael I.|last6=Benoliel|first6=Rafael|last7=Cohen|first7=Milton|last8=Evers|first8=Stefan|last9=Finnerup|first9=Nanna B.|date=June 2015|title=A classification of chronic pain for ICD-11|journal=Pain|volume=156|issue=6|pages=1003–1007|doi=10.1097/j.pain.0000000000000160|issn=1872-6623|pmc=4450869|pmid=25844555}}</ref> Nociceptive pain is divided into "superficial" and "deep" pain. Deep pains are divided into two parts: "deep physical" and "deep visceral" pain.<ref>{{cite book|vauthors=Coda BA, Bonica JJ|veditors=Loeser D, Bonica JJ|title=Bonica's management of pain|edition=3|year=2001|publisher=Lippincott Williams & Wilkins|isbn=978-0-443-05683-3|location=Philadelphia|chapter=General considerations of acute pain|chapter-url-access=registration|chapter-url=https://archive.org/details/painmanagementin0000main}}</ref>

* [[Neuropathic pain]] (caused by damage or malfunction of the [[nervous system]]).<ref name="Treede-2015" /> Neuropathic pain is divided into "[[Peripheral nervous system|peripheral]]" (the source being the [[peripheral nervous system]]) and "[[Central nervous system|central]]" (being from brain and spinal cord).<ref name="Bogduk1994">{{cite book |url=https://archive.org/details/classificationof0000unse_o5f1/page/212 |title=Classification of chronic pain: descriptions of chronic pain syndromes and definitions of pain terms |vauthors=Bogduk N, Merskey H |publisher=IASP Press |year=1994 |isbn=978-0931092053 |edition=second |location=Seattle |page=[https://archive.org/details/classificationof0000unse_o5f1/page/212 212]}}</ref><ref>{{cite book|title=Diagnostic Methods for Neuropathic Pain: A Review of Diagnostic Accuracy Rapid Response Report: Summary with Critical Appraisal.|publisher=Canadian Agency for Drugs and Technologies in Health|date=April 2015|pmid=26180859}}</ref> [[Peripheral neuropathy]] is often described as "burning", "tingling", "electrical", "stabbing", or "pins and needles".<ref name="Paice2003">{{cite journal |vauthors=Paice JA |date=Jul–Aug 2003 |title=Mechanisms and management of neuropathic pain in cancer |url=http://www.supportiveoncology.net/journal/articles/0102107.pdf |url-status=dead |journal=The Journal of Supportive Oncology |volume=1 |issue=2 |pages=107–120 |pmid=15352654 |archive-url=https://web.archive.org/web/20100107161021/http://www.supportiveoncology.net/journal/articles/0102107.pdf |archive-date=2010-01-07 |access-date=2010-05-03}}</ref>

*[[Nociplastic pain]] is pain that arises despite no clear evidence of tissue or somatosensory system damage causing the pain.<ref name="L">{{Cite journal |vauthors=Fitzcharles MA, Cohen SP, Clauw DJ, Littlejohn G, Usui C, Häuser W |date=May 2021 |title=Nociplastic pain: towards an understanding of prevalent pain conditions |journal=Lancet |volume=397 |issue=10289 |pages=2098–2110 |doi=10.1016/S0140-6736(21)00392-5 |pmid=34062144 |s2cid=235245552}}</ref>


In 1994, the [[International Association for the Study of Pain]] recommended using specific features to describe a patient's pain:
# Region of the body involved (e.g., abdomen or lower limbs)
# System whose dysfunction may be causing the pain (e.g., nervous or gastrointestinal systems)
# Duration and pattern of occurrence
# Intensity
# Cause<ref name= Merskey_Bogduk>{{cite book |vauthors=Merskey H, Bogduk N |title=Classification of Chronic Pain |edition=2 nd |location=Seattle |publisher=International Association for the Study of Pain |year=1994 |isbn=978-0931092053 |pages=[https://archive.org/details/classificationof0000unse_o5f1/page/3 3 & 4] |url=https://archive.org/details/classificationof0000unse_o5f1/page/3 }}</ref>

=== Chronic versus acute ===
{{main|Chronic pain}}

Pain is usually transitory, lasting only until the noxious stimulus is removed or the underlying damage or pathology has healed. But some painful conditions, such as [[rheumatoid arthritis]], [[peripheral neuropathy]], [[Cancer pain|cancer]], and [[idiopathic]] pain, may persist for years. Pain that lasts a long time is called "[[Chronic pain|chronic]]" or "persistent", and pain that resolves quickly is called "[[Acute (medicine)|acute]]". Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time between onset and resolution; the two most commonly used markers being 3 months and 6 months since the onset of pain,<ref name = Turk&Okifuji2001>{{cite book | vauthors = Turk DC, Okifuji A | veditors = Bonica JJ, Loeser JD, Chapman CR, Turk DC |title=Bonica's management of pain |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |year=2001 |isbn=978-0781768276 |chapter=Pain terms and taxonomies of pain}}</ref> though some theorists and researchers have placed the transition from acute to chronic pain at 12 months.<ref name="isbn0-443-05683-8"/>{{rp|93}} Others apply "acute" to pain that lasts less than 30 days, "chronic" to pain of at least six months' duration, and "subacute" to pain that lasts from one to six months.<ref name=Thienhaus1>{{cite book | vauthors = Thienhaus O, Cole BE | veditors = Weiner R |title=Pain management: a practical guide for clinicians | url = https://archive.org/details/painmanagementpr00wein | url-access = limited |publisher=CRC Press |location=Boca Raton |year=2002 |pages=[https://archive.org/details/painmanagementpr00wein/page/n60 28] |isbn=978-0849322624 |chapter=Classification of pain}}</ref> A popular alternative definition of "chronic pain", involving no arbitrarily fixed duration, is "pain that extends beyond the expected period of healing".<ref name = Turk&Okifuji2001/> Chronic pain may be classified as "[[cancer pain|cancer-related]]" or "benign."<ref name=Thienhaus1/>

=== Allodynia ===
[[Allodynia]] is pain experienced in response to an ordinarily painless stimulus.<ref name=":0">{{cite journal | vauthors = Jensen TS, Finnerup NB | title = Allodynia and hyperalgesia in neuropathic pain: clinical manifestations and mechanisms | journal = The Lancet. Neurology | volume = 13 | issue = 9 | pages = 924–935 | date = September 2014 | pmid = 25142459 | doi = 10.1016/s1474-4422(14)70102-4 | s2cid = 25011309 }}</ref> It has no biological function and is classified by characteristics of the stimuli as cold, heat, touch, pressure or a pinprick.<ref name=":0"/><ref name="Lolignier 133–139">{{cite journal | vauthors = Lolignier S, Eijkelkamp N, Wood JN | title = Mechanical allodynia | journal = Pflügers Archiv | volume = 467 | issue = 1 | pages = 133–139 | date = January 2015 | pmid = 24846747 | pmc = 4281368 | doi = 10.1007/s00424-014-1532-0 }}</ref>

=== Phantom ===
{{Main|Phantom pain}}
[[Phantom pain]] is pain felt in a part of the body that has been [[amputated]] or from which the brain no longer receives signals. It is a type of neuropathic pain.<ref name="pmid10863043">{{cite journal | vauthors = Kooijman CM, Dijkstra PU, Geertzen JH, Elzinga A, van der Schans CP | title = Phantom pain and phantom sensations in upper limb amputees: an epidemiological study | journal = Pain | volume = 87 | issue = 1 | pages = 33–41 | date = July 2000 | pmid = 10863043 | doi = 10.1016/S0304-3959(00)00264-5 | s2cid = 7565030 | url = https://research.rug.nl/en/publications/phantom-pain-and-phantom-sensations-in-upper-limb-amputees(8dd1fc12-cc0d-400b-aef1-72ed0443f9ad).html }}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The [[prevalence]] of phantom pain in upper limb amputees is nearly 82%, and in lower limb amputees is 54%.<ref name="pmid10863043"/> One study found that eight days after amputation, 72% of patients had phantom limb pain, and six months later, 67% reported it.<ref name="pmid6657285">{{cite journal | vauthors = Jensen TS, Krebs B, Nielsen J, Rasmussen P | title = Phantom limb, phantom pain and stump pain in amputees during the first 6 months following limb amputation | journal = Pain | volume = 17 | issue = 3 | pages = 243–256 | date = November 1983 | pmid = 6657285 | doi = 10.1016/0304-3959(83)90097-0 | s2cid = 10304696 }}</ref><ref name="pmid3991231">{{cite journal | vauthors = Jensen TS, Krebs B, Nielsen J, Rasmussen P | title = Immediate and long-term phantom limb pain in amputees: incidence, clinical characteristics and relationship to pre-amputation limb pain | journal = Pain | volume = 21 | issue = 3 | pages = 267–278 | date = March 1985 | pmid = 3991231 | doi = 10.1016/0304-3959(85)90090-9 | s2cid = 24358789 }}</ref> Some amputees experience continuous pain that varies in intensity or quality; others experience several bouts of pain per day, or it may reoccur less often. It is often described as shooting, crushing, burning, or cramping. If the pain is continuous for an extended period, parts of the intact body may become sensitized, so touching them evokes pain in the phantom limb. Phantom limb pain may accompany [[urination]] or [[defecation]].<ref name = "The challenge of pain">{{cite book | vauthors = Wall PD, Melzack R |title=The challenge of pain |edition=2nd |publisher=Penguin Books |location=New York |year=1996 |isbn=978-0140256703}}</ref>{{rp|61–69}}

[[Local anesthetic]] injections into the nerves or sensitive areas of the stump may relieve pain for days, weeks, or sometimes permanently, despite the drug wearing off in a matter of hours, and small injections of [[:wikt:hypertonic|hypertonic]] saline into the soft tissue between vertebrae produces local pain that radiates into the phantom limb for ten minutes or so and may be followed by hours, weeks, or even longer of partial or total relief from phantom pain. Vigorous vibration or electrical stimulation of the stump, or current from electrodes surgically implanted onto the spinal cord, all produce relief in some patients.<ref name = "The challenge of pain"/>{{rp|61–69}}

[[Mirror box]] therapy produces the illusion of movement and touch in a phantom limb, which in turn may cause a reduction in pain.<ref name="pmid8637922">{{cite journal | vauthors = Ramachandran VS, Rogers-Ramachandran D | title = Synaesthesia in phantom limbs induced with mirrors | journal = Proceedings. Biological Sciences | volume = 263 | issue = 1369 | pages = 377–386 | date = April 1996 | pmid = 8637922 | doi = 10.1098/rspb.1996.0058 | bibcode = 1996RSPSB.263..377R | s2cid = 4819370 }}</ref>

[[Paraplegia]], the loss of sensation and voluntary motor control after serious spinal cord damage, may be accompanied by [[girdle pain]] at the level of the spinal cord damage, [[visceral pain]] evoked by a filling bladder or bowel, or, in five to ten percent of people with paraplegia, phantom body pain in areas of complete sensory loss. This phantom body pain is initially described as burning or tingling but may evolve into severe crushing or pinching pain or the sensation of fire running down the legs or of a knife twisting in the flesh. Onset may or may not occur immediately years after the disabling injury. Surgical treatment rarely provides lasting relief.<ref name = "The challenge of pain"/>{{rp|61–69}}

=== Breakthrough{{anchor|Breakthrough_pain}} ===
Breakthrough pain is transitory pain that comes on suddenly and is not alleviated by the patient's regular [[pain management]]. It is common in cancer patients who often have background pain that is generally well-controlled by medications but who also sometimes experience bouts of severe pain that, from time to time, "breaks through" the medication. The characteristics of breakthrough [[cancer pain]] vary from person to person and according to the cause. Management of breakthrough pain can entail intensive use of [[opioid]]s, including [[fentanyl]].<ref>{{cite journal | vauthors = Mishra S, Bhatnagar S, Chaudhary P, Rana SP | title = Breakthrough cancer pain: review of prevalence, characteristics and management | journal = Indian Journal of Palliative Care | volume = 15 | issue = 1 | pages = 14–18 | date = January 2009 | pmid = 20606850 | pmc = 2886208 | doi = 10.4103/0973-1075.53506 | df = dmy-all | doi-access = free }}</ref><ref>{{cite journal | vauthors = Caraceni A, Hanks G, Kaasa S, Bennett MI, Brunelli C, Cherny N, Dale O, De Conno F, Fallon M, Hanna M, Haugen DF, Juhl G, King S, Klepstad P, Laugsand EA, Maltoni M, Mercadante S, Nabal M, Pigni A, Radbruch L, Reid C, Sjogren P, Stone PC, Tassinari D, Zeppetella G | title = Use of opioid analgesics in the treatment of cancer pain: evidence-based recommendations from the EAPC | journal = The Lancet. Oncology | volume = 13 | issue = 2 | pages = e58–68 | date = February 2012 | pmid = 22300860 | doi = 10.1016/S1470-2045(12)70040-2 | url = https://www.fadin.org/Documenti/164/Recommendations_EAPC_2012.pdf | url-status = dead | archive-url = https://web.archive.org/web/20141019205001/https://www.fadin.org/Documenti/164/Recommendations_EAPC_2012.pdf | archive-date = 19 October 2014 | accessdate = 7 March 2022 }}</ref>

=== Asymbolia and insensitivity ===
{{Main|Pain asymbolia|Congenital insensitivity to pain}}
{{Redirect|Painless}}
[[File:No pain. Science Museum Painless Exhibition Series.webm|thumb|A patient and doctor discuss congenital insensitivity to pain.]]
The ability to experience pain is essential for protection from injury and recognition of the presence of injury. Episodic [[analgesia]] may occur under special circumstances, such as in the excitement of sport or war: a soldier on the battlefield may feel no pain for many hours from a traumatic amputation or other severe injury.<ref>{{cite book | vauthors = Beecher HK | date = 1959 | title = Measurement of subjective responses | url = https://archive.org/details/measurementofsub0000beec | url-access = registration | location = New York | publisher = Oxford University Press}} cited in {{cite book | vauthors = Melzack R, Wall PD | date = 1996 | title = The challenge of pain | edition = 2nd | location = London | publisher = Penguin | page = 7 | isbn = 978-0140256703}}</ref>

Although unpleasantness is an essential part of the [[International Association for the Study of Pain|IASP]] definition of pain,<ref name="IASPdef">{{cite web|title=International Association for the Study of Pain: Pain Definitions|url=https://www.iasp-pain.org/Taxonomy|url-status=dead|archive-url=https://web.archive.org/web/20150113000208/https://www.iasp-pain.org/Taxonomy|archive-date=13 January 2015|access-date=12 January 2015|quote=Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage}} [https://etc.ch/ZTKs Alt URL]{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }} Derived from {{cite journal|vauthors=Bonica JJ|date=June 1979|title=The need of a taxonomy|journal=Pain|volume=6|issue=3|pages=247–248|doi=10.1016/0304-3959(79)90046-0|pmid=460931|s2cid=53161389}}</ref> it is possible in some patients to induce a state known as pain asymbolia, described as intense pain devoid of unpleasantness, with [[morphine]] injection or [[psychosurgery]].<ref name=IASP_definitions/> Such patients report pain but are not bothered by it; they recognize the sensation of pain but suffer little or not at all.<ref name="asymbolia">{{cite book | vauthors = Grahek N |title=Feeling pain and being in pain |date=2007 |publisher=MIT Press |location=Cambridge, Mass. |isbn=978-0262517324 |edition=2nd | url = https://docserver.bis.uni-oldenburg.de/publikationen/bisverlag/2001/grafee01/grafee01.html | archive-url = https://web.archive.org/web/20080927042509/https://docserver.bis.uni-oldenburg.de/publikationen/bisverlag/2001/grafee01/grafee01.html | archive-date = 27 September 2008 }}</ref> Indifference to pain can also rarely be present from birth; these people have normal nerves on medical investigations, and find pain unpleasant, but do not avoid repetition of the pain stimulus.<ref name="pmid12583863">{{cite journal | vauthors = Nagasako EM, Oaklander AL, Dworkin RH | title = Congenital insensitivity to pain: an update | journal = Pain | volume = 101 | issue = 3 | pages = 213–219 | date = February 2003 | pmid = 12583863 | doi = 10.1016/S0304-3959(02)00482-7 | s2cid = 206055264 }}</ref>

Insensitivity to pain may also result from abnormalities in the [[nervous system]]. This is usually the result of [[acquired disorder|acquired]] damage to the nerves, such as [[spinal cord injury]], [[diabetes mellitus]] ([[diabetic neuropathy]]), or [[leprosy]] in countries where that disease is prevalent.<ref name=Brand_1997>{{cite book | vauthors = Brand PW, Yancey P |title=The gift of pain: why we hurt & what we can do about it |publisher=Zondervan Publ |location=Grand Rapids, Mich |year=1997 |isbn=978-0310221449}}</ref> These individuals are at risk of tissue damage and infection due to undiscovered injuries. People with diabetes-related nerve damage, for instance, sustain poorly healing foot ulcers as a result of decreased sensation.<ref name="pmid15472838">{{cite journal | vauthors = Lipsky BA, Berendt AR, Deery HG, Embil JM, Joseph WS, Karchmer AW, LeFrock JL, Lew DP, Mader JT, Norden C, Tan JS | title = Diagnosis and treatment of diabetic foot infections | journal = Clinical Infectious Diseases | volume = 39 | issue = 7 | pages = 885–910 | date = October 2004 | pmid = 15472838 | doi = 10.1086/424846 | first11 = JS | first10 = C | doi-access = free }}</ref>

A much smaller number of people are insensitive to pain due to an inborn abnormality of the nervous system, known as "[[congenital insensitivity to pain]]".<ref name="pmid12583863"/> Children with this condition incur carelessly-repeated damage to their tongues, eyes, joints, skin, and muscles. Some die before adulthood, and others have a reduced life expectancy.<ref>{{Cite journal |last1=Raina* |first1=Triveni |last2=Dash |first2=Bhagya Ranjan |title=AN INTRODUCTORY APPROACH TO PAIN MANAGEMENT THROUGH AYURVEDA WITH BRIEF HOLISTIC REVIEW |url=https://core.ac.uk/outputs/333809971/?utm_source=pdf&utm_medium=banner&utm_campaign=pdf-decoration-v1 |archive-date=27 August 2024 |access-date=27 August 2024 |archive-url=https://web.archive.org/web/20240827103149/https://core.ac.uk/outputs/333809971/?utm_source=pdf&utm_medium=banner&utm_campaign=pdf-decoration-v1 |url-status=live }}</ref> Most people with congenital insensitivity to pain have one of five [[hereditary sensory and autonomic neuropathy|hereditary sensory and autonomic neuropathies]] (which includes [[familial dysautonomia]] and [[congenital insensitivity to pain with anhidrosis]]).<ref name=Axelrod>{{cite journal | vauthors = Axelrod FB, Hilz MJ | title = Inherited autonomic neuropathies | journal = Seminars in Neurology | volume = 23 | issue = 4 | pages = 381–390 | date = December 2003 | pmid = 15088259 | doi = 10.1055/s-2004-817722 | s2cid = 260317729 }}</ref> These conditions feature decreased sensitivity to pain together with other neurological abnormalities, particularly of the [[autonomic nervous system]].<ref name="pmid12583863"/><ref name=Axelrod/> A very rare syndrome with isolated congenital insensitivity to pain has been linked with mutations in the ''[[SCN9A]]'' gene, which codes for a sodium channel ([[Nav1.7|Na<sub>v</sub>1.7]]) necessary in conducting pain nerve stimuli.<ref name="pmid21041956">{{cite journal | vauthors = Raouf R, Quick K, Wood JN | title = Pain as a channelopathy | journal = The Journal of Clinical Investigation | volume = 120 | issue = 11 | pages = 3745–3752 | date = November 2010 | pmid = 21041956 | pmc = 2965577 | doi = 10.1172/JCI43158 }}</ref>