`
`
`
`CLASSIFICATION OF CHRONIC PAIN
`
`i
`
`Grun. Exh. 1017
`PGR for U.S. Patent No. 9,707,245
`
`

`

`
`
`
`
`IASP Subcommittee on Taxonomy 1986
`*Harold Merskey, DM (Canada, Chair)
`*Michael R. Bond, PhD, MD (UK)
`John J. Bonica, MD, DSc (USA)
`*David B. Boyd, MD (Canada)
`Amiram Carmon, MD, PhD (Israel)
`A. Barry Deathe, MD (Canada)
`Henri Dehen, MD (France)
`Ulf Lindblom, MD (Sweden)
`James M. Mumford, PhD, MSc (UK)
`William Noordenbos, MD, PhD (The Netherlands)
`Ottar Sjaastad, MD, PhD (Norway)
`Richard A. Sternbach, PhD (USA)
`Sydney Sunderland, MD, DSc (Australia)
`
`*Subcommittee on Classification
`
`IASP Task Force on Taxonomy 1994
`Harold Merskey, DM (Canada, Chair)
`Robert G. Addison, MD (USA)
`Aleksandar Beric, MD, DSc (USA)
`Helmut Blumberg, MD (Germany)
`Nikolai Bogduk, MD, PhD (Australia)
`Jorgen Boivie, MD (Sweden)
`Michael R. Bond, PhD, MD (UK)
`John J. Bonica, MD, DSc (USA)
`David B. Boyd, MD (Canada)
`A. Barry Deathe, MD (Canada)
`Marshall Devor, PhD (Israel)
`Martin Grabois, MD (USA)
`Jan M. Gybels, MD, PhD (Belgium)
`Per T. Hansson, MD, DMSc, DDS (Sweden)
`Troels S. Jensen, MD, PhD (Denmark)
`John D. Loeser, MD (USA)
`Prithvi P. Raj, MB BS (USA)
`John W. Scadding, MD, MB BS (UK)
`Ottar M. Sjaastad, MD, PhD (Norway)
`Erik Spangfort, MD (Sweden)
`Barrie Tait, MB ChB (New Zealand)
`Ronald R. Tasker, MD (Canada)
`Dennis C. Turk, PhD (USA)
`Arnoud Vervest, MD (The Netherlands)
`James G. Waddell, MD (USA)
`Patrick D. Wall, DM, FRS (UK)
`C. Peter N. Watson, MD (Canada)
`
`ii
`
`

`

`
`
`CLASSIFICATION OF CHRONIC PAIN
`DESCRIPTIONS OF CHRONIC PAIN SYNDROMES
`AND DEFINITIONS OF PAIN TERMS
`Second Edition
`
`prepared by the
`Task Force on Taxonomy
`of the
`International Association for the Study of Pain
`
`Editors
`Harold Merskey, DM
`Department of Psychiatry
`The University of Western Ontario
`Department of Research
`London Psychiatric Hospital
`London, Ontario, Canada
`
`Nikolai Bogduk, MD, PhD
`Faculty of Medicine
`The University of Newcastle
`Newcastle, New South Wales, Australia
`
`IASP PRESS • SEATTLE
`
`iii
`
`

`

`
`
`© 1994 IASP Press (Reprinted 2002)
`International Association for the Study of
`Pain
`
`All rights reserved. No part of this publication may be reproduced, stored in a
`retrieval system, or transmitted, in any form or by any means, electronic,
`mechanical, photocopying, recording, or otherwise, without the prior written
`permission of the publisher.
`
`No responsibility is assumed by IASP for any injury and/or damage to persons or
`property as a matter of product liability, negligence, or from any use of any
`methods, products, instruction, or ideas contained in the material herein. Because
`of the rapid advances in the medical sciences, the publisher recommends that there
`should be independent verification of diagnoses and drug dosages.
`
`Library of Congress Cataloging-in-Publication Data
`
`Classification of chronic pain : descriptions of chronic pain syndromes and
`definitions of pain terms / prepared by the International Association for the
`Study of Pain, Task Force on Taxonomy ; editors, Harold Merskey,
`N. Bogduk. - 2nd ed.
`p.
`cm.
`Includes bibliographical references and
`index. ISBN 0-931092-05-1
`1. Chronic pain-Classification. 2. Pain-Terminology.
`I. Merskey, Harold. II. Bogduk, Nikolai. III. International Association for
`the Study of Pain. Task Force on Taxonomy.
`[DNLM: 1. Pain-classification. 2. Chronic Disease-classification.
`WL 704 C614 19941
`RB127.C58 1994
`616'.0472'012-dc20
`DNLM/DLC
`for Library of Congress 94-8062
`
`IASP Press
`International Association for the Study of
`Pain 909 NE 43rd St., Suite 306
`Seattle, WA 98105 USA
`Fax: 206-547-1703
`www.iasp-pain.org
`www.painbooks.org
`
`Printed in the United States of America
`
`iv
`
`

`

`
`
`CONTENTS
`
`Combined List of Contributors to First and Second Editions
`Introduction
`Future Revisions
`Abbreviations
`
`Part I Topics and Codes
`Scheme for Coding Chronic Pain Diagnoses
`List of Topics and Codes
`A. Relatively Generalized Syndromes
`B. Relatively Localized Syndromes of the Head and Neck
`C. Spinal Pain, Section 1: Spinal and Radicular Pain Syndromes
`Note on Arrangements
`Definitions of Spinal Pain and Related Phenomena
`Principles
`Radicular Pain and Radiculopathy
`D. Spinal Pain, Section 2: Spinal and Radicular Pain Syndromes of the Cervical
`and Thoracic Regions
`E. Local Syndromes of the Upper Limbs and Relatively Generalized
`Syndromes of the Upper and Lower Limbs
`F. Visceral and Other Syndromes of the Trunk Apart from Spinal and
`Radicular Pain
`G. Spinal Pain, Section 3: Spinal and Radicular Pain Syndromes of the Lumbar,
`Sacral, and Coccygeal Regions
`H. Local Syndromes of the Lower Limbs
`
`Part II Detailed Descriptions of Pain Syndromes
`List of Items Usually Provided in Detailed Descriptions of Pain Syndromes
`A. Relatively Generalized Syndromes
`I. Relatively Generalized Syndromes
`B. Relatively Localized Syndromes of the Head and Neck
`II. Neuralgias of the Head and Face
`III. Craniofacial Pain of Musculoskeletal Origin
`IV. Lesions of the Ear, Nose, and Oral Cavity
`V. Primary Headache Syndromes, Vascular Disorders, and
`Cerebrospinal Fluid Syndromes
`Headache Crosswalk
`VI. Pain of Psychological Origin in the Head, Face, and Neck
`VII. Suboccipital and Cervical Musculoskeletal Disorders
`VIII. Visceral Pain in the Neck
`
`
`
`vii
`ix
`xvi
`xvi
`
` 1
`3
`5
`6
`8
`11
`11
`11
`14
`15
`17
`
`23
`
`25
`
`29
`
`36
`
`37
`38
`39
`39
`59
`59
`68
`72
`77
`
`90
`93
`93
`98
`
`
`
`
`
`
`
`v
`
`

`

`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`C. Spinal Pain, Section 1: Spinal and Radicular Pain Syndromes
`D. Spinal Pain, Section 2: Spinal and Radicular Pain Syndromes of the Cervical
`and Thoracic Regions
`IX. Cervical Spinal or Radicular Pain Syndromes
`X. Thoracic Spinal or Radicular Pain Syndromes
`E. Local Syndromes of the Upper Limbs and Relatively Generalized
`Syndromes of the Upper and Lower Limbs
`XI. Pain in the Shoulder, Arm, and Hand
`XII. Vascular Disease of the Limbs
`XIII. Collagen Disease of the Limbs
`XIV. Vasodilating Functional Disease of the Limbs
`XV. Arterial Insufficiency in the Limbs
`XVI. Pain of Psychological Origin in the Lower Limbs
`F. Visceral and Other Syndromes of the Trunk Apart from Spinal and
`Radicular Pain
`XVII. Visceral and Other Chest Pain
`XVIII. Chest Pain of Psychological Origin
`XIX. Chest Pain Referred from Abdomen or Gastrointestinal Tract
`XX. Abdominal Pain of Neurological Origin
`XXI. Abdominal Pain of Visceral Origin
`XXII. Abdominal Pain Syndromes of Generalized Diseases
`XXIII. Abdominal Pain of Psychological Origin
`XXIV. Diseases of the Bladder, Uterus, Ovaries, and Adnexa
`XXV. Pain in the Rectum, Perineum, and External Genitalia
`G. Spinal Pain, Section 3: Spinal and Radicular Pain Syndromes of the Lumbar,
`Sacral, and Coccygeal Regions
`XXVI. Lumbar Spinal or Radicular Pain Syndromes
`XXVII. Sacral Spinal or Radicular Pain Syndromes
`XXVIII. Coccygeal Pain Syndromes
`XXIX. Diffuse or Generalized Spinal Pain
`XXX. Low Back Pain of Psychological Origin with Spinal Referral
`H. Local Syndromes of the Lower Limbs
`XXXI. Local Syndromes in the Leg or Foot: Pain of Neurological Origin
`XXXII. Pain Syndromes of the Hip and Thigh of Musculoskeletal Origin
`XXXIII. Musculoskeletal Syndromes of the Leg
`
`Part III Pain Terms: A Current List with Definitions and Notes on Usage
`
`Index
`
`vi
`
`101
`103
`
`103
`112
`121
`
`121
`128
`131
`132
`134
`136
`137
`
`137
`145
`146
`149
`151
`160
`163
`163
`172
`175
`
`175
`187
`191
`192
`195
`197
`197
`204
`205
`
`207
`
`215
`
`

`

`
`
`COMBINED LIST OF CONTRIBUTORS
`TO FIRST AND SECOND EDITIONS
`
`D.C. Agnew
`Pasadena, CA, USA
`
`M. Backonja
`Madison, WI, USA
`
`H.J.M. Barnett
`London, ON, Canada
`
`P. Barton
`Calgary, AL, Canada
`
`R.W. Beard
`London, England, UK
`
`W.E. Bell *
`Dallas, TX, USA
`
`J.N. Blau
`London, England, UK
`
`L.M. Blendis
`Toronto, ON, Canada
`
`R.A. Boas
`Auckland, New Zealand
`
`N. Bogduk
`Newcastle, NSW, Australia
`
`J. Boivie
`Linkoping, Sweden
`
`M.R. Bond
`Glasgow, Scotland, UK
`
`J.J. Bonica
`Seattle, WA, USA
`
`D.B. Boyd
`London, ON, Canada
`
`R.I. Brooke
`London, ON, Canada
`
`G.W. Bruyn
`Leuven, Belgium
`
`J.G. Cairncross
`London, ON, Canada
`
`A. Carmon
`Jerusalem, Israel
`
`J.E. Charlton
`Newcastle upon Tyne, England, UK
`
`M.J. Cous ins
`St. Leonards, NSW, Australia
`
`A.B. Deathe
`London, ON, Canada
`
`S. Diamond
`Chicago, IL, USA
`
`M.B. Dresser
`Chicago, IL, USA
`
`R.J. Evans
`Toronto, ON, Canada
`
`T. Feasby
`London, ON, Canada
`
`C. Feinmann
`London, England, UK
`
`W. Feldman
`Halifax, NS, Canada
`
`H.L. Fields
`San Francisco, CA, USA
`
`N.L. Gittleson
`Sheffield, England, UK
`
`J.M. Gregg
`Blacksburg, VA, USA
`
`M. Grushka
`Toronto, ON, Canada
`
`J.M. Gybels
`Leuven, Belgium
`
`A. Hahn
`London, ON, Canada
`
`P. Hansson
`Stockholm, Sweden
`
`vii
`
`P.A.J. Hardy
`Gloucester, England, UK
`
`M. Harris
`London, England, UK
`
`M. Inwood
`London, ON, Canada
`
`G.W. Jamieson
`London, ON, Canada
`
`F.W.L. Kerr
`Rochester, MN, USA
`
`I. Klineberg
`Sydney, NSW, Australia
`
`T. Komusi
`St. John's, NF, Canada
`
`D. W. Koopman
`Leiden, The Netherlands
`
`L. Kudrow
`Encino, CA, USA
`
`P.L. LeRoy
`Wilmington, DE, USA
`
`U. Lindblom
`Stockholm, Sweden
`
`S. Lipton
`Liverpool, England, UK
`
`J.D. Loeser
`Seattle, WA, USA
`
`D.M. Long
`Baltimore, MD, USA
`
`D.G. Machin
`Liverpool, England, UK
`
`G. Magni
`Paris, France
`
`A. Mailis
`Toronto, ON, Canada
`
`

`

`
`
`
`
`J. Marbach
`New York, NY, USA
`
`G. J. Mazars
`Paris, France
`
`P. McGrath
`Halifax, NS, Canada
`
`M. Mehta
`Norwich, England, UK
`
`J. Miles
`Liverpool, England, UK
`
`N. Mohl
`Buffalo, NY, USA
`
`F. Mongini
`Turin, Italy
`
`D. Moulin
`London, ON, Canada
`
`J.A. Mountifield
`Toronto, ON, Canada
`
`J.M. Mumford
`Liverpool, England, UK
`
`J. W. Scadding
`London, England, UK
`
`B. Sessle
`Toronto, ON, Canada
`
`J. Shennan
`Liverpool, England, UK
`
`F. Sicuteri
`Florence, Italy
`
`0. Sjaastad
`Trondheim, Norway
`
`A.E. Sola
`Seattle, WA, USA
`
`E. Spangfort
`Huddinge, Sweden
`
`F.G. Spear
`Sheffield, England, UK
`
`R.H. Spector
`Chicago, IL, USA
`
`D.M. Spengler
`Nashville, TN, USA
`
`W. Noordenbos *
`Amsterdam, The Netherlands
`
`J. Spierdijk
`Leiden, The Netherlands
`
`C. Pagni
`Turin, Italy
`
`I. Papo
`Ancona, Italy
`
`C.W. Parry
`London, England, UK
`
`P. Procacci
`Florence, Italy
`
`A. Rapoport
`Stamford, CT, USA
`
`M. Renaer
`Leuven, Belgium
`
`W.J. Roberts
`Portland, OR, USA
`
`
`
`E.L.H. Spierings
`Boston, MA, USA
`
`R.A. Sternbach
`La Jolla, CA, USA
`
`L.-J. Stovner
`Trondheim, Norway
`
`A. Struppler
`Munich, West Germany
`
`Sir S. Sunderland *
`Melbourne, VIC, Australia
`
`M. Swerdlow
`Manchester, England, UK
`
`W.H. Sweet
`Boston, MA, USA
`
`viii
`
`B. Tait
`Christchurch, New Zealand
`
`R.R. Tasker
`Toronto, ON, Canada
`
`M. Trimble
`London, England, UK
`
`E. Tunks
`Hamilton, ON, Canada
`
`F. Turnbull
`Baltimore, MD, USA
`
`G.S. Tyler
`Scottsdale, AZ, USA
`
`J. Van Hees
`Leuven, Belgium
`
`A.C.M. Vervest
`Sneek, The Netherlands
`
`A.P.E. Vielvoye-Kerkmeer
`Leiden, The Netherlands
`
`P. Walker
`Toronto, ON, Canada
`
`H. Wallach
`London, ON, Canada
`
`C.P.N. Watson
`Toronto, ON, Canada
`
`M.V. Wells
`Campbell River, BC, Canada
`
`F. Wolfe
`Wichita, KS, USA
`
`K.J. Zilkha
`London, England, UK
`
`D. Zohn
`McLean, VA, USA
`
`* Deceased
`
`
`
`

`

`
`Page 207
`
`PART III
`PAIN TERMS
`A CURRENT LIST WITH DEFINITIONS AND NOTES ON USAGE
`
`Revisions prepared by an Ad Hoc Subcommittee of the IASP Task Force on Taxonomy
`
`Harold Merskey (Chair)
`Ulf Lindblom
`James M. Mumford
`Peter W. Nathan
`and
`Sir Sydney Sunderland
`
`First Version published in Pain, Vol. 6, 1979, pages 249-252.
`Updated in Pain, Supplement 3, 1986, pages S215-S221.
`Reprinted 1991
`Minor Revisions 1994
`
`
`
`
`
`
`
`
`
`

`

`Page 208 is Blank
`
`
`Page 208
`
`
`
`
`
`

`

`
`Page 209
`
`INTRODUCTION TO THE 1986 LIST
`
`A list of pain terms was first published in 1979
`(Pain, 6, 249-252). Many of the terms were already es-
`tablished in the literature. One, allodynia, quickly came
`into use in the columns of Pain and other journals. The
`terms have been translated into Portuguese (Rev. Bras.
`Anest., 30, 5, [1980] 349-351,) into French (H. Dehen,
`Lexique de la douleur, La Presse Medicale 12, 23,
`[1983] 1459-1460), and into Turkish (as Agri Terimleri,
`translated by T. Aldemir, J. Turkish Soc. Algology, 1
`[1989] 45-46). A supplementary note was added to these
`pain terms in Pain (14 [1982] 205-206).
`The original list was adopted by the first Subcommit-
`tee on Taxonomy of IASP. Subsequent revisions and
`additions were prepared by a subgroup of the Commit-
`tee, particularly Drs. U. Lindblom, P.W. Nathan, W.
`Noordenbos, and H. Merskey. In 1984, in particular re-
`sponse to some observations by Dr. M. Devor, a further
`review was undertaken both by correspondence and dur-
`ing the 4th World Congress on Pain of IASP. Those tak-
`ing part in that review included Dr. Devor, the other
`colleagues just mentioned, and Dr. J.M. Mumford, Sir
`Sydney Sunderland, and Dr. P.W. Wall. Following that
`review, it was agreed to take advantage of the publica-
`tion of the draft collection of syndromes and their sys-
`tem for classification, to issue an updated list of terms
`with definitions and notes on usage.
`The versions now presented are based upon some
`subsequent discussions by correspondence. The form of
`the definitions and notes at this point has been the re-
`sponsibility of the editor (H.M.). It would be difficult
`now to single out individual contributions, but the editor
`remains heavily indebted to those five members of the
`original Subcommittee on Taxonomy who sustained this
`work in the form of an Ad Hoc group and whose names
`are listed at the beginning of this report. Their knowl-
`edge and patience was repeatedly provided freely and
`with good will.
`The revised current list follows. The original com-
`ments provided as an introduction to the terms are given
`
`
`
`
`
`in the following two paragraphs, which indicate both the
`process by which the terms were first delivered and the
`justification for them.
`“The usage of individual terms in medicine often
`varies widely. That need not be a cause of distress pro-
`vided that each author makes clear precisely how he
`employs a word. Nevertheless, it is convenient and help-
`ful to others if words can be used which have agreed
`technical meanings. Following correspondence and
`meetings during the period 1976-1978, the present
`committee agreed on the definitions which follow, and
`the notes have been prepared by the chairman in the
`light of members’ comments. The definitions are in-
`tended to be specific and explanatory and to serve as an
`operational framework, not as a constraint on future de-
`velopment. They represent agreement between diverse
`specialties including anesthesiology, dentistry, neurol-
`ogy, neurosurgery, neurophysiology, psychiatry, and
`psychology. A starting point for some of these defini-
`tions was provided by the reports of a workshop on Oro-
`Facial Pain held at the U.S. National Institute of Dental
`Research in November 1974.
`“The terms and definitions are not meant to provide
`a comprehensive glossary but rather a minimum stan-
`dard vocabulary for members of different disciplines
`who work in the field of pain. We hope that they will
`prove acceptable to all those in the health professions
`who deal with pain. Not only are they a limited selection
`from available terms, but it is emphasized that except for
`pain itself, they are defined primarily in relation to the
`skin and the special senses are excluded. They may be
`used when appropriate for responses to somatic stimula-
`tion elsewhere or to the viscera. Except for Pain, the
`arrangement is in alphabetical order.”
`It is important to emphasize something that was im-
`plicit in the previous definitions but was not specifically
`stated: that the terms have been developed for use in
`clinical practice rather than for experimental work,
`physiology, or anatomical purposes.
`
`CHANGES IN THE 1994 LIST
`
`There was substantial correspondence from 1986 to
`1993 among members of the Task Force and other col-
`leagues. The previous definitions all remain unchanged,
`except for very slight alterations in the wording of the
`definitions of Central Pain and Hyperpathia. Two new
`terms have been introduced here: Neuropathic Pain and
`Peripheral Neuropathic Pain.
`The terms Sympathetically Maintained Pain and
`Sympathetically Independent Pain have also been em-
`
`
`ployed; however, these terms are used in connection
`with syndromes 1-4 and 1-5, now called Complex Re-
`gional Pain Syndromes, Types I and II. These were for-
`merly
`labeled Reflex Sympathetic Dystrophy and
`Causalgia, and the discussion of Sympathetically Main-
`tained Pain and Sympathetically Independent Pain is
`found with those categories.
`Changes have been made in the notes on Allodynia
`to clarify the fact that it may refer to a light stimulus on
`
`
`
`
`
`

`

`damaged skin, as well as on normal skin. Also, in the
`tabulation of the implications of some of the definitions,
`the words lowered threshold have been removed from
`the features of Allodynia because it does not occur regu-
`larly. Small changes have been made to better
`
`describe Hyperpathia in the definition and note. A sentence
`has been added to the note on Hyperalgesia to refer to cur-
`rent views on its physiology, although as with other defini-
`tions, that for Hyperalgesia remains tied to clinical criteria.
`Last, the note on neuropathy has been expanded.
`
`
`Page 210
`
`PAIN TERMS
`
`An unpleasant sensory and emotional experience associated with actual or potential tissue damage,
`or described in terms of such damage.
`Note: The inability to communicate verbally does not negate the possibility that an individual is
`experiencing pain and is in need of appropriate pain-relieving treatment. Pain is always subjective.
`Each individual learns the application of the word through experiences related to injury in early
`life. Biologists recognize that those stimuli which cause pain are liable to damage tissue. Accord-
`ingly, pain is that experience we associate with actual or potential tissue damage. It is unques-
`tionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore
`also an emotional experience. Experiences which resemble pain but are not unpleasant, e.g., prick-
`ing, should not be called pain. Unpleasant abnormal experiences (dysesthesias) may also be pain
`but are not necessarily so because, subjectively, they may not have the usual sensory qualities of
`pain.
`Many people report pain in the absence of tissue damage or any likely pathophysiological cause;
`usually this happens for psychological reasons. There is usually no way to distinguish their experi-
`ence from that due to tissue damage if we take the subjective report. If they regard their experience
`as pain and if they report it in the same ways as pain caused by tissue damage, it should be ac-
`cepted as pain. This definition avoids tying pain to the stimulus. Activity induced in the nociceptor
`and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state,
`even though we may well appreciate that pain most often has a proximate physical cause.
`
`Pain due to a stimulus which does not normally provoke pain.
`Note: The term allodynia was originally introduced to separate from hyperalgesia and hyperesthe-
`sia, the conditions seen in patients with lesions of the nervous system where touch, light pressure,
`or moderate cold or warmth evoke pain when applied to apparently normal skin. Allo means
`“other” in Greek and is a common prefix for medical conditions that diverge from the expected.
`Odynia is derived from the Greek word “odune” or “odyne,” which is used in “pleurodynia” and
`“coccydynia” and is similar in meaning to the root from which we derive words with -algia or -
`algesia in them. Allodynia was suggested following discussions with Professor Paul Potter of the
`Department of the History of Medicine and Science at The University of Western Ontario.
`The words “to normal skin” were used in the original definition but later were omitted in order to
`remove any suggestion that allodynia applied only to referred pain. Originally, also, the pain-
`provoking stimulus was described as “non-noxious.” However, a stimulus may be noxious at some
`times and not at others, for example, with intact skin and sunburned skin, and also, the boundaries
`of noxious stimulation may be hard to delimit. Since the Committee aimed at providing terms for
`clinical use, it did not wish to define them by reference to the specific physical characteristics of
`the stimulation, e.g., pressure in kilopascals per square centimeter. Moreover, even in intact skin
`there is little evidence one way or the other that a strong painful pinch to a normal person does or
`does not damage tissue. Accordingly, it was considered to be preferable to define allodynia in
`terms of the response to clinical stimuli and to point out that the normal response to the stimulus
`could almost always be tested elsewhere in the body, usually in a corresponding part. Further, al-
`lodynia is taken to apply to conditions which may give rise to sensitization of the skin, e.g., sun-
`burn, inflammation, trauma.
`
`
`
`
`
`Pain
`
`
`
`
`
`Allodynia
`
`
`
`
`
`
`
`
`

`

`
`Page 211
`
`
`
`
`
`
`Analgesia
`
`
`Anesthesia
`dolorosa
`
`Causalgia
`
`It is important to recognize that allodynia involves a change in the quality of a sensation, whether
`tactile, thermal, or of any other sort. The original modality is normally non-painful, but the re-
`sponse is painful. There is thus a loss of specificity of a sensory modality. By contrast, hyperalge-
`sia (q.v.) represents an augmented response in a specific mode, viz., pain. With other cutaneous
`modalities, hyperesthesia is the term which corresponds to hyperalgesia, and as with hyperalgesia,
`the quality is not altered. In allodynia the stimulus mode and the response mode differ, unlike the
`situation with hyperalgesia. This distinction should not be confused by the fact that allodynia and
`hyperalgesia can be plotted with overlap along the same continuum of physical intensity in certain
`circumstances, for example, with pressure or temperature.
`
`See also the notes on hyperalgesia and hyperpathia.
`
`Absence of pain in response to stimulation which would normally be painful.
`Note: As with allodynia (q.v.), the stimulus is defined by its usual subjective effects.
`
`Pain in an area or region which is anesthetic.
`
`A syndrome of sustained burning pain, allodynia, and hyperpathia after a traumatic nerve lesion,
`often combined with vasomotor and sudomotor dysfunction and later trophic changes.
`
`Central pain
`
`Pain initiated or caused by a primary lesion or dysfunction in the central nervous system.
`
`Dysesthesia
`
`
`Hyperalgesia
`
`
`Hyperesthesia
`
`
`
`
`
`
`
`An unpleasant abnormal sensation, whether spontaneous or evoked.
`
`Note: Compare with pain and with paresthesia. Special cases of dysesthesia include hyperalgesia
`and allodynia. A dysesthesia should always be unpleasant and a paresthesia should not be unpleas-
`ant, although it is recognized that the borderline may present some difficulties when it comes to
`deciding as to whether a sensation is pleasant or unpleasant. It should always be specified whether
`the sensations are spontaneous or evoked.
`
`An increased response to a stimulus which is normally painful.
`
`Note: Hyperalgesia reflects increased pain on suprathreshold stimulation. For pain evoked by
`stimuli that usually are not painful, the term allodynia is preferred, while hyperalgesia is more ap-
`propriately used for cases with an increased response at a normal threshold, or at an increased
`threshold, e.g., in patients with neuropathy. It should also be recognized that with allodynia the
`stimulus and the response are in different modes, whereas with hyperalgesia they are in the same
`mode. Current evidence suggests that hyperalgesia is a consequence of perturbation of the no-
`ciceptive system with peripheral or central sensitization, or both, but it is important to distinguish
`between the clinical phenomena, which this definition emphasizes, and the interpretation, which
`may well change as knowledge advances.
`
`Increased sensitivity to stimulation, excluding the special senses.
`
`Note: The stimulus and locus should be specified. Hyperesthesia may refer to various modes of
`cutaneous sensibility including touch and thermal sensation without pain, as well as to pain. The
`word is used to indicate both diminished threshold to any stimulus and an increased response to
`stimuli that are normally recognized.
`
`Allodynia is suggested for pain after stimulation which is not normally painful. Hyperesthesia
`includes both allodynia and hyperalgesia, but the more specific terms should be used wherever
`they are applicable.
`
`
`
`

`

`
`Page 212
`
`Hyperpathia
`
`
`
`A painful syndrome characterized by an abnormally painful reaction to a stimulus, especially a
`repetitive stimulus, as well as an increased threshold.
`Note: It may occur with allodynia, hyperesthesia, hyperalgesia, or dysesthesia. Faulty identifica-
`tion and localization of the stimulus, delay, radiating sensation, and after-sensation may be pre-
`sent, and the pain is often explosive in character. The changes in this note are the specification of
`allodynia and the inclusion of hyperalgesia explicitly. Previously hyperalgesia was implied, since
`hyperesthesia was mentioned in the previous note and hyperalgesia is a special case of hyperesthe-
`sia.
`
`Hypoalgesia
`
`
`Diminished pain in response to a normally painful stimulus.
`Note: Hypoalgesia was formerly defined as diminished sensitivity to noxious stimulation, making
`it a particular case of hypoesthesia (q.v.). However, it now refers only to the occurrence of rela-
`tively less pain in response to stimulation that produces pain. Hypoesthesia covers the case of di-
`minished sensitivity to stimulation that is normally painful.
`
`
`
`
`
`
`
`
`
`
`
`Hypoesthesia
`
`
`
`Neuralgia
`
`Neuritis
`
`
`
`Neurogenic
`Pain
`
`Neuropathic
`Pain
`
`
`The implications of some of the above definitions may be summarized for convenience as follows:
`
`owered threshold:
``
`Allodynia:
`increased response:
`Hyperalgesia:
`raised threshold:
`Hyperpathia:
`increased response:
`
`raised threshold:
`Hypoalgesia:
`lowered response:
`
`The above essentials of the definitions do not have to be symmetrical and are not symmetrical at
`present. Lowered threshold may occur with allodynia but is not required. Also, there is no cate-
`gory for lowered threshold and lowered response-if it ever occurs.
`
`stimulus and response mode differ
`stimulus and response mode are the same
`stimulus and response mode may be the
`same or different
`stimulus and response mode are the same
`
`Decreased sensitivity to stimulation, excluding the special senses.
`
`Note: Stimulation and locus to be specified.
`
`Pain in the distribution of a nerve or nerves.
`
`Note: Common usage, especially in Europe, often implies a paroxysmal quality, but neuralgia
`should not be reserved for paroxysmal pains.
`Inflammation of a nerve or nerves.
`
`Note: Not to be used unless inflammation is thought to be present.
`
`Pain initiated or caused by a primary lesion, dysfunction, or transitory perturbation in the periph-
`eral or central nervous system.
`
`Pain initiated or caused by a primary lesion or dysfunction in the nervous system.
`
`Note: See also Neurogenic Pain and Central Pain. Peripheral neuropathic pain occurs when the
`lesion or dysfunction affects the peripheral nervous system. Central pain may be retained as the
`term when the lesion or dysfunction affects the central nervous system.
`
`Neuropathy
`
`A disturbance of function or pathological change in a nerve: in one nerve, mononeuropathy; in
`several nerves, mononeuropathy multiplex; if diffuse and bilateral, polyneuropathy.
`
`
`
`
`
`

`

`
`Page 213
`
`
`
`Nociceptor
`
`
`
`Noxious
`Stimulus
`
`
`Pain threshold
`
`
`
`Pain tolerance
`level
`
`
`Paresthesia
`
`
`
`
`Peripheral
`neurogenic
`pain
`
`Peripheral
`neuropathic
`pain
`
`Note: Neuritis (q.v.) is a special case of neuropathy and is now reserved for inflammatory proc-
`esses affecting nerves. Neuropathy is not intended to cover cases like neurapraxia, neurotmesis,
`section of a nerve, or transitory impact like a blow, stretching, or an epileptic discharge. The term
`neurogenic applies to pain due to such temporary perturbations.
`
`A receptor preferentially sensitive to a noxious stimulus or to a stimulus which would become
`noxious if prolonged.
`
`Note: Avoid use of terms like pain receptor, pain pathway, etc.
`
`A noxious stimulus is one which is damaging to normal tissues.
`
`Note: Although the definition of a noxious stimulus has been retained, the term is not used in this
`list to define other terms.
`
`The least experience of pain which a subject can recognize.
`
`Note: Traditionally the threshold has often been defined, as we defined it formerly, as the least
`stimulus intensity at which a subject perceives pain. Properly defined, the threshold is really the
`experience of the patient, whereas the intensity measured is an external event. It has been common
`usage for most pain research workers to define the threshold in terms of the stimulus, and that
`should be avoided. However, the threshold stimulus can be recognized as such and measured. In
`psychophysics, thresholds are defined as the level at which 50% of stimuli are recognized. In that
`case, the pain threshold would be the level at which 50% of stimuli would be recognized as pain-
`ful. The stimulus is not pain (q.v.) and cannot be a measure of pain.
`
`The greatest level of pain which a subject is prepared to tolerate.
`
`Note: As with pain threshold, the pain tolerance level is the subjective experience of the individ-
`ual. The stimuli which are normally measured in relation to its production are the pain tolerance
`level stimuli and not the level itself. Thus, the same argument applies to pain tolerance level as to
`pain threshold, and it is not defined in terms of the external stimulation as such.
`
`An abnormal sensation, whether spontaneous or evoked.
`
`Note: Compare with dysesthesia. After much discussion, it has been agreed to recommend that
`paresthesia be used to describe an abnormal sensation that is not unpleasant while dysesthesia be
`used preferentially for an abnormal sensation that is considered to be unpleasant. The use of one
`term (paresthesia) to indicate spontaneous sensations and the other to refer to evoked sensations is
`not favored. There is a sense in which, since paresthesia refers to abnormal sensations in general,
`it might include dysesthesia, but the reverse is not true. Dysesthesia does not include all abnormal
`sensations, but only those which are unpleasant.
`
`Pain initiated or caused by a primary lesion or dysfunction or transitory perturbation in the periph-
`eral nervous system.
`
`Pain initiated or caused by a primary lesion or dysfunction in the peripheral nervous system
`
`.
`
`
`
`
`
`