Narrative Review
The IASP classification of chronic pain for ICD-11 :
chronic neuropathic pain
Joachim Scholz
a,b
, Nanna B. Finnerup
c,d
, Nadine Attal
e,f
, Qasim Aziz
g
, Ralf Baron
h
, Michael I. Bennett
i
,
Rafael Benoliel
j
, Milton Cohen
k
, Giorgio Cruccu
l
, Karen D. Davis
m,n
, Stefan Evers
o,p
, Michael First
q
,
Maria Adele Giamberardino
r
, Per Hansson
s,t
, Stein Kaasa
u,v,w
, Beatrice Korwisi
x
, Eva Kosek
y
,
Patricia Lavand’homme
z
, Michael Nicholas
aa
, Turo Nurmikko
bb
, Serge Perrot
cc
, Srinivasa N. Raja
dd
, Andrew S.
C. Rice
ee
, Michael C. Rowbotham
ff
, Stephan Schug
gg
, David M. Simpson
hh
, Blair H. Smith
ii
, Peter Svensson
jj,kk
,
Johan W.S. Vlaeyen
ll,mm
, Shuu-Jiun Wang
nn,oo
, Antonia Barke
x
, Winfried Rief
x
, Rolf-Detlef Treede
pp,
*, Classification
Committee of the Neuropathic Pain Special Interest Group (NeuPSIG), Task Force for the Classification of Chronic
Pain of the International Association for the Study of Pain (IASP)
Abstract
The upcoming 11th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD) of the World
Health Organization (WHO) offers a unique opportunity to improve the representation of painful disorders. For this purpose, the
International Association for the Study of Pain (IASP) has convened an interdisciplinary task force of pain specialists. Here, we
present the case for a reclassification of nervous system lesions or diseases associated with persistent or recurrent pain for $3
months. The new classification lists the most common conditions of peripheral neuropathic pain: trigeminal neuralgia, peripheral
nerve injury, painful polyneuropathy, postherpetic neuralgia, and painful radiculopathy. Conditions of central neuropathic pain
include pain caused by spinal cord or brain injury, poststroke pain, and pain associated with multiple sclerosis. Diseases not explicitly
mentioned in the classification are captured in residual categories of ICD-11. Conditions of chronic neuropathic pain are either
insufficiently defined or missing in the current version of the ICD, despite their prevalence and clinical importance. We provide the
short definitions of diagnostic entities for which we submitted more detailed content models to the WHO. Definitions and content
models were established in collaboration with the Classification Committee of the IASP’s Neuropathic Pain Special Interest Group
(NeuPSIG). Up to 10% of the general population experience neuropathic pain. The majority of these patients do not receive
satisfactory relief with existing treatments. A precise classification of chronic neuropathic pain in ICD-11 is necessary to document
this public health need and the therapeutic challenges related to chronic neuropathic pain.
Keywords: Chronic pain, Neuropathic pain, Diagnosis, Classification, ICD-11, WHO
1. Neuropathic pain
Lesions or diseases involving the somatosensory nervous system
may paradoxically not only lead to a loss of function but also to
increased pain sensitivity and spontaneous pain. This neuro-
pathic pain is usually chronic, ie, it either persists continuously or
manifests with recurrent painful episodes. Pain may result from
etiologically diverse disorders affecting the peripheral or the
central nervous system. The cause can be a metabolic disease,
eg, diabetic neuropathy, a neurodegenerative, vascular or
autoimmune condition, a tumor, trauma, infection, exposure to
toxins, or a hereditary disease. Chronic pain also occurs in
neurological conditions of unknown etiology, eg, idiopathic
neuropathies.
5
The mechanistic underpinnings of pain hyper-
sensitivity and spontaneous pain in these conditions are complex,
and their relationship to the underlying pathological disease
process often remains unclear. On the other hand, differences in
pain phenotypes offer an opportunity to distinguish pain
syndromes clinically.
1,9,30
Neurophysiological investigations
may reveal some mechanistic clues, eg, activity increases in
somatosensory nerve fibers or changes in the endogenous
control of pain.
14,17
However, a lack of suitable noninvasive tests
usually precludes an in-depth evaluation of active pain mecha-
nisms in patients. Although imaging studies and quantitative
sensory tests help elucidate important pathophysiological
aspects of pain in patients, current knowledge of neuropathic
pain mechanisms is based largely on animal models.
Chronic neuropathic pain is a major factor contributing to the
global burden of disease.
21
Its prevalence ranges between 6.9%
and 10% of the general population.
28
How strongly pain is
associated with a particular neurological disease varies. Pain may
be the most prominent or sole disease manifestation as, eg, in
postherpetic neuralgia, or it may occur only in a subgroup of
patients with the same disease as, eg, in chemotherapy-induced
peripheral neuropathies. Even among patients with the same
underlying cause of neuropathic pain, painful symptoms and signs
usually differ.
4
However, when present, neuropathic pain frequently
causes major suffering and disability. Therapeutic management is
challenging. Medications recommended as first-line treatments
provide less than satisfactory relief in many patients.
11
A suspected diagnosis of neuropathic pain requires specific
investigations to ascertain that the pain originates in the nervous
system. The distribution of pain must correspond to the
underlying lesion or disease of the somatosensory nervous
system. The neuroanatomical relation to the underlying cause
must still be recognizable even if pain is not felt in the entire
innervation territory of an affected peripheral nerve or root, or the
somatotopic representation corresponding to a lesion or disease
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of the central nervous system, or if pain extends somewhat
outside these boundaries. Objective signs of a sensory disorder in
the distribution of pain increase diagnostic certainty. These signs
may indicate a sensory deficit or exaggerated responses to
normally painful (hyperalgesia) or painless stimuli (allodynia). The
definite diagnosis of neuropathic pain requires demonstration of
the cause, eg, neurophysiological tests confirming a peripheral
neuropathy or imaging results showing the involvement of
somatosensory fiber tracts after spinal cord injury.
6,10,25
Neuro-
pathic pain also requires specific treatment, involving both
pharmacological and nonpharmacological approaches.
8,11
Evi-
dence of high or moderate quality supports the use of
gabapentin, pregabalin, and inhibitors of serotonin and nor-
adrenalin reuptake, and tricyclic antidepressants as medications
of first choice. Dermal patches releasing lidocaine or capsaicin
and subcutaneous injection of botulinum toxin offer topical
treatment options. Opioids should be reserved for patients not
responding to therapeutic alternatives with a lower risk of adverse
effects.
11
Analgesics such as nonsteroidal anti-inflammatory
drugs have no proven efficacy against pain of neuropathic
origin.
18,29
These particular requirements for evaluation and
treatment call for an accurate representation of neuropathic pain
in diagnostic classifications of the relevant clinical conditions.
2. Shortcomings of ICD-10
A structured classification of conditions associated with neuropathic
pain is critically needed.
12
To date, the International Classification of
Headache Disorders (ICHD) is the only disease classification
providing systematic coverage of neuropathic pain conditions, but
these are limited to cranial nerve injuries and neuralgias.
12,15
Despite its clinical and economic significance, neuropathic
pain is not adequately represented in the current version of the
International Statistical Classification of Diseases and Related
Health Problems (ICD) of the World Health Organization (WHO).
The ICD is the most widely used source for diagnostic codes and
the standard instrument for disease classification in clinical
practice, epidemiology, and health management.
31
The ICD
organizes diseases and clinical syndromes by etiology, affected
organ, or body region. In the current version of the ICD (ICD-10),
painful conditions that do not fit this scheme can be classified as
acute (R52.0) or chronic pain (R52.2), with a separate code for
chronic intractable pain (R52.1). These codes can be combined
with neurological diagnoses, eg, diabetic polyneuropathy
(G63.2*). The asterisk behind the code indicates a clinical
syndrome in need of another etiological code, marked by
a dagger. In this example, type 2 diabetes mellitus with
neurological complications (E11.4†) would be a suitable speci-
fication. Thus, 3 codes are required to fully describe painful
diabetic polyneuropathy, one of the most common manifesta-
tions of neuropathic pain that affects up to 30% of patients with
type 2 diabetes.
3
There are very few explicit references to conditions of
neuropathic pain in ICD-10. They include trigeminal neuralgia
(G50.0), postzoster neuralgia (G53.0* B02.2†), and phantom limb
syndrome with pain (G54.6). The code for postzoster neuralgia,
better known as postherpetic neuralgia, applies only if the
disorder involves a cranial nerve, although thoracic nerve roots
are far more commonly affected by the disease.
24
Hereditary
neuropathies that are predominantly characterized by painful
symptoms or signs are not listed at all or incorrectly classified. For
example, erythromelalgia is designated as peripheral vascular
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
J. Scholz and N.B. Finnerup contributed equally to this work. A. Barke, W. Rief, and R.-D. Treede contributed equally to this work.
Departments of
a
Anesthesiology and,
b
Pharmacology, Columbia University Medical Center, New York, NY, United States,
c
Department of Clinical Medicine, Danish Pain
Research Cen ter, Aarhus University, Aarhus, Denmark,
d
Department of Neurology, Aarhus University Hospital, Aarhus, Denmark,
e
INSERM U 987, Assistance
Publique—H ˆopitaux de Paris, H ˆopital Ambroise Par ´e, Boulogne Billancourt, France,
f
Universit ´e Versailles Saint Quentin en Yvelines, Versailles, France,
g
Centre for
Neuroscience and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of
London, London, United Kingdom,
h
Department of Neurology, Universit ¨atsklinikum Schleswig-Holstein, Kiel, Germany,
i
Academic Unit of Palliative Care, University of
Leeds, Leeds, United Kingdom,
j
Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Newark, NJ, United States,
k
St. Vince nt’s Clinical School,
University of New South Wales, Sydney, Australia,
l
Department of Human Neuroscience, Sapienza University, Rome, Italy,
m
Department of Surgery and Institute of Medical
Science, University of Toronto, Toronto, ON, Canada,
n
Division of Brain, Imaging and Behavior-Systems Neuroscience, Krembil Research Institute, University Health
Network, Toronto, ON, Canada,
o
Department of Neurology, Krankenhaus Lindenbrunn, Coppenbr ¨ugge, Germany,
p
Faculty of Medicine, University of M ¨unster, M ¨unster,
Germany,
q
Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, United States,
r
Department of Medicine and Science of
Aging, Centro Studi dell’ Invecchiamento e Medic ina Traslazionale (CeSI-Met), G D’Annunzio University of Chieti, Chieti, Italy,
s
Department of Pain Management and
Research, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway,
t
Department of Molecular Medicine and Surgery, Karolinska Institutet,
Stockholm, Sweden,
u
European Palliative Care Research Centre (PRC), Oslo, Norway,
v
Department of Oncology, Oslo University Hospital, Oslo, Norway,
w
Institute of
Clinical Medicine, University of Oslo, Oslo, Norway,
x
Division of Clinical Psychology and Psychotherapy, Department of Psychology, Philipps-University Marburg, Marburg,
Germany,
y
Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden,
z
Department of Anesthesiology and Acute Postoperative Pain Service, Saint Luc
Hospital, Catholic University of Louvain, Brussels, Belgium,
aa
Pain Management Research Institute, Royal North Shore Hospital, University of Sydney, Sydney, Australia,
bb
Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, United Kingdom,
cc
INSERM U 987, Pain Clinic, Cochin Hospital, Paris Descartes University,
Paris, France,
dd
Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United
States,
ee
Pain Research, Department of Surgery and Cancer, Imperial College, London, United Kingdom,
ff
California Pacific Medical Center Research Institute, San
Francisco, CA, United States,
gg
Anaesthesiology and Pain Medicine, Medical School, University of Western Australia and Royal Perth Hospital, Perth, Australia,
hh
Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States,
ii
Division of Population Health and Genomics, University of Dundee,
Dundee, Scotland,
jj
Section of Clinical Oral Physiology, School of Dentistry, Aarhus University, Aarhus, Denmark,
kk
Department o f Dental Medicine, Karolinska Institute,
Huddinge, Sweden,
ll
Research Group Health Psychology, University of Leuven, Leuven, Belgium,
mm
Experimental Health Psychology, Maastricht University, Maastricht, the
Netherlands,
nn
Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan,
oo
Brain Research Center, National Yang-Ming University, Taipei, Taiwan,
pp
Department of Neurophysiology, CBTM, Medical Faculty Mannheim of Heidelberg University, Mannheim, Germany
*Corresponding author. Department of Neurophysiology, Centre for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University,
Ludolf-Krehl-Str.13-17, 68167 Mannheim, Germany. Tel.: 149 (0)621 383 71 400; fax: 149-(0)621 383 71 401. E-mail address: Rolf-Detlef.Treede@medma.uni-heidelberg.
de (R.-D. Treede).
Supplemental digital co ntent is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the
journal’s Web site (www.painjournalonline.com). SDC includ es a complete reference list of the diagnoses entered into the foundation with the foundation IDs as well as the
extension codes (specifier). Since the complete list is co ntained, the material is identical for all papers of the series.
PAIN 160 (2019) 53–59
© 2018 International Association for the Study of Pain
http://dx.doi.org/10.1097/j.pain.0000000000001365
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disease (I73.8) because painful episodes associated with the
disease are accompanied by an erythema. A hereditary variant of
the disease, in which intense pain, not reddening, is the leading
symptom, remains unspecified.
7
The complexity of ICD-10 codes and the incomplete or
inaccurate coverage of relevant clinical conditions risk under-
reporting of chronic pain. This has practical consequences for
clinicians, hospitals, and other health care providers. Under-
reporting also hinders efficient resource management by insurers
and the development of sound public health strategies by
policymakers. The current epidemic of opioid abuse in North
America illustrates the importance of a reliable classification of
chronic pain to enable the monitoring of safe and effective
analgesics use in cancer and noncancer pain, including pain of
neuropathic origin.
13
3. The IASP Task Force Initiative for the classification
of chronic pain in the International Classification
of Diseases
To generate a systematic and improved classification of conditions
associated with clinically relevant pain and to ensure representation
of these diagnoses in the upcoming revision of the ICD, the
International Association for the Study of Pain (IASP) established
a Task Force that works in close cooperation with WHO
representatives.
27
The classification is dedicated exclusively to
chronic pain syndromes, defined as persistent or recurrent pain
lasting $3 months. As we have previously outlined, conditions of
neuropathic pain are divided into 2 broad categories for peripheral
or central nervous disorders. Diseases not explicitly listed in the
classification will be captured in residual categories.
27
During the
process of drafting and editing the definitions of individual diseases
and detailed content models of neuropathic pain, the Task Force
conferred with the Classification Committee of the IASP’s
Neuropathic Pain Special Interest Group (NeuPSIG). Content
models underwent initial field testing in Australia, Germany, Japan,
and Norway. Revised models were subjected to further field testing
by the WHO in WHO-led field tests. We will report the results of
these field tests separately. Overall, utility and specificity of the
diagnostic criteria were ranked highly. A version for preparing
implementation of ICD-11 was released by the WHO in June
2018.
32
The complete revision will be submitted to the WHO’s
Executive Board in January and the World Health Assembly in May
2019. After endorsement, member states are expected to report
health statistics according to ICD-11 from 2022 onward.
4. The classification of chronic neuropathic pain
Some conditions of persistent neuropathic pain produce distinct
symptoms that would allow for diagnosing chronic pain before the
3-month threshold. One example is trigeminal neuralgia, which is
characterized by a pain distribution in one or more branches of the
fifth cranial nerve, abrupt pain paroxysms, and provocation of
these pain attacks by normally innocuous mechanical stimuli or
orofacial movements. Periods of remission vary, but the neuralgia
never disappears completely.
6,15
Similarly, pain associated with
polyneuropathy caused by type 2 diabetes or central pain after
spinal cord injury usually persists so that it may seem unnecessary
to wait 3 months before diagnosing chronic neuropathic pain.
3,23
Nonetheless, in the absence of objective markers delineating
acute and chronic phases of pain, the arbitrary definition of 3
months was chosen because it provides for clear operationaliza-
tion in line with widely used research criteria and subject enrolment
in analgesic treatment trials.
26
The proposed classification differentiates neuropathic pain of
peripheral and central origin.
16
It comprises 9 common con-
ditions associated with persistent or recurrent pain (Fig. 1 and
supplementary Table 1, available at http://links.lww.com/PAIN/
A658). Short definitions of these conditions are listed below.
These definitions are part of more detailed content models
included in the so-called foundation layer of ICD-11. The models
provide minimum criteria of possible neuropathic pain and
describe investigations that support a definitive diagnosis.
6,10
They also contain extension codes for pain severity (combining
intensity, distress, and disability), temporal characteristics, and
psychological or social factors,
26
as well as a link to the
International Classification of Functioning (ICF).
19,33
4.1. Chronic neuropathic pain
Chronic neuropathic pain is chronic pain caused by a lesion or
disease of the somatosensory nervous system.
16
The pain may
be spontaneous or evoked, as an increased response to a painful
stimulus (hyperalgesia) or a painful response to a normally
nonpainful stimulus (allodynia). The diagnosis of chronic neuro-
pathic pain requires a history of nervous system injury or disease
and a neuroanatomically plausible distribution of the pain.
Negative (eg, decreased or loss of sensation) and positive
sensory symptoms or signs (eg, allodynia or hyperalgesia)
indicating the involvement of the somatosensory nervous system
must be compatible with the innervation territory of the affected
nervous structure. These criteria apply to all diagnostic entities of
chronic neuropathic pain.
4.1.1. Chronic peripheral neuropathic pain
Chronic peripheral neuropathic pain is chronic pain caused by
a lesion or disease of the peripheral somatosensory nervous
system.
4.1.1.1. Trigeminal neuralgia
Trigeminal neuralgia is a manifestation of orofacial neuropathic
pain restricted to one or more divisions of the trigeminal nerve.
The pain is recurrent, abrupt in onset and termination, triggered
by innocuous stimuli, and typically compared with an electric
shock or described as shooting or stabbing. Some patients
experience continuous pain between these painful paroxysms.
The diagnosis comprises idiopathic trigeminal neuralgia,
classical neuralgia produced by vascular compression of the
trigeminal nerve, and secondary neuralgia caused by a tumor or
cyst at the cerebellopontine angle or multiple sclerosis.
6
As for other conditions of chronic neuropathic pain, the
detailed content model includes a discussion of the etiology.
4.1.1.2. Chronic neuropathic pain after peripheral nerve
injury
Chronic neuropathic pain after peripheral nerve injury is persistent
or recurrent pain caused by a peripheral nerve lesion. History of
a plausible nerve trauma, pain onset in temporal relation to the
trauma, and pain distribution within the innervation territory of
a peripheral nerve (or nerves) are required for the diagnosis.
Negative and positive sensory symptoms or signs must be
compatible with the innervation territory of the affected nerve (or
nerves). Formation of a neuroma may lead to pain at the lesion site.
Consistent with the new concept of “multiple parenting” in ICD-
11 (Fig. 1), the diagnosis of chronic neuropathic pain after
peripheral nerve injury is also listed in the section on postsurgical
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and posttraumatic pain.
22
However, the content model for the
diagnosis is stored in the foundation layer of ICD-11.This
hierarchical structure of the classification allows for multiple
referencing of a content model without duplicating the diagnosis.
4.1.1.3. Painful polyneuropathy
Chronic pain occurs in polyneuropathies caused by metabolic,
autoimmune, familial or infectious diseases, exposure to
environmental or occupational toxins, or treatment with a neurotoxic
drug. Chronic pain also occurs in polyneuropathies of unknown
etiology. Pain may be the initial symptom of a neuropathy or develop
overthecourseofthedisease(Box1).Negativeandpositivesensory
symptoms or signs must be compatible with the anatomical
distribution pattern of the polyneuropathy. Chemotherapy-induced
peripheral neuropathy is one form of painful polyneuropathy included
in the classification of chronic cancer-related pain.
2
Figure 1. Classification of chronic neuropathic pain in ICD-11. Top and 2nd level diagnoses are part of ICD-1 1 Mortality and Morbidity Linearisation (MMS).
32
Specific entities of chronic neuropathic pain are included at the next level. According to the new concept of multiple parenting in ICD-11, these entities may be
referred to from other divisions of the chronic pain classification, eg, chronic posttraumatic pain or chronic secondary headaches and orofacial pains.
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4.1.1.4. Postherpetic neuralgia
Postherpetic neuralgia is defined as pain persisting for $3
months after the onset or healing of herpes zoster. The
innervation territory of the first (ophthalmic) branch of the
trigeminal nerve and thoracic dermatomes are the locations
most frequently affected by chronic pain after herpes zoster.
Postherpetic neuralgia may emerge in continuation of the acute
pain associated with the skin rash or develop after a painless
interval. Negative and positive sensory symptoms or signs must
be compatible with the innervation territory of the affected cranial
nerve or peripheral dermatome (or dermatomes).
4.1.1.5. Painful radiculopathy
Chronic painful radiculopathy is persistent or recurrent pain caused
by a lesion or disease involving the cervical, thoracic, lumbar, or
sacral nerve roots. Degenerative changes of the spinal column
including ligaments and intervertebral disks are the most frequent
cause, but painful radiculopathy may also result from trauma, tumor,
or neoplastic meningitis, from infections, hemorrhage or ischemia,
diabetes mellitus, rheumatoid arthritis, or from an iatrogenic lesion,
eg, during injection therapy or surgery. Pain within the affected
dermatomes (radicular pain) is required for the diagnosis. The pain
may be spontaneous but is typically exacerbated or provoked by
taking or maintaining a certain body position or during movement.
Negative and positive sensory symptoms or signs must be
compatible with the innervation territory of the affected nerve root
(or roots). Musculoskeletal pain associated with painful radiculop-
athy should be classified separately.
20
4.1.1.6. Other specified and unspecified chronic peripheral
neuropathic pain
ICD-11 contains a residual category for other specified conditions
of chronic peripheral neuropathic pain that are not covered by the
diseases listed above, eg, chronic neuropathic pain caused by
a carpal tunnel syndrome. An additional category for unspecified
conditions provides for the classification of disorders for which
insufficient information is available to assign a precise diagnosis.
4.1.2. Chronic central neuropathic pain
Chronic central neuropathic pain is chronic pain caused by
a lesion or disease of the central somatosensory nervous system.
4.1.2.1. Chronic central neuropathic pain associated with
spinal cord injury
Chronic central neuropathic pain associated with spinal cord
injury is caused by a lesion or disease of the somatosensory
pathways in the spinal cord. The definition of spinal cord injury
comprises impairments of spinal cord function resulting from
external force or a disease process. The pain may be
spontaneous or evoked, as an increased response to a painful
stimulus (hyperalgesia) or a painful response to a normally
nonpainful stimulus (allodynia). The diagnosis requires a history of
spinal cord lesion or disease and a neuroanatomically plausible
distribution of the pain, ie, pain felt in dermatomes at or below the
level of injury in areas with sensory disturbance (Box 1).
This cause of central neuropathic pain is also included in the
classification of chronic postsurgical and posttraumatic pain.
22
4.1.2.2. Chronic central neuropathic pain associated with
brain injury
Chronic central neuropathic pain associated with brain injury is
caused by a lesion or disease of the somatosensory cortex,
connected brain regions, or associated pathways in the brain.
History of a plausible brain trauma, pain onset in temporal relation
to the trauma, and a pain distribution that is neuroanatomically
plausible are required for the diagnosis. Negative or positive
sensory symptoms or signs indicating the involvement of the brain
must be present in the body region corresponding to the brain
injury.
See also the classification of chronic postsurgical and post-
traumatic pain.
22
4.1.2.3. Chronic central poststroke pain
Chronic central poststroke pain is caused by a cerebrovascular
lesion, infarct or hemorrhage, of the brain or brainstem. The pain
may be spontaneous or evoked, as an increased response to
a painful stimulus (hyperalgesia) or a painful response to
a normally nonpainful stimulus (allodynia). The diagnosis of
central poststroke pain requires a history of stroke and a neuro-
anatomically plausible distribution of the pain, ie, pain felt in the
body region represented in the central nervous structures
affected by the stroke. Negative or positive sensory symptoms
or signs indicating the involvement of the brain must be present in
the body region affected by the stroke.
Case vignette 1: Chronic painful polyneuropathy
A 56-year-old woman with type 2 diabetes mellitus for 2 years complains about pain in the feet that started approximately 4 months ago. The pain intensity is 5 to 7 on a scale from
0 to 10. The pain may get worse at night or when she is walking. In addition, she noticed numbness and tingling in the feet. The examination reveals a stocking-like distribution of
deficits in the sense of touch. The Achilles tendon reflex is weak. An electrophysiological examination shows slow conduction in the sural and peroneal nerves. The patient has
a body mass index of 30. Her fasting blood glucose concentration is 132 mg/dL, and the HbA1 measures 7%. Painful polyneuropathy caused by type 2 diabetes mellitus was
diagnosed. The treatment plan consisted of improved blood glucose management, medication for neuropathic pain, and foot care education.
Case vignette 2: Chronic central neuropathic pain associated with spinal cord injury
A 40-year-old man, who 5 y ears ag o suffered an inco mplete sp inal c ord injury at the thoracic level, reports di ffuse pai n in bo th le gs. He d escrib es an o ngoing pa in of burning
and s queezing character as well as sensations of pins and needles. The averag e pain in tensity is 6/10. In addition, he somet imes experiences pain provoked by light touch.
These painful sensations devel oped gradu ally over the firs t 6 mont hs a fter the injury. On ph ysical e xamination, he exhibits decreased de tection of both mechanical and
thermal stimuli from dermatom e T4 down, hypersensi tivity to cold and touch-evoked allodyni a on the lower legs. Th e diagnosis was ch ronic central neu ropathic pain
associated with spinal cord injury. Following referral to a multidisciplinary c enter for pai n th erapy, he rece ived comprehensive care incl uding medication for neuropathic
pain, physical and cognitive behavioral therapy.
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