Updated Diagnostic Criteria for Neuropathic Pain in SCI, Stroke, MS

The ACTTION-APS Pain Taxonomy (AAPT) initiative invited a working group with extensive expertise in the clinical management of central pain and/or central pain research to meet in Copenhagen, Denmark, in July 2015 to develop diagnostic criteria for central neuropathic pain. The diagnostic criteria focus on neuropathic pain from spinal cord injury (SCI), stroke, and multiple sclerosis (MS), and were recently published in the Journal of Pain.¹

The meeting was a combined effort of the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the US Food and Drug Administration (FDA) and the American Pain Society (APS).

“In some cases, central pain is easy to identify — for example, if a patient experiences diffuse burning, pricking pain from the waist down following SCI,” wrote Eva Widerstrom-Noga, PhD, DDS, professor of neurological surgery at the Miami Project to Cure Paralysis at the University of Miami Miller School of Medicine in Florida, and colleagues. “However, neuropathic pain in more localized areas is much more difficult to diagnose due to the lack of uniform characteristics. Therefore, a careful examination to exclude other causes of pain is critically important.”

Central Neuropathic Pain from Spinal Cord Injury

Of patients with spinal cord injury, 40% to 50% will develop central neuropathic pain. This pain can be peripheral or central, and determining the origin of the pain is not always obvious unless there is evidence of peripheral nerve injury.

Core Diagnostic Criteria

• Chronic central pain from a spinal cord injury develops at or below the level of lesion
• Pain onset is either acute or delayed after injury, but rarely occurs >12 months after injury; onset >12 months should be examined for other causes (eg, syringomyelia)
• Evidence of a spinal cord lesion or disease (including syringomyelia) must be provided to support central neuropathic pain diagnosis
• No other explanation for the pain is available

Common Features

• Central pain is often constant, but can be intermittent or paroxysmal
• Some patients feel pain in response to light touch or cold stimuli
• Non-painful stimulations such as paresthesias and dysesthesias are very common 

Diagnosis

• The neuropathic pain diagnostic questionnaire (DN4; Doleur Neuropathique 4)² is suggested  as the most accurate for diagnosing SCI-related neuropathic pain, but has only been tested in a few central pain studies^3,4
• The Spinal Cord Injury Pain Instrument was recently developed to identify central pain from spinal cord injuries;⁵ its utility beyond this modality has not yet been established

Central Neuropathic Pain After Stroke

Central pain occurs in 3% to 8% of patients after stroke with onset usually occurring in the first year.

Core Diagnostic Criteria

• Central neuropathic pain developing in the area of the body affected by stroke
• Diagnostic testing confirming a stroke, or patient’s history strongly suggestive of a stroke
• Continuous or recurring pain after stroke, with pain duration of at least 3 months
• Pain associated with sensory changes in neuroanatomically concordant areas, indicated with either 1 positive or 1 negative sensory sign
• No other explanation for pain

Common Features

• Features of central pain from stroke are similar to those resulting from spinal cord injury
• Pain is often constant but can also be intermittent or paroxysmal
• Pain upon light touch or cold stimuli in some patients
• Common paresthesias and dysesthesias

Central Neuropathic Pain From Multiple Sclerosis

Pain in MS varies and affects an estimated 28% to 86% of patients. Specific central pain syndromes in MS include secondary trigeminal neuralgia and Lhermitte’s sign.

“Pain in MS has a distribution that is compatible with a brain or a spinal segmental localization. For secondary trigeminal neuralgia, MRI should indicate a lesion in the relevant site in the pons, ie, along the course of trigeminal primary afferents, or alternatively neurophysiological recordings of trigeminal reflexes and trigeminal evoked potentials should show the latency delays typical of MS,” the investigators wrote.

Core Diagnostic Criteria

• Continuous or recurrent pain after established diagnosis of MS
• Pain lasting at least 3 months
• Pain located within the area corresponding to an MS lesion in the brain or spinal cord
• Pain associated with sensory changes in neuroanatomically concordant areas, indicated with 1 positive or 1 negative sensory sign
• No other explanation for the pain is available

Common Features

• Central pain in MS is similar to other pain conditions
• Pain may be constant or intermittent
• Pain may be evoked by touch or cold
• Neuropathic pain is often described as “burning,” “pricking,” “squeezing,” “tingling,” and “aching,” and is frequently  associated with other abnormal sensory signs of lesions of the somatosensory nervous system such as numbness or paresthesia
• Trigeminal neuralgia is a paroxysmal facial pain found in patients with MS that can occur randomly but is often triggered by innocuous movement; it has an abrupt onset and lasts a few seconds and some patients experience pain between paroxysms
• Lhermitte’s sign is a sensation that feels like a transient electric shock in the back; it is related to neck movement

Studies are needed to assess the reliability and validity of these proposed criteria, according to the report’s authors. In particular, studies focusing on central pain — vs general pain — are needed to examine specific pain syndromes in different disorders and gain a better understanding of predictors, mechanisms, associated factors, and treatments. They also note that central pain conditions are associated with pain phenotypes that are likely dependent on the underlying mechanisms of the disease.

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References

1. Widerstrom-Noga E, Loeser JD, Jensen TS, Finnerup NB. AAPT diagnostic criteria for central neuropathic pain [published online June 15, 2017]. Journal of Pain. doi:10.1016/j.jpain.2017.06.003
2. Bouhassira D, Attal N, Alchaar H, et al. Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4). Pain. 2005;114(1-2):29-36.
3. Hallstrom H, Norrbrink C. Screening tools for neuropathic pain: can they be of use in individuals with spinal cord injury? Pain. 2011;152:772-779.
4. Harno H, Haapaniemi E, Putaala J, et al. Central poststroke pain in young ischemic stroke survivors in the Helsinki Young Stroke Registry. Neurology. 2014;83:1147-1154.
5. Bryce TN, Richards JS, Bombardier CH,et al. Screening for neuropathic pain after spinal cord injury with the Spinal Cord Injury Pain Instrument (SCIPI): a preliminary validation study. Spinal Cord. 2014;52:407-412.