Neuropathic pain phenotyping by international consensus (NeuroPPIC) for genetic studies

Abstract

For genetic research to contribute more fully to furthering our knowledge of neuropathic pain we require an agreed, valid and feasible approach to phenotyping, in order to allow collaboration and replication in samples of sufficient size. Results from genetic studies on neuropathic pain have been inconsistent and have met with replication difficulties, in part because of differences in phenotypes used for case ascertainment. Since there is no consensus on the nature of these phenotypes, nor the methods of collecting them, this study aimed to provide guidelines on collecting and reporting phenotypes in cases and controls for genetic studies. Consensus was achieved through a staged approach: (1) systematic literature review to identify all neuropathic pain phenotypes used in previous genetic studies; (2) Delphi survey to identify the most useful neuropathic pain phenotypes, their validity and feasibility; and (3) meeting of experts to reach consensus on the optimal phenotype(s) to be collected from neuropathic pain patients for genetic studies. A basic ‘entry-level’ set of phenotypes was identified for any genetic study of neuropathic pain. This set identifies cases of ‘possible’ neuropathic pain, and controls, and includes: (1) a validated symptom-based questionnaire to determine whether any pain is likely to be neuropathic; (2) body chart or checklist to identify whether the area of pain distribution is neuroanatomically logical; and (3) details of pain history (intensity, duration, any formal diagnosis). This NeuroPPIC ‘entry-level’ set of phenotypes can be expanded by more extensive and specific measures, as determined by scientific requirements and resource availability.

Are Opioids Effective in Relieving Neuropathic Pain?

“…The presence of several genetic polymorphisms acting on opioid function makes a mechanism-based treatment approach harder than predicted [170]. In the future genotyping of NP can provide further information [234], since phenotyping is still far from providing mechanisms, and thus the role of opioids in NP will probably remain in the shadows [235].…”

Perineural steroid injections around ilioinguinal, iliohypogastric, and genitofemoral nerves for treatment of chronic refractory neuropathic pain: A retrospective study

“…Though it is ideal to use validated tools to screen for neuropathic pain, 29 the diagnosis of neuropathic pain is essentially clinical. 30 However, validated tools and investigations (e.g., Douluer Neuropathique 4, quantitative sensory testing), can help establish this diagnosis with greater accuracy while also helping to delineate the mechanism and potential treatment. 31 The success rate for analgesia reported in our study (25 responders out of 63 subjects exposed to the treatment) is encouraging because pharmacological therapies recommended for neuropathic pain 13 were ineffective for all of our patients who received perineural injections of LA and steroids.…”

Feasibility of Topical Applications of Natural High-Concentration Capsaicinoid Solutions in Patients with Peripheral Neuropathic Pain: A Retrospective Analysis

“…This homogeneity is due to the fact that most of our patients were being sent by orthopaedic and cardiovascular surgeons. However, even if all the patients met the IASP criteria for definite neuropathic pain, a recent consensus of the NeuPSIG group report that, without additional investigations, the presence of neuropathic pain can only be seen as “probable” to “definite” [23]. Of note, seeing the presence of an “appropriate history” and the “presence of lesion or disease,” we considered a high a priori probability for the presence of a neuropathic pain.…”