Definition of Localized Neuropathic Pain (LNP)
Central pain syndromes may arise from vascular lesions in the brain - brainstem or thalamus - or the spinal cord. Examples include NP following traumatic brain or spinal cord injury, infarct or haemorrhage, or as a consequence of diseases such as syringomyelia, multiple sclerosis, and Parkinson disease.1
Thus, NP can arise from a wide variety of diseases or injuries that cause damage to either the central or peripheral nervous system.
NP may have a multifocal distribution, as in polyneuropathy, or pain may be localized to the region of the affected nerve, as in mononeuropathy, where there is a lesion or dysfunction of a single nerve.
Based on the International Association for the Study of Pain (IASP) definition of neuropathic pain, a definition for localized neuropathic pain has been proposed: Localized neuropathic pain is a type of neuropathic pain characterized by a circumscribed and consistent area of maximum pain.3
PHN caused by herpes zoster infection is typically associated with localized NP.2 Another example of localized NP is scar pain2.
Approximately 60 % of neuropathic pain is localized on a circumscribed area3.
How is neuropathic pain (NP) diagnosed?
Neuropathic pain is a common condition but often under- or misdiagnosed in daily practice, and neuropathic pain with localized symptoms may require a specific treatment regimen, often known only to pain specialists. Early diagnosis of neuropathic pain is often a challenge in primary care. Moreover, so far no standard diagnostic procedure for localized NP (LNP) is available.4
An LNP screening tool may help at the primary care level for early initial diagnosis of probable NP or LNP in chronic pain patients, and for the choice of adequate treatment.4
What are the typical localized neuropathic pain (LNP) symptoms?
Neuropathic pain is characterized by abnormal sensory perceptions generally distinguished as positive signs such as burning or shooting pain, tingling, prickling, tightness, or electrical sensations, and negative signs such as loss of noxious, mechanical, or thermal perception with the very frequent concomitant occurrence of paresthesias, allodynia, or hyperalgesia. Patients with localized neuropathic pain should be able to point to the location(s) of their pain or abnormal sensations on the skin in order to distinguish LNP from widely distributed or even widespread pain, the area of maximal pain remaining relatively constant over time.4
1 Baron R Neuropathic pain: a clinical perspective. Handb Exp Pharmacol. 2009; 194:3-30.
2 Paster Z et al. Treatment of the localized pain of postherpetic neuralgia. Postgrad Med. 2010; 122:91-107.
3 Mick G, et al. What is localized neuropathic pain? A first proposal to characterize and define a widely used term. Pain Manag. 2012 Jan;2(1):71-7.
4 Mick G, et al. Is an easy and reliable diagnosis of localized neuropathic pain (LNP) possible in general practice? Development of a screening tool based on IASP criteria. Curr Med Res Opin 2014;30(7):1357-66