Diagnosis of neuropathic pain

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Dtsch Med Wochenschr. 2007 Oct;132(41):2139-44.

Diagnosis of neuropathic pain

Baron R, Treede RD.

Sektion Neurologische Schmerzforschung und Therapie, Klinik für

Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel,

Kiel.

Pain usually is the consequence of tissue damage that is signalled

to the brain via the nociceptive system (nociceptive pain). Damage

to the nociceptive system - in addition to causing sensory deficit -

may paradoxically also induce a chronic pain state (neuropathic

pain).

Diagnostic workup of patients with neuropathic pain follows the

usual procedure of Neurology, i. e. the aim is to identify the

location of neural damage and the underlying disorder, so that a

mechanism-oriented treatment may be initiated. Medical history -

supported by specific questionnaires and a pain drawing by the

patient - provides the basis for diagnosis.

In the course of the physical examination, the sensory exam

including careful documentation of the spatial extent of positive

and negative signs is the most important part, since neuropathic

pain is due to damage to the somatosensory system. Techniques for

the objective documentation of sensory signs have been developed (e.

g. by the DFNS), but their broad availability is still in the

process of being implemented.

Thus, laboratory exams main serve the purpose of identifying the

underlying etiology. Symptomatic treatment of neuropathic pain is

relatively uniform, independent of etiologies (e. g. traumatic,

metabolic, inflammatory), but differs from that of nociceptive pain.

Typical analgesics have little efficacy in neuropathic pain - except

for opioids. Major pharmacological treatment options include

anticonvulsants (Ca-channel modulators, Na-channel blockers),

antidepressants (noradrenaline reuptake inhibitors) and topicals

(lidocaine, capsaicin). These medications exert specific molecular

pharmacological effects against the pathophysiological mechanisms of

neuropathic pain.