[Diagnosis of neuropathic pain]. / Diagnostik bei Neuropathischen Schmerzen.

ABSTRACT

Neuropathic pain arises from damage, or pathological change, in the peripheral or central nervous system. As such, the term neuropathic pain represents a varying set of symptoms rather than a single diagnosis. There is no diagnostic gold standard for neuropathic pain and so making a diagnosis is based on clinical judgement. The essential elements of this process are to identify painful symptoms and a clinical history that all match a neuro-anatomical or dermatomal pattern. Abnormal responses to nerve damage account for many of the clinical features of neuropathic pain. Painful symptoms arising in an area of altered sensation (numbness or hyper-excitability) is the hallmark of neuropathic pain. Cardinal features are spontaneous pains (pain arising without stimulus) and abnormal responses to non-painful (allodynia) or painful stimuli. The diagnostic work-up includes screening tools such as pain questionnaires and pain drawings as well as information on the history of the disease and a detailed clinical-neurological examination. Bedside examination is straightforward. The aim is to identify altered sensation in the painful area and so responses should be compared with a non-painful adjacent or contra-lateral area. A combination of characteristic painful symptoms in an area of altered sensation on bedside testing is usually enough to make a diagnosis of neuropathic pain. When doubt arises, more detailed examination using Quantitative Sensory Testing or conventional electrophysiology can be helpful.