Table. 2.

Recognition of Neuropathic Pain: Sensory Symptoms and Signs of Neuropathic Pain, Clinical and Laboratory Tests, and Underlying Mechanisms

Sensory symptom and sign Bedside examination Laboratory examination Mechanism
1. Negative sensory symptoms and signs
1) Reduced touch Touch skin with cotton wool Graded von Frey hair Aβ fibers
2) Reduced pin prick Prick skin with a pin single stimulus von Frey hair specific (e.g., 100-g) Aδ fibers
3) Reduced cold and warm Thermal response to cold and warm objects (20℃ and 45℃) Detection of pain threshold for warm and cold objects Aδ/C fibers
4) Reduced vibration Tuning fork on the medial malleolus Vibrometer Aβ fibers
2. Positive sensory symptoms and signs
1) Spontaneous pain
(1) Paresthesia Grade (0-10) Area in cm2 grade (0-10) Spontaneous activity in long-term Aβ afferent fibers
(2) Dysesthesia Grade (0-10) Area in cm2 grade (0-10) Spontaneous activity in Aδ/C afferent fibers
(3) Paroxysms Grade (0-10) Threshold for evocation Spontaneous activity in C nociceptors
(4) Superficial burning pain Grade (0-10) Area in cm2 grade (0-10) Spontaneous activity in C nociceptors
(5) Deep pain Grade (0-10) Area in cm2 grade (0-10) Spontaneous activity in joint/muscle nociceptors
2) Evoked pain
(1) Touch evoked hyperalgesia Stroking skin with brush None Central sensitization: C fiber input and loss of C fiber input
(2) Static hyperalgesia Gentle mechanical pressure Evoked pain to pressure Peripheral sensitization
(3) Punctate hyperalgesia Pricking skin with a pin von Frey hair Central sensitization: Aδ afferent fibers input
(4) Punctate repetitive hyperalgesia (windup-like pain) Pricking skin with a pin 60 times/30 sec von Frey hair Central sensitization: Aδ afferent fibers input
(5) Aftersensation Measurement of pain duration after stimulation Measurement of pain duration after stimulation Central sensitization
(6) Cold hyperalgesia Stimulation skin with cool metal roller Evoked pain to cold stimuli Central sensitization and disinhibition
(7) Heat hyperalgesia Stimulation skin with warm metal roller Evoked pain to heat stimuli Peripheral sensitization
(8) Chemical hyperalgesia Topical capsaicin Topical capsaicin Peripheral sensitization
(9) Sympathetic maintained pain Sympathetic blockade Modulation of sympathetic outflow Sympathetic afferent coupling

Reproduced from the article of Jensen and Baron (Pain 2003; 102: 1-8) [2].

Korean J Pain 2020;33:108~120 https://doi.org/10.3344/kjp.2020.33.2.108
© Korean J Pain