A role for peripheral afferents in the pathophysiology and treatment of at-level neuropathic pain in spinal cord injury? A case report.
At-level neuropathic pain is a frequent symptom following spinal cord injury, but the underlying pathophysiology is not completely understood. We report a patient suffering from treatment-resistant at-level pain characterized by ongoing pain and mechanical allodynia for three years after an incomplete spinal lesion. Quantitative sensory testing revealed severe thermosensory deficits in the neuropathic pain area. However, topical application of capsaicin in the neuropathic pain area induced a burning pain sensation, a marked decrease in heat pain threshold and an increase in mechanical allodynia. Treatment with topical lidocaine patches (5%) led to considerable pain relief. These results indicate a functional connection between peripheral, spinal and supraspinal nociceptive pathways and that peripheral afferents may contribute to at-level neuropathic pain after spinal cord injury in this patient. Lesioned peripheral afferents in combination with central neuronal hyperexcitability are discussed as a likely underlying pain mechanism.
Wasner
Gunnar
G
Prince of Wales Medical Research Institute, Gate 1 Barker St., Randwick, Sydney, NSW 2031, Australia. g.wasner@unsw.edu.au
Naleschinski
Dennis
D
Baron
Ralf
R
D000287:Administration, Topical; D000344:Afferent Pathways / Q000187:drug effects / Q000503:physiopathology*; D002211:Capsaicin / Q000008:administration & dosage*; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D016103:Spinal Fractures / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D013904:Thoracic Vertebrae / Q000293:injuries*
D008012:Lidocaine; D002211:Capsaicin