Deafferentation pain exacerbated by subarachnoid lidocaine and relieved by subarachnoid morphine. Case report.

Abstract

BACKGROUND AND OBJECTIVES:

Neuropathic pain syndromes are often resistant to traditional pharmacologic treatment. The authors describe a patient with chronic deafferentation pain of the legs associated with peripheral neuropathy that was refractory to multidisciplinary pain clinic management.

METHODS:

Numerous medications had been tried, including nortriptyline, mexiletine, and oral and parenteral opioids. Spinal cord stimulation was also ineffective, despite a satisfactory pattern of stimulation-induced paresthesias. For diagnostic purposes, differential spinal anesthesia with lidocaine and morphine was performed, with evoked potential monitoring used to evaluate the intensity of spinal anesthetic block.

RESULTS:

Paradoxically, lidocaine spinal anesthesia exacerbated pain, whereas subarachnoid morphine provided rapid pain relief. Long-term pain control has been maintained with an implanted spinal infusion pump.

CONCLUSIONS:

Evoked potential data acquired during lidocaine spinal anesthesia and the rapid pain relief provided by subarachnoid morphine suggest that deafferentation pain may involve segmental, opioid-sensitive dorsal horn pain generators. The long-term pain relief afforded the patient demonstrates that subarachnoid opioids may be efficacious for some forms of neuropathic pain.

• Authors: R P Iacono, M V Boswell, M Neumann
• Journal: Regional anesthesia (Reg Anesth) 1994 May-Jun Vol. 19 Issue 3 Pg. 212-5 ISSN: 0146-521X [Print] United States
• PMID: 7999658 (Publication Type: Case Reports, Journal Article)

Chemical References

• Morphine
• Lidocaine

Topics

• Adult
• Anesthesia, Spinal
• Drug Resistance, Multiple
• Electric Stimulation
• Evoked Potentials, Somatosensory (drug effects)
• Female
• Humans
• Infusion Pumps, Implantable
• Injections
• Lidocaine (administration & dosage, adverse effects)
• Morphine (administration & dosage, therapeutic use)
• Pain (drug therapy, physiopathology)
• Pain Clinics
• Peripheral Nervous System Diseases (drug therapy, physiopathology)
• Spinal Cord
• Subarachnoid Space