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Intravenous lorazepam for pain relief of intractable neuralgia
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PA. IAJZ*~, B.R.Tasked, J.O. Dostrom&, Depts of Neummrg.l 6 Physiol.2,Universityof lbronto,Toronto,Cmada, @I56lA8. %rpose:III an attempt to quantify abnormal single unit activity
[II
664 Slide
Fri 3:00 Room 50
in central pain we have analyzed the activity of single units located in the ventral nuclear group of a patient with burning pain below the level of a complete traumatic spinal cord transection at C5. tkthds d lksults: Single unit activity was recorded and discriminated using Cells located in the parasagittal plane 14 w lateral to standard techniques. the midline responded to tactile stimulation in small facial and intraoral receptive fields, which were typical of cells responding to somatosensory stimulation (n=531) in patients with normal somatosensory function (normals). The plane located 2 w lateral contained many cells with receptive fields, not on the hand as observed in normals, but on the occiput and neck. Cells with receptive fields on the neck and occiput had never previously been observedin normals. Thus, on the basis of cellularlocationin an area of thalamuswhich
normallyrepresentspartsof the body below the levelof the spinalcord transection and the abnormallylarge representation of regionsadjacentto these same partsof the body,we proposethat the cells in the 16 nunlateral planehave lost theirnormalafferentinput. Analysisof the autopowerspectra of spike trainsindicatesthat cells (n=lO)in the 16 mm lateralplane exhibiteda highermean firingrate and greatertendencyto fire In burststhan cells (n=lO)in the 14 mn lateralplane (PCO.005).Finally,electrical stimulation at recordingsites in the 16 w lateral plane evokeda burning sensationin the occiput,neck and upper extremity. Similarresultshave been observed in some but not all patients with central pain syndromes. COlElmSLoos: These results demonstrate that stimulation evoked dysesthesia is at least spatially related to abnormal neuronal activity in the central nervous system of some patients with central pain.
INTFWENWSLLlRAzEpAMFDRPAINRELIEZFOF INTRAcTABLE:~I EKXJCXCM, AJ. Psychiatry Service, Massachusetts General Hospital,HarvardMedicalSchool,Boston,MA 02114,U.S.A. Aim: To determine the efficacy of I.V. lorazepam in the treatment of intractable neuralgia. Method: 24 inpatients with intractable neuralgia were selected for-treatment with.V. lorazepam, xylocaine, morphine and saline if their neuralgia was resistant to oral anticonvulsant,antidepressantand narcotic drugs, asvell as interruptionof afferent sensory input. Iorazepam 2 mg diluted with saline was infused through a peripheral vein over 5 mins. Analgesia was rated with a 100 mn visual analog scale (VAS) every 5 mins. If there was no discernahle relief, nor sedation, a further 2 mg was infused in an identical manner every 10 mins. This was repeated up to a maximurnof 10 mg oflorzepam or until relief was obtained or until the point of sonmolence. I&inintensity was then rated hourly by the patient's VAS. Results: 1. 18 of 24 patients (75%) reported significant relief after I.V. lorazepam. 6 (24%) had ongoing relief for nore than 24 hrs. 2. Average dosage: 5 ng (range 2-lo), degree of relief: 50 mn decrease (range 20-lOO), duration: 12 hrs (range +-24+). 3. Good responders exhibiteddeafferentation neuralgia in 7%, allodynia in 5% and hypoaesthesia in 5%. Rowever, this profile did not differ significantly frun nonresponders.4. Poor response was associated with major depression, 6 of 18 lorazepam responders had depression, while 5 of 6 nonresponders had depression. 5. Side effects of sedation and amnesia were brief (1-2 hrs) and not treatment limiting. 6. TIE comparative efficacy of lorazepam to xylocaine, placeboand nxxphinewas notable.I.V. xylocaine eased the pain in 54%, morphine in 2%, and placebo in %. 14 lorazepam responders had not responded to xylocaine or mrphine Conclusions: 1. LorazepamI.V. is a safe effective agent for the aculereli?f o intractable neuralgic pain. 2. Iorazepam has significant differential e$I ficacy as an analgesic compared to n-orphine,xylocaine or saline.
m4u?-cs~oNIT~
It?CRtlRALPAI?l
PA. IAJZ*~, B.R.Tasked, J.O. Dostrom&, Depts of Neummrg.l 6 Physiol.2,Universityof lbronto,Toronto,Cmada, @I56lA8. %rpose:III an attempt to quantify abnormal single unit activity
[II
664 Slide
Fri 3:00 Room 50
in central pain we have analyzed the activity of single units located in the ventral nuclear group of a patient with burning pain below the level of a complete traumatic spinal cord transection at C5. tkthds d lksults: Single unit activity was recorded and discriminated using Cells located in the parasagittal plane 14 w lateral to standard techniques. the midline responded to tactile stimulation in small facial and intraoral receptive fields, which were typical of cells responding to somatosensory stimulation (n=531) in patients with normal somatosensory function (normals). The plane located 2 w lateral contained many cells with receptive fields, not on the hand as observed in normals, but on the occiput and neck. Cells with receptive fields on the neck and occiput had never previously been observedin normals. Thus, on the basis of cellularlocationin an area of thalamuswhich
normallyrepresentspartsof the body below the levelof the spinalcord transection and the abnormallylarge representation of regionsadjacentto these same partsof the body,we proposethat the cells in the 16 nunlateral planehave lost theirnormalafferentinput. Analysisof the autopowerspectra of spike trainsindicatesthat cells (n=lO)in the 16 mm lateralplane exhibiteda highermean firingrate and greatertendencyto fire In burststhan cells (n=lO)in the 14 mn lateralplane (PCO.005).Finally,electrical stimulation at recordingsites in the 16 w lateral plane evokeda burning sensationin the occiput,neck and upper extremity. Similarresultshave been observed in some but not all patients with central pain syndromes. COlElmSLoos: These results demonstrate that stimulation evoked dysesthesia is at least spatially related to abnormal neuronal activity in the central nervous system of some patients with central pain.
INTFWENWSLLlRAzEpAMFDRPAINRELIEZFOF INTRAcTABLE:~I EKXJCXCM, AJ. Psychiatry Service, Massachusetts General Hospital,HarvardMedicalSchool,Boston,MA 02114,U.S.A. Aim: To determine the efficacy of I.V. lorazepam in the treatment of intractable neuralgia. Method: 24 inpatients with intractable neuralgia were selected for-treatment with.V. lorazepam, xylocaine, morphine and saline if their neuralgia was resistant to oral anticonvulsant,antidepressantand narcotic drugs, asvell as interruptionof afferent sensory input. Iorazepam 2 mg diluted with saline was infused through a peripheral vein over 5 mins. Analgesia was rated with a 100 mn visual analog scale (VAS) every 5 mins. If there was no discernahle relief, nor sedation, a further 2 mg was infused in an identical manner every 10 mins. This was repeated up to a maximurnof 10 mg oflorzepam or until relief was obtained or until the point of sonmolence. I&inintensity was then rated hourly by the patient's VAS. Results: 1. 18 of 24 patients (75%) reported significant relief after I.V. lorazepam. 6 (24%) had ongoing relief for nore than 24 hrs. 2. Average dosage: 5 ng (range 2-lo), degree of relief: 50 mn decrease (range 20-lOO), duration: 12 hrs (range +-24+). 3. Good responders exhibiteddeafferentation neuralgia in 7%, allodynia in 5% and hypoaesthesia in 5%. Rowever, this profile did not differ significantly frun nonresponders.4. Poor response was associated with major depression, 6 of 18 lorazepam responders had depression, while 5 of 6 nonresponders had depression. 5. Side effects of sedation and amnesia were brief (1-2 hrs) and not treatment limiting. 6. TIE comparative efficacy of lorazepam to xylocaine, placeboand nxxphinewas notable.I.V. xylocaine eased the pain in 54%, morphine in 2%, and placebo in %. 14 lorazepam responders had not responded to xylocaine or mrphine Conclusions: 1. LorazepamI.V. is a safe effective agent for the aculereli?f o intractable neuralgic pain. 2. Iorazepam has significant differential e$I ficacy as an analgesic compared to n-orphine,xylocaine or saline.