A Delphi consensus statement of the Neuropathic Pain Special Interest Group of the Italian Neurological Society on pharmacoresistant neuropathic pain

To improve patient care and help clinical research, the Neuropathic Pain Special Interest Group of the Italian Neurological Society appointed a task force to elaborate a consensus statement on pharmacoresistant neuropathic pain. The task force included 19 experts in neuropathic pain. These experts participated in a Delphi survey consisting of three consecutive rounds of questions and a face-to-face meeting, designed to achieve a consensus definition of pharmacoresistant neuropathic pain. In the three rounds of questions, the participants identified and described the main distinguishing features of pharmacoresistance. In the face-to-face meeting the participants discussed the clinical features determining pharmacoresistance. They finally agreed that neuropathic pain is pharmacoresistant when "the patient does not reach the 50% reduction of pain or an improvement of at least 2 points in the Patient Global Impression of Change, having used all drug classes indicated as first, second, or third line in the most recent and widely agreed international guidelines, for at least 1 month after titration to the highest tolerable dose." Our consensus statement might be useful for identifying eligible patients for invasive treatments, and selecting patients in pharmacological trials, thus improving patient care and helping clinical research.

High prevalence of neuropathies in patients with end-stage liver disease

OBJECTIVES

Peripheral neuropathy has been reported in association with end-stage liver disease, but there is only a limited number of reports on the incidence and features of these neuropathies.

MATERIALS AND METHODS

In this study, 83 patients awaiting liver transplantation were evaluated for the presence of peripheral and autonomic neuropathy.

RESULTS

Sixty-five percent of the patients had evidence of neuropathy, in agreement with peripheral NCS or cardiovascular autonomic function test. The neuropathy was more frequent in patients with advanced hepatic failure, evaluated with the MELD score. The most frequent abnormalities in nerve conduction studies were sensory-motor neuropathies and sensory neuropathies, with a length-dependent pattern.

CONCLUSION

Peripheral neuropathy and autonomic neuropathy are common in patients with end-stage liver disease with different etiology and correlate with the severity of the liver disease.

A further critical evaluation of requests for electrodiagnostic examinations

The aim of this study was to evaluate the impact of electrophysiological (EDX) tests in the clinical management and diagnosis of patients, and the appropriateness of the referral diagnosis. A study was carried out in three electrodiagnostic services in the Torino area, over a 12-month period. In our study 3,900 individuals (2,340 females, 1,560 males) were evaluated. Patients underwent EDX examinations including nerve conduction study, electromyography and repetitive stimulation test. Most patients had been sent for EDX tests by specialists. Specialists suspected mainly polyneuropathy, whilst general practitioners suspected mainly carpal tunnel syndrome. Seventy-two percent of the requests were correctly formulated, 55% by general practitioners and 77% by specialists. There was a concordance between the results of the EDX tests and diagnostic hypothesis 40% of the time. This study confirms the usefulness and diagnostic impact of EDX examinations and evidences the amount of time and resources wasted as a result of incorrect or incomplete requests.

Pain affects the quality of life of neuropathic patients

The aim of this study was to verify the extent to which the presence of pain affects the quality of life (QoL) of neuropathic patients. The patients were selected in our Department of Peripheral Nervous System Diseases. We enrolled 120 consecutive patients with chronic polyneuropathy who had not received continuous pain therapy during the two months preceding study entry, and administered them the Total Neuropathy Score (TNS), the official Italian version of the SF-36 and the Italian Pain Questionnaire (QUID). Our main finding was that the QoL is affected not only by the presence of neuropathy, but also by the presence and intensity of pain: the physical aspect of the QoL correlated only weakly with the TNS, but pain was closely related to a worsening in this parameter; moreover, the mental domains of the SF-36 were only correlated with pain. Pain per se worsens the QoL of neuropathic patients, regardless of disease severity.

Somatosensory- and motor-evoked potential monitoring during spine and spinal cord surgery

STUDY DESIGN

Prospective, observational study.

SETTING

Regional Trauma Center, Torino, Italy.

OBJECTIVES

Complex spinal surgery carries a significant risk of neurological damage. The aim of this study is to determine the reliability and applicability of multimodality motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SEPs) monitoring during spine and spinal cord surgery in our institute.

METHODS

Recordings of MEPs to multipulse transcranial electrical stimulation (TES) and cortical SEPs were made on 52 patients during spine and spinal cord surgery under propofol/fentanyl anaesthesia, without neuromuscular blockade.

RESULTS

Combined MEPs and SEPs monitoring was successful in 38/52 patients (73.1%), whereas only MEPs from at least one of the target muscles were obtained in 12 patients (23.1%); both MEPs and SEPs were absent in two (3.8%). Significant intraoperative-evoked potential changes occurred in one or both modalities in five (10%) patients. Transitory changes were noted in two patients, whereas three had persistent changes, associated with new deficits or a worsening of the pre-existing neurological disabilities. When no postoperative changes in MEP or MEP/SEP modalities occurred, it was predictive of the absence of new motor deficits in all cases.

CONCLUSION

Intraoperative combined SEP and MEP monitoring is a safe, reliable and sensitive method to detect and reduce intraoperative injury to the spinal cord. Therefore, the authors suggest that a combination of SEP/MEP techniques could be used routinely during complex spine and/or spinal cord surgery.

Thalidomide sensory neurotoxicity: a clinical and neurophysiologic study

The clinical and neurophysiologic data from 65 patients taking thalidomide were reviewed. Thalidomide sensory neurotoxicity was found to be cumulative dose dependent but occurs only when the total dose is relatively high (>20 g). The risk of developing sensory neuropathy is around 10% below this threshold but increases with higher doses.

Thalidomide neuropathy: clinical, electrophysiological and neuroradiological features

OBJECTIVE

Thalidomide is a promising therapy for multiple myeloma. Sensory neuropathy is a side effect of thalidomide and resulted to be partially reversible in 50% of cases, suggesting a sensory ganglionopathy. Spinal cord magnetic resonance imaging (MRI) was found to be useful in the diagnosis of sensory ganglionopathies and we use it to determine if thalidomide neuropathy has features of a ganglionopathy.

MATERIAL AND METHODS

Six patients with multiple myeloma developed thalidomide-induced polyneuropathy. Nerve conduction studies, somatosensory-evoked potentials (SEPs) and cervical and dorsal spinal cord MRI were obtained in all.

RESULTS

All patients had a sensory neuropathy, with clinical or electrophysiological abnormalities involving all four limbs. Spinal cord MRI showed high signal intensity in the posterior columns in only one patient, with abnormal central conduction time at SEPs.

CONCLUSION

Our results suggest that thalidomide can induce either an axonal length-dependent neuropathy or, less frequently, a ganglionopathy.

Intracranial stimulation of the facial nerve: normative values with magnetic coil in 240 nerves

This study was aimed at defining normative values of latency and amplitude of the compound muscle action potential (CMAP) from the orbicularis oculi muscle, obtained by transcranial magnetic stimulation. We evaluated the dependence of latency and amplitude on the age of the subjects, in order to calculate cut-off values for each age decade. A total of 120 healthy normal subjects, aged 15-78 years, were studied. CMAP from the orbicularis oculi muscle, pars inferior, was excited by means of transcranial magnetic stimulation of the homolateral scalp. A suitable mathematical model was developed to evaluate the mean variation of the latency and amplitude of CMAP for each age decade in the studied population. Mean values were, respectively, 4.62+/-0.40 ms for latency and 4.17+/-0.72 mV for amplitude. We found an increase in latency of about 0.12 ms for every ten years, that became 0.15 ms if referring only to subjects over 20 years, and a decrease in amplitude of 0.18 mV each ten years. Normality interval values for the latency and amplitude were calculated for each age decade. Our data, obtained in a representative population for range of age of evaluated subjects, provide normality values and variability coefficients useful for future confronting works.

Terminal latency index in polyneuropathy with IgM paraproteinemia and anti-MAG antibody

Criteria for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) are met by the polyneuropathy associated with immunoglobulin M (IgM) paraproteinemia and anti-myelin-associated glycoprotein (MAG) antibody (MAG-CIDP). However, MAG-CIDP differs from other types of CIDP, mainly in its poorer response to treatment. The utility of terminal latency index (TLI) as an electrophysiological marker for MAG-CIDP has been debated. In this study we confirmed its diagnostic usefulness and evaluated TLI threshold values for motor nerves investigated in routine nerve conduction studies. Median, ulnar, peroneal, and tibial TLIs of 11 subjects with MAG-CIDP, 18 with CIDP, and 76 healthy controls were compared, and threshold values for MAG-CIDP evaluated as the lowest value with a likelihood ratio higher than 10. Mean TLI values and TLIs of all but the peroneal nerve were significantly lower in MAG-CIDP. Median nerve TLI of 0.26 and ulnar nerve TLI of 0.33 were identified as the threshold TLI values for MAG-CIDP.

Chronic triventricular hydrocephalus: morphological and functional study before and after ventriculoperitoneal shunting

We have neuroradiologically and neuropsycho-physiologically studied a case of chronic hydrocephalus due to congenital acqueductal stenosis, before and after ventriculoperitoneal shunting. The aims of the study were: 1) to point out the correlation between neuroimaging (Computerized Tomography/Magnetic Resonance Imaging) and mapping of Computerized Spectral Analysis EEG (CSA-EEG); 2) to monitor evoked bioelectrical activity by neurophysiological evaluation of acoustic and visual N1 and P3. Both bioelectrical activity and neuroimaging evaluation showed a considerable recovery of the neurobiological substratum after neurosurgical shunting, while neuropsychological investigation showed a slight improvement in all cognitive tasks.