Mononeuritis multiplex secondary to Lyme neuroborreliosis

Lyme neuroborreliosis (LNB) typically presents as a painful radiculitis or a cranial mononeuropathy with lymphocytic meningitis (Bannwarth’s syndrome). Isolated peripheral mononeuropathy or multiple mononeuropathy is less frequently recognised. A 58-year-old female with a background of IgA nephropathy and chronic kidney disease presented with a painful left ulnar neuropathy followed within 3 months by superficial radial neuropathy. Initial serum and cerebrospinal fluid (CSF) analysis were unremarkable; nerve conduction study was in keeping with a mononeuritis multiplex. A superficial radial nerve biopsy demonstrated inflammation with axonal injury consistent with a pathologically possible vasculitis. Borrelia antibodies were identified using enzyme-linked immunosorbent assay and immunoblot in serum consistent with active recent Lyme borreliosis. A 6-week course of doxycycline was initiated with gradual resolution of pain and improved power. A repeat nerve conduction study demonstrated improvement in sensory and motor responses. This case report identifies a peripheral nerve syndrome of a mononeuritis multiplex secondary to LNB in the absence of CSF pleocytosis with excellent outcome following antibiotic treatment. Peripheral nervous system manifestations of Lyme borreliosis can mimic a vasculitic neuropathy and therefore should be considered in individuals presenting with a painful mononeuritis multiplex.     

苯对接触工人外周神经传导速度的影响

[目的 ]探讨苯对周围神经系统的影响。 [方法 ]对苯接触观察对象 13人、苯中毒者 14人为接触组 ,另选无毒物接触史的工人 48人为对照组 ,应用神经肌电图检测方法进行运动和感觉神经传导速度测定。 [结果 ]接触组尺神经及下肢腓浅神经感觉传导速度显著慢于对照组 (P <0 .0 5 ) ,其余所检神经传导速度与对照组相比差异无显著性 (P >0 .0 5 )。接触组下肢腓浅神经感觉传导速度异常率显著高于对照组。正中神经远端潜伏期较对照组明显延长 (P <0 .0 5 )。[结论 ]苯对周围神经存在一定程度的影响 ,感觉神经传导速度对于诊断周围神经病的价值优于运动神经传导速度     

锰对人体神经传导速度影响的研究

目的：探讨锰对周围神经传导速度的影响。方法：对病例组40人和对照组48人进行了周围神经传导速度的检测。结果：病例组所检测的周围神经传导速度都有不同程度的异常。其中腓浅神经感觉传导速度较对照组明显减慢,正中神经远端潜伏期较对照组明显延长,均具有显著性差异（P＜0．01）。结论：提示锰不仅对中枢神经系统产生损害,同时对周围神经系统也产生不同程度的损害。周围神经传导速度检测可以慢性锰中毒的诊断提供参考指标。     

Normal nerve conduction velocity and vibrotactile perception thresholds in computer users

OBJECTIVES: A literature report described significantly raised vibration threshold within the territory of the median nerve in a group of office workers and concluded that the results indicated a change in the function of large sensory fibres. The aim of the present cross-sectional study was to compare vibrotactile perception thresholds and nerve conduction measurements in the upper extremity between female computer users (secretaries) and female non-users (nurses). METHODS: Eighty-two secretaries, aged 25-65 (median 44) years and 35 nurses, aged 24-57 (median 46) years went through nerve conduction measurements on the dominant hand and also a vibration threshold test with readings over the hand at five sites which tested cutaneous innervation of the median, ulnar, and radial nerves. RESULTS: There was no significant difference in any parameter of the nerve conduction testing and there was no significant difference in any parameter of the vibration threshold test between secretaries and nurses. The numerical differences between groups were small and in both directions and thus do not indicate a power problem. CONCLUSIONS: We saw no signs of early neural deficits of large sensory fibres in subjects who intensively use computer keyboard equipment.     

Occupational exposure to pesticides and nerve conduction studies among Korean farmers

This study aimed to determine whether occupational exposure to pesticides was associated with decreased nerve conduction studies among farmers. On 2 separate occasions, the authors performed a cross-sectional study of a group of 31 male farmers who periodically applied pesticides. The study included questionnaire interviews and nerve conduction studies on the median, ulnar, posterior tibial, peroneal, and sural nerves. Although all mean values remained within laboratory normal limits, significant differences between the first and second tests were found in sensory conduction velocities on the median and sural nerves, and motor conduction velocities on the posterior tibial nerve. Lifetime days of pesticide application was negatively associated with nerve conduction velocities at most nerves after adjusting for potential confounders. These findings may reflect a link between occupational pesticide exposure and peripheral neurophysiologic abnormality that deserves further evaluation.     

Electroneurographic findings in workers exposed to mercury]

25 mercury-exposed workers as well as 27 age-matched controls were investigated in an electroneurographic study. The population of mercury-exposed workers was found to have --an increased latency of distal motor action potential at both median and peroneal nerves --an increased latency of distal sensory action potential at median nerve --a decrease of amplitudes of evoked muscle potentials at both median and peroneal nerves --a reduced motor nerve conduction velocity at both examined nerves --a reduced antidromic sensory nerve conduction velocity at median nerve. To detect early changes in nerval function we recommend regularly electroneurographic examinations of mercury-exposed people.     

20名手传振动作业工人的神经肌电图分析

目的探讨手传振动对作业工人周围神经的损害情况。方法对20名从事手传振动作业工人和30名无接触职业危害的健康成人进行神经肌电图检查分析。结果①MCV检测结果显示正中神经运动传导远端潜伏期延长（占85．0％）、MCV减慢（占35．0％）（P〈0．01）;②SCV捡测结果显示正中神经SCV减慢（占40．0％）、尺神经SCV减慢（占30．0％）（P〈0．01）;③肌电图检查结果表现为小力收缩时多相电位增多（占42．5％）及安静时出现纤颤电位（占15．0％）（P〈0．05或P〈0．01）。结论振动对作业工人周围神经损伤明显,神经肌电图检查最早表现为正中神经运动传导远端潜伏期延长,随着损伤加重,进一步出现神经传导速度减慢,运动和感觉同时受累。     

Variability of quantitative sensory testing: implications for clinical practice

The conventional estimation of motor, sensory, and mixed nerve conduction velocities reflects activity in the fastest conducting, heavily myelinated nerve fibers that are only a small proportion of the total. Unmyelinated and thinly myelinated fibers are not evaluated by this technique and numerically represent the largest group of fibers in human cutaneous nerves. The availability of new quantitative techniques to study this aspect of sensory function is an important addition to standard electrodiagnosis. Patient understanding and cooperation is essential because subjective responses are evaluated. We evaluated a reference range for 20 healthy subjects as well as variability on repeated testing. Vibration and thermal thresholds were measured bilaterally at several sites. Measurements were repeated at intervals ranging from two days to three months. There was no side difference but substantial site differences were noted for all measurements. Intraindividual variation was substantial but within the expected range for a psychophysiologic test. Close correlation was noted between various measurements at same and different sites, indicating a great degree of interindividual variation. The Marstock method is recommended for routine clinical use.     

Electrophysiology and nerve biopsy in men exposed to lead

ABSTRACT Twenty lead-exposed men were selected on the basis of a maximum level of lead in the blood of 70-140 μg/100 ml within the past year. There was no clinical evidence of neuropathy attributable to lead and haemoglobin levels were normal. In individuals, maximum motor and sensory conduction and the amplitude of the evoked potentials were normal or borderline in the median, peroneal and sural nerves, except in the distal portion of the deep peroneal nerve. In this nerve, motor conduction was slowed because of compression by metal-lined safety shoes; changes in this segment are not included in the findings. When the average conduction velocity in lead-exposed men was compared with the average in nerves of controls matched for age, distal motor latency was slightly prolonged in the median nerve. The average latency for proximal muscle supplied by the peroneal nerve was prolonged, and the maximum motor conduction velocity was slowed in the median nerve from elbow to wrist (0·01 > p <0·001). In addition, the average maximum sensory conduction was slightly slowed along the distal and intermediate portion of the superficial peroneal and sural nerves (p <0·001). The average minimum sensory conduction velocities were normal, as were the average amplitudes of the evoked muscle action potentials and the average ratio of amplitude of the muscle action potential evoked by stimuli at a proximal and a distal nerve site. The average amplitude of the sensory potentials recorded in the median and the superficial peroneal nerves tended to be increased. Electromyography of the abductor pollicis brevis and anterior tibial muscles showed that the only abnormality was an increased incidence of polyphasic potentials in the anterior tibial muscle of seven men. Neither the slowing in conduction nor the histological findings in the sural nerves of eight men were related to the level of lead in the blood. The slight slowing in conduction suggests a minor defect in the excitable membrane of the nerve fibre: it was not attributable to histological abnormalities in the sural nerve, in which the number of myelinated and unmyelinated nerve fibres was normal and demyelination was absent. In teased fibres, those with paranodal remyelination were slightly increased, and few fibres had segments with diminished diameter. The mechanism of the defect causing the slight slowing in conduction in lead-exposed men seems to differ from the lesion in patients with clinical evidence of lead neuropathy, which is axonal in type. It is, therefore, doubtful whether the slight slowing in the nerves of the group of lead-exposed men should be classified as a subclinical neuropathy.     

Subclinical lead neuropathy

It had been shown that subclinical impairment of the peripheral nerves may occur in neurologically symptom-free lead workers. In a cross-sectional study, 78 workers from two storage battery plants and one engineering shop were studied; their lead exposure had been monitored with regular blood lead measurements (PbB). The reference group comprised 34 unexposed manual workers. An exposure-effect relationship between occupational lead exposure and nerve functions emerged, as nerve conduction velocities decreased with increasing PbBs. The strongest correlations were found between PbB measures and sensory and motor conduction velocities of the median nerve. An exposure-response relationship also emerged as the proportion of subjects with abnormal nerves increased with increasing exposure levels. In a prospective study 24 workers were followed-up from the commencement of their lead work for one year and 16 for two years. The lead exposed showed a tendency of decreasing conduction velocities of arm nerves, but as a group they did not differ statistically significantly from the control group. When the lead exposed were divided into two groups using the median PbBs as the splitting point, the ones with PbBs over 30 micrograms/100 ml showed slowing of serveral nerve conduction velocities, while in the lower exposure the conduction velocities remained at the initial level. Again the clearest difference was noted in conduction velocities of the median nerve. Nerve conduction velocities, especially in the arm nerves slow down in lead exposure and this impairment is caused by really low lead exposure as noted in the prospective follow-up study, which can be regarded as intervention study.     

Vibration-induced multifocal neuropathy in forestry workers: electrophysiological findings in relation to vibration exposure and finger circulation

Objectives: To investigate neural conduction in the upper limbs of symptomatic forestry workers with and without exposure to hand-transmitted vibration. A further aim was to assess the possible relationships between vibration exposure, nerve conduction and finger circulation in the forestry workers who used chain saws. Methods: A detailed neurophysiological investigation was performed on the upper extremities of 20 chain saw workers, 20 forestry operators with heavy manual work but without vibration exposure, and 20 healthy male controls. All subjects were screened to exclude polyneuropathy. Measurements of sensory and motor nerve conduction (velocity and amplitude) were obtained bilaterally from the median, ulnar and radial nerves. To assess peripheral vascular function, the forestry workers underwent a cold test with plethysmographic measurement of finger systolic blood pressure (FSBP). In the chain saw operators, vibration exposure was evaluated according to the International Standard ISO 5349. Indices of daily vibration exposure and lifetime cumulative vibration dose were estimated for each chain saw operator. Results: Sensory nerve conduction in several segments of the median and radial nerves was significantly reduced in the chain saw operators compared with that in the workers doing heavy manual work and the controls. The neurophysiological pattern more frequently observed in the chain saw operators was a multifocal nerve conduction impairment to several neural segments with predominant involvement of sensory rather than motor fibres. Sensory nerve conduction velocities in the hands of the chain saw operators were inversely related to both daily and lifetime cumulative vibration exposures. In the vibration-exposed forestry workers, neither were sensori-motor complaints associated with vascular symptoms (finger whiteness) nor were electrophysiological data related to cold-induced changes in FSBP. Conclusions: Exposure to hand-transmitted vibration, in addition to ergonomic stress factors, can contribute to peripheral nerve disorders occurring in forestry workers who operate chain saws. The findings of this study suggest the existence of an exposure-effect relationship for vibration-induced neuropathy. Different underlying mechanisms are likely to be involved in the pathogenesis of the neurological and vascular components of the hand-arm vibration syndrome. Received: 18 November 1999 / Accepted: 25 April 2000     

Neurologic Disorders in Immunocompetent Patients with Autochthonous Acute Hepatitis E

Neurologic disorders, mainly Guillain-Barré syndrome and Parsonage–Turner syndrome (PTS), have been described in patients with hepatitis E virus (HEV) infection in industrialized and developing countries. We report a wider range of neurologic disorders in nonimmunocompromised patients with acute HEV infection. Data from 15 French immunocompetent patients with acute HEV infection and neurologic disorders were retrospectively recorded from January 2006 through June 2013. The disorders could be divided into 4 main entities: mononeuritis multiplex, PTS, meningoradiculitis, and acute demyelinating neuropathy. HEV infection was treated with ribavirin in 3 patients (for PTS or mononeuritis multiplex). One patient was treated with corticosteroids (for mononeuropathy multiplex), and 5 others received intravenous immunoglobulin (for PTS, meningoradiculitis, Guillain-Barré syndrome, or Miller Fisher syndrome). We conclude that pleiotropic neurologic disorders are seen in HEV-infected immunocompetent patients. Patients with acute neurologic manifestations and aminotransferase abnormalities should be screened for HEV infection.     

Neurophysiological studies on workers exposed to lead.

Nerve conduction and somatosensory evoked potential studies were undertaken on 46 workers exposed to a combination of organic and inorganic lead. In addition electroencephalograms were carried out on 20 of the workers; the results were compared with those obtained for workers not exposed to lead. The workers exposed to lead had a mean blood lead concentration of 2.35 mumol/l (48.7 micrograms/100 ml), whereas the concentration for workers not exposed to lead was 0.76 mumol/l (15.8 micrograms/100 ml). The mean maximum motor conduction velocities of the median and the posterior tibial nerves were significantly lower in the workers exposed to lead than in the controls. Similarly, the distal latency for these two nerves was significantly prolonged for the workers exposed to lead. No significant differences for the two groups of workers were seen in the nerve conduction and distal latency measurements of the median (sensory) and the sural nerves. The EEG studies of the 20 workers exposed to lead showed no abnormalities. The somatosensory evoked potential of the median (sensory) and posterior tibial nerves were significantly prolonged when measured at the negative and positive deflections. The results suggest that, in addition to nerve conduction velocities, somatosensory evoked potential and distal latency are suitable measurements to detect subclinical neurological damage among workers exposed to lead. As these changes were seen at blood lead concentrations of 2.35 mumol/l (48.7 micrograms/100 ml) there may be a need for more stringent monitoring of workers exposed to lead.     

Neurophysiological studies on workers exposed to lead

Nerve conduction and somatosensory evoked potential studies were undertaken on 46 workers exposed to a combination of organic and inorganic lead. In addition electroencephalograms were carried out on 20 of the workers; the results were compared with those obtained for workers not exposed to lead. The workers exposed to lead had a mean blood lead concentration of 2.35 mumol/l (48.7 micrograms/100 ml), whereas the concentration for workers not exposed to lead was 0.76 mumol/l (15.8 micrograms/100 ml). The mean maximum motor conduction velocities of the median and the posterior tibial nerves were significantly lower in the workers exposed to lead than in the controls. Similarly, the distal latency for these two nerves was significantly prolonged for the workers exposed to lead. No significant differences for the two groups of workers were seen in the nerve conduction and distal latency measurements of the median (sensory) and the sural nerves. The EEG studies of the 20 workers exposed to lead showed no abnormalities. The somatosensory evoked potential of the median (sensory) and posterior tibial nerves were significantly prolonged when measured at the negative and positive deflections. The results suggest that, in addition to nerve conduction velocities, somatosensory evoked potential and distal latency are suitable measurements to detect subclinical neurological damage among workers exposed to lead. As these changes were seen at blood lead concentrations of 2.35 mumol/l (48.7 micrograms/100 ml) there may be a need for more stringent monitoring of workers exposed to lead.     

Neuropathy and the automatic analysis of electromyographic signals from vibration exposed workers.

An automatic analysis of the electromyographic activity of the extensor digitorum communis, first dorsal interosseus and opponens pollicis muscles was performed, and both motor and sensory conduction velocities of the median and ulnar nerves were measured in the study of neuropathic changes that occur in traumatic vasospastic disease. Twenty-eight forest workers and 10 pneumatic-tool operators, all with a long occupational exposure to local vibration of the hands, were studied with these neurophysiological methods and general clinical and roentgenological examinations. Twenty male manual workers with a similar age distribution served as the comparison group. The most sensitive measures which separated the subjects with traumatic vasospastic disease from the nonexposed workers were the conduction velocity of the slower motor fibers of the ulnar nerve, the distal sensory conduction velocity and the motor distal latency of the median nerve. The duration and rise time of the averaged muscular potentials of intrinsic hand muscles correlated especially with those nerve conduction velocities which were the most sensitive in exhibiting neuropathic changes.     

Peripheral nerve conduction velocities in chain-saw operators.

The motor, sensory and mixed nerve conduction velocities of median and posterior tibial nerves were measured in seventeen forest workers engaged in chain-saw operation for 2 to 16 yr (mean 12 yr). The conduction velocities were significantly diminished in the distal part of the upper limb. The sensory nerve conduction velocities (SCV) of the median nerve at the part of the palm were slow in 12 workers; longer residual latency, in 6; and the mixed nerve conduction velocities slowed at the part of the forearm, in 6. From the relationships of the nerve conduction velocities to white finger attacks and electromyograms, it was assumed that vibration directly affected the distal part of the sensory and motor nerve fibers in the upper limbs, and that the diminished SCV in the palm was one of the most sensitive indices of vibration effects.     

Effect of Perinatal Food Deficiencies on the Compound Action Potential Evoked in Sensory Nerves of Developing Rats

The aim of this study was to analyze the possible alterations produced by inadequate perinatal food intake, in quantity (undernutrition) or quality (malnutrition), on the generation and propagation of the compound action potential (CAP) evoked in sensory sural nerves, during the postnatal development of the rat. Low intensity stimulation (2–3 times the threshold of the most excitable nerve fibers; X T) of the sural nerve evoked an early potential (CAP-A component) which is due to activation of low-threshold, fast-conducting myelinated group A afferent fibers. Meanwhile, at higher stimulus intensity (20–30T) it produced a second, long-lasting potential (CAP-C component) probably due to activation of high-threshold, slow-conducting group Aδ or C afferent fibers. Compared to control nerves, the CAP-A component, but not the CAP-C component of undernourished and malnourished nerves showed significant changes in amplitude, area, electrical threshold and conduction velocity (except absolute refractory period) at several postnatal ages. Our results may suggest that a relative large number of myelinated group A afferent fibers in the sural nerve of undernourished and malnourished animals suffer severe alterations on their electrophysiological properties of generation and propagation of the action potential during the postnatal development of the rat.     

铅、汞、锰中毒伴发周围神经损害调查

目的 调查铅、汞、锰中毒对周围神经的损害。方法 对病例组73人和对照组39人进行了植物神经功能检查和周围神经传导速度检测。结果 病例组的植物神经功能异常和周围神经传导速度异常的检出率均比对照组明显增高,差异具有非常显著性(P<0.01)。结论 铅、汞、锰对周围神经均可产生损害。中毒性周围神经病可用周围神经传导速度检测作为诊断的参考指标。     

丙烯酰胺的毒性研究

本文AAM的急性毒性试验,昆明小鼠经口LD_(50)为154mg/kg。动物慢性中毒以后肢瘫痪、坐骨运动神经传导速度减慢和周围神经病理损伤为主,并有剂量—反应关系。AAM对皮肤粘膜有一定的刺激作用。Amse试验、染色体畸变和微核试验皆为阴性。     

Exploratory electromyography in the study of vibration-induced white finger in rock drillers.

Electrophysiological observations made in the hands of a group of 16 rock-drillers were compared with 15 controls. Motor and sensory conduction velocities in the median and ulnar nerves together with the latency, duration, and amplitude of the evoked action potentials were measured. The differences between the groups were statistically significant mainly in latency, duration, and amplitude, especially of the sensory action potentials. Measurement of the conduction velocities, in general, proved to be less sensitive, and the only significant change observed was in the sensory conduction velocity in the median nerve when the first digit in the right hand was stimulated. The most interesting result was evidence of an increased prevalence of possible carpal tunnel syndrome in the exposed (44% compared with 7% in the control group). A similar set of data, but exclusively sensory and not standardised for age and sex, was obtained from 25 university students for comparison with the assigned groups. The results showed that apart from sensory duration the control group had values that were closest to the students while the vibration group had values furthest away.