The electrophysiologic features of sciatic neuropathy in 100 patients

We reviewed the electrophysiologic data of 100 consecutive patients with sciatic neuropathy in order to better understand this disorder. Most patients (93%) had electrodiagnostic signs of significant axonal loss. Seven patients had predominantly signs of demyelination; 6 were due to compression and 1 was idiopathic. The peroneal division was more severely affected than the tibial division in 64% of patients. Tibialis anterior EMGs were abnormal in 92%, and the EDB CMAP was low in amplitude or absent in 80%. CMAP and SNAP amplitudes and EMGs were all normal in the tibial division in 12%. In contrast, the tibial division was more severely affected in only 8 patients. Of those, 5 were due to thigh trauma (gunshot wounds or femur fracture), 2 from gunshot wounds to the hip, and the other was chronic and idiopathic. Sciatic neuropathies are commonly, but not always, axonal loss lesions that affect the peroneal greater than tibial division. © 1995 John Wiley & Sons, Inc.     

Application of angiotensin II to healthy rat sciatic nerve can produce neuropathy without associated vasculopathy

Elevated angiotensin II (AII) levels have been associated with hypertension, diabetes, and polyneuropathy. It is unknown whether AII applied to healthy nerve can be used to model a confined neuronal injury by producing localized vasculopathy and associated neuropathy. In this study, angiotensin II (2.2 μg/ml) or saline was infused constantly via osmotic pump onto the sciatic nerve of 20 rats for 12 weeks. Nerve conduction studies were repeated every 4 weeks, and sciatic nerve was collected for pathological analysis at 12 weeks. Animals infused with AII showed a significant decrease in nerve fiber diameter (P < 0.001), axon diameter (P < 0.001), and myelin thickness (P < 0.001), despite the absence of electrophysiological changes. Surprisingly, there was no significant difference in vessel diameter or wall thickness. AII can cause structural alterations in healthy nerve without associated changes in vasculature, implying the existence of additional previously unrecognized mechanisms of AII-induced neuronal injury.     

Focal posterior interosseous neuropathy in the presence of hereditary motor and sensory neuropathy,type I

A 30-year-old male with hereditary motor and sensory neuropathy, type I (HMSN I), presented with asymmetric weakness of finger extension and radial deviation with left wrist extension, previously felt to be a manifestation of the peripheral neuropathy. Nerve conduction studies confirmed HMSN I; however, needle EMG revealed marked, ongoing axonal loss in muscles innervated by the left posterior interosseous nerve (PIN) only. At surgery there was focal fusiform swelling in the PIN at exit from the supinator muscle, compatible with localized hypertrophic neuropathy, which has not been reported before in HMSN I. A concomitant focal mononeuropathy should be considered in cases of hereditary neuropathy with marked asymmetry of weakness. © 1996 John Wiley & Sons, Inc.     

The single-fiber EMG in chronic demyelinating neuropathy

Various parameters of single- fiber electromyography (SFEMG) were studied in 19 patients with electrophysiologically and histologically proven chronic demyelinating neuropathy. The mean duration of disease at the time of testing was four years. Motor nerve conduction in the median nerve was abnormal in all patients, whereas sensory nerve conduction was abnormal in all but one. Needle EMG in the extensor digitorum communis (EDC) muscle showed rare fibrillations and fasciculations and some abnormal motor unit potentials in most of patients. SFEMG in the EDC muscle showed an increased fiber density in seven cases (37%) and minimally abnormal jitter in 14 cases (74%). Single-fiber action potentials were stable, whereas blocking was rare. Fiber density was significantly increased in patients with fibrillation in the conventional needle EMG. Our study showed that the SFEMG is mildly abnormal in many patients with demyelinating neuropathy and that this test is useful in detecting and quantitating axonal degeneration in demyelinating neuropathy.     

Cerebrolysin improves sciatic nerve dysfunction in a mouse model of diabetic peripheral neuropathy

To examine the effects of Cerebrolysin on the treatment of diabetic peripheral neuropathy, we first established a mouse model of type 2 diabetes mellitus by administering a high-glucose, high-fat diet and a single intraperitoneal injection of streptozotocin. Mice defined as diabetic in this model were then treated with 1.80, 5.39 or 8.98 mL/kg of Cerebrolysin via intraperitoneal injections for 10 consecutive days. Our results demonstrated that the number, diameter and area of myelinated nerve fibers increased in the sciatic nerves of these mice after administration of Cerebrolysin. The results of several behavioral tests showed that Cerebrolysin dose-dependently increased the slope angle in the inclined plane test (indicating an improved ability to maintain body position), prolonged tail-flick latency and foot-licking time (indicating enhanced sensitivity to thermal and chemical pain, respectively, and reduced pain thresholds), and increased an index of sciatic nerve function in diabetic mice compared with those behavioral results in untreated diabetic mice. Taken together, the anatomical and functional results suggest that Cerebrolysin ameliorated peripheral neuropathy in a mouse model of type 2 diabetes mellitus.     

不同病程糖尿病周围神经病患者的临床及肌电图特点分析

目的:探讨不同病程糖尿病周围神经病(DPN)患者的临床及肌电图特点.方法:对2015年3月～2016年3月在北京市隆福医院肌电图室检查的164例不同病程2型糖尿病合并周围神经病症状患者的临床及肌电图特点进行回顾性分析.结果:164例DPN患者中男性78例,女性86例,年龄50～87岁.病程5年以下患者以正常肌电图为最常见,肌电图异常者以交感神经皮肤反射(SSR)异常最为多见;病程10年以上以远端对称性多发性周围神经病、自主神经病、嵌压性周围神经病为最常见3种类型.不同年龄组患者上述3种类型分布无明显差异.结论:糖尿病病程是影响DPN进展的重要因素,年龄与疾病进展无明显相关性.肌电图检查对于早期评价DPN具有重要价值.     

Bilateral intraneural perineurioma presenting as ulnar neuropathy at the elbow

We describe a 36-year-old woman with progressive bilateral ulnar neuropathy. Sonographic and magnetic resonance imaging studies revealed extensive focal ulnar nerve enlargement at the elbow. Histological studies gave evidence of an intraneural perineurioma. Because intraneural perineurioma usually appears as a single mass lesion at sites other than typical entrapment sites, this mode of presentation is unusual. We discuss the nature of this benign tumor and the differential diagnosis of nerve enlargement. Knowledge of possible causes of nerve thickening is crucial when performing imaging in patients with neuropathies.     

Sciatic neuropathy associated with persistent sciatic artery.

Persistent sciatic artery is a congenital vascular anomaly of the arterial supply to the lower extremity. Thrombosis, distal embolization, aneurysmal dilatation, and rupture of this vessel with compression of the sciatic nerve have been recorded. Although rare in occurrence, complications of persistent sciatic artery should be included in the differential diagnosis of sciatic neuropathy. We present a case of an acute sciatic neuropathy secondary to pseudoaneurysm formation of a persistent sciatic artery. We demonstrate the diagnostic usefulness of magnetic resonance imaging.     

Pitfalls in the electrodiagnostic studies of sacral plexopathies

This retrospective review characterizes the electrodiagnostic (EDX) features and etiologies of sacral plexopathies (SPs) and discusses difficulties in their identification. The EDX findings of 171 clinically suspected SPs were reviewed using the following criteria: reduced/absent sensory nerve action potentials (SNAPs) of the sural or superficial peroneal nerve, denervation of plexus-innervated muscles, and the absence of paraspinal denervation. Sixty cases localized unequivocally to the sacral plexus. The majority were cancer-related, followed by traumatic, idiopathic, and iatrogenic causes. Final diagnoses in the remaining 111 cases were indeterminate. Lesions localized to either the plexus or L4-5, S1 roots in 52 cases, the plexus or sciatic nerve in 32 cases, and were equally compatible with an SP, sciatic neuropathy, or radiculopathy in 27 cases. Findings in the EDX evaluation of SPs are often complex and difficult to localize to a specific site due to multiple complicating factors. Frequently, SPs cannot be diagnosed definitively by EDX assessment alone.     

Mixed carcinomatous neuropathy in patients with lung cancer and lymphoma

A clinical, electrophysiological and histological study of the peripheral nerve was performed on 62 patients with lung cancer and 30 patients with lymphoma. There was a mild peripheral neuropathy (MPN) in 17.7% of patients with lung cancer and in 10% of those with lymphoma. MPN was related to the degree of weight loss. Histological studies of 5 patients with MPN demonstrated a loss of large myelinated fibers in all patients, axonal degeneration in 2 and remyelination in 3 patients. Electromyographic and histological findings indicate a primary axonal neuropathy with remyelination, probably secondary to axonal damage. 2 patients with lymphoma developed a severe neuropathy that remitted in 1 patient. The main pathological abnormality was segmental demyelination in both cases. Immunofluorescence studies were negative in all cases with mild or severe neuropathy.     

多灶性运动神经病的临床和电生理特征

目的研究多灶性运动神经病(MMN)的临床和电生理特征。方法回顾性分析16例MMN患者的临床资料和电生理检查结果。结果本组患者均为中青年起病,平均年龄(28.2±2.4)岁;16例患者均有非对称性四肢无力,肌力Ⅱ～Ⅳ级,上肢无力重于下肢,右侧重于左侧,4例有轻度肌萎缩,无感觉减退;肌电图检查发现所有患者均存在节段性运动神经传导阻滞(CB),病变神经的运动神经传导速度(MCV)均减慢,感觉神经传导速度(SCV)减慢1例。结论MMN是一种不对称的周围神经病,主要累及运动神经;神经电生理检查对诊断起重要作用,节段性运动神经CB是MMN特征性的神经电生理表现。     

Sciatic neuropathy due to popliteal fossa nerve block

Introduction: Sciatic neuropathy after popliteal nerve block (PNB) for regional anesthesia is considered uncommon but has been increasingly recognized in the literature. We identified a case of sciatic neuropathy that occurred after bunionectomy during which a PNB had been performed. Methods: To understand the frequency of PNB‐related sciatic neuropathy, we performed a retrospective review of sciatic neuropathies at our center over a 5‐year period. Results: Forty‐five cases of sciatic neuropathy were reviewed. Similar to earlier reports, common etiologies of sciatic neuropathy, including compression, trauma, fractures, and hip arthroplasty, were noted in the majority of our cases (60%, n = 27). Unexpectedly, PNB was the third most common etiology (16%, n = 7). Conclusions: Our results suggest PNB is a relatively common etiology of sciatic neuropathy and is an important consideration in the differential diagnosis. These findings should urge electromyographers to assess history of PNB in sciatic neuropathies, particularly with onset after surgery. Muscle Nerve 56 : 822–824, 2017     

Consensus criteria for the diagnosis of multifocal motor neuropathy

At this time, there are no widely accepted criteria for the diagnosis of multifocal motor neuropathy. Furthermore, there is insufficient empirical data to define clinical and laboratory features that may reliably separate certain lower motor neuron syndromes with overlapping features as distinct. The AAEM therefore developed five criteria through a formal consensus process that are described in this document to act as a guide for diagnosing multifocal motor neuropathy with a high level of confidence (definite multifocal motor neuropathy) or with a moderate level of confidence (probable motor neuropathy). In brief, the diagnosis requires clinical weakness without objective sensory loss or upper motor neuron signs in the distribution of two or more named nerves that is due to conduction block in two or more motor nerves outside of common entrapment sites. Furthermore, normal results are required for sensory nerve conduction studies.     

Clinical and Electrodiagnostic Features Of Nontraumatic Sciatic Neuropathy

Introduction: In this study we sought to characterize etiologies and features of sciatic neuropathy unrelated to penetrating nerve trauma. Methods: This investigation was a retrospective review of 109 patients with electrodiagnostically confirmed sciatic neuropathies. Results: Hip replacement surgery represented the most common (34.9%) etiology, whereas inflammatory sciatic neuropathy was seen in 7.3%. Electrodiagnostic testing revealed an axonal neuropathy in 95.4% and a demyelinating neuropathy in 4.6%. Predominant involvement of the peroneal division was seen in 39.4% and was tibial in 5.5%. Nine of 31 (29.0%) patients who had MRI or neuromuscular ultrasound study showed abnormalities within the sciatic nerve. At the final visit, 46.4% of patients required assistance for ambulation. Young age, lack of severe initial weakness, and presence of tibial compound muscle action potential or sural sensory nerve action potential were predictors of favorable outcome. Discussion: Sciatic neuropathies are usually axonal on electrodiagnostic testing, affect preferentially the peroneal division, and are commonly associated with incomplete recovery. Muscle Nerve 59 :309–314, 2019     

Chronic axonal-demyelinating polyradicular neuropathy associated with mycosis fungoides: a case report

Abstract Case of a 58-year-old patient diagnosed as having mycosis fungoides (MF) who presented with sensory ataxia, limbs weakness and neurophysiological and laboratory signs indicative of autoimmune chronic mixed axonal-demyelinating sensory-motor polyradicular neuropathy. The possibility that MF may be associated with an immunomediated peripheral neuropathy, even in the absence of a direct invasion of the nerves and widespread visceral involvement, should be considered.