Role of repeat skeletal muscle biopsy: How useful is it?

Introduction: The role of skeletal muscle biopsy is established; however, to our knowledge, no study has systematically evaluated the utility of a repeat biopsy. Methods: This study was a retrospective clinicopathologic review of 66 patients (mean age 38.1 years, 39 men) with at least 1 repeat muscle biopsy obtained between February 1992 and November 2011. Clinical data determined how results of the subsequent biopsy impacted patient management. Results: Repeat biopsy yielded a definitive diagnosis in 16 of 66 patients (24%). In the remaining patients, a repeat study provided clinically useful information or directly answered the clinical question (n = 30, 45%) by excluding a differential consideration (n = 19), supporting treatment continuation (n = 8), prompting treatment change (n = 1), confirming the original diagnosis (n = 1), or establishing a likely diagnosis (n = 1). Conclusion: Repeat muscle biopsy plays a role in the evaluation of patients with suspected myopathy in certain clinical circumstances. Muscle Nerve 47: 835–839, 2013     

Primary angiitis of the central nervous system: report of eight cases from Southern China

Background and purpose:  This study is to report the clinical, neuroimaging and pathological characteristics of patients with primary angiitis of the central nervous system (PACNS) from Southern China.
Methods:  Eight patients with PACNS admitted between August 1995 and April 2006 were retrospectively studied. Records of clinical features, neuroimaging, brain biopsy and therapy were analyzed.
Results:  Primary angiitis of the central nervous system occurred predominantly in youth and middle-aged adults. Headache, hemiplegia and speech disturbance were the most predominant manifestations. The cerebrospinal fluid (CSF) was slightly abnormal in only one case, MRI was abnormal in seven, magnetic resonance angiography in seven, diffusion-weighted imaging in five and digital subtraction angiography in four. Brain biopsy in four cases revealed lymphocytic angiitis. All cases had good outcome with the treatment of single corticoid or cyclophosphamide.
Conclusion:  We report eight cases of PACNS from Southern China associated with neurological and neuroimaging abnormalities; these patients presented a mild to moderate inflammatory disease that was correlated with few CSF abnormalities and good response to single steroid or cyclophosphamide treatment without relapses. Although brain biopsy represents the gold standard for diagnosis of PACNS, considering the difficulty and challenge of identification of this disease, combination with other examinations might be necessary to arrive at an early and definitive diagnosis.     

脂质沉积性肌病的临床和病理特点

目的总结脂质沉积性肌病（lipid storage myopathy,LSM）的临床和病理特点,为早期诊断和治疗提供参考。方法对5例脂质沉积性肌病患者的临床资料进行回顾性分析。结果 5例脂质沉积性肌病患者均为慢性或亚急性起病,主要表现为不同程度的肌无力和对运动不耐受、血清肌酶均升高、神经电生理检查显示肌源性损害,病理检查发现肌纤维内空泡样变,脂滴明显增多,脂滴空泡呈＂串珠＂样排列。给予能量支持、低脂饮食、糖皮质激素等治疗后患者的临床症状好转。结论脂质沉积性肌病的确诊依靠肌肉活检,该病预后良好,及时的诊断和综合治疗可明显改善患者的生活质量。     

Muscle-fiber conduction velocity and electromyography as diagnostic tools in patients with suspected inflammatory myopathy: a prospective study

Combinations of different techniques can increase the diagnostic yield from neurophysiological examination of muscle. In 25 patients with suspected inflammatory myopathy, we prospectively performed needle electromyography (EMG) and measured muscle-fiber conduction velocity (MFCV) in a single muscle, using a technique with direct muscle-fiber stimulation and recording. Results of MFCV were compared with final diagnosis, EMG, and needle muscle biopsy. Diagnostic accuracy of combined MFCV and EMG studies was 72%, compared to 60% for EMG alone. This improvement was due to a gain in specificity. The MFCV did not prove useful in discriminating inflammatory myopathy from other myopathies. Furthermore, we found a correlation of 92% between variability of MFCV and myopathic changes in muscle biopsy. We conclude that the utility of electrodiagnostic examination can be increased if EMG examination is combined with MFCV studies.     

High prevalence of sporadic late-onset nemaline myopathy in a cohort of whole-exome sequencing negative myopathy patients

Sporadic late-onset nemaline myopathy (SLONM) is an enigmatic, supposedly very rare, putatively immune-mediated late-onset myopathy, typically presenting with subacutely progressive limb-girdle muscular weakness, yet slowly progressing cases have been described too. We systematically studied (para)clinical and histopathological findings in a cohort of 18 isolated yet suspected inherited myopathy patients, showing late-onset, slowly progressive limb-girdle muscle weakness, remaining unsolved after whole-exome sequencing. The presence of a monoclonal gammopathy of unknown significance (MGUS) and anti-HMGCR antibodies was determined. Biopsies were systematically re-evaluated and systematic immunohistochemical and electron microscopy studies were performed to particularly evaluate the presence of rods and/or inflammatory features. Ten patients showed rods as core feature on muscle biopsy on re-evaluation, four of these had an IgG κ MGUS in blood. As such, these ten patients represented suspected slowly progressing SLONM patients, with auxiliary data supporting this diagnosis: 1) additional muscle biopsy features pointing towards Z-disk and myofibrillar pathology; 2) a common selective pattern of muscle involvement on MRI; 3) inflammatory features on muscle biopsy. Findings in this proof-of-concept study highlight difficulties in reliably diagnosing slowly progressing SLONM and the probably underestimated prevalence of this entity in cohorts of whole exome sequencing negative myopathy patients, initially considered having an inherited myopathy.     

19Electrogastrography differentiates enteric myopathy from neuropathy in adults with severe motility disorders of the gut

Background:  Chronic intestinal pseudo-obstruction, enteric dysmotility and slow transit constipation are severe motility disorders of the gut that usually are associated with an underlying enteric neuropathy or myopathy. Electrogastrography (EGG) is a non-invasive technique that records gastric myoelectric activity.
Aim of the study:  To determine whether EGG can differentiate enteric myopathy from neuropathy as the primary pathology in patients with severe motility disorders of the gut.
Material and methods:  This is a retrospective analysis of patients with various motility disorders of the gut that underwent full thickness small bowel biopsy. A single bipolar channel measured the EGG. The ability of EGG to differentiate between myopathy and neuropathy was tested by comparing 21 variables from EGG.
Results:  A total of 38 patients, 35 (92%) females, mean age 42 ± 13 years, were analysed. Twenty patients had enteric dysmotility (19 with neuropathy and one with myopathy), 12 had slow transit constipation (10 with neuropathy and two with myopathy), and six had chronic intestinal pseudo-obstruction (three with neuropathy and three with myopathy). Patients with myopathy showed higher percentage of fasting time with DF in bradygastric and tachygastric frequency bands and a higher postprandial DF (Table) than did patients with neuropathic motility disorders.
Conclusions:  Patients with visceral myopathy exhibited more arrhythmia during fasting and a higher DF following the test meal and this indicates that myopathies are associated with more electrical disturbances than neuropathies. EGG may be considered for differentiating between these two disease entities.
 

     

8.

Spinal cord sarcoidosis: report of seven cases     

L. Varron  C. Broussolle  J.-P. Candessanche  R. Marignier  H. Rousset  J. Ninet  P. Sève 《European journal of neurology》2009,16(3):289-296

Background:  Spinal cord involvement in sarcoidosis is rare, occurring in <1% of patients with sarcoidosis.
Methods:  We report seven cases of spinal cord sarcoidosis, seen in two French hospitals over a 13-year period. Presentation of disease, methods of diagnosis and response to treatment, with quantification according to the reduction of the modified Rankin scale (MRS), were noted.
Results:  Six patients presented insidious paresthesias or weakness and one a sudden paraplegia. Average MRS at diagnosis was to 2. Spine MRI showed one or several intramedullary lesions in all cases. Diagnosis was confirmed by extra-neural tissue biopsies in all cases, including mediastinoscopy (two patients), coelioscopy (one patient), bronchoscopy (one patient), salivary gland biopsy (one patient) and skin biopsy (two patients). The average follow-up for the group was 49.4 months. All patients responded to corticosteroid therapy with a median reduction of MRS of one point. Five patients received immunosuppressive therapy: cyclophosphamide (two patients), methotrexate (two patients), azathioprine (one patient), mycophenolate mofetyl (one patient), with an inconstant benefit. Patients who received cyclophosphamide presented severe fungaemia.
Conclusion:  Based on our study and literature analysis, we propose an algorithm for treatment of spinal cord sarcoidosis.     

9.

Muscular fatigue and decremental response to repetitive nerve stimulation in X-linked spinobulbar muscular atrophy     

K. Inoue  S. Hemmi  M. Miyaishi  Y. Kutoku  T. Murakami  K. Kurokawa  Y. Sunada 《European journal of neurology》2009,16(1):76-80

Background and Purpose:  We report decremental responses to repetitive nerve stimulation (RNS) in 11 patients diagnosed with X-linked spinobulbar muscular atrophy (X-SBMA).
Methods:  The compound muscle action potential (CMAP) of the right abductor digiti minimi (ADM) and trapezius (TZ) in response to a 3-Hz stimulation of the ulnar nerve at the wrist and accessory nerve at the neck were recorded by surface electrodes.
Results:  A decremental response to RNS was observed in 90.9% of the TZ muscle and 27.2% in the ADM muscle of patients with X-SBMA.
Conclusion:  These electrophysiological features of X-SBMA are considered to be useful for diagnosis of X-SBMA. Furthermore, the waning phenomena that mostly appeared in the TZ muscle and increment of CMAP in RNS after the exercise also suggest a unique manifestation in X-SBMA.     

10.

脂质沉积性肌病的临床分析（附2例报道）     

陈中杰  王显锏  郑维红 《中国临床神经科学》2009,17(6):618-621

目的：对2例脂质沉积性肌病（LSM）的临床资料予以分析报道。方法：收集2例经病理检查确诊的LSM病例的临床资料,结合相关文献分析其临床表现、病理特征和实验室检查结果。结果：LSM临床以肢带肌近端无力为主要表现,有明显的运动不耐受特点,部分受累肌有压痛;肌电图示以肌源性损害为主;肌酶以肌酸激酶轻中度升高为主,对糖皮质激素反应早且明显;病理特征为肌纤维内有大量脂质颗粒沉积,并以Ⅰ型肌纤维为主。结论：LSM以肢带型肌无力综合征为临床表现时极易误诊为多发性肌炎等,确诊依赖于肌肉病理学检查。     

11.

Inflammatory myopathies: clinical,diagnostic and therapeutic aspects   总被引：8，自引：0，他引：8  

Mastaglia FL  Garlepp MJ  Phillips BA  Zilko PJ 《Muscle & nerve》2003,27(4):407-425

The three major forms of immune-mediated inflammatory myopathy are dermatomyositis (DM), polymyositis (PM), and inclusion-body myositis (IBM). They each have distinctive clinical and histopathologic features that allow the clinician to reach a specific diagnosis in most cases. Magnetic resonance imaging is sometimes helpful, particularly if the diagnosis of IBM is suspected but has not been formally evaluated. Myositis-specific antibodies are not helpful diagnostically but may be of prognostic value; most antibodies have low sensitivity. Muscle biopsy is mandatory to confirm the diagnosis of an inflammatory myopathy and to allow unusual varieties such as eosinophilic, granulomatous, and parasitic myositis, and macrophagic myofasciitis, to be recognized. The treatment of the inflammatory myopathies remains largely empirical and relies upon the use of corticosteroids, immunosuppressive agents, and intravenous immunoglobulin, all of which have nonselective effects on the immune system. Further controlled clinical trials are required to evaluate the relative efficacy of the available therapeutic modalities particularly in combinations, and of newer immunosuppressive agents (mycophenolate mofetil and tacrolimus) and cytokine-based therapies for the treatment of resistant cases of DM, PM, and IBM. Improved understanding of the molecular mechanisms of muscle injury in the inflammatory myopathies should lead to the development of more specific forms of immunotherapy for these conditions.     

12.

Take two: Utility of the repeat skeletal muscle biopsy     

Samah K. Aburahma MD  Matthew P. Wicklund MD  Dianna Quan MD 《Muscle & nerve》2019,60(1):41-46

Introduction: The utility of repeat muscle biopsy has not been adequately evaluated. Methods: A retrospective review was undertaken of 144 repeat muscle biopsies performed from 1980 to 2017. Repeat biopsy was considered clinically relevant if it provided a new diagnosis, changed the existing diagnosis, or led to treatment changes or further investigations. Results: Repeat biopsy was abnormal in 118 cases, different from the initial biopsy in 67 cases, and specific in 40 cases. Factors with a significant effect on clinical relevance of the repeat biopsy (P < 0.05) were an abnormal, specific, or inflammatory initial biopsy, proximal muscle weakness, absence of myalgia, and a repeat biopsy that is different, specific, or consistent with polymyositis or inclusion body myositis. Conclusions: Utility of repeat biopsy was limited to weak patients whose initial biopsy showed inflammatory myositis. Ongoing advances in the diagnosis of immune inflammatory myopathies have led to evolution of the role of repeat biopsy. Muscle Nerve, 2019     

13.

98例神经肌肉病的临床、肌电图与病理研究   总被引：3，自引：1，他引：2  

王秀艳  吴丽娟  孙江玲  袁云  石昕  孙相如 《中风与神经疾病杂志》2003,20(1):24-26

目的 探讨肌电图（EMG），肌活检对神经肌肉病的诊断价值。比较EMG，肌活检及初始临床诊断3者之间的关系。方法 将98例神经肌肉病分成肌病。重症肌无力和运动神经元病3组进行研究。结果 肌病组（80例），68.8%(55/80)肌活检，75%（60/80）EMG呈肌源性损害；重症肌无力组（10例）；针极EMG（不包括重视频率电刺激）及肌活检均未显示特异性改变；运动神经元病组（8例），75?/8）肌活检，100%（8/8）EMG呈神经源性损害。结论 肌活检对肌病明确诊断可提供直接信息。对运动神经元病只能做出神经源性损害结果。缺乏特异性。EMG对神经肌肉病只能做出分类诊断；单纯凭借初始临床资料易导致该类疾病误诊。     

14.

Predictive value of clinical characteristics in patients with suspected cauda equina syndrome     

P. M. Domen  P. A. Hofman  H. van Santbrink  W. E. J. Weber 《European journal of neurology》2009,16(3):416-419

Background and purpose:  Overlooking a potential diagnosis of cauda equina syndrome (CES) can result in severe long-term neurologic deficits. There is a growing trend to order urgent magnetic resonance imaging (MRI) scans of the lumbar spine in any patient presenting with signs suspicious for CES. A substantial number of these MRI scans do not show cauda compression. The purpose of this study is to assess whether clinical characteristics can predict MRI-confirmed cauda compression.
Methods:  We retrospectively studied 58 consecutive cases of suspected CES who presented at our hospital's emergency room.
Results:  Eight of 58 patients had cauda compression on MRI. When measured, MRI + CES patients (6) had more than 500 ml urinary retention. Moreover, when these patients had at least two of the following characteristics: bilateral sciatica, subjective urinary retention or rectal incontinence symptoms, MRI was more probable to demonstrate cauda compression with an OR of 48.00, 95% (CI 3.30–697.21), which was also significant ( P of 0.04). The presence of other symptoms or signs alone was not significantly different between both groups.
Conclusion:  In our series, urinary retention of more than 500 ml alone or in combination with two or more specific clinical characteristics were the most important predictors of MRI confirmed cauda compressions.     

15.

Timing subdural haematoma     

S. Mohamed  P. Rezaie  S. Al-Sarraj 《Neuropathology and applied neurobiology》2002,28(2):160-160

Background and aim:  Alpers syndrome or progressive neuronal degeneration of childhood with liver disease is a rare and probably heterogeneous familial disorder of unknown aetiology. We investigated mitochondrial DNA (mtDNA) levels in three cases with Alpers syndrome.
Methods:  Three unrelated patients presented with status epilepticus and liver dysfunction between 6 months and 3 years of age. The clinical course was severely progressive and death occurred 7 days to 2 years after initial presentation. Neuropathology was performed in cases 1 and 3 and confirmed a diagnosis of Alpers syndrome. Total genomic DNA extracted from frozen skeletal muscle, liver, heart and kidney was subjected to quantitative Southern blot analysis using two probes (one for mtDNA and the other for the nuclear-encoded 18S ribosomal DNA) and comparison with age-matched controls.
Results:  Case 1 had 25% residual mtDNA levels in liver, 33% in skeletal muscle, 55% in cardiac muscle and normal levels in kidney. Case 2 had 19% residual mtDNA levels in liver and 42% in skeletal muscle. Case 3 had normal mtDNA levels in skeletal muscle, the only tissue available for study.
Discussion:  We conclude that Alpers syndrome may be associated with depleted levels of mtDNA. The underlying genetic defect is likely to involve mtDNA maintenance. Quantitative determination of residual mtDNA levels should be performed in all cases where there is a suspicion of Alpers syndrome.     

16.

Myopathies presenting with head drop: Clinical spectrum and treatment outcomes     

《Neuromuscular disorders : NMD》2020,30(2):128-136

Dropped head syndrome can be the presenting feature of a wide spectrum of neurological conditions. In this study, we aimed to define the clinical characteristics and treatment outcomes of 107 patients, where head drop was the presenting or predominant clinical feature of a myopathy. Median age at presentation was 68 years (range 42–88). A specific diagnosis was reached in 53% of patients: Inflammatory myopathy (n = 16), myopathy with rimmed vacuoles (n = 10), radiation-induced myopathy (n = 8), sporadic late-onset nemaline myopathy (n = 7), myofibrillar myopathy (n = 4), facioscapulohumeral dystrophy (n = 3), inclusion body myositis (n = 2), mitochondrial myopathy (n = 2), scleroderma-associated myopathy (n = 2), and single cases of necrotizing autoimmune myopathy, drug-induced myopathy, and B-cell chronic lymphocytic leukemia-myopathy. Splenius capitis had the highest diagnostic yield for a muscle biopsy (67%). When tested, 31/35 (89%) of patients had abnormal pulmonary function tests, 15/30 (50%) abnormal swallow evaluation, 24/65 (37%) abnormal electrocardiogram and 5/38 (13%) abnormal transthoracic echocardiogram. 23/43 (53%) treated patients responded to treatment. Patient-reported limb weakness and neck flexion weakness on physical examination were associated with good response to treatment. A wide spectrum of acquired and hereditary myopathies can present with head drop, some of which are potentially treatable. Establishing a diagnosis is crucial for timely treatment administration, screening for swallowing and cardiorespiratory involvement, and counseling regarding prognosis.     

17.

A clinical approach to muscle diseases     

Jackson CE 《Seminars in neurology》2008,28(2):228-240

Muscle diseases constitute a large variety of both acquired and hereditary disorders that can affect muscle structure, metabolism, or the function of the muscle channel. A successful clinical approach to a patient with a suspected myopathy is based on a thorough medical history and neurological examination. Associated clinical symptoms such as myoglobinuria, contractures, myotonia, cardiac disease, and respiratory insufficiency can be extremely helpful in limiting the differential diagnosis. In addition, a phenotypic approach to diagnosis according to the patient's predominant pattern of weakness is essential for guiding the physician in selecting the most appropriate diagnostic studies. Although muscle biopsy remains a useful tool, molecular genetic studies are now available for the noninvasive diagnosis of many muscle diseases.     

18.

误诊为多发性肌炎的脂质沉积性肌病——附3例报告     

管玉青  谢作善  郑卉  潘速跃 《中国神经精神疾病杂志》2012,38(2):101-104

目的探讨脂质沉积性肌病(lipid storage myopathy,LSM)的临床特征、病理改变、代谢异常及治疗。方法回顾性分析我院确诊的3例LSM患者的临床表现、肌肉病理所见及血、尿代谢检查结果 ,结合文献报道总结LSM的临床特点和发病机制,并对多发性肌炎的诊断标准进行讨论。结果 3例患者均有对称性肌无力和/或肌痛,肌酶谱增高,最初均诊断为多发性肌炎,经激素治疗可好转,但病情反复。肌肉病理显示肌纤维大小不等,大量肌纤维内可见类圆形空泡,油红O染色见肌纤维内大量红染的脂滴沉积。经调整饮食、口服维生素B2、左卡尼汀等药物治疗后,症状改善明显。结论应用Bohan/Peter标准可能导致对多发性肌炎的过度诊断。对临床表现为肌无力、肌痛的患者,不要盲目应用激素治疗,应积极进行骨骼肌活检,明确诊断。     

19.

Diagnostic outcome of muscle biopsy          下载免费PDF全文

Aziz Shaibani MD  Duaa Jabari MD  Moussa Jabbour MD  Chia Arif MD  Minjae Lee PhD  Mohammad Hossein Rahbar PhD 《Muscle & nerve》2015,51(5):662-668

Introduction: We reviewed the diagnostic yield of muscle biopsy according to the presence or absence of muscle weakness, hyperCKemia, and electromyogaphic (EMG) abnormalities. Methods: In a retrospective study, 698 muscle biopsy reports were analyzed. Logistic regression models for myopathy and specific myopathy were fit, and receiver‐operating characteristic (ROC) curves were generated to assess prediction accuracy. The probability of finding specific myopathy was considered the main indication of a positive muscle biopsy. Results: Isolated hyperCKemia was poorly predictive of either myopathy or specific myopathy. Combined myopathic EMG, proximal weakness, and hyperCKemia were predictive. The predictability increased proportionally to the creatine kinase (CK) level in patients with proximal weakness and myopathic EMG. Cross validation showed accuracy around 70% for a probability threshold of 50%. Conclusions: The presence of hyperCKemia, proximal weakness, and myopathic EMG together were associated with highly positive diagnostic outcome of muscle biopsy. Isolated hyperCKemia had a poor diagnostic yield. Muscle Nerve 51 :662–668, 2015     

20.

Cutaneous accumulation of abnormal polyglutamine proteins of patients with dentatorubral-pallidoluysian atrophy     

M. Ohta  R. Okuyama  E. Ogawa  K. Kisu  H. Sato  M. Aoki  S. Aiba 《European journal of neurology》2009,16(11):1246-1249

Background and purpose:  Dentatorubral-pallidoluysian atrophy (DRPLA) is a hereditary spinocerebellar degeneration caused by expansion of a trinucleotide CAG repeat encoding a polyglutamine tract in a disease protein atrophin-1. The clinical features include ataxia, choreoathetosis, and dementia, which result from neural degeneration caused by the mutant atrophin-1.
Methods:  We performed skin biopsy in two patients with DRPLA.
Results:  We found multiple clear cells in the epidermis, which were positive for proteins containing an expanded polyglutamine stretches. The clear cells were p63 (+), S-100 (−), and cytokeratin 20 (−), showing that they were keratinocytes. Negative or weak signals of pan-cytokeratin were consistent with the finding of decreased tonofilaments at the electron microscopic level.
Conclusions:  The presence of clear keratincoytes showed that the mutant proteins interfered in cellular functions not only in neural cells but also in keratinocytes. The skin is accessible by biopsy, making it important in the diagnosis. Furthermore, the polyglutamine staining in the skin may be useful for evaluation of therapeutic modalities for DRPLA and other polyglutamine diseases.     

Spinal cord sarcoidosis: report of seven cases

Background:  Spinal cord involvement in sarcoidosis is rare, occurring in <1% of patients with sarcoidosis.
Methods:  We report seven cases of spinal cord sarcoidosis, seen in two French hospitals over a 13-year period. Presentation of disease, methods of diagnosis and response to treatment, with quantification according to the reduction of the modified Rankin scale (MRS), were noted.
Results:  Six patients presented insidious paresthesias or weakness and one a sudden paraplegia. Average MRS at diagnosis was to 2. Spine MRI showed one or several intramedullary lesions in all cases. Diagnosis was confirmed by extra-neural tissue biopsies in all cases, including mediastinoscopy (two patients), coelioscopy (one patient), bronchoscopy (one patient), salivary gland biopsy (one patient) and skin biopsy (two patients). The average follow-up for the group was 49.4 months. All patients responded to corticosteroid therapy with a median reduction of MRS of one point. Five patients received immunosuppressive therapy: cyclophosphamide (two patients), methotrexate (two patients), azathioprine (one patient), mycophenolate mofetyl (one patient), with an inconstant benefit. Patients who received cyclophosphamide presented severe fungaemia.
Conclusion:  Based on our study and literature analysis, we propose an algorithm for treatment of spinal cord sarcoidosis.     

Muscular fatigue and decremental response to repetitive nerve stimulation in X-linked spinobulbar muscular atrophy

Background and Purpose:  We report decremental responses to repetitive nerve stimulation (RNS) in 11 patients diagnosed with X-linked spinobulbar muscular atrophy (X-SBMA).
Methods:  The compound muscle action potential (CMAP) of the right abductor digiti minimi (ADM) and trapezius (TZ) in response to a 3-Hz stimulation of the ulnar nerve at the wrist and accessory nerve at the neck were recorded by surface electrodes.
Results:  A decremental response to RNS was observed in 90.9% of the TZ muscle and 27.2% in the ADM muscle of patients with X-SBMA.
Conclusion:  These electrophysiological features of X-SBMA are considered to be useful for diagnosis of X-SBMA. Furthermore, the waning phenomena that mostly appeared in the TZ muscle and increment of CMAP in RNS after the exercise also suggest a unique manifestation in X-SBMA.     

脂质沉积性肌病的临床分析（附2例报道）

目的：对2例脂质沉积性肌病（LSM）的临床资料予以分析报道。方法：收集2例经病理检查确诊的LSM病例的临床资料,结合相关文献分析其临床表现、病理特征和实验室检查结果。结果：LSM临床以肢带肌近端无力为主要表现,有明显的运动不耐受特点,部分受累肌有压痛;肌电图示以肌源性损害为主;肌酶以肌酸激酶轻中度升高为主,对糖皮质激素反应早且明显;病理特征为肌纤维内有大量脂质颗粒沉积,并以Ⅰ型肌纤维为主。结论：LSM以肢带型肌无力综合征为临床表现时极易误诊为多发性肌炎等,确诊依赖于肌肉病理学检查。     

Inflammatory myopathies: clinical,diagnostic and therapeutic aspects

The three major forms of immune-mediated inflammatory myopathy are dermatomyositis (DM), polymyositis (PM), and inclusion-body myositis (IBM). They each have distinctive clinical and histopathologic features that allow the clinician to reach a specific diagnosis in most cases. Magnetic resonance imaging is sometimes helpful, particularly if the diagnosis of IBM is suspected but has not been formally evaluated. Myositis-specific antibodies are not helpful diagnostically but may be of prognostic value; most antibodies have low sensitivity. Muscle biopsy is mandatory to confirm the diagnosis of an inflammatory myopathy and to allow unusual varieties such as eosinophilic, granulomatous, and parasitic myositis, and macrophagic myofasciitis, to be recognized. The treatment of the inflammatory myopathies remains largely empirical and relies upon the use of corticosteroids, immunosuppressive agents, and intravenous immunoglobulin, all of which have nonselective effects on the immune system. Further controlled clinical trials are required to evaluate the relative efficacy of the available therapeutic modalities particularly in combinations, and of newer immunosuppressive agents (mycophenolate mofetil and tacrolimus) and cytokine-based therapies for the treatment of resistant cases of DM, PM, and IBM. Improved understanding of the molecular mechanisms of muscle injury in the inflammatory myopathies should lead to the development of more specific forms of immunotherapy for these conditions.     

Take two: Utility of the repeat skeletal muscle biopsy

Introduction: The utility of repeat muscle biopsy has not been adequately evaluated. Methods: A retrospective review was undertaken of 144 repeat muscle biopsies performed from 1980 to 2017. Repeat biopsy was considered clinically relevant if it provided a new diagnosis, changed the existing diagnosis, or led to treatment changes or further investigations. Results: Repeat biopsy was abnormal in 118 cases, different from the initial biopsy in 67 cases, and specific in 40 cases. Factors with a significant effect on clinical relevance of the repeat biopsy (P < 0.05) were an abnormal, specific, or inflammatory initial biopsy, proximal muscle weakness, absence of myalgia, and a repeat biopsy that is different, specific, or consistent with polymyositis or inclusion body myositis. Conclusions: Utility of repeat biopsy was limited to weak patients whose initial biopsy showed inflammatory myositis. Ongoing advances in the diagnosis of immune inflammatory myopathies have led to evolution of the role of repeat biopsy. Muscle Nerve, 2019     

98例神经肌肉病的临床、肌电图与病理研究

目的 探讨肌电图（EMG），肌活检对神经肌肉病的诊断价值。比较EMG，肌活检及初始临床诊断3者之间的关系。方法 将98例神经肌肉病分成肌病。重症肌无力和运动神经元病3组进行研究。结果 肌病组（80例），68.8%(55/80)肌活检，75%（60/80）EMG呈肌源性损害；重症肌无力组（10例）；针极EMG（不包括重视频率电刺激）及肌活检均未显示特异性改变；运动神经元病组（8例），75?/8）肌活检，100%（8/8）EMG呈神经源性损害。结论 肌活检对肌病明确诊断可提供直接信息。对运动神经元病只能做出神经源性损害结果。缺乏特异性。EMG对神经肌肉病只能做出分类诊断；单纯凭借初始临床资料易导致该类疾病误诊。     

Predictive value of clinical characteristics in patients with suspected cauda equina syndrome

Background and purpose:  Overlooking a potential diagnosis of cauda equina syndrome (CES) can result in severe long-term neurologic deficits. There is a growing trend to order urgent magnetic resonance imaging (MRI) scans of the lumbar spine in any patient presenting with signs suspicious for CES. A substantial number of these MRI scans do not show cauda compression. The purpose of this study is to assess whether clinical characteristics can predict MRI-confirmed cauda compression.
Methods:  We retrospectively studied 58 consecutive cases of suspected CES who presented at our hospital's emergency room.
Results:  Eight of 58 patients had cauda compression on MRI. When measured, MRI + CES patients (6) had more than 500 ml urinary retention. Moreover, when these patients had at least two of the following characteristics: bilateral sciatica, subjective urinary retention or rectal incontinence symptoms, MRI was more probable to demonstrate cauda compression with an OR of 48.00, 95% (CI 3.30–697.21), which was also significant ( P of 0.04). The presence of other symptoms or signs alone was not significantly different between both groups.
Conclusion:  In our series, urinary retention of more than 500 ml alone or in combination with two or more specific clinical characteristics were the most important predictors of MRI confirmed cauda compressions.     

Timing subdural haematoma

Background and aim:  Alpers syndrome or progressive neuronal degeneration of childhood with liver disease is a rare and probably heterogeneous familial disorder of unknown aetiology. We investigated mitochondrial DNA (mtDNA) levels in three cases with Alpers syndrome.
Methods:  Three unrelated patients presented with status epilepticus and liver dysfunction between 6 months and 3 years of age. The clinical course was severely progressive and death occurred 7 days to 2 years after initial presentation. Neuropathology was performed in cases 1 and 3 and confirmed a diagnosis of Alpers syndrome. Total genomic DNA extracted from frozen skeletal muscle, liver, heart and kidney was subjected to quantitative Southern blot analysis using two probes (one for mtDNA and the other for the nuclear-encoded 18S ribosomal DNA) and comparison with age-matched controls.
Results:  Case 1 had 25% residual mtDNA levels in liver, 33% in skeletal muscle, 55% in cardiac muscle and normal levels in kidney. Case 2 had 19% residual mtDNA levels in liver and 42% in skeletal muscle. Case 3 had normal mtDNA levels in skeletal muscle, the only tissue available for study.
Discussion:  We conclude that Alpers syndrome may be associated with depleted levels of mtDNA. The underlying genetic defect is likely to involve mtDNA maintenance. Quantitative determination of residual mtDNA levels should be performed in all cases where there is a suspicion of Alpers syndrome.     

Myopathies presenting with head drop: Clinical spectrum and treatment outcomes

Dropped head syndrome can be the presenting feature of a wide spectrum of neurological conditions. In this study, we aimed to define the clinical characteristics and treatment outcomes of 107 patients, where head drop was the presenting or predominant clinical feature of a myopathy. Median age at presentation was 68 years (range 42–88). A specific diagnosis was reached in 53% of patients: Inflammatory myopathy (n = 16), myopathy with rimmed vacuoles (n = 10), radiation-induced myopathy (n = 8), sporadic late-onset nemaline myopathy (n = 7), myofibrillar myopathy (n = 4), facioscapulohumeral dystrophy (n = 3), inclusion body myositis (n = 2), mitochondrial myopathy (n = 2), scleroderma-associated myopathy (n = 2), and single cases of necrotizing autoimmune myopathy, drug-induced myopathy, and B-cell chronic lymphocytic leukemia-myopathy. Splenius capitis had the highest diagnostic yield for a muscle biopsy (67%). When tested, 31/35 (89%) of patients had abnormal pulmonary function tests, 15/30 (50%) abnormal swallow evaluation, 24/65 (37%) abnormal electrocardiogram and 5/38 (13%) abnormal transthoracic echocardiogram. 23/43 (53%) treated patients responded to treatment. Patient-reported limb weakness and neck flexion weakness on physical examination were associated with good response to treatment. A wide spectrum of acquired and hereditary myopathies can present with head drop, some of which are potentially treatable. Establishing a diagnosis is crucial for timely treatment administration, screening for swallowing and cardiorespiratory involvement, and counseling regarding prognosis.     

A clinical approach to muscle diseases

Muscle diseases constitute a large variety of both acquired and hereditary disorders that can affect muscle structure, metabolism, or the function of the muscle channel. A successful clinical approach to a patient with a suspected myopathy is based on a thorough medical history and neurological examination. Associated clinical symptoms such as myoglobinuria, contractures, myotonia, cardiac disease, and respiratory insufficiency can be extremely helpful in limiting the differential diagnosis. In addition, a phenotypic approach to diagnosis according to the patient's predominant pattern of weakness is essential for guiding the physician in selecting the most appropriate diagnostic studies. Although muscle biopsy remains a useful tool, molecular genetic studies are now available for the noninvasive diagnosis of many muscle diseases.     

误诊为多发性肌炎的脂质沉积性肌病——附3例报告

目的探讨脂质沉积性肌病(lipid storage myopathy,LSM)的临床特征、病理改变、代谢异常及治疗。方法回顾性分析我院确诊的3例LSM患者的临床表现、肌肉病理所见及血、尿代谢检查结果 ,结合文献报道总结LSM的临床特点和发病机制,并对多发性肌炎的诊断标准进行讨论。结果 3例患者均有对称性肌无力和/或肌痛,肌酶谱增高,最初均诊断为多发性肌炎,经激素治疗可好转,但病情反复。肌肉病理显示肌纤维大小不等,大量肌纤维内可见类圆形空泡,油红O染色见肌纤维内大量红染的脂滴沉积。经调整饮食、口服维生素B2、左卡尼汀等药物治疗后,症状改善明显。结论应用Bohan/Peter标准可能导致对多发性肌炎的过度诊断。对临床表现为肌无力、肌痛的患者,不要盲目应用激素治疗,应积极进行骨骼肌活检,明确诊断。     

Diagnostic outcome of muscle biopsy

Introduction: We reviewed the diagnostic yield of muscle biopsy according to the presence or absence of muscle weakness, hyperCKemia, and electromyogaphic (EMG) abnormalities. Methods: In a retrospective study, 698 muscle biopsy reports were analyzed. Logistic regression models for myopathy and specific myopathy were fit, and receiver‐operating characteristic (ROC) curves were generated to assess prediction accuracy. The probability of finding specific myopathy was considered the main indication of a positive muscle biopsy. Results: Isolated hyperCKemia was poorly predictive of either myopathy or specific myopathy. Combined myopathic EMG, proximal weakness, and hyperCKemia were predictive. The predictability increased proportionally to the creatine kinase (CK) level in patients with proximal weakness and myopathic EMG. Cross validation showed accuracy around 70% for a probability threshold of 50%. Conclusions: The presence of hyperCKemia, proximal weakness, and myopathic EMG together were associated with highly positive diagnostic outcome of muscle biopsy. Isolated hyperCKemia had a poor diagnostic yield. Muscle Nerve 51 :662–668, 2015     

Cutaneous accumulation of abnormal polyglutamine proteins of patients with dentatorubral-pallidoluysian atrophy

Background and purpose:  Dentatorubral-pallidoluysian atrophy (DRPLA) is a hereditary spinocerebellar degeneration caused by expansion of a trinucleotide CAG repeat encoding a polyglutamine tract in a disease protein atrophin-1. The clinical features include ataxia, choreoathetosis, and dementia, which result from neural degeneration caused by the mutant atrophin-1.
Methods:  We performed skin biopsy in two patients with DRPLA.
Results:  We found multiple clear cells in the epidermis, which were positive for proteins containing an expanded polyglutamine stretches. The clear cells were p63 (+), S-100 (−), and cytokeratin 20 (−), showing that they were keratinocytes. Negative or weak signals of pan-cytokeratin were consistent with the finding of decreased tonofilaments at the electron microscopic level.
Conclusions:  The presence of clear keratincoytes showed that the mutant proteins interfered in cellular functions not only in neural cells but also in keratinocytes. The skin is accessible by biopsy, making it important in the diagnosis. Furthermore, the polyglutamine staining in the skin may be useful for evaluation of therapeutic modalities for DRPLA and other polyglutamine diseases.