线粒体脑肌病伴高乳酸血症和卒中样发作综合征的临床特点分析

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的临床、影像学、肌肉病理及分子生物学特点。方法回顾性分析6例MELAS患者的临床资料。结果首发症状表现为肢体抽搐4例,轻偏瘫1例,失语1例;其他症状包括发作性头痛和视力障碍。合并心脏功能异常2例,ECG提示预激综合征。6例患者行血乳酸运动试验,均为阳性。6例患者MRI检查显示大脑皮质和皮质下与血管分布不一致的长T_1、长T_2病灶。3例伴有脑萎缩,其中2例为小脑萎缩,1例为全脑萎缩。1例患者4个月后复查头颅MRI提示病灶完全消失。磁共振波谱可见病灶内多个体素的乳酸峰值升高,N-乙酰天冬氨酸值降低,乳酸/胆碱比降低。2例患者肌肉组织活检的病理均见到不同程度的萎缩肌纤维,未见到破碎红纤维。5例患者基因检测发现线粒体DNA(mtDNA)A3243G点突变,1例患者发现mtDNA T3271C点突变。结论 MELAS综合征临床表现复杂多样,以头痛、肢体抽搐及反复卒中样发作为突出特点。卒中样发作期影像学主要表现为脑内与供血区分布不一致的病灶;血乳酸运动试验阳性;典型肌肉病理检查MGT染色可见破碎红纤维;分子遗传学检查可发现基因突变。最终确诊有赖于基因检测。     

五例MELAS综合征的临床分析

目的 报道5例线粒体脑肌病伴乳酸酸中毒和卒中样发作(MELAS)综合征患者的临床、肌肉病理表现和近期随访结果. 方法 同顾性分析安徽中医学院神经病学研究所附属医院神经内科自2008年12月至2011年6月5例MELAS综合征患者的临床表现、血清酶学、电生理、影像学、肌肉活检组织病理及近期随访的结果. 结果 3例首发症状为头痛,以偏瘫和上消化道出血为首发症状各1例,病程中有全身抽搐发作4例,精神症状2例.肌酸激酶4例正常,1例轻度升高.肌电图4例未见异常,1例肌源性损害.头颅MRI示5例均有明显异常,以永久性脑梗死和脑萎缩为主.肌肉组织病理检查5例均发现强反应性血管(SSVs),且SSVs的细胞色素C氧化酶的酶活性增强.经过线粒体保护等综合治疗,随访6个月3例已恢复到能正常工作,2例病情轻度好转. 结论 MELAS综合征患者的头颅MRI均有明显异常,肌活检组织病理及组织酶学染色是诊断该病关键手段,一般预后良好.     

线粒体脑肌病伴高乳酸血症和卒中样发作三例

目的分析3例线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)患者的临床表现影像学特点并探讨其发病机制。方法对3例MELAS患者的临床资料进行分析。结果 3例患者均以卒中样发作为主要表现,伴有内分泌、循环系统等多系统症状。患者头颅影像学有异常表现,肌肉活检示破碎红纤维。结论MELAS的初步诊断主要依据临床表现和影像学特点,肌肉活检可以为进一步明确诊断提供重要的依据。     

线粒体脑肌病伴高乳酸血症和脑卒中样发作综合征的临床、影像学及病理学特点

目的探讨线粒体脑肌病伴高乳酸血症和脑卒中样发作(MELAS)综合征的临床、影像及病理学特点。方法回顾性分析7例MELAS综合征患者的临床资料。结果本组患者中,男1例,女6例,平均年龄21.3岁;均为卒中样起病伴癫痫发作,其中视力减退6例,运动后乏力5例,认知功能障碍2例,精神异常1例。头颅MRI检查示顶、枕叶和(或)颞叶T1WI/T2WI长或稍长信号及Flair高信号病灶,呈脑回样改变,均未见强化。4例患者肌肉活检发现有肌纤维变性,横纹消失或断裂,肌膜下出现不规则的不整红边纤维(RRF)。2例行基因检测发现有mtDNA A3243G位点突变。结论 MELAS综合征好发于青少年,以卒中样起病伴癫痫发作,可有视听力减退以及认知功能障碍等;影像学特征为病变主要累及双侧大脑半球后部皮质,呈脑回样改变;肌肉活检发现RRF。     

MELAS综合征和Leigh病患者临床对比

目的对比研究和总结线粒体脑肌病伴乳酸血症和脑卒中样发作(mitochondrial encephalomyopathywith lactic acidosis and stroke-like episodes,MELAS)综合征和Leigh病患者的临床、影像学以及病理学特点。方法对10例MELAS综合征、7例Leigh病和1例MELAS综合征-Leigh病叠加患者的临床、影像学及组织病理学特点进行系统分析。结果 10例MELAS综合征患者主要临床表现为运动不耐受、发作性头痛和脑卒中样发作,脑CT及MRI检查结果示病灶多位于枕、顶、颞叶皮质及皮质下,光镜下观察肌肉组织可见不整红边纤维(ragged red fiber,RRF),抗线粒体抗体(anti-mitochondrial antibody,AMA)免疫组化染色可见大量破碎样棕褐色肌纤维(ragged brown fibers,RBFs),3例MELAS综合征患者行脑活检可见棕色AMA阳性的小血管及神经细胞。7例Leigh病患者主要临床表现为眼外肌麻痹、视力下降、肌阵挛样发作及智力发育迟缓,头颅MRI检查结果示双侧底节区、脑干异常信号,肌肉活检未见RRF。4例MELAS综合征、4例Leigh病患者以及1例MELAS综合征-Leigh病叠加患者行MRS检查结果示病变区乳酸水平明显增高。结论 MELAS综合征和Leigh病的临床及影像学特点相比存在明显差别,前者脑部病灶以脑叶皮质及皮质下受累为主,同时表现为脑和肌肉受累症状,肌肉活检可发现RRF;Leigh病患者主要表现为脑干、基底节及视神经受累表现,肌肉活检未见RRF。     

MELAS综合征的临床、影像学及病理研究

目的探讨线粒体脑肌病中MELAS综合征患者的临床表现、影像学、组织病理学特点及诊断方法。方法对5例MELAS综合征患者的临床、影像学及神经电生理、肌肉和脑组织病理学特点进行系统分析,3例行肌活检,其中1例患者行肌肉电镜检查;2例行脑活检。结果 MELAS综合征患者主要临床表现为运动不耐受、脑卒中发作、抽搐发作、偏盲、偏头痛发作、听力下降、视力下降。5例患者中血乳酸增高4例,肌电图提示肌源性损害4例,脑电图检查提示重度异常脑电图5例,头颅MRI检查主要为颞、枕、顶叶的不对称病灶;3例患者肌肉组织有破碎红纤维,1例行肌肉电镜检查发现异常线粒体,2例患者脑组织活检可见皮质组织成分层样改变。结论根据患者的临床及影像学特点,并结合肌肉及脑组织活检可对线粒体脑肌病MELAS综合征进行诊断。     

15例MELAS综合征临床分析

目的 探讨线粒体脑肌病伴高乳酸血症和卒中样发作(Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes,MELAS)综合征的临床表现、核磁共振成像(Magnetic resonance imaging,MRI)特征、肌肉病理表现、基因突变特点、易误诊疾病,以提高临床医生对该病的认识。方法 回顾性分析本院2015年1月-2020年12月收治的15例MELAS综合征患者的临床资料。结果 15例MELAS综合征患者平均发病年龄30岁,临床表现中具有脑卒中样发作10例,癫痫11例,精神异常7例,认知功能下降6例,视力异常6例,听力异常2例,头痛8例,呕吐3例。MRI以颞顶枕叶病灶多见,不符合脑血管分布,且病灶呈“游走性”。15例患者均有静止性乳酸水平升高。15例肌肉活检可见典型破碎红纤维; 3例行基因检测,3例mtDNA A3243G突变; 曾误诊疾病:脑炎8人次,脑梗死4人次,继发性癫痫3人次,可逆性后部脑白质病变1人次。结论 临床上MELAS综合征极易漏诊、误诊,需结合临床表现、MRI特征、肌肉活检、基因检测协助诊断。     

线粒体脑肌病伴高乳酸血症和卒中样发作的诊断

目的 分析总结线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)的临床表现和辅助检查结果,探讨在MELAS诊断中存在的问题,提出MELAS早期临床诊断的可行性.方法 归纳总结34例MELAS患者的临床表现,寻找对MELAS患者相对特异的症状组合.同时总结分析各项辅助检查结果,结合文献复习解读血和脑脊液的乳酸水平、神经影像、肌肉活体组织检查(活检)和基因检查对于MELAS诊断的意义和局限性.结果 本组患者最常见的临床表现依次为:癫癎发作、头痛、智能下降、卒中样发作、发育异常、四肢无力和易疲劳、眼肌麻痹.血空腹乳酸或运动后乳酸升高23例(67.6%).32例头颅MRI异常的患者最常见的受累部位依次为枕叶、顶叶、颞叶、基底节、额叶、小脑和深部白质.32例患者行肌肉活检,有阳性发现的共24例(75%),阴性的8例(25%).14例患者行基因检查,9例发现A3243G位点突变,5例未发现该位点突变.结论 认识MELAS的各种临床表现,争取在卒中样发作出现前早期诊断是完全可行的.     

线粒体脑肌病伴高乳酸血症和卒中样发作综合征的肌肉病理和电镜特征

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的肌肉病理和电镜特征。方法收集2013年1月-2019年1月郑州大学第五附属医院和郑州大学第一附属医院经肌肉病理和基因测序同时确诊的33例MELAS综合征的资料,对他们肌肉病理和电镜结果进行回顾性分析。结果光镜下25例改良Gomori染色可见破碎红纤维; 28例SDH染色可见破碎蓝纤维,氧化酶活性明显增高; 26例可见肌间小动脉血管壁深染(strongly succinatedehydrogenase-reactive,SSV),即SSV现象,其中2例未见到破碎蓝纤维和破碎红纤维; 22例COX染色光镜下见到氧化酶活性消失或减低,即COX阴性肌纤维。15例患者行电镜检查,均可见到线粒体的数量和结构异常,线粒体内结晶样包涵体呈"停车场"样排列。结论破碎红纤维(RRF)、SSV现象和COX阴性肌纤维是MELAS综合征主要的肌肉活检病理改变;线粒体内结晶样包涵体呈"停车场"样排列是MELAS综合征电镜的典型改变,这些特征对MELAS综合征的诊断具有十分重要的价值。     

伴消化系统症状的成年型线粒体脑肌病伴乳酸血症和卒中样发作一例

线粒体脑肌病伴乳酸血症和卒中样发作(MELAS)是线粒体脑肌病中最为常见的临床类型,是以乳酸血症和卒中样发作为特征的脑和肌肉能量代谢障碍综合征.患者临床表现复杂多样,易被误诊为脑炎、脑梗死、癫痢、多发性肌炎、重症肌无力等疾病.笔者报告l例首诊被误诊为"脑梗死",后经肌肉组织活检和基因检测等证实为MELAS型线粒体脑肌病的病例,并结合文献对该病进行分析及讨论.     

Mitochondrial Encephalopathy With Lactic Acidosis and Stroke-like Episodes (MELAS) May Respond to Adjunctive Ketogenic Diet

BackgroundMitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome can present management challenges. Refractory seizures and stroke-like episodes leading to disability are common.PatientWe analyzed the clinical, electrophysiologic, and radiologic data of a 22-year-old woman with multiple episodes of generalized and focal status epilepticus and migratory cortical stroke-like lesions who underwent muscle biopsy for mitochondrial genome sequencing.ResultsAlthough initial mitochondrial genetic testing was negative, muscle biopsy demonstrated a mitochondrial DNA disease-causing mutation (m.3260A > G). New antiepileptic medications were added with each episode of focal status epilepticus with only temporary improvement, until a modified ketogenic diet and magnesium were introduced, leading to seizure freedom despite development of a new stroke-like lesion, and subsequent decrease in frequency of stroke-like episodes. We propose a metabolic model in which the ketogenic diet may lead to improvement of the function of respiratory chain complexes.ConclusionsThe ketogenic diet may lead to improvement of mitochondrial dysfunction in MELAS, which in turn may promote better seizure control and less frequent stroke-like episodes.     

Hyperthyroidism associated with papilloedema and pyramidal tract involvement

Summary In a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes [MELAS] who had normal mitochondrial enzyme activity, high doses of coenzyme Q₁₀ (CoQ) were administered. Clinical improvement with decreased serum lactate and pyruvate levels was observed. Though the mechanism of action of CoQ is not known, a trial is worthwhile in patients with MELAS.     

A 4–base pair deletion in the mitochondrial cytochrome b gene associated with parkinsonism/MELAS overlap syndrome

Five patients with diminished activity of complex III of the mitochondrial respiratory chain have been screened for mutations in the mitochondrial cytochrome b (cyt b) gene. In 1 patient, a young boy with an akinetic rigid syndrome and a mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), a novel 4–base pair deletion was identified. This mutation in this highly conserved gene is considered to be pathogenic since it is a heteroplasmic frame shift mutation predicted to lead to a truncated protein. Ann Neurol 1999;45:130–133     

Acute hearing loss in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS)

The mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare congenital disorder of mitochondrial DNA. Patients with this syndrome may present acute onset of sensorineural hearing loss, which is genetic in origin. An impression of the MELAS syndrome is favored because hearing loss is part of the syndrome for some patients with epilepsy. We report a 20-year-old man who suffered from acute onset of bilateral hearing loss with epilepsy and two stroke-like events which recovered without any sequela. Epilepsy with complex partial seizures was controlled by antiepileptic drugs. Brain magnetic resonance images showed high signal lesions in bilateral temporal lobes. Serum levels of pyruvate and lactate were elevated. Muscle biopsy showed ragged-red fibers and molecular genetic study showed a point mutation of the mitochondrial A3243G gene. Mitochondrial disease with the MELAS syndrome was diagnosed and then he was treated with Co-enzyme Q10 and carnitine. The symptoms recovered gradually.     

CPEO and carnitine deficiency overlapping in MELAS syndrome

Mitochondrial myopathy, encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is one of the mitochondrial encephalomyopathies that has distinct clinical features including stroke-like episodes with migraine-like headache, nausea, vomiting, encephalopathy and lactic acidosis. We report a 27-year-old woman who presented with partial seizure, stroke-like episodes including hemiparesis, hemianopia and hemihypethesia, sensorineural hearing loss, migraine-like headache, and lactic acidosis. Brain computed tomographic scan showed encephalomalacia in the right parieto-occipital area and recent hypodensity in the left temporoparieto-occipital area with cortical atrophy. Muscle biopsy revealed ragged-red fibers and paracrystaline inclusions in the mitochondria. Genetic study revealed an A to G point mutation at nucleotide position (np) 3243 of mitochondrial DNA. External ophthalmoplegia and ptosis were also found during two exaggerated episodes in this patient. Therefore, the overlapping syndrome of chronic progressive external ophthalmoplegia in the MELAS syndrome is considered in this case. Furthermore, we also found carnitine deficiency in this patient and she was responsive well to steroid therapy. Muscle biopsy also revealed excessive lipid droplets deposits. Therefore, the carnitine defiency may occur in MELAS syndrome with the A to G point mutation at np 3243. We recommend the steroid or carnitine supplement therapy be applied to the MELAS syndrome with carnitine deficiency.     

Linear cortical cystic lesions: Characteristic MR findings in MELAS patients

BackgroundMitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a progressive neurodegenerative disorder with stroke-like lesions. The common MRI findings are gyral swelling and high signal intensity on T2WI/FLAIR images crossing the vascular territories. We have observed a linear cystic lesion and a laminar necrosis in the affected cortices of MELAS patients. Herein, we evaluated these cortical MRI findings in each subtype of mitochondrial disease.Patients and methodsWe retrospectively reviewed the MRI findings of 71 consecutive patients with clinically and genetically confirmed mitochondrial diseases. The cortical cystic lesions and laminar necrotic lesions were evaluated on T1, T2, and FLAIR images in each subtype of mitochondrial disease, as were their clinical and other imaging characteristics.ResultsThe cortical cystic lesion was observed in 21 of the 71 patients (29.6%) with mitochondrial diseases. Laminar necrosis was detected in only three patients (4.2%). MELAS was the most frequent subtype with cortical cystic lesions, accounting for 81.0%, and all showed the linear pattern except for one patient whose pattern was beaded-like.ConclusionA cortical linear cystic lesion was a common MRI finding in our series of patients with mitochondrial disease, especially in those with MELAS, but laminar necrosis was not. These findings can help differentiate MELAS from infarction.     

Vasogenic edema on MELAS: a serial study with diffusion-weighted MR imaging

The authors performed a serial study of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like syndrome (MELAS) who presented with diffusion-weighted MRI (DWI). DWI demonstrated a higher apparent diffusion coefficient in the lesion than in the control region during the acute stage of stroke. Vasogenic edema is present in stroke-like episodes in MELAS.     

Elevated thyroid peroxidase antibodies with encephalopathy in MELAS syndrome

Both the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) and Hashimoto's encephalopathy can present with nonspecific encephalopathy. Hashimoto's encephalopathy is an association of steroid-responsive encephalopathy with elevated thyroid peroxidase antibodies. Steroid-responsive encephalopathy, however, is not characteristic of the MELAS syndrome, which typically presents with stroke-like episodes and lactic acidosis in cerebrospinal fluid and blood. Here, a patient is described with goiter, recurrent encephalopathy and elevated thyroid peroxidase antibodies who apparently responded to steroid therapy; however, magnetic resonance imaging was atypical for Hashimoto's encephalopathy, and she was diagnosed with MELAS syndrome. This syndrome can present with apparent steroid-responsive encephalopathy and elevated thyroid peroxidase antibodies, mimicking Hashimoto's encephalopathy, and should be suspected if lactic acidosis is present and typical features are detected on magnetic resonance imaging.     

Is the mitochondrial complex I ND5 gene a hot‐spot for MELAS causing mutations?

We identified two novel heteroplasmic mitochondrial DNA point mutations in the gene encoding the ND5 subunit of complex I: a 12770A-->G transition identified in a patient with MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) and a 13045A-->C transversion in a patient with a MELAS/Leber's hereditary optic neuropathy/Leigh's overlap syndrome. Biochemical analysis of muscle homogenates showed normal or very mildly reduced complex I activity. Histochemistry was normal. Our observations add to the evidence that mitochondrial ND5 protein coding gene mutations frequently associate with the MELAS phenotype, and it highlights the role of complex I dysfunction in MELAS.     

MELAS--mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes syndrome--two cases confirmed by biochemical and molecular investigations. Differential diagnosis of stroke causes

Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes syndrome (MELAS) is a maternally inherited multisystem disease caused by mutations of the mitochondrial DNA. The characteristic clinical features are: encephalopathy manifesting as dementia and seizures, stroke-like episodes at young age (usually < 40), lactic acidosis and myopathy with ragged-red fibres. Other frequent manifestations include: sensorineural deafness, diabetes, hypoparathyroidism, peripheral neuropathy and cardiomyopathy. We present two patients with MELAS who were diagnosed 4 and 9 years respectively following the onset of the disease despite the characteristic clinical pictures. The differential diagnostics of inborn and acquired disorders causing stroke is included. We regard that mitochondrial diseases are still insufficiently known and are frequently misdiagnosed. The knowledge is indispensable for establishing diagnosis and accurate genetic counselling. Although there is no specific therapy for mitochondrial diseases to date, coenzyme Q and various vitamins as well as moderate degree exercise might be recommended.