10例平山病临床特征分析

目的:研究平山病(HD)患者的临床表现、神经电生理改变及颈部磁共振成像(MRI)特点.方法:对10例HD患者的临床表现、神经电生理特征及颈部MRI表现进行回顾性分析.结果:10例患者平均发病年龄(17.3±3.7)岁,均有大小鱼际肌、骨间肌及前臂远端肌群萎缩,呈斜坡样改变.肌电图检测提示患侧上肢远端肌肉呈神经原性损害,而患肢对侧肌肉萎缩较轻,对侧同名肌肉或上肢近端肌肉也呈神经原性损害改变.颈部MRI可见低位颈髓萎缩,其中以C6、C7明显;过屈位扫描时下段颈髓前移、变平,硬脊膜向前移位,脊髓后方硬膜下间隙增宽.结论:神经电生理检查在HD的早期诊断、鉴别诊断及疾病发展观察中起重要作用;颈部MRI检查为HD诊断提供可靠依据.     

平山病的临床、电生理及影像学特点

目的 探讨平山病的临床、电生理及影像学特点.方法 回顾性分析8例平山病患者的临床资料.结果 本组患者均为男性,发病年龄14～ 26岁;主要表现为上肢远端的肌无力和肌萎缩;6例为单侧上肢受累;部分肌萎缩使前臂呈现“斜坡”样的特殊形状.肌电图示局限于上肢相应阶段的脊髓前角细胞损害;颈椎自然位MRI示C5～T1椎体水平脊髓萎缩、变扁,过屈位MRI可见颈髓向前移位,硬脊膜外腔增宽.本组患者均采用颈托治疗并定期随访,病情均处于稳定状态.结论 平山病男性多见,一般20岁以前隐袭起病;主要表现上肢远端肌无力、肌萎缩;肌电图改变为下颈段脊髓前角损害;MRI示下颈段脊髓萎缩.     

平山病的临床、神经电生理及影像学特点

目的分析平山病的临床特征、神经电生理及影像学特点,以提高对平山病的诊断水平。方法分析15例平山病的患者临床、神经电生理、影像学资料。结果 1 15例均为青春期男性,均表现为上肢远端肌肉萎缩及无力,尺侧肌肉萎缩较重。单侧者12例,双侧者3例。8例手指伸展时出现震颤,6例伴寒冷麻痹;2肌电图均提示受累侧及对侧上肢远端肌肉神经源性受损,尺神经和正中神经分别有12例和3例复合肌肉动作电位(CMAP)波幅下降的现象;3颈髓MRI均可见颈髓下段轻度萎缩,3例髓内异常信号。过屈位颈MRI显示下段颈髓前移、变平,硬脊膜向前移位,硬脊膜外间隙内半月形信号影,11例在增宽的硬膜外腔见流空血管信号,6例增强扫描见硬脊膜外腔强化的静脉丛。结论在临床上遇到年青患者出现非对称性、局限于上肢远端肌群无力和萎缩时,应考虑平山病的诊断;神经电生理和颈髓MRI自然位+过屈位动态检查是诊断平山病的重要手段。     

平山病中心位及过屈位颈髓磁共振成像特点

目的 观察平山病颈部正常位及过屈位磁共振成像（MRI）特点,对平山病发病机制进行初步探讨。方法 20例确诊平山病患者进行正常位及过屈位颈段脊髓MRI检查。结果 20例患者经中立位颈髓MRI检查结果显示,其中10例下颈段脊髓存在萎缩变平现象且与萎缩侧肢体一致,萎缩节段以第6颈椎水平最明显。过屈位颈段MRI检查发现14例（70%）存在硬膜囊后壁前移现象,硬膜外腔内可见月牙形长T1长T2信号影,向前压迫脊髓;14例（70%）硬膜外腔内有异常扩张的血管流空信号,3例（15%）髓内有长T1长T2信号。结论 颈部前屈动力学改变以及血管因素可能在平山病发病机制中起一定作用。     

长期误诊的平山病1例报告

正平山病(Hirayama disease,HD)又称青年上肢远端肌萎缩症,1959年由日本平山惠等首先报道。HD是一种少见的良性自限性下运动神经元疾病,主要累及手和前臂,出现进行性加重的肌无力及肌萎缩,并有"寒冷麻痹"现象。其临床表现易与运动神经元病、多灶性运动神经病(multifocal motor neuropathy,MMN)等混淆,误诊率较高,需结合过屈位颈椎MRI、神经肌电图等检查方法予以鉴别。我科     

平山病的MRI诊断初探

目的研究平山病颈椎自然位和屈颈位MRI表现特点,了解该病的临床特征和发病机制,探讨MRI检查对此病的诊断价值。方法 6例经临床确诊的平山病患者,表现为上肢远端肌肉萎缩伴肌无力,5例单侧上肢萎缩无力,1例双侧不对称性受累。6例患者均行颈椎自然位MR平扫和屈颈位MR平扫及增强扫描。结果 6例患者在颈椎自然位MRI均可见颈椎生理曲度变直,4例下颈段脊髓萎缩变细;屈颈位MRI检查6例下颈段脊髓萎缩变细、前移,轴位示脊髓不同程度变扁平,硬膜囊向前移位,硬膜外间隙增宽,5例脊髓后硬膜外间隙可见异常信号影伴血管流空信号,增强扫描后明显强化。结论颈椎自然位和屈颈位MRI是诊断平山病的重要依据,尤其屈颈位MRI平扫及增强表现有其特征性。     

单肢肌萎缩/平山病:41例患者临床、电生理和颈椎MRI特征分析

目的 探讨单肢肌萎缩(MMA)/平山病患者的临床、肌电图及颈椎MRI特征。方法 2009年5月至2014年5月就诊本科,符合诊断标准的患者,连续登记并详细记录及分析人口学资料、临床、电生理和颈椎自然位和屈曲位MRI资料。结果(1)共41例,男39例、女2例,发病年龄14～24岁、平均年龄(16.87±2.62)岁。病程1～121月、平均病程(22.13±26.25)月。双上肢均有临床症状者6例(14.6%),症状局限单侧者35例(85.4%); 单侧者左12例(29.3%)、右23例(56.1%)。冷麻痹22例,指震颤9例,手麻木4例; 41例均有手固有肌萎缩,均无感觉障碍;(2)症状侧尺和正中神经运动潜伏期延长,小指展肌、拇短展肌运动波幅减低,小指展肌/拇短展肌波幅比值减小;(3)症状侧针肌电图显示异常自发活动者的出现率,在第一骨间肌和小指展肌为100%、拇短伸肌90.1%、拇短展肌86.3%、肱桡肌16.8%、肱二头肌13.8%; 在仅限于单侧症状的35例患者中,无症状侧手固有肌也显示异常自发活动者占51.4%;(4)32例患者完成颈椎MRI检查。自然位时32例均显示颈2-颈7椎体后方下缘连线与椎体相交; 均显示下段颈髓萎缩变扁平,其中位于C5-C7节段14例,C5-C6节段6例,C6-C7节段7例,C5-T1节段5例; 屈颈位时15例显示硬膜腔后壁前移,移位的硬膜后方可见硬膜外占位,内有流空信号,恢复自然位后占位消失。9例显示髓内可疑T₂异常高信号。结论 MMA/平山病主要见于青少年男性; 电生理表现为低位颈髓前角细胞病变,且无症状侧可显示临床下神经源性损害; 小指展肌/拇短展肌波幅比值减小,是有鉴别意义的电生理指标; 屈颈位颈椎MRI对于诊断很重要。结合临床、神经电生理及影像表现,有助于更全面认识本病。     

平山病的临床与神经电生理及颈椎磁共振特点分析

目的探讨平山病的临床、神经电生理与颈椎磁共振特点。方法收集11例平山病青少年患者资料,分析其临床、神经电生理与颈椎磁共振特征,总结规律。结果 11例患者发病年龄15~17岁,均隐匿起病,均以单侧上肢远端力弱、肌肉萎缩为主要临床表现,体格检查均可见大小鱼际肌、骨间肌为主肌群不同程度肌力下降、肌萎缩伴肌束震颤。神经传导速度检查可见尺神经及正中神经CMAP波幅降低,针电极肌电图可见运动单位时限增宽,波幅增高,并可见纤颤电位、正锐波等自发电位。颈椎磁共振可见下段颈髓受压变细并局部萎缩,过屈位磁共振可见迂曲条状血管流空影。结论平山病具有其独特的临床表现,需重视其诊断与早期治疗,神经电生理及颈椎磁共振检查尤其过屈位磁共振对于该病诊断具有重要价值。     

平山病11例临床特征分析

目的探讨平山病的临床特征,提高对平山病的诊断和治疗水平。方法回顾性分析自2011年1月~2014年6月徐州医学院附属医院就诊的11例平山病患者的临床资料,同时对相关文献进行回顾分析。结果本组患者中男性10人,女性1人,平均发病年龄为19.5岁(16~23岁),所有患者均表现为上肢远端的肌无力和肌萎缩,5例患者为单侧上肢受累(右上肢4例,左上肢1例),6例患者为双上肢受累,9例患者受累手指出现震颤,2例患者出现肌束颤动。肌电图示所有患者均呈慢性神经源性改变。颈椎MRI自然位9例患者出现脊髓萎缩,所有11例患者均出现颈椎生理曲度变直以及颈髓非对称性扁平,2例患者低位颈髓髓内出现高信号。颈椎MRI屈颈位显示10例患者出现背侧硬脊膜前移、硬脊膜外间隙增宽,9例患者硬膜外出现流空信号,所有11例患者硬膜外均出现新月形信号影,8例患者佩戴颈托,其中6例患者获益。结论平山病罕见,容易误诊,通过患者的临床表现、神经电生理检查、神经影像学检查(屈颈位MRI)可以确诊。平山病是自限性疾病,颈托通过限制颈椎前屈可能阻止疾病的进展,因此早期诊断十分重要。     

16例平山病临床特征分析

目的 分析平山病的临床特征,提高对平山病的认识,便于早诊断和早治疗.方法 回顾性分析16例确诊的平山病患者的临床表现、神经电生理特征及颈椎MRI资料.结果 患者均为青少年男性,平均发病年龄19.25岁.主要表现为局限于上肢远端的肌无力和肌萎缩.肌电图显示C7~T1神经支配区肌肉神经源性异常,运动单位电位时限增宽,波幅增高.屈颈位MRI显示所有病例下颈髓后方硬膜外间隙增宽,T2像可见新月形高信号影,相应脊髓受压前移变扁.结论 结合临床表现、神经电生理学及颈椎影像学检查可确诊平山病,其治疗以配戴颈托及患肢功能训练为主.     

10例平山病肌电图特点分析

目的:总结分析平山病的肌电图特点,为该病诊断与鉴别诊断提供神经电生理依据。方法:收集10例平山病患者临床、肌电图与常规和屈颈位MRI影像学资料,进行回顾性对比分析。结果:10例患者肌电图被检肌肉146块中78块异常,主要分布在C7-T1神经支配区,出现纤颤、正相自发电位,运动单位电位时限增宽、波幅增高。检测38条运动神经传导速度、36条感觉神经传导速度均在正常范围。结论:平山病的肌电图特点为下颈髓节段性前角损害,与屈颈位MRI显示的病变部位一致,对诊断与鉴别诊断具有临床实用价值。     

Imaging features in Hirayama disease

Purpose: To evaluate the MR findings in clinically suspected cases of Hirayama disease. Materials and Methods: The pre and post contrast neutral and flexion position cervical MR images of eight patients of clinically suspected Hirayama disease were evaluated for the following findings: localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature, loss of attachment between the posterior dural sac and subjacent lamina, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component with flow voids. The distribution of the above features in our patient population was noted and correlated with their clinical presentation and electromyography findings. Observations: Although lower cervical cord atrophy was noted in all eight cases of suspected Hirayama disease, the rest of the findings were variably distributed with asymmetric cord flattening, abnormal cervical curvature, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component seen in six out of eight (75%) cases. An additional finding of thoracic extension of the enhancing epidural component was also noted in five out of eight cases. Conclusion: Dynamic post contrast MRI evaluation of cervicothoracic spine is an accurate method for the diagnosis of Hirayama disease.     

Flexion myelopathy due to tic of neck

A 22-year-old male developed a tic of neck-flexion at the age of 14. The tic occurred 40 to 50 times per minute on its peak at age 16. Since then he noticed the atrophy and weakness of his both upper limbs. His right leg became weak at age 22. On admission, neurological examination revealed tic of lip and neck, severe muscle atrophy and weakness of bilateral upper limbs, mild muscle weakness and spasticity of right lower limb and hyperreflexia in four limbs. Needle EMG studies revealed fibrillation, positive sharp wave and giant MUP in the biceps, triceps and first interossei muscles. There were no abnormal findings suggesting cervical spondylosis or disc herniation on neck roentgenogram and neck MRI in neutral position. Neck MRI in the ventro-flexed position showed a flattening of the lower cervical cord and a band-like isointensity lesion in the posterior epidural space at C4-6. This isointensity lesion was considered to represent a congestion of the internal vertebral venous plexus. These findings suggest that frequent neck flexion by itself causes the injury of the lower cervical cord through (1) over-stretching of the cord, (2) compression of the cord by dural sac, (3) arterior ischemia, and/or (4) stagnant hypoxia due to venous congestion. Flexion myelopathy may represent one of the most important mechanisms of cervical cord injury accompanied with involuntary movement of neck.     

A case of monomelic amyotrophy of the upper limb: MRI findings and the implication on its pathogenesis

Monomelic amyotrophy of the upper limb or Hirayama disease is mostly considered as an anterior horn disorder resulting from local ischemia, triggered by arterial compression from an anterior shifting of the posterior cervical dura upon neck flexion. However, such a dural shifting is not universally seen. We report on a Caucasian male patient who developed a slowly progressive unilateral distal hand weakness in his teens. His clinical and electromyographic findings were consistent with Hirayama disease. Local anterior cervical cord atrophy was observed without dural shifting on the dynamic magnetic resonance imaging. Axial magnetic resonance imaging demonstrated signal changes of "snake-eye" appearance in the cervical anterior horn region, similar to ischemic myelopathies caused by various etiologies. This case illustrated that even without dural shifting, a mechanism of anterior spinal cord ischemia could still be responsible for the pathogenesis of Hirayama disease.     

Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremity

OBJECTIVE: To investigate specificity and significance of dynamic changes of the cervical dural sac and spinal cord during neck flexion in juvenile muscular atrophy of the distal upper extremity. BACKGROUND: The disorder affects young people-predominantly men-and is progressive for several years. One autopsy case showed ischemic necrosis of the cervical anterior horn, suggesting that the disorder is a type of cervical myelopathy. Some authors classify it as monomelic amyotrophy, implying that it is a focal motor neuron disease. METHODS: Neuroradiologic examinations including myelography, CT myelography, and MRI in a fully flexed neck position were performed on 73 patients with this disorder and on 20 disease control subjects. RESULTS: A distinctive finding in the disorder was forward displacement of the cervical dural sac and compressive flattening of the lower cervical cord during neck flexion. The forward displacement was significantly greater in patients with disease duration less than 10 years than in age-matched control subjects and patients in a late, nonprogressive stage. CONCLUSIONS: Radiologic abnormalities of the lower cervical dural sac and spinal cord support the hypothesis that this disorder is a type of cervical myelopathy.     

A case of Hirayama disease

We report a male patient with Hirayama disease aged 13. The disease was insidiously progressive and he had severe disability of the right hand at presentation. He had muscular atrophy in the intrinsic muscles of the right hand and in the distal muscles of the right forearm. The atrophy was pronounced on the ulnar side. Cold paresis was also noticed. There was no sensory disturbance. On Electromyography, neurogenic changes were recorded in several atrophic muscles. Motor and sensory nerve conduction was normal. MR images of the spinal cord were normal when it was performed with a conventional method (i.e., without neck flexion). However, characteristic MR findings were obtained when the patient lay with maximum neck flexion. The posterior wall of the cervical dural canal was shifted anteriorly at the C3-7 vertebral level, which caused cord compression at the lower cervical spinal canal. The epidural space was crescent-shaped and showed high signal intensity on T2-weighted imaging. These clinical features are typical of Hirayama disease. Pediatrician should be aware of this disease and treat it as soon as possible in order to prevent progression of the atrophy.     

Juvenile muscular atrophy of the distal upper limb (Hirayama disease) associated with atopy

Juvenile muscular atrophy of the distal upper limb (Hirayama disease) is a rare disease predominantly affecting the anterior horn cells of the cervical spinal cord in young men. Although the disease is considered to be a type of cervical myelopathy, the mechanism remains unknown. An immunological study of five consecutive patients with this disorder who were examined in the neurology clinic at Kyushu University Hospital during the past 2 years were performed. All developed distal muscular atrophy and weakness of one or both upper limbs in the second decade, and showed forward displacement of the dural sac and passive dilatation of the posterior venus plexus at the lower cervical portion on MRI during neck flexion. Four of the five patients had one or more coexistent airway allergies, such as allergic rhinitis, pollinosis, and asthma, and all five patients had a family history of atopic or allergic disorders in close relatives. Four of the five patients had mild eosinophilia. All five patients commonly had IgE specific to two mite antigens, Dermatophagoides pteronyssinus and Dermatophagoides farinae, whereas three of them also showed a raised total serum IgE concentration. The frequency of mite antigen specific IgE was significantly higher in the present patients with Hirayama disease than in 82 healthy controls (26/82, p<0.005). These findings suggest that atopy may be one of the contributing factors for Hirayama disease.     

A case of flexion myelopathy presenting juvenile segmental muscular atrophy of upper extremities--a successful treatment by cervical spine immobilization

A 24-year-old man was well until 1982, when he noticed weakness and atrophy of right arm especially those of biceps muscles. These symptoms did not progress until 1988. In 1988 weakness of left elbow flexion appeared and he was admitted to our hospital. On examination, he had weakness and atrophy of both upper extremities. Fasciculation was noticed in the proximal part of right arm. When his head was bent forward, dysesthesia appeared around radial side of his arm. There were no long tract sign or objective sensory loss. EMG showed neurogenic change over both his upper extremities. In plain cervical roentgenogram there existed abnormal kyphosis of cervical vertebrae. In MRI imaged with his neck flexed, cervical cord was compressed by the posterior surface of 4th cervical vertebral body, which corresponded to the top of cervical kyphosis. Based on these signs and examinations, a diagnosis of flexion myelopathy was made. Spinal immobilization by wiring and bone graft implantation ranging from C2 to C6 was performed to limit the range of anterior nuchal flexion. After this operation, improvement of muscle strength along with the disappearance of dysesthesia on neck flexion was observed. Clinically, this case closely resembles to juvenile type of distal and segmental muscular atrophy of upper extremities (Hirayama type). From our study, pathomechanism of this case seems to be a flexion myelopathy at C4 level. This view is supported also by the good recovery after the operation. This case suggests that nonprogressive atrophy of upper extremities due to flexion myelopathy can be successfully treated by cervical spine immobilization.     

Hirayama disease: an uncommon cause of distal upper extremity deficit

Hirayama disease is a myelopathy related to flexion movements of the neck that produce ischemic damage in the anterior horn of the cervical cord. The disease affects young people and is characterized by a distal upper extremity deficit that develops gradually. The diagnosis is confirmed by cervical magnetic resonance imaging (MRI) in flexion demonstrating a forward shift of the posterior dural sac and spinal cord compression. On radiology, there should be suggestive signs in neutral position such as cord atrophy, intramedullary bilateral high signal intensity on T2-weighted images, straightening of the cervical spine, and loss of attachment between the posterior dural sac and subjacent lamina. Exploration should be completed by an MR study in neck flexion. We report here on two typical cases of the disease and also include a review of the literature.