平山病患者的临床、肌电图和磁共振研究

Prospective study of clinical,electromyographic and MRI features in patients with Hirayama disease

目的探讨平山病(HD)患者的临床表现、肌电图和磁共振(MRI)特点。方法收集2009-05-2012-02收治的HD患者的人口学资料、临床表现、电生理和颈椎MRI表现,并进行分析。另设年龄、性别匹配的健康对照组进行电生理检查。结果 (1)HD患者共25例,均为男性,年龄15～24岁,平均年龄(17.64±2.20)岁。临床表现局限于单侧者22例,其中右侧15例、左侧7例;双侧者3例。手或/和前臂肌肉萎缩25例,冷麻痹13例,手指震颤5例。(2)有临床表现侧小指展肌和拇短展肌肌肉电位波幅均减低,且二者波幅比值减小。(3)异常自发活动出现率在第一骨间肌和小指展肌100%、拇短伸肌89.3%、拇短展肌85.7%;在单侧有临床表现的22例中,11例(50%)患者的无症状侧显示异常自发活动。(4)完成MRI扫描的14例中,自然位均显示第2～7颈椎体后方下缘连线与椎体相交、下段颈髓萎缩变扁平;屈曲位时硬膜腔后壁前移7例。结论 HD多见于男性,以右侧多发。结合临床、肌电图以及影像学表现,有助于临床更全面认识HD。

Objective To investigate prospectively the characteristics of clinical manifestations, electromyography （EMG） and cervical MRI in patients with Hirayama disease （HD）. Methods The consecutive HD patients referral to our department form 2009-05 to 2012-02 were registered; and the demographic data, clinical presentations, electrophysiological and cervical MRI findings were recorded in details. Electrophysiological examination was adopted in the age and gender-match control group. Results （1） There were totally 25 patients, and all were males with the age range of 15-24 years old and （17.64 ± 2.20） years on average. 22 patients show unilateral （15 on the left and 7 the right side） and 3 show bilateral involvement. Muscls atrophy was observed in hand or/and forearm in all 25 cases; cold paresis was noted in 13 cases and tremulous movement of the extended fingers in 5. （2） On the affected side, compound muscle action potential （CMAP） amplitude of abductor digiti minimi （ADM） and abductor pollicis brevis （APB） decreased and the mean ADM/APB ratio decreased. （3） The incidence rate of abnormal spontaneous activity （AbSA） shown by needle EMG in the first interosseous muscle was 100%, ADM 100%, extensor pollicis brevis 89.3% and APB 85.7%; among 22 cases with unilateral involvement, there were 50% patients revealing AbSA on the asymptomatic side. （4） Among the 14 patients who performed cervical MRI, MRI revealed part of the vertebral body met or crossed the line drawn from the dorsocaudal aspect of C2 through C7 and lower cord atrophy in all cases with neutral- position of neck; anterior shifting of the posterior dura in 7 cases with neck flexion. Conclusions HD is found mainly in male adolescent, with more frequently involvement of right upper extremity. EMG shows lesions of anterior horn cells at the level of low cervical cord, and subclinical neurogenic damage may occur on the asymptomatic side. The decreased ADM/APB CMAP ratio is a meaningful electrophysiological parameter in patients with HD. The cervical MRI findings may help to choose an alternative measure of intervention. The comprehensively analysis of findings in the clinical, EMG and imaging helps us to fully recognize HD.