The “split-leg” syndrome in ALS: specific or variable?

IF 2.5 4区 医学 Q2 CLINICAL NEUROLOGY Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration Pub Date : 2019-07-24 DOI:10.1080/21678421.2019.1643376
M. de Carvalho, M. Swash
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引用次数: 1

Abstract

The “split hand” in amyotrophic lateral sclerosis (ALS), first described by Wilbourn (1), is characterized by predominant atrophy and weakness of the thenar muscles, with relative sparing of the hypothenar muscles. This clinical observation was confirmed by neurophysiological studies, evaluating compound muscle action potential (CMAP) amplitude and the number of motor units (MUs) (2–4). A split-hand index has been proposed (4), with a cutoff value for the differential diagnosis between ALS versus non-ALS. The physiological basis for the split-hand phenomenon is not clear, but both cortical and peripheral mechanisms may be important (5). More recently, a “split-leg phenomenon” has been described, with a greater reduction in the number of MUs and CMAP in plantar flexors compared with dorsiflexors (6). However, subsequent studies have described predominant dorsiflexor weakness, contrary to the original report (7). We here describe an ALS patient with “splitleg” features in one leg, but with an inverted splitleg phenomenon in his opposite leg, implying a measure of inconsistency of the predominant pattern of distal lower limb (LL) involvement. A 63-year-old man followed in our ALS clinic in Lisbon for progressive LL weakness and atrophy presented 6 years ago with right foot-drop. LL weakness progressed proximally, with fasciculation and cramps in the legs, without pain or sensory loss. He is now able to walk only with foot orthoses and a cane. He has no bulbar, respiratory, or upper limb (UL) symptoms. On recent examination, proximal (MRC 4) and distal (MRC 0-2) segments of the LLs were weak and atrophic. In the right leg plantar flexion was MRC 2, but foot dorsiflexion was absent. In the left leg foot dorsiflexion was MRC 2, but plantar flexion was absent. The knee jerks were brisk (þþþ). The right ankle jerk was just present, but the left ankle jerk and both plantar responses were absent. Nociceptive and large fiber-dependent sensibility in LLs was normal. In the ULs there was no weakness or atrophy, but fasciculations were present in proximal and distal muscles bilaterally, and the tendon reflexes were brisk (þþþ). A Hoffman sign was detected on the right side. The bulbar region was normal. Brain and spinal-cord MRI and CSF analysis were unremarkable. Laboratory investigation excluded autoimmune disorders, and respiratory tests have been repeatedly normal. Current electrophysiological investigation shows normal motor conduction velocities were normal in ULs (both ulnar nerves), and normal sensory potentials in UL and LLs (ulnar, sural, and peroneal nerves, bilaterally). LL motor conduction studies are summarized in Table 1. Needle electromyography (EMG) of the ULs confirmed the presence of fasciculation potentials in proximal (biceps) and distal (first dorsal interosseous) muscles, associated with chronic neurogenic changes in first dorsal interosseous muscles. In the LLs, frequent complex fasciculation potentials and very unstable MUs were detected in both vastus medialis muscles, with marked neurogenic changes. Fibrillation and sharp-waves were detected in tibialis anterior and gastrocnemius medialis bilaterally, but motor unit potentials were not recruited in right tiabilis anterior, extensor digitorum brevis, or in left gastrocnemius medialis and abductor hallucis. However, a few very polyphasic and unstable motor units with very high
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肌萎缩性侧索硬化症的“裂腿”综合征:特异性还是变异性?
Wilbourn(1)首次描述了肌萎缩性侧索硬化症(ALS)的“裂手”,其特征是大鱼际肌肉主要萎缩和无力,而小鱼际肌肉相对较少。这一临床观察得到了神经生理学研究的证实,评估了复合肌肉动作电位(CMAP)振幅和运动单位数(MUs)(2-4)。有人提出了一个断手指数(4),该指数具有一个临界值,可用于ALS与非ALS的鉴别诊断。劈手现象的生理基础尚不清楚,但皮质和外周机制可能很重要(5)。最近,一种“劈腿现象”被描述,与背屈肌相比,足底屈肌的MUs和CMAP数量更少(6)。然而,随后的研究描述了主要的背屈肌无力,与最初的报道相反(7)。我们在这里描述了一位单侧腿有“劈腿”特征的ALS患者。但他的另一条腿有倒劈腿现象,这意味着下肢远端(LL)受累的主要模式不一致。一名63岁男性因6年前出现右脚下垂的进行性下肢无力和萎缩来到我们里斯本的ALS诊所。下肢近端无力进展,伴腿肌束和痉挛,无疼痛或感觉丧失。他现在只能靠脚矫形器和拐杖走路。他没有球、呼吸或上肢(UL)症状。在最近的检查中,LLs的近端(mrc4)和远端(mrc0 -2)节段虚弱和萎缩。右腿足底屈曲mrc2,但足背屈曲无。左腿足背屈曲mrc2,足底屈曲无。膝盖的抽搐很轻快(þþ)。右脚踝抽搐只是存在,但左脚踝抽搐和两个足底反应不存在。伤害性和大纤维依赖性敏感性在LLs中是正常的。在ULs中,没有虚弱或萎缩,但双侧近端和远端肌肉存在束状带,肌腱反射轻快(þ)。在右边发现了霍夫曼的标志。球区正常。脑、脊髓MRI及脑脊液分析无明显差异。实验室检查排除自身免疫性疾病,呼吸系统检查多次正常。目前的电生理调查显示,ULs(双侧尺神经)的运动传导速度正常,ULs和LLs(双侧尺神经、腓肠神经和腓神经)的感觉电位正常。表1总结了LL运动传导研究。ULs的针肌电图(EMG)证实在近端(二头肌)和远端(第一背骨间肌)肌肉中存在束状电位,与第一背骨间肌的慢性神经源性改变有关。在LLs中,双股内侧肌检测到频繁的复杂束状电位和非常不稳定的MUs,并伴有明显的神经源性改变。双侧胫前肌和腓肠肌内侧肌可见纤颤和锐波,但右侧胫前肌、趾短伸肌、左侧腓肠肌内侧肌和外展幻觉肌未见运动单位电位。然而,一些非常多相和不稳定的运动单位具有非常高的
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来源期刊
CiteScore
5.40
自引率
10.70%
发文量
64
期刊介绍: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration is an exciting new initiative. It represents a timely expansion of the journal Amyotrophic Lateral Sclerosis in response to the clinical, imaging pathological and genetic overlap between ALS and frontotemporal dementia. The expanded journal provides outstanding coverage of research in a wide range of issues related to motor neuron diseases, especially ALS (Lou Gehrig’s disease) and cognitive decline associated with frontotemporal degeneration. The journal also covers related disorders of the neuroaxis when relevant to these core conditions.
期刊最新文献
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