Matamala José Manuel, Cea Gabriel, Salinas Rodrigo, Vidal Aarón, López Ingeborg, Marileo Roberto, Stuardo Andrés
Departamento de Ciencias Neurológicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Servicio de Neurorradiología, Instituto de Neurocirugía Dr. Asenjo (INCA), Santiago, Chile.
Rev Med Chil. 2021 Jan;149(1):142-146. doi: 10.4067/S0034-98872021000100142.
Monomelic amyotrophy, also known as Hirayama disease, is a rare lower motor neuron syndrome due to localized lower motor neuron loss in the spinal cord at the cervical level. Clinically, monomelic amyotrophy is defined by the insidious onset of unilateral atrophy and weakness involving the hand and forearm, typically beginning in the second or third decade of life. We report 19-year-old man with a two years history of slowly progressive unilateral weakness and atrophy of his right-hand muscles. Neurological examination revealed weakness and atrophy in his intrinsic hand muscles, with sparing of the abductor pollicis brevis muscle. Also, mild atrophy of the ulnar aspect of the forearm was detected with sparing of the brachioradialis muscle. Electromyography showed active and chronic neurogenic changes affecting C8 and T1 myotomes, with mild chronic neurogenic changes on C7 myotome. Magnetic resonance imaging of his cervical spine revealed spinal cord atrophy involving C5 to C7 segments, associated with forward displacement of the posterior wall of the dura in cervical spine flexion. The clinical features associated with the imaging and electrophysiological findings support the diagnosis of monomelic amyotrophy.
单肢肌萎缩症，也称为平山病，是一种罕见的下运动神经元综合征，由于颈段脊髓局部下运动神经元丢失所致。临床上，单肢肌萎缩症的定义为隐匿起病，累及手部和前臂的单侧萎缩和无力，通常始于生命的第二个或第三个十年。我们报告一名19岁男性，有两年缓慢进展的右手肌肉单侧无力和萎缩病史。神经系统检查发现其手部固有肌无力和萎缩，拇短展肌未受累。此外，检测到前臂尺侧轻度萎缩，肱桡肌未受累。肌电图显示影响C8和T1肌节的活动性和慢性神经源性改变，C7肌节有轻度慢性神经源性改变。其颈椎磁共振成像显示脊髓萎缩累及C5至C7节段，与颈椎屈曲时硬脊膜后壁向前移位有关。与影像学和电生理检查结果相关的临床特征支持单肢肌萎缩症的诊断。
