Lịch sử và giúp kiểm tra thần kinh ở địa hóa các tổn thương đến một thành phần cụ thể của đơn vị động cơ. Tiến bộ yếu kém có thể là do rối loạn sau đây: • các tế bào sừng phía trước, chẳng hạn như teo cơ bắp cột sống, bệnh tế bào thần kinh khác của động cơ. • | 172 18. Pediatric Neuromuscular Disorders Localization and Differential Diagnosis The history and neurological examination help in localizing the lesion to a specific component of the motor unit. Progressive weakness can be due to disorders of the following Anterior horn cells such as spinal muscular atrophy or other motor neuron diseases. Peripheral nerves such as hereditary or acquired idiopathic metabolic infectious and inflammatory neuropathies . Neuromuscular junction such as myasthenia gravis. Muscle such as muscular dystrophies congenital metabolic or inflammatory myopathies. The history and neurological examination help localize to a disorder of the muscles. Gait abnormality can be caused by proximal or distal lower extremity weakness. In the vignette there is clear indication of proximal muscle weakness. With proximal weakness the pelvis is not stabilized and waddles from side to side as the child walks Fenichel 1997 . Lumbar lordosis and protuberance of the abdomen are due to weakness of the abdomen back and pelvic girdle muscles. Progressive proximal weakness of insidious onset in children is often an indication of an underlying myopathic process in particular a muscular dystrophy preferred diagnosis . On the other hand juvenile spinal muscular atrophy which is a neurogenic process involving the anterior horn cells also manifests with progressive proximal weakness predominantly affecting the lower extremities lumbar lordosis and a waddling gait. Juvenile SMA has other distinctive clinical features including minipolymyoclonus that can be prominent fasciculations of the tongue signs of bulbar involvement variable reflexes and extensor plantar responses in some cases. Neurogenic and myopathic processes can usually be differentiated by the clinical features and also by diagnostic studies particularly needle EMG and muscle biopsy. Disorders of the neuromuscular junction such as juvenile myasthenia gravis are easily clinically excluded by the case presented in
