[Usefulness of electromyography in diagnostics of the neuro-muscular diseases].

INTRODUCTION

Electrophysiological examinations still play an important role in initial diagnostics of neuromuscular disorders and monitoring of the disease progress or recovery process.

AIM OF THE STUDY

Evaluation of neurophysiological examinations usefulness in differential diagnosis, indicating diagnostic and/or therapeutic management in patients with suspicion of neuromuscular disorders.

MATERIAL AND METHODS

109 patients were included, hospitalized at Department of Pediatric Neurology Jagiellonian University and treated at Neuromuscular, Neurologic, Orthopedic and Rehabilitation Outpatient Clinics of the Children's Hospital in Krakow. 6 groups of patients were indicated: I-11 patients with benign acute childhood myositis, BACM), II-18 children with gait disturbances, III-36 patients with suspicion of neuropathy, IV-11 patients hospitalized with suspicion of muscular disorders, V-18 children with SMA suspicion and V-15 patients with suspicion of myasthenia (MG). Neurophysiological examinations were conducted within 5 years (from May, 2004 to May, 2009) with Keypoint device from MedtronicDantec.

RESULTS

In the first group, EMG examination, performed in the acute phase of the disease, did not reveal any abnormalities. Indicators of inflammatory process were normal, however in 5 patients transient elevation of CK was found. Diagnosis of BACM in this group was established. Couple-month observation of children after BACM did not reveal deficits of muscular tone and strength, recurrence of the disease, or elevation of CK, despite consecutive respiratory tract infections. In 4/18 patients with gait disturbances EMG examination revealed abnormalities. In 1 patient myogenic injury of the muscles was found, in 3 conduction in motor fibers of examined peripheral nerves was disturbed. In 14/18 children EMG examination did not reveal any pathological changes. In 17/36 children from group III diagnosis of inflammatory neuropathy was established (Guillain-Barre Syndrome, GBS), in 2 chronic inflammatory demyelinating polyneuropathy, and in 2 others multifocal motor neuropathy with conduction block. In 7/36 patients familial sensory-motor polyneuropathy was diagnosed. Neuroboreliosis was cause of neuropathy in 2 children. In 1 child, segmental inflammation of anterior horns of the spinal cord evoked by Coxackie virus was revealed. Friedreich disease, Nieman-Pick disease, thoracic outlet syndrome was found in others. In 1 boy symptoms of polyneuropathy and encephaloptahy occurred in the course of tal intoxication. In group IV EMG examination showed myopathic injury of the muscles in 9 children. In 2 others the examination results were normal. Kearns-Syre syndrome was found in one of them and Duchenne disease in the second one, 16, 5 years old boy without pain complaints, Becker disease in 2 and in next 2 patients encephalopathy and in rare cases BaCM, congenital dystrophy and myotubular myopathy. SMA was diagnosed based on clinical manifestation and EMG examination in 18 patients. EMG examination showed lower motor neuron injury in every child with SMA type I and II. MG was diagnosed in 15 patients based on clinical manifestation and positive result of fatigability test. Ocular myasthenia was found in 2 patients, bulbar type of MG was found in 1 and systemic myasthenia in 12 children. In electrophysiological fatigability test amplitude of the first response was normal in every patient and decrease of amplitude in response 4:1 in patients with MG was from 26 to 88%.

CONCLUSIONS

Electromyographic examination remains important diagnostic tool of neuromuscular disorders. In order to limit extension of differential diagnostics EMG should be performed in its early stage.