PDF(Pubmed)
Abstract：
BACKGROUND: Paramyotonia congenita (PMC) stands as a rare sodium channelopaty of skeletal muscle, initially identified by Eulenburg. The identification of PMC often relies on electromyography (EMG), a diagnostic technique. The child\'s needle EMG unveiled trains of myotonic discharges with notably giant amplitudes, alongside irregular wave trains of myotonic discharges. This distinctive observation had not surfaced in earlier studies.
METHODS: We report the case of a 3-year-old female child with PMC, who exhibited laryngeal stridor, muffled speech, myotonia from birth. Cold, exposure to cool water, crying, and physical activity exacerbated the myotonia, which was relieved in warmth, yet never normalized. Percussion myotonia was observable in bilateral biceps. Myotonia symptoms remained unchanged after potassium-rich food consumption like bananas. Hyperkalemic periodic paralysis was excluded. Cranial magnetic resonance imaging yielded normal results. Blood potassium remained within normal range, while creatine kinase showed slight elevation. Exome-wide genetic testing pinpointed a heterozygous mutation on chromosome SCN4A: c.3917G>A (p.G1306E). After a six-month mexiletine regimen, symptoms alleviated.
CONCLUSIONS: In this case revealed the two types of myotonic discharges, and had not been documented in other studies. We underscore two distinctive features: Giant-amplitude potentials and irregular waves.
METHODS: We report the case of a 3-year-old female child with PMC, who exhibited laryngeal stridor, muffled speech, myotonia from birth. Cold, exposure to cool water, crying, and physical activity exacerbated the myotonia, which was relieved in warmth, yet never normalized. Percussion myotonia was observable in bilateral biceps. Myotonia symptoms remained unchanged after potassium-rich food consumption like bananas. Hyperkalemic periodic paralysis was excluded. Cranial magnetic resonance imaging yielded normal results. Blood potassium remained within normal range, while creatine kinase showed slight elevation. Exome-wide genetic testing pinpointed a heterozygous mutation on chromosome SCN4A: c.3917G>A (p.G1306E). After a six-month mexiletine regimen, symptoms alleviated.
CONCLUSIONS: In this case revealed the two types of myotonic discharges, and had not been documented in other studies. We underscore two distinctive features: Giant-amplitude potentials and irregular waves.
摘要：
背景：先天性副肌强直（PMC）是一种罕见的骨骼肌钠通道，最初由Eulenburg识别。PMC的识别通常依赖于肌电图（EMG），诊断技术.孩子的针头肌电图揭示了一系列肌强直性放电，其幅度特别大，与肌强直放电的不规则波列一起。这种独特的观察结果在早期的研究中没有出现。
方法：我们报告一例3岁女性儿童患有PMC，表现出喉鸣，低沉的演讲，从出生起的肌强直。冷,暴露在冷水中，哭泣,体力活动加剧了肌强直，在温暖中得到了解脱，但从未正常化。双侧肱二头肌可观察到打击乐肌强直。在食用香蕉等富含钾的食物后，肌强直症状保持不变。排除高钾血症性周期性麻痹。颅磁共振成像结果正常。血钾保持在正常范围内,而肌酸激酶显示轻微升高。全外显子组遗传检测在SCN4A染色体上发现了杂合突变：c.3917G>A（p。G1306E)。经过6个月的美西律治疗,症状缓解。
结论：在这种情况下，揭示了两种类型的肌强直放电，并且在其他研究中没有记录。我们强调了两个显着特征：巨幅电位和不规则波。
方法：我们报告一例3岁女性儿童患有PMC，表现出喉鸣，低沉的演讲，从出生起的肌强直。冷,暴露在冷水中，哭泣,体力活动加剧了肌强直，在温暖中得到了解脱，但从未正常化。双侧肱二头肌可观察到打击乐肌强直。在食用香蕉等富含钾的食物后，肌强直症状保持不变。排除高钾血症性周期性麻痹。颅磁共振成像结果正常。血钾保持在正常范围内,而肌酸激酶显示轻微升高。全外显子组遗传检测在SCN4A染色体上发现了杂合突变：c.3917G>A（p。G1306E)。经过6个月的美西律治疗,症状缓解。
结论：在这种情况下，揭示了两种类型的肌强直放电，并且在其他研究中没有记录。我们强调了两个显着特征：巨幅电位和不规则波。
