BACKGROUND: 

Malignant hyperthermia (MH) is an inherited muscle disorder induced by volatile anesthetics and depolarizing muscle relaxants. While the incidence of MH is high in young, there are few reports on the clinical features of pediatric MH. In this study, we selected pediatric cases from an MH database and analyzed the clinical findings by age group. We hypothesized that there would be age-related differences in the clinical characteristics.

METHODS: 

A retrospective analysis of MH data collected in our database during 1960 to 2020 was performed to identify pediatric subjects (≤18 years) with a Clinical Grading Scale of ≥35, indicating “very likely” or “almost certain” MH. We compared clinical characteristics among the 0 to 24 month, 2 to 12 year, and 13 to 18 year (youngest, middle, and oldest, respectively) age groups.

RESULTS: 

Data were available for 187 patients: 15 in the youngest age group, 123 in the middle-aged group, and 49 in the oldest age group. Of these, 55 patients (29.4%) had undergone muscle biopsy and muscle contracture test. The mortality rates during the study period were 13.3%, 13.8%, 20.4%, and 15.5% in the youngest, middle, and oldest cohorts and overall, respectively. In contrast, the overall mortality rate from 2000 to 2020 was 8.8%. The most frequent initial symptoms of MH were elevated temperature (46.7%) and generalized muscular rigidity (26.7%) in the youngest cohort, masseter spasm (35.0%) and generalized muscular rigidity (19.5%) in the middle cohort, and elevated end-tidal carbon dioxide (26.5%) and tachycardia (22.4%) in the oldest cohort. Physical examination revealed that elevated temperature, sinus tachycardia, and respiratory acidosis occurred frequently in all groups. The middle cohort had high frequencies of masseter spasm (58.4%; P = .02) and dark urine (75.5%; P = .01) compared to those in the oldest groups, and had a higher peak creatine kinase level compared to those in the 3 groups. Skeletal muscle symptoms tended to be more common in patients administered succinylcholine (generalized muscular rigidity, P = .053; masseter spasm, P < .0001; dark urine, P < .0001). In particular, masseter spasm and dark urine were more common in the middle cohort when succinylcholine was administered (masseter spasm: versus youngest cohort, P = .06, versus oldest cohort, P = .027; dark urine: versus youngest cohort, P = .0072, versus oldest cohort, P = .0015).

CONCLUSIONS: 

The clinical characteristics of pediatric patients with MH vary according to age group. The difference in initial symptoms of MH depending on age group is noteworthy information for the early diagnosis of MH.

中文翻译：

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小儿恶性高热的年龄特异性临床特征：日本 60 年来 187 例病例回顾

背景： 

恶性高热（MH）是一种由挥发性麻醉剂和去极化肌肉松弛剂引起的遗传性肌肉疾病。虽然青年人MH的发病率较高，但有关儿童MH的临床特征的报道较少。在这项研究中，我们从 MH 数据库中选择了儿科病例，并按年龄组分析了临床结果。我们假设临床特征存在与年龄相关的差异。

方法： 

对我们数据库中 1960 年至 2020 年期间收集的 MH 数据进行回顾性分析，以确定临床分级量表≥35 的儿科受试者（≤18 岁），表明“很可能”或“几乎肯定”MH。我们比较了 0 至 24 个月、2 至 12 岁和 13 至 18 岁（分别为最小、中间和最大）年龄组的临床特征。

结果： 

可获得 187 名患者的数据：最年轻年龄组 15 名，中年组 123 名，最年长组 49 名。其中，55名患者（29.4%）接受了肌肉活检和肌肉挛缩测试。研究期间，最年轻、中等和最年长队列的死亡率以及总体死亡率分别为 13.3%、13.8%、20.4% 和 15.5%。相比之下，2000年至2020年的总体死亡率为8.8%。MH 最常见的初始症状是最年轻队列中的体温升高（46.7%）和全身性肌肉强直（26.7%），中间队列中的咬肌痉挛（35.0%）和全身性肌肉强直（19.5%），以及终末期升高。最老的队列中出现潮汐二氧化碳（26.5%）和心动过速（22.4%）。体格检查发现各组均频繁出现体温升高、窦性心动过速、呼吸性酸中毒等症状。与最年长的组相比，中间组的咬肌痉挛（58.4%；P = .02）和深色尿（75.5%；P = .01）的发生率较高，并且与最年长的组相比，其峰值肌酸激酶水平更高。 3组。骨骼肌症状在服用琥珀胆碱的患者中更为常见（全身肌肉僵硬，P = .053；咬肌痉挛，P < .0001；深色尿液，P < .0001）。特别是，当给予琥珀胆碱时，咬肌痉挛和深色尿液在中间队列中更为常见（咬肌痉挛：与最年轻队列相比，P = .06，与最老队列相比，P = .027；深色尿液：与最年轻队列相比，P = .0072，与最古老的队列相比，P = .0015）。

结论： 

MH 儿科患者的临床特征因年龄组而异。MH 初始症状随年龄组的差异是 MH 早期诊断的重要信息。