Clinical Features of Suspected Malignant Hyperthermia in China from 2015 to 2020: A Retrospective Study from China Malignant Hyperthermia Emergency Assistance Group

Abstract

Malignant hyperthermia (MH) is a rare but fatal pharmacogenetic disorder, triggered by inhalational anesthetics or succinylcholine. Since the first nonprofit academic organization China Malignant Hyperthermia Emergency Assistance WeChatbased Group (CMHEA Group) was established in 2015, they have actively participated in the diagnosis and treatment of MH patients. Based on the CMHEA Group, the aim of the study was to retrospectively analyze the characteristics of suspected MH in China from 2015 to 2020. Methods: We conducted a retrospective analysis of the suspected MH patients from 2015 to 2020, for analyzing the current clinical diagnosis, treatment and prognosis of MH in China.Results: A total of 58 suspected MH cases occurred from 2015 to 2020, of these, 36 cases were collected with detailed data. The MH clinical grading score of 36 patients ranged from 33 to 73, with a median of 55. Abnormal hyperthermia and hypercarbia were the most common early signs of MH. Four patients were confirmed carrying six different potential MH-causative mutations. Of the total 58 cases, 14 patients (24.1%) received dantrolene and the whole mortality rate was 53.4%. Compared to the patients not receiving dantrolene treatment, the survival rate of patients receiving dantrolene treatment was significantly higher than that of patients not receiving dantrolene (78.6% vs 36.4%, p = 0.007). Conclusion:The current main diagnostic methods of suspected MH in China are still clinical diagnosis. Hence, it is critical to keep dantrolene for immediate accessibility with the introduction of domestic dantrolene to China. The WeChat group model has played an important but limited role in quick diagnosis and treatment of MH.

Improving Dantrolene Mobilization in Regions with Limited Availability

“…From 2015 to 2020, a total of 58 suspected malignant hyperthermia (MH) cases were reported in mainland China with a mortality rate as high as 53.4%, 1 which was similar to the range reported in the predantrolene era in the United States. 2 Due to the low incidence of MH and the high cost of dantrolene, the stocking of the drug could constitute a significant economic challenge for hospitals.…”

The Anesthesiologists’ Perception of Malignant Hyperthermia and Availability of Dantrolene in China: A Cross-Sectional Survey

“… 9 A total of 58 suspected MH cases occurred from 2015 to 2020 were reported in a retrospective study. 6 It is worth noting that these figures likely underestimate the actual incidence of MH. Therefore, a nationwide MH registration institution should be established to standardize the management of MH cases, collect susceptibility information, and compile genetic data.…”

“… 5 A retrospective analysis of the suspected MH patients from 2015 to 2020 reported a mortality rate of 53.4%. 6 Lack of awareness concerning the availability and accessibility of the orphan drug dantrolene was considered to attribute to the high mortality rates with MH. Intravenous dantrolene was not available in mainland China until Oct 2020, however, the current reserve of domestic dantrolene is not clear.…”

Diagnosis and rescue of malignant hyperthermia induced by anesthesia during radical surgery in a cervical cancer patient using the National Remote Emergency System: A case report

“…From 1985 to October 2020, there were 136 MH cases in China, with a mortality rate of 55.9%. [8,9] The rapid deterioration poses a significant challenge for clinicians in terms of prompt diagnosis. The rarity of MH limits the familiarity of anesthesiologists with this disease, making timely diagnosis and appropriate treatment difficult to achieve.…”

“…In 2022, Tan et al analyzed the genetic testing results of 4 Chinese MH patients and identified 2 RYR1 mutations (c.5317C>T and c.12587T>C) and 1 CACNA1S mutation (c.5399T>C) in the same patient. [9] Therefore, we postulate that the mutation within the RYR1 gene may represent a potential pathogenic locus for MH. In individuals with MH, exposure to triggers such as inhalational anesthetics or depolarizing muscle relaxants causes abnormal RYR1 channels to release excessive calcium ions, resulting in severe muscle rigidity and hypermetabolism, ultimately leading to MH.…”