Clinical reassessment of malignant hyperthermia in Abitibi-Témiscamingue

Abstract

Purpose: In 1992, 1812 individuals (I.2% of the population) were labelled at risk for malignant hyperthermia (MH) ~n seven families from Abitibi-Temiscamingue, To evaluate the effective risk in this population, a multidisciplinary study was undertaken which included clinical, genealogical and molecular aspects. This paper presents the clinical aspects of the study. Method: For each of the 1546 individuals reached, all anaesthetic exposures were screened for elements relevant to MH. Malignant hyperthermia events were analyzed with "the clinical grading scale." All 44 reports of caffeine halothane contracture tests were reappraised, Finally, a genealogical study was done to complete each family tree up to the initial French settlers in order to identify links between these seven families through common ancestors. Results: Following this reassessment, the families were compared and classified into four groups. Two families (1097 individuals) are not considered to be at a higher risk for MH than the population in general. Two families are styli considered possibly at risk. finally, one family (402 individuals) is highly at risk and two other families are probably at nsk. Family trees did not show any link up to the colonization of Abitibi-Temiscamingue in the beginning of this Century but common ancestors were found around the 9 th generation, Conclusion: Th~s chnical reassessment will help to focus education and prevention on a much smaller group of tndividuals still considered potentially at risk for MH, By adequate evaluation of phenotypes, combined with the use of a genealogical approach, it will be possible to target families for molecular research.Objectifs : En 1992, 1812 Jndividus (soit 1.2% de la population) 6taient etiquetes comme susceptibles fi I'hyperthermie maligne (HM) darts sept families de rAbitibi-Temiscamingue./kiln d'&aluer le risque reel de cette population, une etude multidisoplinaire rut initiee incluant les volets clinique, genealogique et moleculaire. Cet article presente les aspects cliniques de cette etude. M&hode : Pour chacun des 1546 individus rejoints, routes les procedures anesthesiques furent evaluees afin de retrouver des slgnes revelateurs d'HM, Les episodes d'HM furent examines ~. I'aide d'une 6chelle de gradation clinique. Les 44 rapports rews& de tests de contracture cafeine-halothane furent pris en consideration, Finalement, une etude genealogique de chaque ascendance, jusqu'aux premiers arnvants fran(jais, rut menee afin d'identifier les liens entre ces sept families & travers des anc&res communs, R~sultats : Suite ~ la rews~on clinique, les families furent comparees et classees en quatre groupes. Deux farnilles (I 097 individus) ne sont pas conslderees plus ~ risque que la population en general, Deux autres families sont encore consid&ees comme ayant un nsque possible, finalement, une famille (402 individus) est consid&ee hautement nsque et deux autres famtlles sont ctassees comme ayant un risque probable, rexamen des ascendances montre qu'on ne retrouve pas d'ancCtres commun...

Trends and Outcomes of Malignant Hyperthermia in the United States, 2000 to 2005

“…Geographic differences in the prevalence of MH susceptibility have been previously reported. 16,17 It is not clear if different geographical prevalence rates of MH susceptibility influence the rate of mortality from this condition. Our findings indicate that after adjusting for age, sex, comorbidities, and hospital characteristics, mortality was significantly higher in the south, as compared with the West and Northeast regions of the United States (table 4).…”

Prevalence of malignant hyperthermia diagnosis in obstetric patients in the United States, 2003 to 2014

“…We also observed a geographic variation in the prevalence of MH diagnosis, with an elevated prevalence in the South region. Geographical variation is explained by the concentration of MH families in a given geographic area [22]. Rosero et al also observed a higher prevalence of MH diagnosis in the South census region.…”

Malignant hyperthermia

“…A recent report suggested that the MH susceptible (MHS) trait may be present in 1:2,000–3,000 of the French population [6]. Bachand and colleagues examined the incidence of MH in Quebec, Canada, where many families had been biopsied [7]. They traced the pedigrees of the patients to the original immigrants from France and found an incidence of MH susceptibility of 0.2% in this province.…”