Abstract
Purpose
In 1992. 1812 individuals (1.2% of the population) were labelled at risk for malignant hyperthermia (MH) in seven families from Abitibi-Témiscamingue. 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 still considered possibly at rsk. Finally, one family (402 individuals) is highly at risk and two other families are probably at risk. Family trees did not show any link up to the colonization of Abitibi-Témiscamingue in the beginning of this Century but common ancestors were found around the 9th generation.
Conclusion
This clinical reassessment will help to focus education and prevention on a much smaller group of individuals 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.
Résumé
Objectifs
En 1992, 1812 individus (soit 1.2% de la population) étaient étiquetés comme susceptibles à l’hyperthermie maligne (HM) dans sept familles de l’Abitibi-Témiscamingue. Afin d’évaluer le risque réel de cette population, une étude multidisciplinaire fut initiée incluant les volets clinique, généalogique et moléculaire. Cet article présente les aspects cliniques de cette étude.
Méthode
Pour chacun des 1546 individus rejoints, toutes les procédures anesthésiques furent évaluées afin de retrouver des signes révélateurs d’HM. Les épisodes d’HM furent examinés à l’aide d’une échelle de gradation clinique Les 44 rapports révisés de tests de contracture caféine-halothane furent pris en considération. Finalement, une étude généalogique de chaque ascendance, jusqu’aux premiers arrivants français, fut menée afin d’identifier les liens entre ces sept families à travers des ancêtres communs.
Résultats
Suite à la révision clinique, les families furent comparées et classées en quatre groupes. Deux families (1097 individus) ne sont pas considérées plus à risque que la population en général. Deux autres families sont encore considérées comme ayant un nsque possible. Finalement, une famille (402 individus) est considérée hautement à risque et deux autres families sont classées comme ayant un nsque probable. L’examen des ascendances montre qu’on ne retrouve pas d’ancêtres communs aux cas avant la 9th génération. Ces ancêtres communs ne sont pas onginaires de la région: en effet, celle-d a été ouverte à la colonisation vers 1900 soit depuis 3–4 générations seulement.
Conclusion
Cette révision clinique permettra de concentrer l’éducation et la prévention vers un groupe d’individus encore considéré potentiellement à nsque pour l’HM. En évaluant mieux les divers phénotypes. en combinaison avec l’utilisation d’une approche généalogique, il sera possible de cibler les meilleures families pour la recherche en génétique moléculaire.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Britt BA. Malignant hyperthermiaa review.In: Schönbaum E, Lomax P (Eds.). Thermorégulation: Pathology, Pharmacology and Therapy. New York: Pergamon Press Inc., 1991: 179–92.
Gronert GA, Antognini JF. Malignant hyperthermia.In: RD Miller (Ed.). Anesthesia, 2nd ed. New York: Churchill Livingstone, 1986: 1075–93.
MacLennan DH, Duff C, Zorzato F, et al. Ryanodine receptor gene is a candidate for predisposition to malignant hyperthermia. Nature 1990; 343: 559–61.
Levitt RC, Olckers A, Meyers S, et al. Evidence for the localization of a malignant hyperthermia susceptibility locus (MHS2) to human chromosome 17q. Genomics 1992; 14: 562–6.
Iles DE, Lehmann-Horn F, Scherer SW, et al. Localization of the gene encoding the α2/δ-subunits of the L-type voltage-dependent calcium channel to chromosome 7q and analysis of the segregation of flanking markers in malignant hyperthermia susceptible families. Hum Mol Genet 1994; 3: 969–75.
Sudbrak R, Procaccio V, Klausnitzer M, et al. Mapping of a further malignant hyperthermia susceptibility locus to chromosome 3q13.1. Am J Hum Genet 1995; 56: 684–91.
Levitt RC. Prospects for the diagnosis of malignant hyperthermia susceptibility using molecular genetic approaches. Anesthesiology 1992; 76: 1039–48.
MacLennan DH. Discordance between phenotype and genotype in malignant hyperthermia. Curr Opin Neurol 1995; 8: 397–401.
Larach MG, for the North American Malignant Hyperthermia Group. Standardization of the caffeine halothane muscle contracture test. Anesth Analg 1989; 69: 511–5.
Laracb MG, Localio AR, Allen GC, et al. A clinical grading scale to predict malignant hyperthermia susceptibility. Anesthesiology 1994; 80: 771–9.
Sato N, Brum JM, Mitsumoto H, DeBoer GE. Effects of cocaine on the contracture response to 1% halothane in patients undergoing diagnostic muscle biopsy for malignant hyperthermia. Can J Anaesth 1995; 42: 158–62.
Islander G, Henriksson K-G, Ranklev-Tivetman E. Malignant hyperthermia susceptibility without central core disease (CCD) in a family where CCD is diagnosed. Neuromuscul Disord 1995; 5: 125–7.
Fletcher JE, Rosenberg H, Pathophysiology of malignant hyperthermia.In: Hopkins PM, Ellis FR (Eds.). Hyperthermic and Hypermetabolic Disorders. Cambridge: Cambridge University Press. 1996: 132–56.
West SP. Genetics of malignant hyperthermia.In: Hopkins PM, Ellis FR (Eds.). Hyperthermic and Hypermetabolic Disorders. Cambridge: Cambridge University Press. 1996: 184–201.
Larach MG, Landis JR, Shirk SJ, Diaz M, for The North American Malignant Hyperthermia Registry. Prediction of malignant hyperthermia susceptibility in man: improving sensitivity of the caffeine halothane contracture test. Anesthesiology 1992; 77: A1052.
Author information
Authors and Affiliations
Additional information
This study was supported by a grant from Hydro-Québec/Fonds de la recherche en santé du Québec.
Rights and permissions
About this article
Cite this article
Bachand, M., Vachon, N., Boisvert, M. et al. Clinical reassessment of malignant hyperthermia in Abitibi-Témiscamingue. Can J Anaesth 44, 696–701 (1997). https://doi.org/10.1007/BF03013380
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF03013380