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Malignant Hyperthermia in PICU—From Diagnosis to Treatment in the Light of Up-to-Date Knowledge. CHILDREN 2022; 9:children9111692. [DOI: 10.3390/children9111692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/04/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Malignant Hyperthermia (MH) is a rare, hereditary, life-threatening disease triggered by volatile anesthetics and succinylcholine. Rarely, MH can occur after non-pharmacological triggers too. MH was detected more often in children and young adults, which makes this topic very important for every pediatric specialist, both anesthesiologists and intensivists. MH crisis is a life-threatening severe hypermetabolic whole-body reaction. Triggers of MH are used in pediatric intensive care unit (PICU) as well, volatile anesthetics in difficult sedation, status asthmaticus or epilepticus, and succinylcholine still sometimes in airway management. Recrudescence or delayed onset of MH crisis hours after anesthesia was previously described. MH can also be a cause of rhabdomyolysis and hyperpyrexia in the PICU. In addition, patients with neuromuscular diseases are often admitted to PICU and they might be at risk for MH. The most typical symptoms of MH are hypercapnia, tachycardia, hyperthermia, and muscle rigidity. Thinking of the MH as the possible cause of deterioration of a patient’s clinical condition is the key to early diagnosis and treatment. The sooner the correct treatment is commenced, the better patient´s outcome. This narrative review article aims to summarize current knowledge and guidelines about recognition, treatment, and further management of MH in PICU.
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Age-Specific Clinical Features of Pediatric Malignant Hyperthermia: A Review of 187 Cases Over 60 Years in Japan. Anesth Analg 2021; 135:128-135. [PMID: 34962895 DOI: 10.1213/ane.0000000000005837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
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.
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Cooper MG, Loadsman JA. The <i>Anaesthesia and Intensive Care</i> Jeanette Thirlwell Best Paper Award turns 21, and our first Junior Investigator Award. Anaesth Intensive Care 2019; 46:562-564. [PMID: 30447662 DOI: 10.1177/0310057x1804600603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | - J A Loadsman
- Senior Staff Specialist, Department of Anaesthetics, Royal Prince Alfred Hospital and Conjoint Associate Professor, Sydney Medical School, University of Sydney
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Beam TA, Loudermilk EF, Kisor DF. Pharmacogenetics and pathophysiology of CACNA1S mutations in malignant hyperthermia. Physiol Genomics 2016; 49:81-87. [PMID: 28011884 DOI: 10.1152/physiolgenomics.00126.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/14/2016] [Indexed: 12/27/2022] Open
Abstract
A review of the pharmacogenetics (PGt) and pathophysiology of calcium voltage-gated channel subunit alpha1 S (CACNA1S) mutations in malignant hyperthermia susceptibility type 5 (MHS5; MIM #60188) is presented. Malignant hyperthermia (MH) is a life-threatening hypermetabolic state of skeletal muscle usually induced by volatile, halogenated anesthetics and/or the depolarizing neuromuscular blocker succinylcholine. In addition to ryanodine receptor 1 (RYR1) mutations, several CACNA1S mutations are known to be risk factors for increased susceptibility to MH (MHS). However, the presence of these pathogenic CACNA1S gene variations cannot be used to positively predict MH since the condition is genetically heterogeneous with variable expression and incomplete penetrance. At present, one or at most six CACNA1S mutations display significant linkage or association either to clinically diagnosed MH or to MHS as determined by contracture testing. Additional pathogenic variants in CACNA1S, either alone or in combination with genes affecting Ca2+ homeostasis, are likely to be discovered in association to MH as whole exome sequencing becomes more commonplace.
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Affiliation(s)
- Teresa A Beam
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, Natural and Health Sciences, Fort Wayne, Indiana; and
| | - Emily F Loudermilk
- Department of Pharmaceutical and Biomedical Sciences, Ohio Northern University, College of Pharmacy, Ada, Ohio
| | - David F Kisor
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, Natural and Health Sciences, Fort Wayne, Indiana; and
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Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: a review. Orphanet J Rare Dis 2015; 10:93. [PMID: 26238698 PMCID: PMC4524368 DOI: 10.1186/s13023-015-0310-1] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 07/22/2015] [Indexed: 02/06/2023] Open
Abstract
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane, isoflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stressors such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:10,000 to 1: 250,000 anesthetics. However, the prevalence of the genetic abnormalities may be as great as one in 400 individuals. MH affects humans, certain pig breeds, dogs and horses. The classic signs of MH include hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, hyperkalaemia, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. An increase in end-tidal carbon dioxide despite increased minute ventilation provides an early diagnostic clue. In humans the syndrome is inherited in an autosomal dominant pattern, while in pigs it is autosomal recessive. Uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation leads to the pathophysiologic changes. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 400 variants have been identified in the RYR1 gene located on chromosome 19q13.1, and at least 34 are causal for MH. Less than 1 % of variants have been found in CACNA1S but not all of these are causal. Diagnostic testing involves the in vitro contracture response of biopsied muscle to halothane, caffeine, and in some centres ryanodine and 4-chloro-m-cresol. Elucidation of the genetic changes has led to the introduction of DNA testing for susceptibility to MH. Dantrolene sodium is a specific antagonist and should be available wherever general anesthesia is administered. Increased understanding of the clinical manifestation and pathophysiology of the syndrome, has lead to the mortality decreasing from 80 % thirty years ago to <5 % in 2006.
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Affiliation(s)
- Henry Rosenberg
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ, 07039, USA.
| | - Neil Pollock
- Department of Anesthesia and Intensive Care, Palmerston North Hospital, Palmerston North, New Zealand.
| | - Anja Schiemann
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
| | - Terasa Bulger
- Department of Anesthesia and Intensive Care, Palmerston North Hospital, Palmerston North, New Zealand.
| | - Kathryn Stowell
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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Heytens L, Forget P, Scholtès JL, Veyckemans F. The Changing Face of Malignant Hyperthermia: Less Fulminant, More Insidious. Anaesth Intensive Care 2015; 43:506-11. [DOI: 10.1177/0310057x1504300415] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Modern anaesthetic techniques have resulted in the clinical presentation of malignant hyperthermia to be more often indolent and/or insidious than truly fulminant, as previously known in the anaesthetic community. We present four recently referred cases to illustrate this point: one late-onset case, two patients with slowly progressive hypercapnia as the sole sign and a fourth patient with postoperative myalgias and elevated creatine kinase. We also discuss the reasons for the shift in typical clinical presentation. The more insidious character of malignant hyperthermia is most likely due to the lower triggering potency of modern volatile anaesthetics, the mitigating effects of several intravenous drugs (neuromuscular blocking agents, alpha 2 adrenergic receptor agonists, beta-adrenergic blockade) or techniques (neuraxial anaesthesia) and the routine use of end-tidal CO2 monitoring leading to the early withdrawal of triggering drugs. Awareness among anaesthetists of this change in presentation is important since the clinical diagnosis is often more doubtful and, if corroborative evidence is not sought, the diagnosis may be delayed or missed altogether.
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Affiliation(s)
- L. Heytens
- Department of Anaesthesiology, University Hospital Antwerp, Edegem, Belgium
| | - P. Forget
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Universitê Catholique de Louvain, Brussels, Belgium
| | - J. L. Scholtès
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Universitê Catholique de Louvain, Brussels, Belgium
| | - F. Veyckemans
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Universitê Catholique de Louvain, Brussels, Belgium
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Schuster F, Johannsen S, Moegele S, Metterlein T, Roewer N, Anetseder M. The effect of succinylcholine on malignant hyperthermia events in susceptible swine. BMC Anesthesiol 2014; 14:14. [PMID: 24606822 PMCID: PMC3973851 DOI: 10.1186/1471-2253-14-14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/05/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND While the impact of volatile anaesthetics to induce malignant hyperthermia (MH) is abundantly clear, the role of succinylcholine still remains controversial. To evaluate the influence of succinylcholine on porcine MH events, the authors investigated the hemodynamic and metabolic responses in MH susceptible (MHS) and non-susceptible (MHN) swine following either succinylcholine or halothane application alone or a combination of both substances. METHODS With approval of the local animal care committee 27 MHS and 30 MHN pigs were anaesthetized and mechanically ventilated. Fiberoptic probes for continuous PCO2 measurement were inserted into the femoral vein and the triceps muscle. Group A received succinylcholine 4 mg/kg, group B incremental doses of halothane (0.5, 1.0 vol%) and group C succinylcholine and halothane simultaneously. Vital signs were recorded continuously. RESULTS Prior to drug application measured values did not differ between MHS and MHN. While MHN pigs did not show relevant alterations, succinylcholine, halothane and the combination of both lead to significant hemodynamic and metabolic changes in MHS swine. CONCLUSIONS Hemodynamic and metabolic alterations following succinylcholine were similar to halothane in MHS pigs. The combination of both pharmacological agents potentiated the observed effects. According to these results succinylcholine acted as an independent and supportive factor during onset of an MH episode.
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Affiliation(s)
- Frank Schuster
- Department of Anaesthesia and Critical Care, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
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Klingler W, Heiderich S, Girard T, Gravino E, Heffron JJA, Johannsen S, Jurkat-Rott K, Rüffert H, Schuster F, Snoeck M, Sorrentino V, Tegazzin V, Lehmann-Horn F. Functional and genetic characterization of clinical malignant hyperthermia crises: a multi-centre study. Orphanet J Rare Dis 2014; 9:8. [PMID: 24433488 PMCID: PMC3896768 DOI: 10.1186/1750-1172-9-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 01/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malignant hyperthermia (MH) is a rare pharmacogenetic disorder which is characterized by life-threatening metabolic crises during general anesthesia. Classical triggering substances are volatile anesthetics and succinylcholine (SCh). The molecular basis of MH is excessive release of Ca2+ in skeletal muscle principally by a mutated ryanodine receptor type 1 (RyR1). To identify factors explaining the variable phenotypic presentation and complex pathomechanism, we analyzed proven MH events in terms of clinical course, muscle contracture, genetic factors and pharmocological triggers. METHODS In a multi-centre study including seven European MH units, patients with a history of a clinical MH episode confirmed by susceptible (MHS) or equivocal (MHE) in vitro contracture tests (IVCT) were investigated. A test result is considered to be MHE if the muscle specimens develop pathological contractures in response to only one of the two test substances, halothane or caffeine. Crises were evaluated using a clinical grading scale (CGS), results of IVCT and genetic screening. The effects of SCh and volatile anesthetics on Ca2+ release from sarcoplasmic reticulum (SR) were studied in vitro. RESULTS A total of 200 patients met the inclusion criteria. Two MH crises (1%) were triggered by SCh (1 MHS, 1 MHE), 18% by volatile anesthetics and 81% by a combination of both. Patients were 70% male and 50% were younger than 12 years old. Overall, CGS was in accord with IVCT results. Crises triggered by enflurane had a significantly higher CGS compared to halothane, isoflurane and sevoflurane. Of the 200 patients, 103 carried RyR1 variants, of which 14 were novel. CGS varied depending on the location of the mutation within the RyR1 gene. In contrast to volatile anesthetics, SCh did not evoke Ca2+ release from isolated rat SR vesicles. CONCLUSIONS An MH event could depend on patient-related risk factors such as male gender, young age and causative RyR1 mutations as well as on the use of drugs lowering the threshold of myoplasmic Ca2+ release. SCh might act as an accelerant by promoting unspecific Ca2+ influx via the sarcolemma and indirect RyR1 activation. Most MH crises develop in response to the combined administration of SCh and volatile anesthetics.
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Affiliation(s)
- Werner Klingler
- Department of Neuroanesthesiology, Ulm University, Ludwig-Heilmeyer-Str. 2, Günzburg 89312, Germany
- Division of Neurophysiology, Ulm University, Albert-Einstein Allee 11, Ulm 89081, Germany
- Rare Disease Center, University Hospital Ulm, Ulm 89081, Germany
| | - Sebastian Heiderich
- Department of Neuroanesthesiology, Ulm University, Ludwig-Heilmeyer-Str. 2, Günzburg 89312, Germany
- Division of Neurophysiology, Ulm University, Albert-Einstein Allee 11, Ulm 89081, Germany
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover 30625, Germany
| | | | | | | | - Stephan Johannsen
- Department of Anesthesia and Critical Care, University of Würzburg, Würzburg, Germany
| | - Karin Jurkat-Rott
- Division of Neurophysiology, Ulm University, Albert-Einstein Allee 11, Ulm 89081, Germany
- Rare Disease Center, University Hospital Ulm, Ulm 89081, Germany
| | - Henrik Rüffert
- University of Leipzig, Helios Kliniken Leipziger Land Leipzig, Germany
| | - Frank Schuster
- Department of Anesthesia and Critical Care, University of Würzburg, Würzburg, Germany
| | - Marc Snoeck
- Department of Anesthesia, Canisius-Wilhelmina Hospital, University of Nijmegen, Nijmegen, The Netherlands
| | - Vincenzo Sorrentino
- Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, via A. Moro 2, Siena 53100, Italy
| | | | - Frank Lehmann-Horn
- Division of Neurophysiology, Ulm University, Albert-Einstein Allee 11, Ulm 89081, Germany
- Rare Disease Center, University Hospital Ulm, Ulm 89081, Germany
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Schuster F, Johannsen S, Schneiderbanger D, Roewer N. Evaluation of suspected malignant hyperthermia events during anesthesia. BMC Anesthesiol 2013; 13:24. [PMID: 24053352 PMCID: PMC3848727 DOI: 10.1186/1471-2253-13-24] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
Background Malignant hyperthermia (MH), a metabolic myopathy triggered by volatile anesthetics and depolarizing muscle relaxants, is a potentially lethal complication of general anesthesia in susceptible patients. The implementation of modern inhalation anesthetics that research indicates as less potent trigger substances and the recommended limitations of succinylcholine use, suggests there may be considerable decline of fulminant MH cases. In the presented study, the authors analyzed suspected MH episodes during general anesthesia of patients that were referred to the Wuerzburg MH unit between 2007 and 2011, assuming that MH is still a relevant anesthetic problem in our days. Methods With approval of the local ethics committee data of patients that underwent muscle biopsy and in vitro contracture test (IVCT) between 2007 and 2011 were analyzed. Only patients with a history of suspected MH crisis were included in the study. The incidents were evaluated retrospectively using anesthetic documentation and medical records. Results Between 2007 and 2011 a total of 124 patients were tested. 19 of them were referred because of suspected MH events; 7 patients were diagnosed MH-susceptible, 4 MH-equivocal and 8 MH-non-susceptible by IVCT. In a majority of cases masseter spasm after succinylcholine had been the primary symptom. Cardiac arrhythmias and hypercapnia frequently occurred early in the course of events. Interestingly, dantrolene treatment was initiated in a few cases only. Conclusions MH is still an important anesthetic complication. Every anesthetist must be aware of this life-threatening syndrome at any time. The rapid onset of adequate therapy is crucial to avoid major harm and possibly lethal outcome. Dantrolene must be readily available wherever MH triggering agents are used for anesthesia.
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Affiliation(s)
- Frank Schuster
- Department of Anesthesia and Critical Care, University of Wuerzburg, Oberduerrbacher Str, 6, D-97080 Wuerzburg, Germany.
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Fernandes CR, Pinto Filho WA, Cezar LC, Alves Gomes JM, Florencio da Cunha GK. Fatal Recrudescence of Malignant Hyperthermia in an Infant with Moebius Syndrome. Braz J Anesthesiol 2013; 63:296-300. [DOI: 10.1016/s0034-7094(13)70234-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Accepted: 06/12/2012] [Indexed: 10/26/2022] Open
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Pollock N, Langton EE, Stowell KM, Bulger TF. Safety of exposure of malignant hyperthermia non-susceptible patients and their relatives to anaesthetic triggering agents. Anaesth Intensive Care 2011; 39:887-94. [PMID: 21970134 DOI: 10.1177/0310057x1103900514] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As the reliability of malignant hyperthermia normal in vitro contracture test results has been questioned, this study set out to determine the reliability of malignant hyperthermia normal results in New Zealand. Three hundred and twenty-nine anaesthetics were administered to malignant hyperthermia normal patients, identified through the Palmerston North Hospital malignant hyperthermia database. Anaesthetic records were retrieved and scrutinised for a malignant hyperthermia reaction using the Malignant Hyperthermia Clinical Grading Scale. Patients were exposed to one or more of eight triggering agents and multiple anaesthetic agents were administered in 41% of cases. Six variables were analysed, and although a minority of variables were abnormal in a small number of patients, none of the findings supported a malignant hyperthermia reaction. While the analysis was limited by the adequacy of the anaesthesia records, it was supported by negative DNA analysis in 55% of patients. This study supports several previous studies in demonstrating that patients in New Zealand tested non-susceptible to malignant hyperthermia can safely be given triggering agents.
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Affiliation(s)
- N Pollock
- Department of Anaesthesia, Palmerston North Hospital, Palmerston North, New Zealand.
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Rosenberg H, Davis M, James D, Pollock N, Stowell K. Malignant hyperthermia. Orphanet J Rare Dis 2007; 2:21. [PMID: 17456235 PMCID: PMC1867813 DOI: 10.1186/1750-1172-2-21] [Citation(s) in RCA: 264] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 04/24/2007] [Indexed: 11/10/2022] Open
Abstract
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stresses such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:5,000 to 1:50,000-100,000 anesthesias. However, the prevalence of the genetic abnormalities may be as great as one in 3,000 individuals. MH affects humans, certain pig breeds, dogs, horses, and probably other animals. The classic signs of MH include hyperthermia to marked degree, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. Early recognition of the signs of MH, specifically elevation of end-expired carbon dioxide, provides the clinical diagnostic clues. In humans the syndrome is inherited in autosomal dominant pattern, while in pigs in autosomal recessive. The pathophysiologic changes of MH are due to uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation. Due to ATP depletion, the muscle membrane integrity is compromised leading to hyperkalemia and rhabdomyolysis. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 90 mutations have been identified in the RYR-1 gene located on chromosome 19q13.1, and at least 25 are causal for MH. Diagnostic testing relies on assessing the in vitro contracture response of biopsied muscle to halothane, caffeine, and other drugs. Elucidation of the genetic changes has led to the introduction, on a limited basis so far, of genetic testing for susceptibility to MH. As the sensitivity of genetic testing increases, molecular genetics will be used for identifying those at risk with greater frequency. Dantrolene sodium is a specific antagonist of the pathophysiologic changes of MH and should be available wherever general anesthesia is administered. Thanks to the dramatic progress in understanding the clinical manifestation and pathophysiology of the syndrome, the mortality from MH has dropped from over 80% thirty years ago to less than 5%.
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Affiliation(s)
- Henry Rosenberg
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ 07039, USA
| | - Mark Davis
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ 07039, USA
| | - Danielle James
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ 07039, USA
| | - Neil Pollock
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ 07039, USA
| | - Kathryn Stowell
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ 07039, USA
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Brand JC. Preoperative diagnosis of malignant hyperthermia. SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2003. [DOI: 10.1080/22201173.2003.10872985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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