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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant hyperthermia syndrome (MHS) is rare, inherited, and triggered by volatile anesthetics and depolarizing muscle relaxants. While potentially fatal, if recognized and treated early recovery is usual. However, the condition is often not recognized until an extreme increase in temperature develops with profound circulatory depression. In this stage the syndrome is irreversible, despite specific treatment with dantrolene. At present, the only reliable diagnostic test for susceptibility to malignant hyperthermia requires sampling of viable muscle for in vitro contracture tests with caffeine and halothane. Until our malignant hyperthermia diagnostic center was opened, such tests could not be performed in Israel. Since then we encountered a 22-year-old man who developed the partial picture of malignant hyperthermia syndrome during anesthesia for inguinal herniorrhaphy. He received dantrolene and recovered. 4 months later in vitro contracture tests with caffeine and halothane performed on biopsied muscle confirmed the diagnosis.
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PMID:[In vitro diagnosis of malignant hyperpyrexia syndrome]. 179 53

In vitro pharmacological responses of fresh biopsy specimens of human skeletal muscle were used as indicators of some intrinsic muscle properties. The measured parameters that were utilized for the current study were contractures induced in vitro by caffeine or by caffeine plus halothane. The opportunity to study such specimens arose from clinical testing for diagnosing the genetic predisposition to malignant hyperthermia, a potentially fatal complication of anaesthesia. The current analysis covers data from over 1,000 subjects, most of whom were clinical suspects and relatives of these. Responsiveness of the muscle specimens varied over two orders of magnitude. The frequency distribution curves suggest that the variation does not represent a continuum but that there are three or more clusters of functional variants. Muscle specimens from males were on average more responsive to caffeine than were those from females. Correlations within father-son and brother-brother pairs indicated complete heritability of responsiveness; this might have been expected but the surprise was a lack of correlation within mother-daughter pairs. There was an intermediate correlation in father-daughter pairs. The sex difference in heritability could be due to gender-related modifying genes or due to secondary modification of the muscle response in females by sex-related, perhaps hormonal factors. Among the effects of age appeared to be poor development in early childhood of the potentiation of the caffeine contracture by halothane.
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PMID:Pharmacogenetics of caffeine and caffeine-halothane contractures in biopsies of human skeletal muscle. 184 76

A 5-year-old boy with acute lymphatic leukemia in remission developed signs of malignant hyperthermia (MH) during general anesthesia for removal of a central venous access port. The anesthetic procedure for implantation of the port 17 months before had been uneventful despite use of the same triggering agents, halothane and succinylcholine. Meanwhile, the patient had received chemotherapy (COALL-03-85). The first sign of MH was masseter spasm following succinylcholine; then tachycardia, acidosis, myoglobinuria, and CPK elevation (8953 IU) appeared. There was only moderate temperature elevation to 37.8 degree C. Rapid improvement and complete recovery occurred after dantrolene i.v. The patient's father was found to have undiagnosed muscle pain and an elevated CPK level. An in vitro contracture test with halothane and caffeine revealed susceptibility to MH and supported the patient's diagnosis and genetic predisposition. Referring to several other cases in the literature concerning MH in patients with lymphomas and leukemias, a possible correlation between the two diseases is discussed. As the MH crisis in our patient was most probably genetic in origin, a common acquired cause such as a viral infection seems less probable. We do not believe the chemotherapy our patient received between the two anesthetics was the cause since about one-half of the patients in the literature had not had chemotherapeutic pretreatment at the time of the MH crisis. We believe that a common genetic predisposition is the most likely link between the two diseases. In any case, patients with leukemias and lymphomas should be monitored very carefully for symptoms of MH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Malignant hyperthermia in a child with acute lymphatic leukemia]. 186 72

A 4-year-old boy with Williams syndrome developed masseter spasm after halothane and suxamethonium. He did not develop malignant hyperthermia; the surgery was accomplished with a nontriggering anaesthetic and no further problems.
Anaesthesia 1991 Feb
PMID:Williams syndrome: masseter spasm during anaesthesia. 188 3

A patient for fixation of ankle arthrodesis diagnosed as having malignant hyperthermia trait preoperatively is reported. A 17 year old man was anesthetized with enflurane for orthopedic surgery of the knee joint. At that time malignant hyperthermia developed. He was critically ill, but resuscitated and recovered from acute renal failure on 7th day after operation. Ca2+ release test was performed. Ca2+ releasing speed was prominently accelerated in this patient. We could identify him as having malignant hyperthermia trait. Epidural anesthesia with procaine chloride was given cautiously. No drug which may induce malignant hyperthermia was used. Nevertheless, malignant hyperthermia occurred. This disease has various forms of presentation. The mechanism is equivocal, and in some cases, it is difficult to judge it immediately. This patient was managed without complication. We consider that tourniquet and stress provoked signs of malignant hyperthermia in this patient.
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PMID:[The anesthetic management of a patient with the malignant hyperthermia trait diagnosed preoperatively]. 187 46

Dantrolene is the only known specific treatment of malignant hyperthermia (MH). Following official approval an intravenous formulation of dantrolene became clinically available for emergency treatment of MH. At that time it had been anticipated, that with dantrolene therapy combined with constant vigilance each case of MH could be treated successfully and the mortality rate should be close to zero. Surprisingly enough, reports of death due to MH continue to be published up to the present. Analysis of case reports revealed the following reasons for the discrepancy between the expectations and the clinical reality: 1. Delay in early diagnosis due to preoccupation with the name-giving symptom hyperthermia: lack of MH-sensitive monitoring (i.e. capnometry, pulse oximetry, blood gas analysis). 2. Preoccupation with non specific facets of therapy: measures such as cooling, change of the anaesthesia machine, transfer of the patient to the intensive care unit or the administration of drugs which have been shown to be ineffective in treating MH may not only be a waste of time, but fully disregard the prime factor in therapy--intravenous administration of dantrolene. 3. Administration of an insufficient amount of dantrolene and delayed start of specific therapy due to failure to have immediate access to intravenous dantrolene. 4. Failure to increase minute ventilation immediately after making the diagnosis to meet elevated metabolic demands. A recommendation is presented how to diagnose, to treat and prevent MH, considering present day diagnostic and therapeutic measures in the presence of the presumptive diagnosis of MH.
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PMID:[Reasons for the persistent lethality of malignant hyperthermia and recommendations for its reduction]. 188 26

This retrospective study was undertaken to examine the management and outcome of children who developed isolated masseter muscle spasm (MMS) after the administration of intravenous succinylcholine during anesthetic induction. The inhalation anesthetics used for induction were continued in all of these cases. The medical records of 68 patients (male/female ratio, 1.7:1), identified from approximately 42,000 anesthetics given during the period 1980-1989, were reviewed. Fifty-seven children (2.3-12 yr old) were diagnosed as having isolated MMS, i.e., MMS without spasm of other muscles; 11 experienced generalized rigidity in combination with MMS. Anesthetic and postoperative management of these two groups differed. The overall incidence of MMS was 0.3% of inhalation anesthetics during which succinylcholine was given. Intraoperative arrhythmias occurred in 33% of the patients who developed isolated MMS and more frequently in older children. Most children experienced some degree of hypercarbia and/or metabolic acidosis, but the significance of these abnormalities in the spontaneously ventilating, fasting child is unknown. Serum creatine kinase levels when measured 18-24 h postoperatively were elevated in all but one child (n = 45). There was no long-term morbidity and no mortality. We conclude that failure of the masseter muscles to relax after succinylcholine is not uncommon in children. Based on our experience, and accepting that MMS may be part of the clinical spectrum of malignant hyperthermia, we believe that anesthesia can be continued safely in cases of isolated MMS when careful monitoring accompanies diagnostic evaluation. This differs from the current practice of discontinuing the anesthetic or switching to a nontriggering anesthetic technique.
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PMID:Masseter muscle spasm in children: implications of continuing the triggering anesthetic. 186 39

Malignant hyperthermia (MH) is a rare but serious complication of general anesthesia that potentially carries a high mortality and morbidity. It is associated with excessive release of calcium into skeletal muscle following exposure to certain drugs, including the volatile general anesthetics. Since these are recognized membrane fluidizing agents it has been speculated that this condition might represent a generalized defect in membrane physical properties either at rest or inducible by fluidizing agents. If this hypothesis were found to be correct, malignant hyperthermia might conveniently be detected by examining membrane physical properties of easily accessible cells rather than the cumbersome method of muscle biopsy currently employed. To test this hypothesis we identified patients proven to be susceptible to MH by muscle biopsy and a cohort of patients not susceptible to MH as defined by negative muscle biopsy testing. Erythrocytes were isolated from both groups and membrane physical properties examined using conventional, widely available, steady-state fluorescence polarization techniques. Erythrocyte membranes were evaluated with multiple probes both in the basal condition and following fluidization with either increasing temperature or two concentrations of a fluidizing alcohol. We report, contrary to previous publications, that no discernable differences were detectable between MH-positive or negative patients. Thus, we find no evidence for a generalized membrane defect in MH and conclude that the determination of erythrocyte membrane physical properties, by these techniques, are of no use in the preoperative screening for this disorder.
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PMID:Erythrocyte membrane fluidity in malignant hyperthermia. 193 56

Malignant hyperthermia is caused by an abnormal increase in Ca2+ levels in skeletal muscle in response to anesthetics, including halothane. Since fatty acid production is elevated in skeletal muscle from individuals with malignant hyperthermia, the effects of fatty acids on the threshold of halothane-induced Ca2+ release were examined. In the absence of fatty acids halothane caused Ca2+ release from porcine and human heavy sarcoplasmic reticulum fractions, but only at concentrations above the clinically relevant range. Oleic acid (20 microM), an unsaturated fatty acid, reduced the threshold at which halothane induced Ca2+ release to concentrations used for anesthesia. Stearic acid, a saturated fatty acid had considerably less effect on the threshold of halothane action. The greater sensitivity of malignant hyperthermia muscle to halothane can be explained by elevated fatty acid production.
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PMID:Fatty acids markedly lower the threshold for halothane-induced calcium release from the terminal cisternae in human and porcine normal and malignant hyperthermia susceptible skeletal muscle. 194 69

An overview of several perioperative complications and their management strategies is presented. Operative hypothermia, malignant hyperthermia, bronchospasm, and side effects of spinal opioid agents are discussed. Ramifications of these complications may extend well beyond the operative period and influence patient outcome. Therefore, it is necessary that the surgeon have a fundamental understanding of the pathophysiology and modalities of treatment in the context of anesthesia and surgery.
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PMID:Perioperative complications of anesthesia. 194 66


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