Malignant hyperthermia in maxillofacial surgery: Literature review supported by case presentation.

OBJECTIVE: Malignant hyperthermia (MH) is characterized by a state of hypermetabolism after exposure to halogenated inhalational anesthetics or succinylcholine. The aims of this study were to carry out an updated review on the subject and report an illustrative case of MH in urgent maxillofacial surgery. MATERIAL AND METHODS: A search of the PubMed/MEDLINE database using the keyword "malignant hyperthermia" was performed including articles published over the last 11 years in English, Spanish or Portuguese. Exclusion criteria were similar presentations but not associated with MH and cases not related to the use of anesthetic drugs as a trigger of the condition. CASE REPORT: A 45-year-old man (75 kg, ASA status IE) with a negative family history for neuromuscular diseases, victim of a car accident with a facial fracture, underwent surgery under balanced general anesthesia and developed signs of MH 4 h after anesthesia induction. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed, subsequently, by muscle biopsy. RESULTS/DISCUSSION: Overall, 44 cases of MH were found. According to the recent literature, MH shows a male predilection (3:1) and the mean age of patients is 32.2 ± 22.2 years. The most frequently cited causative agents were sevoflurane (30.5%), isoflurane (22.2%), and sevoflurane + succinylcholine (13.8%). The most common clinical indicators included hypercarbia (88.8%), hyperthermia (86.1%), and tachycardia (63.8%). Dantrolene was administered in 24 cases. The outcome was favorable in 31 cases (86.1%). The in vitro muscle contracture test (IVCT) was performed in only 15 patients and all of them tested positive. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed by muscle biopsy. CONCLUSION: The mortality from MH is still high and an early clinical diagnosis and specific treatment with dantrolene are necessary for a favorable outcome. A complete understanding will allow better management of patients with MH. At present, the best management is to identify susceptible patients and to avoid triggering agents, combined with vigilant monitoring.

Oral Management of Steinert's Disease and Role of Anxiolysis.

BACKGROUND: Myotonic dystrophy type I (DM1) is a genetic autosomal dominant disorder; malignant hyperthermia is a possible complication. It may occur following administration of some halogenated general anesthetics, muscle relaxants, or surgical stress. AIM: The purpose of this case report is to evaluate the dental management of patients with Steinert's disease. CASE REPORT: The patient needed dental extraction. A locore-gional paraperiosteal anesthesia was performed using bupiva-caine without vasoconstrictor and sedation with nitrous oxide. The syndesmotomy of the elements 3.1, 4.1, and 4.2 was executed. The elements were dislocated through a straight lever and avulsed with an appropriate clamp. The socket was courted, washing with saline solution, inserting a fibrin sponge, and applying sutures (silk 3-0). CONCLUSION: Dental treatment of the patient with Steinert's dystrophy must be carried out under a hospital environment and the use of local anesthetic without vasoconstrictor and with use of nitrous oxide; anxiolysis is recommended. CLINICAL SIGNIFICANCE: This case report describes the precautions to perform oral surgery in patients with Steinert's disease and emphasizes the role of anxiolysis to avoid episodes of malignant hyperthermia.

Myotoxicity of local anesthetics is equivalent in individuals with and without predisposition to malignant hyperthermia.

PURPOSE: Malignant hyperthermia (MH) is an inherited muscle disorder caused by abnormal elevations of intracellular calcium (Ca2+) in skeletal muscle. There are several reports of myotoxicity caused by local anesthetics, and the increased intracellular Ca2+ is considered to be an important cause. However, there is insufficient evidence regarding myotoxicity in MH-susceptible individuals when large doses of local anesthetics are administered. This study investigated the effect of MH predisposition on myotoxicity. METHODS: Human skeletal muscle samples were obtained from 22 individuals to determine susceptibility to MH, and were evaluated according to whether their Ca2+-induced Ca2+ release (CICR) rates were accelerated or not. This study was performed using surplus muscle that remained after the CICR rate test. We calculated the 50% effective concentration (EC50) values of three local anesthetics, namely lidocaine, levobupivacaine, and ropivacaine using the ratiometric dye Fura-2 AM. Significance was tested using the unpaired t test. RESULTS: In the accelerated and unaccelerated groups, respectively, the mean ± SD of the EC50 values were 1.52 ± 0.72 and 1.75 ± 0.37 mM for lidocaine (p = 0.42), 0.72 ± 0.36 and 0.79 ± 0.46 mM for levobupivacaine (p = 0.68), and 1.21 ± 0.35 and 1.62 ± 0.57 mM for ropivacaine (p = 0.06). These values were similar in individuals with and without MH predisposition. CONCLUSION: The myotoxicity of local anesthetics was equivalent in individuals with and without predisposition to MH.

[Isoflurane-induced malignant hyperthermia during intensive-care treatment]. / Isofluranassoziierte maligne Hyperthermie im Rahmen der Intensivtherapie.

Malignant hyperthermia (MH), an inherited myopathia varying in severity and course, is induced by halogenated anesthetic agents and depolarizing muscle relaxants. First recognized as a distinct disease entity in 1960, MH is defined as an anesthesia-related disease due to the agents by which it is triggered. Given the wide use of these preparations in prehospital emergency medicine and intensive care treatment, physicians in other disciplines may also encounter MH.

[Malignant hyperthermia - problem in dental surgery. An introductory report]. / Hipertermia zlosliwa - problem w chirurgii stomatologicznej. Doniesienie wstepne.

Malignant hyperthermia is a genetic defect of uncontrolled hypermetabolic skeletal muscle response to anesthetic triggering drugs. Some congenital myopathies are regarded as risk increasing factors. The use of volatile anaesthetics or suxamethonium (succinylcholine) in patients who are predisposed to malignant hyperthermia leads to an increase in Ca2+ release from sarcoplasmic reticulum, which in turn causes a set of biochemical and clinical symptoms, which can be a cause of death, if dantrolene is not administered adequately. The aim of the study was to draw attention to the problem of malignant hyperthermia, which is hardly ever described in Polish literature, and requires the necessity of intensifying the cooperation between the dentist and specialists from other medical fields. The origin of the article was a case of congenital myopathy with recognized malignant hyperthermia in an 18-year-old patient, in whom surgical extraction of teeth was indicated. The course of diagnostics and treatment showed once more that contemporary medicine is in need of holistic approach, and in consequence, promising and effective cooperation of many specialists.

Hiperpirexia maligna / Malignant hyperpyrexia

Se revisa el tema de la hiperpirexia maligna y otros síndromes hipertérmicos. Tras una descripción de la fisiopatología se proponen pautas de diagnóstico, diagnóstico diferencial y tratamiento ante un aumento de la temperatura de un paciente. Dentro de esta entidad es fundamental el diagnóstico precoz y el tratamiento inmediato, el cual puede ser instaurado siguiendo una protocolización estricta, que incluye una distribución de las tareas entre varios componentes del equipo anestesicoquirúrgico, incluyendo la enfermería. La colaboración de varios profesionales es imprescindible. Se destaca la ausencia de seguimiento y apoyo a nivel nacional, y se aporta una dirección de correo electrónico para ayuda (AU)

This article reviews malignant hyperpyrexia and other hyperthermic syndromes. The physiopathology of these syndromes is described and strategies for their diagnosis, differential diagnosis and treatment are proposed. Early diagnosis and immediate treatment are essential. The latter can be initiated by following a strict protocol, which includes the distribution of tasks among the various components of the anesthesiology-surgical care team, including nurses. The collaboration of various professionals is essential. The lack of follow-up and national support is highlighted and an e-mail address for support is provided (AU)

[Case of suspected malignant hyperthermia following local infiltration anesthesia].

A 49-year-old man with no past history of malignant hyperthermia (MH) and scheduled for hernia repair was suspected of MH after local infiltration anesthesia at other hospital. Although intravenous diazepam was not effective for increased body temperature, tachycardia, and convulsion, dantrolene was effective for these signs. However, blood test showed no abnormal finding. At our hospital, he was scheduled for hernia repair and muscle biopsy under total intravenous anesthesia. No event occurred intra- and postoperatively. The examination for muscle biopsy revealed that the function of his ryanodine receptor 1 is abnormal. The events which had occurred at other hospital were uncertain of being associated with MH.

Functional studies of RYR1 mutations in the skeletal muscle ryanodine receptor using human RYR1 complementary DNA.

BACKGROUND: Malignant hyperthermia is associated with mutations within the gene encoding the skeletal muscle ryanodine receptor, the calcium channel that releases Ca from sarcoplasmic reticulum stores triggering muscle contraction, and other metabolic activities. More than 200 variants have been identified in the ryanodine receptor, but only some of these have been shown to functionally affect the calcium channel. To implement genetic testing for malignant hyperthermia, variants must be shown to alter the function of the channel. A number of different ex vivo methods can be used to demonstrate functionality, as long as cells from human patients can be obtained and cultured from at least two unrelated families. Because malignant hyperthermia is an uncommon disorder and many variants seem to be private, including the newly identified H4833Y mutation, these approaches are limited. METHODS: The authors cloned the human skeletal muscle ryanodine receptor complementary DNA and expressed both normal and mutated forms in HEK-293 cells and carried out functional analysis using ryanodine binding assays in the presence of a specific agonist, 4-chloro-m-cresol, and the antagonist Mg. RESULTS: Transiently expressed human ryanodine receptor proteins colocalized with an endoplasmic reticulum marker in HEK-293 cells. Ryanodine binding assays confirmed that mutations causing malignant hyperthermia resulted in a hypersensitive channel, while those causing central core disease resulted in a hyposensitive channel. CONCLUSIONS: The functional assays validate recombinant human skeletal muscle ryanodine receptor for analysis of variants and add an additional mutation (H4833Y) to the repertoire of mutations that can be used for the genetic diagnosis of malignant hyperthermia.

Thermoregulation: physiological and clinical considerations during sedation and general anesthesia.

Mild hypothermia is common during deep sedation or general anesthesia and is frequently associated with patient discomfort and shivering. Greater declines in temperature can produce an even greater number of significant detrimental effects. This article reviews principles of thermoregulation and influences of anesthetic agents. An understanding of these will provide a foundation for strategies to reduce heat loss and better manage patient discomfort when it occurs.

Intramuscular injection of malignant hyperthermia trigger agents induces hypermetabolism in susceptible and nonsusceptible individuals.

BACKGROUND AND OBJECTIVE: A new minimally invasive metabolic test for the diagnosis of susceptibility for malignant hyperthermia measuring intramuscular p(CO(2)) and lactate following local application of caffeine and halothane in humans was recently proposed. The present study tested the hypothesis that a more simplified test protocol allows a differentiation between malignant hyperthermia susceptible (MHS) and malignant hyperthermia nonsusceptible (MHN) and control individuals. METHODS: With approval of the local ethics committee and informed consent, microdialysis and p(CO(2)) probes with attached microtubing were placed into the lateral vastus muscle of six MHS, seven MHN and seven control individuals. Following equilibration, boluses of 500 microl caffeine 80 mmol l(-1) and halothane 10 vol% dissolved in soybean oil were injected locally. p(CO(2)) and lactate were measured spectrophotometrically. RESULTS: The maximal rate of p(CO(2)) increase was significantly higher in MHS than in MHN and control individuals following application of halothane and caffeine, respectively. Intramuscular caffeine injection leads to a significantly higher increase of local lactate levels in MHS than in MHN and control individuals, whereas halothane increased local lactate levels in all investigated groups. Haemodynamic and systemic metabolic parameters did not differ between the investigated groups. CONCLUSION: Local caffeine and halothane injection increased intramuscular metabolism in MHS individuals significantly more than in the two other groups. In contrast to previous investigations, direct injection of the concentrations of halothane described here increased lactate and p(CO(2)) even in MHN skeletal muscle.

Immediate postoperative death due to hypothalamic injury following surgery for craniopharyngioma.

Autonomic disturbances due to hypothalamic injury that result in postoperative death are rare complications following surgery for craniopharyngioma. We discuss the case of a child who died due to hypothalamic injury following radical excision of a multi-compartmental craniopharyngioma. Mechanisms and clinical manifestations of hypothalamic injury and ways to avoid this fatal complication are discussed.

Malignant hyperthermia: a pharmacogenetic disorder.

Malignant hyperthermia (MH) is a pharmacogenetic disorder triggered by volatile anesthetics or depolarizing muscle relaxants in predisposed individuals. Exercise or stress-induced MH episodes, in the absence of any obvious pharmacological trigger, have been reported, but these are rare. A considerable effort has taken place over the last two decades to identify mutations associated with MH and characterize their functional effects. A number of different, but complementary systems, have been developed and implemented to this end. The results of such studies have identified commonalities in functional affects of mutations, and also uncovered unexpected complexities in both the structure and function of the skeletal muscle calcium-release channel. The following review is an attempt to provide a summary of the background to current MH research, and highlight some recent advances in our knowledge of the molecular basis of the phenotypic expression of this disorder.

Fatal hyperthermia due to dental treatment.

A 12-year-old boy with mental retardation and cerebral palsy developed hyperthermia during dental treatment performed while he was conscious. During the treatment, he was highly excited, and shortly after completion of the procedure, general muscular spasms occurred. His axillary temperature was 41.6 degrees C then. He was transferred to another general hospital and there he was judged to have become afebrile and was discharged. His condition deteriorated during the night, and he was readmitted to the same hospital the following morning. The patient did not respond to the therapy and died from multiple organ failure on the 13th day. It was thought that hyperthermia had led to rhabdomyolysis and DIC. The cause of death is discussed. Hyperthermia in a handicapped patient is not always transient or benign, and can be life threatening.

Síndrome de hipertermia maligna: reporte de un caso en un hospital rural / Malignant hyoperthermia syndrome: report of one case in a rural hospital

Introducción: Desarrollo de cuadro clínico compatible con síndrome de hipertermia maligna (S.H.M.). Caso Clínico: Se presenta un caso clínico de S.H.M. desencadenado durante la inducción inhalatoria con sevofluorano en un hospital de baja complejidad, con diagnóstico precoz, buena evolución del paciente y confirmación posterior a través del test de contractura cafeína-halotano. Discusión: Se plantean diagnósticos diferenciales, uso de drogas seguras y una estrategia anestésico quirúrgica; la dificultad en la intubación que acompaña a casi el 50 por ciento de estos pacientes y la influencia del diagnóstico precoz en la supervivencia. Conclusiones: Tener presente al S.H.M. dentro de los diagnósticos diferenciales. Tarea del anestesiólogo: "mantener y actualizar la educación y entrenamiento". (AU)

Local anesthesia and malignant hyperthermia: review of the literature and recommendations for the dermatologic surgeon.

BACKGROUND: Malignant hyperthermia (MH) is a rare syndrome that is a major cause of anesthetic-related morbidity and mortality in otherwise well patients. The role of local anesthetics, stress, and epinephrine in inducing this syndrome has been subjected to controversy. OBJECTIVE: To examine the role of local anesthetics, stress, and epinephrine in producing clinically relevant adverse effects in patients with MH. METHODS: A critical review of the literature. RESULTS: Local anesthesia is safe for use in usual doses in MH-susceptible patients. The role of stress and epinephrine in precipitating episodes of MH is likely minimal, but controversy remains in the anesthesia and dental literature. CONCLUSION: Recommendations for diagnosis, treatment, and safety precautions to be taken by dermatologic surgeons when treating MH patients are made.

Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs.

Five dogs, 4 of which were Greyhounds, suffered adverse effects secondary to the ingestion of spent hops. Mean time to onset of clinical signs was 3 hours, and clinical signs included marked hyperthermia, restlessness, panting, vomiting, signs of abdominal pain, and seizures. Four of the 5 dogs died despite aggressive therapeutic measures, and there was rapid onset of rigor mortis in 3. The overrepresentation of Greyhounds, coupled with the clinical signs, was suggestive of a malignant hyperthermia-like response to the ingestion of hops. It also is possible that hops contain an uncoupler of oxidative phosphorylation.