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

The anaesthetic records of 61 patients who had experienced adverse reactions thought to be malignant hyperthermia (MH) were reviewed retrospectively to evaluate the diagnostic importance of clinical symptoms. Using the in vitro contracture test, 38 (62%) patients were identified as MH susceptible (MHS), the remainder showing normal test results (MHN). Generalized rigidity, ventricular arrhythmias, cyanosis and postoperative myoglobinuria were observed significantly more often in MHS patients. Median values of body temperature and creatine kinase serum concentrations were significantly greater in the MHS group. Masseter spasm and sinus tachycardia were as common in MHS as in MHN individuals. Statistical models using generalized rigidity, ventricular arrhythmias, cyanosis and fever exceeding 38 degrees C for prediction of MH showed a maximum sensitivity and specificity of 78% and thus are not acceptable for clinical use. For definitive diagnosis of MH, the well established in vitro contracture test remains essential.
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PMID:Prediction of malignant hyperthermia susceptibility: statistical evaluation of clinical signs. 233 13

Malignant hyperthermia (MH) reactions can be classified into four categories: the fulminant form, the abortive MH, the masseter spasm and atypical presentations. The latter group includes syndromes such as hyperthermia and heat strokes, sudden death and the neuroleptic malignant syndrome. The different signs and symptoms of each category are recalled thus offering criteria for the differential diagnosis with other clinical entities.
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PMID:Malignant hyperthermia: the clinical syndrome. 237 8

Malignant hyperthermia (MH) is a pharmacogenetic disorder. It is classically described as a hypermetabolic state triggered by halogenated anaesthetics and/or depolarizing muscle relaxants. In fact, since Denborough and Lovel's case, it has been shown that MH has a great number of clinical forms. The overwhelming picture of muscular hypercatabolism with fulminating hyperthermia and generalized rigidity is becoming rare. A better knowledge of the first symptoms explains in part the better prognosis: masseter spasm after suxamethonium, an increase in expired CO2 concentration, unexplained tachycardia, ventricular arrhythmias. The use of dantrolene reduced the mortality of MH. The different types of clinical manifestations are due to genetic differences, the concentration of the anaesthetic agent, and the length of time of exposure to the drug. The severity of the episode is linked to environmental factors such as stress, physical exercise, ambient temperature, concomitant use of other drugs. Masseter spasm after suxamethonium is specific for MH, but not pathognomonic. It occurs in 1% of cases in children when using halothane with suxamethonium. However, in those patients who displayed such a spasm, more than 50% had a positive contracture test. Masseter spasm is often associated with severe rhabdomyolysis in patients with muscle dystrophy, especially Duchenne's dystrophy. In the latter case, major cardiac problems may occur at the time of anaesthetic induction. Even if there are no other signs of MH, all patients who have had a masseter spasm must be considered as open to doubt, and should be further explored. MH is often difficult to diagnose in medium severity types.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Clinical features of malignant hyperthermia crisis]. 251 11

The occurrence of masseteric muscle spasm (MMS) in children is thought to be frequent and to be associated usually with malignant hyperpyrexia (MH). We have found a lower incidence of MMS in children and 50% had no muscle abnormality. Clinical features that support a diagnosis of MH include high serum creatine kinase (CK) concentration and the presence of myoglobinuria. There is evidence to suggest that suxamethonium does increase jaw tone in adults and children, and an exaggerated response may be taken clinically to be MMS. However, MMS should still be regarded as an early warning sign of MH.
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PMID:Is there a relationship between masseteric muscle spasm and malignant hyperpyrexia? 273 Aug 25

Investigation of malignant hyperthermia (MH) was started in 1975; by March 1986, 79 suspected cases had been reported. In vitro contracture tests were performed in 66 probands or their parents; in 61 of these (92%), MH was confirmed and 5 (8%) proved negative. In 4 lethal crises, the parents refused biopsy, but because of well-documented clinical histories these were also included as confirmed MH reactions. We were able to analyse 65 cases of documented MH, and 9 patients are still to be investigated. About 18% of all Austrian hospitals (29 of 158) had reported 1-14 MH reactions (mean 2.7/hospital); it must therefore be assumed that a high number of crises are either not detected or not reported, and the total incidence of MH cannot be estimated. In our hospital (the University Hospital of Vienna), the incidence was 1:23,600 (including children and adults), whereas in Bludenz (Vorarlberg), the incidence was as low as 1:1,300 (in children only). This might partly be explained by genetic factors (such as inbreeding); we identified 3 families, all from Vorarlberg (which is a small, secluded mountain area), in which both parents were carriers of the MH trait. Fulminant crises (of which three times as many were rigid as were non-rigid) accounted for 58%, and masseter spasm for 26%, of all MH reactions. There was a significant influence of sex (72% males) and age (71% less than 20 years) on incidence. Neuromuscular symptoms or other signs reported to be associated with MH were found in only 5 patients (8%). During crises, cardiac symptoms (81%) and cyanosis (71%) were frequently observed; rigidity (45%) and body temperature above 39 degrees C (27%) showed remarkably low incidences. The overall mortality was 17% (11 of 65); it was significantly increased if the maximum temperature exceeded 39 degrees C, after acute surgery or anaesthesia lasting greater than 60 min, and in patients aged over 20 y. Most crises required no specific therapy; dantrolene was administered to only 10 patients. In the future, earlier detection via better monitoring, improved documentation, and mandatory reporting of suspected MH reactions should allow a more detailed description of MH and could further decrease the mortality associated with this condition.
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PMID:[Malignant hyperthermia in Austria. I. Epidemiology and clinical aspects]. 354 44

The case histories are presented including the anaesthetic and postoperative management, of two children, a two-year-old with undiagnosed Duchenne muscular dystrophy (DMD) and a three-year-old with known DMD. The child with undiagnosed DMD had no symptoms of DMD and had received halothane twice before, without succinylcholine, with no apparent difficulty. Following an uneventful induction of anaesthesia with halothane, nitrous oxide and O2, succinylcholine resulted in bilateral masseter muscle spasm and then, in rapid sequence, ventricular tachycardia and cardiac arrest. Resuscitation was difficult, prolonged and associated with hyperkalaemia (K+ = 12.57 mEq X L-1), severe metabolic and respiratory acidosis, high peripheral venous pressure and massive hepatosplenomegaly, but not hyperthermia. The patient was finally resuscitated but died two days later. Skeletal muscle biopsy results were consistent with malignant hyperthermia. The second patient was known to have DMD but did not receive prophylactic or intraoperative dantrolene nor have his anaesthetic machine flushed with oxygen for an extended period prior to induction of anaesthesia. This child was anaesthetized with fentanyl and N2O and, with the exception of a high intraoperative heart rate (155-160 beats X min-1), had an uncomplicated anaesthetic and operation (intraoperative axillary temperatures ranged between 36.8-37.9 degrees C). Postoperatively his temperature rapidly increased to 38.8 degrees C and then 40.3 degrees C and he became metabolically acidotic. Intravenous administration of dantrolene for 48 hours reduced the temperature and allowed normal recovery and discharge. A postoperative muscle biopsy was consistent with DMD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Duchenne muscular dystrophy and malignant hyperthermia--two case reports. 374 23

Questionnaires were sent to all anesthesia departments in Denmark to determine the total number of anesthetics given per year, and the distribution of different types of anesthesia. All cases of suspected malignant hyperthermia forwarded to the Danish Malignant Hyperthermia Register during a 6.5 yr period were reviewed and divided into subgroups according to clinical criteria. The incidence of suspected malignant hyperthermia in these subgroups was calculated in relation to type of anesthesia. The results are based on information about 386,250 anesthetics and 154 cases of suspected malignant hyperthermia. All cases of malignant hyperthermia occurred during general anesthesia, and more than 75% during anesthesia with a combination of potent inhalation agents and succinylcholine. The incidence of fulminant malignant hyperthermia was low: 1 in 250,000 total anesthetic procedures, but 1 in 62,000 anesthetic procedures with a combination of potent inhalation agents and succinylcholine. Masseter spasm occurred in 1 of 12,000 anesthetic procedures in which succinylcholine was administered. Suspicion of malignant hyperthermia was raised in 1 of 16,000 anesthetics total, but in 1 of 4,200 anesthetics with the above-mentioned combination of agents.
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PMID:Incidence of malignant hyperthermia in Denmark. 401 31

Units for the investigation of susceptibility to malignant hyperthermia (MH) were set up in Denmark in 1977 and in Sweden in 1981. Two hundred and ten patients from 76 families have been investigated. The diagnosis of MH susceptibility (MHS) was made by in vitro exposure of muscle from vastus medialis to halothane and to caffeine. MHS criteria for the patients in this paper were established from examination of 31 control biopsies, obtained from the same muscle and with the same anaesthesia as the MH patients. The criteria have since been changed to those presented elsewhere in this issue. In our laboratories the halothane test (exposure to 0.5-2% halothane) was the more sensitive: 88% of MHS patients reacted to it. The caffeine test was positive in 68% of MHS patients, 0.5-2.0 mmol litre-1 solutions being the most discriminating. Forty-two percent of MHS patients reacted to only one test. Fulminant MH was the most common reason for investigation; all these families contained MHS members. Masseter spasm occurred as sole sign in 21 families, of which 11 were MHS. Only 10% of MHS patients had other signs or symptoms of neuromuscular disease such as muscle cramps or muscular dystrophy. Three families had experienced sudden infant death syndrome (SIDS), and two teenage brothers in a MHS family died suddenly, but death was unrelated to anaesthesia.
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PMID:Investigation of malignant hyperthermia in Denmark and Sweden. 648 40

Spasm of muscle in association with suxamethonium is not uncommon. As an accepted early sign of malignant hyperpyrexia (MH), patients have been referred for MH screening who have shown only this abnormality. Case histories of 277 probands have been analysed and grouped according to final diagnosis, depending on results of muscle biopsy and in vitro screening. When muscle spasm is induced with suxamethonium, malignant hyperpyrexia must be considered a probable diagnosis.
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PMID:Suxamethonium spasm. A differential diagnostic conundrum. 671 53

Succinylcholine, a depolarizing muscle relaxant with both activating and desensitizing effects, is used to facilitate endotracheal intubation. The activating effects were found to be above-normal on induction of anesthesia in 7 neurological patients: generalized muscle spasm in 1 myotonic patient, contractures or prolonged contractions in "anatomically" denervated muscles (1 patient), in "functionally" denervated muscles (1 patient) and in "centrally" denervated muscles (4 patients). One of these four presented hyperkalemia and cardiocirculatory collapse. It is important to differentiate these anomalous responses to succinylcholine from those occurring as early signs of rhabdomyolysis or malignant hyperthermia.
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PMID:Increased activation effects of succinylcholine in neurological patients. 686 44


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