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

A moderate malignant hyperthermia developed in a Labrador Retriever anaesthetized with isoflurane for a femoral shaft fracture repair. Signs of malignant hyperthermia included progressive increases in PETCO2 and rectal temperature up to 39.8 degrees C, tachycardia, cyanosis, and elevated serum levels of potassium, inorganic phosphorus, AST, CK and alkaline phosphatase. Treatment initiated in the early recovery period consisted of hyperventilation with 100% oxygen, stomach lavage with iced water, body surface cooling, and intravenous administration of cold isotonic saline solution. Cooling was continued until the rectal temperature had dropped to 37.3 degrees C. After treatment the dog recovered uneventfully. Clinical signs, pathophysiology, therapy, prevention of malignant hyperthermia and its association with other disorders are discussed.
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PMID:[Malignant hyperthermia as a complication of anesthesia in the dog]. 144 May 99

A comparative study of mechanical and energetic parameters of superfused muscle strips from normal pigs and malignant hyperthermia susceptible (MHS) pigs has been conducted. Phosphorus nuclear magnetic resonance spectroscopy at 80.9 MHz and mechanical measurements were used to assess muscle metabolic state. At rest, biceps femoris biopsies of MHS pigs displayed reduced phosphocreatine level, higher inorganic phosphate, and a more acidic internal pH. In normal stimulated fibers, caffeine infusion (8 or 16 mM) induced twitch potentiation and contracture while twitch tension was reduced and contracture more pronounced in malignant fibers. In normal and malignant fibers, calcium ionophore A23187 produced effects similar to those of caffeine, with the exception of twitch potentiation, which was not observed. With caffeine or A23187, the ATP level remained constant throughout the rest-stimulation-recovery protocol for normal and malignant fibers but phosphocreatine dropped to undetectable levels upon stimulation of malignant fibers. In both treatments some heterogeneity in the resonances of inorganic phosphate was observed in malignant fibers together with a more severe acidosis which might play a role in the impairment of the excitation-contraction process.
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PMID:In vitro correlation between force and energy metabolism in porcine malignant hyperthermic muscle studied by 31P NMR. 165 12

Malignant hyperthermia (MH) is a potentially fatal, anesthetic-induced syndrome. Currently, the only accurate means of diagnosing susceptibility to this syndrome is the testing of biopsied skeletal muscle for its contracture response to halothane and caffeine. A less invasive means of diagnosis is needed. The authors previously reported that MH-susceptible patients studied by in vivo phosphorus nuclear magnetic resonance (31P NMR) spectroscopy demonstrated a higher resting inorganic phosphate (Pi) to phosphocreatine (PCr) ratio in their skeletal muscle, as well as a slower postexercise recovery of PCr/Pi, when compared to normal controls. In the present blinded study, the authors compared in vivo 31P NMR determination of resting Pi/PCr and recovery rate of PCr/Pi in forearm muscles to in vitro halothane/caffeine contracture test results in 42 patients. Forty-three control subjects were studied to establish normal NMR values of resting Pi/PCr and recovery rate of PCr/Pi. Their findings were compared with those of 27 patients shown to be MH-susceptible and 15 patients MH-negative by contracture testing. The MH-susceptible group had a significantly (P less than 0.005) higher resting Pi/PCr value (0.202 +/- 0.044) than either the MH-negative (0.152 +/- 0.043) or the control (0.141 +/- 0.026) group. The MH-susceptible group also had a significantly (P less than 0.02) slower postexercise recovery rate of PCr/Pi (1.50 +/- 0.872 PCr.Pi-1.min-1) than either the MH-negative (2.11 +/- 1.07 PCr.Pi-1.min-1) or control (2.25 +/- 0.828 PCr.Pi-1.min-1) group. Twenty-six of the 27 MH-susceptible patients demonstrated abnormal NMR test results (a resting Pi/PCr greater than or equal to 0.18 or recovery rate less than 1.0 PCr.Pi-1.min-1), and 13 of the 15 MH-negative patients had normal NMR results. Although neither NMR parameter alone was diagnostically reliable, an NMR test utilizing both parameters was quite accurate. The NMR test and contracture test demonstrated an overall agreement of 93% with a copositivity of 96% and conegativity of 87%. The sensitivity and specificity of the NMR test is estimated to be 98.8% +/- 11.8% and 95.3% +/- 20.3%, respectively. The role of 31P NMR in the diagnosis of MH susceptibility and possible mechanisms underlying the observations are discussed.
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PMID:A blinded comparison of noninvasive, in vivo phosphorus nuclear magnetic resonance spectroscopy and the in vitro halothane/caffeine contracture test in the evaluation of malignant hyperthermia susceptibility. 185 40

Malignant hyperthermia, a disorder of uncertain genetic transmission related to use of certain anesthetics and muscle relaxants, is uncommon and potentially fatal. It has been most commonly linked to succinylcholine chloride (Anectine, Quelicin, Sucostrin) and halothane (Fluothane). The most important treatment method, after discontinuation of the triggering agent(s), is immediate administration of dantrolene sodium (Dantrium). Diagnostic testing of susceptibility is available but has significant limitations. If the new phosphorus nuclear magnetic resonance spectroscopy proves to be an accurate test for susceptibility and becomes more readily available, decreases in the current case-fatality rate of 10% may follow.
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PMID:Malignant hyperthermia. Quick recognition and treatment to avoid death. 272 33

Previous studies demonstrated that lipid profiles of humans and pigs susceptible to malignant hyperthermia (MH) differ from those of normal humans and pigs. Lipid extraction techniques retaining in vivo lipid profiles most closely were used in the present study to determine if stimulation of lipolysis by the processes of homogenization or extraction might account for the reported differences in lipid profiles. No differences were observed among three genotypes of British Landrace pigs with respect to cholesterol levels, triglyceride levels, or total lipid phosphorus values of whole muscle (longissimus dorsi). Phospholipid distributions were the same for all three groups. Individual free fatty acids and fatty acids acylated to triglycerides were similar among the genotypes. These results do not support altered lipid profiles in vivo in MH-susceptible swine. Previously used homogenization and extraction procedures most likely affect the lipolytic activity to a different extent in muscle from MH-susceptible pigs and normal pigs.
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PMID:Lipid analysis of skeletal muscle from pigs susceptible to malignant hyperthermia. 319 66

Porcine stress syndrome (PSS) which is an example of malignant hyperthermia (MH) in swine has previously been attributed to oxidative stress primarily due to an inherited antioxidant abnormality in MH susceptible (MHS) animals. C-phenyl-N-tert-butyl nitrone (PBN), a free radical spin trap, was selected to investigate whether free radicals are involved in MH. If free radicals cause the MH stress attack, then PBN should alter the time required for the onset of the stress attack, or perhaps protect the animal from experiencing the stress attack. In vivo phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) was used to monitor metabolism in three to four week old normal and MHS piglets administered halothane as the stress challenge. Malignant hyperthermia was not reproducibly induced by halothane anesthesia. For those animals which did develop MH a dramatic fall in the level of PCr and a rise in the level of Pi was detected by 31P MRS. Intravenous administration of PBN prior to halothane exposure had no effect on the number of animals experiencing the stress attack. PBN does not appear to prevent, delay or reverse the onset of halothane-induced MH in three to four week old MHS piglets. The primary events leading to the MH syndrome do not appear to be influenced by the intervention of the type of free radicals normally trapped by PBN.
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PMID:In vivo 31P NMR spectroscopy studies of halothane induced porcine stress syndrome. No effect of C-phenyl N-tert-butyl nitrone (PBN). 822 33

A xenobiotic, well tolerated by the majority of treated patients, can cause serious complications in patients with individual susceptibility. Based on the hypothesis that such a phenomenon may occur in rare cases of rhabdomyolysis attributed to fenoverine (DCI), we designed a protocol to look for a genetic predisposition. Six patients were included who had previously had an episode of rhabdomyolysis after taking fenoverine. A seventh patient was added, who had only experienced myalgia without cytolysis. All patients were investigated by the following tests: 31-phosphorus nuclear magnetic resonance spectroscopy, histopathological examination of the muscle, muscle contraction tests and biochemical analysis of the muscle. All patients examined proved to have muscle abnormalities. The pathology found varied greatly from patient to patient: mitochondrial myopathy, lipid storage myopathy, sensitivity to malignant hyperthermia or disorders of oxidative metabolism. The probability of finding by chance such rare muscle disorders associated with the equally rare rhabdomyolysis attributed to fenoverine is practically zero. We conclude that there is a cause and effect link between underlying abnormalities and the muscular cytolysis attributed to fenoverine.
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PMID:Research into individual predisposition to develop acute rhabdomyolysis attributed to fenoverine. 890 30

Our aim was to develop an exercise protocol using 31P-magnetic resonance spectroscopy (31P-MRS), which can discriminate between malignant hyperthermia-susceptible (MHS) individuals and controls. MRS spectra of the forearm muscles were recorded at rest, during and after a standardized exercise protocol in 10 MHS patients and compared with spectra obtained in 10 controls. There was no difference in resting intracellular pH (pHi) or PCr/(Pi+PCr) ratio between the groups (PCr = phosphocreatine, Pi = inorganic phosphorus). At the end of the exercise and during the initial recovery phase, the pHi and PCr/(Pi+PCr) ratio were significantly lower in the MHS group ([pHi: 6.37 (0.07) for MHS vs 6.70 (0.05) for controls, P < 0.005; PCr/(Pi+PCr): 0.784 (0.017) for MHS vs 0.954 (0.020) for controls, P < 0.0005]). For PCr/(Pi+PCr), complete separation between the two groups was observed during the initial recovery phase. The mean recovery time of PCr/(Pi+PCr) was 0.57 min for the control group and 1.28 min for the MHS group. The slower recovery of PCr/(Pi+PCr) is likely to be caused by a combination of several factors, including the lower pHi in MHS subjects at the start of recovery (inhibiting ATP production) and excessive sarcoplasmic calcium overload (causing continued enzyme activation and ATP consumption). Our exercise protocol can be a valuable adjunct to discriminate between MHS and non susceptible subjects.
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PMID:Slower recovery of muscle phosphocreatine in malignant hyperthermia-susceptible individuals assessed by 31P-MR spectroscopy. 940 43

31P nuclear magnetic resonance spectroscopy was performed on 19 to 55 kg weighing pigs of different MHS genotypes to study the changes of phosphorus components (inorganic phosphate --Pi, phosphocreatine--PCr and adenosine triphosphate--ATP) of muscle metabolism as well as intramuscular pH under application of halothane. Aim of the present study was to observe the changes in energy metabolism and to perform a comparison with also measured blood parameters. Both, NN and Nn pigs did not show any changes during halothane exposure in phosphorus spectra, but in all animals a partially metabolically compensated respiratoric acidosis was found. In all MHS positive pigs a rapid fall of PCr and a corresponding raise of Pi levels in muscle was observed.
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PMID:[In vivo investigations of stress susceptibility in pigs by means of magnetic resonance spectroscopy]. 941 Jul 28

Phosphorus magnetic resonance spectroscopy (P-MRS) has now been used in the investigation of muscle energy metabolism in health and disease for over 15 years. The present review describes the basics of the metabolic observations made by P-MRS including the assumptions and problems associated with the use of this technique. Extramuscular factors, which may affect the P-MRS results, are detailed. The important P-MRS observations in patients with mitochondrial myopathies, including the monitoring of experimental therapies, are emphasized. The findings in other metabolic myopathies (those associated with glycolytic defects or endocrine disturbances) and in the destructive myopathies (the dystrophies and the inflammatory myopathies) are also described. Observations made in normal and abnormal fatigue, fibromyalgia, and malignant hyperthermia are considered. Finally, a summary of the possible diagnostic use of P-MRS in exercise intolerance is provided.
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PMID:Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. 1095 34


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