1/143. Suxamethonium, masseter spasm and later malignant hyperthermia.A 25-year-old man admitted with severe upper torso trauma displayed masseter muscle spasm after suxamethonium given during resuscitation. Anaesthesia was initially maintained with intravenous agents during transfer and X-ray angiography. However, during surgery to correct a brachial artery injury, malignant hyperthermia was triggered when isoflurane was given, 2.5 h after the suxamethonium. He responded to treatment, including dantrolene administration. Peak serum and urine myoglobin were 12,947 micrograms.l-1 and 54,571 micrograms.l-1, respectively, while maximum serum creatinine kinase was 17,300 IU. The patient made an uneventful recovery and later proved positive for malignant hyperthermia susceptibility on muscle contracture tests.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
2/143. Screening of the ryanodine receptor gene in 105 malignant hyperthermia families: novel mutations and concordance with the in vitro contracture test.malignant hyperthermia (MH) in man is an autosomal dominant disorder of skeletal muscle Ca(2 )-regulation. During anesthesia in predisposed individuals, it is triggered by volatile anesthetics and depolarizing muscle relaxants. In >50% of the families, MH susceptibility is linked to the gene encoding the skeletal muscle ryanodine receptor (RYR1), the calcium release channel of the sarcoplasmic reticulum, on chromosome 19q12-13.2. To date, 21 RYR1 mutations have been identified in a number of pedigrees. Four of them are also associated with central core disease (CCD), a congenital myopathy. Screening for these 21 mutations in 105 MH families including 10 CCD families phenotyped by the in vitro contracture test (IVCT) according to the European protocol revealed the following approximate distribution: 9% Arg-614-Cys, 1% Arg-614-Leu, 1% Arg-2163-Cys, 1% Val-2168-Met, 3% Thr-2206-Met and 7% Gly-2434-Arg. In one CCD family, the disease was caused by a recently reported MH mutation, Arg-2454-His. Two novel mutations, Thr-2206-Arg and Arg-2454-Cys were detected, each in a single pedigree. In the 109 individuals of the 25 families with RYR1 mutations cosegregation between genetic result and IVCT was almost perfect, only three genotypes were discordant with the IVCT phenotypes, suggesting a true sensitivity of 98.5% and a specificity of minimally 81.8% for this test. Screening of the transmembraneous region of RYR1 did not yield a new mutation confirming the cytosolic portion of the protein to be of main functional importance for disease pathogenesis.- - - - - - - - - - ranking = 1.5keywords = muscle (Clic here for more details about this article) |
3/143. survival of an oral surgery patient with malignant hyperthermia.malignant hyperthermia is a life-threatening complication of general anesthesia. Its cause is not precisely known but it appears to be related to a genetic defect that allows increased release or decreased reaccumulation of calcium by the sarcoplasmic reticulum whech then results in a hypermetabolic state. As with any unexpected complication when a patient is under general anesthesia, early diagnosis and treatment are essential. The early clinical signs that the surgeon and anesthesiologist shoulc be alert to are unexplained tachycardia, unexplained tachypnea, muscular rigidity, and increased temperature. Therapy should be accurate and immediate. The essentials of therapy are discontinuance of the anesthetic agent; immediate, active, and aggressive cooling; administration of procaine or procaine amide, 1 mg/kg/min until the pulse slows; correction of electrolyte and acid-base imbalances; maintenance of urinary output with furosemide and large volumes of fluids, intravenously; and supportive care. A thorough knowledge of the management of malignant hyperthermia ahd the pathophysiology of the complications that may occur with general anesthesia will allow the oral surgeon to fully meet his obligations to his patients.- - - - - - - - - - ranking = 448.15122615842keywords = rigidity (Clic here for more details about this article) |
4/143. malignant hyperthermia in infancy and identification of novel RYR1 mutation.malignant hyperthermia (MH) has been reported as non-existent in children less than 1 yr old, although several unconfirmed reports have been published. A case report of MH in a 6-month-old child is presented, with confirmation of MH susceptibility by in vitro contracture testing of quadriceps muscle at 13 yr old. Genetic analysis revealed a novel RYR1 mutation that substitutes arginine 2452 for tryptophan in a region of the calcium channel mutated in several other MH pedigrees.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
5/143. A double mutation in families with periodic paralysis defines new aspects of sodium channel slow inactivation.Hyperkalemic periodic paralysis (HyperKPP) is an autosomal dominant skeletal muscle disorder caused by single mutations in the SCN4A gene, encoding the human skeletal muscle voltage-gated Na( ) channel. We have now identified one allele with two novel mutations occurring simultaneously in the SCN4A gene. These mutations are found in two distinct families that had symptoms of periodic paralysis and malignant hyperthermia susceptibility. The two nucleotide transitions predict phenylalanine 1490-->leucine and methionine 1493-->isoleucine changes located in the transmembrane segment S5 in the fourth repeat of the alpha-subunit Na( ) channel. Surprisingly, this mutation did not affect fast inactivation parameters. The only defect produced by the double mutant (F1490L-M1493I, expressed in human embryonic kidney 293 cells) is an enhancement of slow inactivation, a unique behavior not seen in the 24 other disease-causing mutations. The behavior observed in these mutant channels demonstrates that manifestation of HyperKPP does not necessarily require disruption of slow inactivation. Our findings may also shed light on the molecular determinants and mechanism of Na( ) channel slow inactivation and help clarify the relationship between Na( ) channel defects and the long-term paralytic attacks experienced by patients with HyperKPP.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
6/143. exercise rhabdomyolysis in military aircrew: two cases and a review of aeromedical disposition.INTRODUCTION: exercise rhabdomyolysis (ER) is a rare, sometimes catastrophic condition where muscle fibers breakdown in response to exertion and release their breakdown products into the circulation. While ER was brought to the medical community's attention largely through reports from military training establishments we are unaware of ER having resulted from the activities of military aircrew. This paper reports two cases of ER in military aircrew and discusses the condition and the approaches taken in determining their future aeromedical disposition. case reports: rhabdomyolysis occurred in two military pilots as a result of their aircrew duties. One, an experienced pilot, suffered rhabdomyolysis as a result of centrifuge based G-training, while the other, a cadet in training, suffered rhabdomyolysis precipitated by exertion during moderately warm weather. Further investigation revealed the second case to also have the malignant hyperthermia Trait. AEROMEDICAL DISPOSTION: After wide consultation and lengthy deliberations both of these aircrew were returned to their full previous flying status. No further complications or recurrences have occurred.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
7/143. malignant hyperthermia in a patient with Graves' disease during subtotal thyroidectomy.We report the case of a 31-year-old man with Graves' disease who manifested malignant hyperthermia during subtotal thyroidectomy. His past medical history and family history were unremarkable. Before surgery, his condition was well controlled with propylthiouracil, beta-adrenergic blocker and iodine. During the operation, anesthesia was induced by intravenous injection of vecuronium and thiopental, followed by suxamethonium for endotracheal intubation. anesthesia was maintained with nitrous oxide and sevoflurane. One hour after induction of anesthesia, his end tidal carbon dioxide concentration (ET(CO2)) increased from 40 to 50 mmHg, heart rate increased from 90 to 100 beats per min and body temperature began to rise at a rate of 0.3 degrees C per 15 min. Suspecting thyroid storm, propranolol 0.4 mg and methylprednisolone 1,500 mg were administered, which, however, had little effect. Despite the lack of muscular rigidity, the diagnosis of malignant hyperthermia was made based on respiratory acidosis. Sevoflurane was discontinued and dantrolene was given by intravenous bolus. Soon after the treatment, ET(CO2), heart rate and body temperature started to fall to normal levels. His laboratory findings showed abnormally elevated serum creatine phosphokinase and myoglobin but normal thyroid hormone levels. Since dantrolene is efficacious in thyrotoxic crisis and malignant hyperthermia, an immediate intravenous administration of dantrolene should be considered when a hypermetabolic state occurs during anesthesia in surgical treatment for a patient with Graves' disease.- - - - - - - - - - ranking = 448.15122615842keywords = rigidity (Clic here for more details about this article) |
8/143. Intolerance to neuroleptics and susceptibility for malignant hyperthermia in a patient with proximal myotonic myopathy (PROMM) and schizophrenia.We report a patient with proximal myotonic myopathy who was treated with neuroleptics because of exacerbating schizophrenia. Under therapy with fluanxol, the patient developed muscle stiffness and oculogyric cramps. Treatment with both amisulpride and olanzapine lead to markedly elevated serum creatine kinase levels. An in-vitro contracture test was positive for halothane. Thus, in patients with all kinds of multisystemic myotonic myopathies, a susceptibility for malignant hyperthermia and intolerance towards neuroleptics should be taken into account.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
9/143. malignant hyperthermia associated with exercise-induced rhabdomyolysis or congenital abnormalities and a novel RYR1 mutation in new zealand and Australian pedigrees.malignant hyperthermia (MH) is rarely associated with specific myopathies or musculoskeletal abnormalities. Three clinical investigations of MH associated with either non-specific myopathies or congenital disorders in three separate families are presented. Two of these cases also show evidence of exercise-induced rhabdomyolysis. In each case MH susceptibility was confirmed by in vitro contracture testing of quadriceps muscle. dna sequence analysis of each kindred revealed the presence of a common novel mutation that results in an arginine401-cysteine substitution in the skeletal muscle ryanodine receptor gene (RYR1). Haplotype analysis using chromosome 19q markers indicated that the three families are likely to be unrelated, providing confirmation that the MH/central core disease region 1 of RYR1 is a mutation hot spot.- - - - - - - - - - ranking = 1keywords = muscle (Clic here for more details about this article) |
10/143. malignant hyperthermia: how to spot it early.malignant hyperthermia is a rare but potentially fatal metabolic syndrome triggered in susceptible patients by certain inhalational anesthetics and depolarizing muscle relaxants. Vigilant monitoring and quick intervention are essential in preventing organ damage and death.- - - - - - - - - - ranking = 0.5keywords = muscle (Clic here for more details about this article) |
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