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

This study provides the first comprehensive characterisation of the calcium (Ca) homeostasis defects found in muscle and lymphocytes of a malignant hyperthermia (MH)-susceptible dog. Novel findings regarding this dog are reported, compared to controls. First, a canine stress syndrome occurs, analogous to the porcine stress syndrome; susceptibility can be identified by exercise challenge testing. Secondly, caffeine causes Ca release from muscle sarcoplasmic reticulum in a greater amount and at a greater rate. Thirdly, there is a compensatory increase in Ca sequestration by sarcoplasmic reticulum. Fourthly, lymphocytes have lower cytosolic-free Ca and a greater ability to prevent Ca increase. Halothane increases Ca by a greater amount and rate. Fifthly, muscle is more resistant to the contracture-producing effects of caffeine, as occurs in the non-rigid variant of MH susceptibility in man. This resistance, despite increased caffeine-induced release through the Ca channel, may be attributable to increased Ca sequestration by sarcoplasmic reticulum. Finally, erythrocyte osmotic fragility and creatine kinase tests fail to distinguish between the MH-susceptible dog and controls.
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PMID:Canine stress syndrome/malignant hyperthermia susceptibility: calcium-homeostasis defect in muscle and lymphocytes. 230 Jul 6

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

Erythrocyte osmotic fragility, serum creatine kinase (CK) and its isoenzymes (CK-MM, CK-MB and CK-BB) were determined in pigs susceptible (SMH) and resistant (RMH) to malignant hyperthermia at three different body weights (Group 1, 10 to 25 kg; Group 2, 26 to 55 kg; Group 3, 56 to 95 kg). The halothane challenge test was used for determining susceptibility to malignant hyperthermia (MH). Significantly (P less than 0.05) greater erythrocyte haemolysis at saline concentrations of 80 to 100 mM NaCl occurred only between SMH and RMH pigs for body weight group 2. The determination of blood enzyme activities revealed also a significant (P less than 0.001) increase for total CK, CK-MM and CK-BB in SMH and RMH pigs of body weight Group 2. Furthermore in SMH pigs, total CK, CK-MM and CK-MB activities were significantly (P less than 0.05) greater in the animals of body weight Group 2. It was concluded that, in SMH pigs, weighing between 26 and 55 kg, there is a relationship between erythrocyte osmotic fragility, plasma CK, CK isoenzyme activities and muscle development.
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PMID:Erythrocyte osmotic fragility, serum creatine kinase and its isoenzymes related to body weight in porcine malignant hyperthermia. 236 58

A 6 month old domestic shorthaired cat died of suspected malignant hyperthermia. Anesthesia was induced and maintained with halothane vaporized in oxygen and nitrous oxide, after acepromazine premedication. Before an incision was made, the cat's heart rate dropped from 140 to 90 beats/min concomitant with a drop in blood pressure. Glycopyrrolate administration resulted in severe ventricular tachycardia (340 beats/min). Halothane and nitrous oxide were discontinued and the surgery was abandoned. Lidocaine administration resulted in a normal sinus rhythm. In recovery, the cat was tachypneic and struggling, with a rectal temperature of 40.1 degrees C that quickly increased to 41.4 degrees C. While the cat was being cooled, cardiac dysrhythmias progressed to ventricular fibrillation that was not responsive to cardiorespiratory resuscitation. Blood specimens obtained while the cat was being cooled showed hyperkalemia (10.0 mEq/L) and increased serum creatine kinase activity (780 IU/L). There was extreme extensor rigidity (rigor mortis) within 5 min of cardiac arrest. Results of microscopic and electron microscopic examination of muscle showed occasional perivascular infiltrates of lymphocytes with infrequent perimysial and epimysial neutrophils and a few sarcomeres with streaming of Z-bands (suggesting a contracted state). Histochemical evaluation of skeletal muscle showed no significant difference between type I and type II fibers.
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PMID:Suspected malignant hyperthermia after halothane anesthesia in a cat. 260 80

Signs of malignant hyperthermia, including progressive increases in PaCO2, skin temperature and heart rate, and elevated serum levels of potassium, inorganic phosphate, and creatine kinase, were identified in a halothane-anesthetized horse. Treatment was discontinuing halothane administration, applying ice and cold fluids, and hyperventilating with 100% oxygen. After an initial recovery, bilateral hindlimb myopathy and pigmenturia developed. The myopathy resolved after treatment with oral dantrolene, IV fluids, and hydrocortisone. Results of caffeine-halothane challenge, using semimembranosus muscle collected 2 weeks after the episode, were considered within normal limits for horses. The intraoperative abnormalities were evidently predictive of postanesthetic myopathy but the cause in this horse remained unclear.
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PMID:Postanesthetic equine myopathy suggestive of malignant hyperthermia. A case report. 260 79

Striated musculature is considered unusually tolerant to all kinds of injuries, and rhabdomyolysis associated with drug overdose or chronic drug intake is a rare event. This may be because striated musculature, in contrast to other tissues such as liver and kidney, shows little affinity for most drugs. Several different types of drug-induced rhabdomyolysis may be distinguished, and the clinical features of the condition may vary widely, from moderate myalgia to involvement of groups of muscles to involvement of the total skeletal musculature. In clinically asymptomatic rhabdomyolysis, early diagnosis is only made if routine laboratory tests include determination of serum creatine kinase. Determination of myoglobin in serum and urine is more sensitive and allows earlier diagnosis of muscle necrosis. Myoglobinaemia may lead to toxin-induced tubular necrosis, and impairment of renal function or even acute renal failure. About 10% of all cases of acute renal failure are due to rhabdomyolysis. Fulminant rhabdomyolysis may be associated with excessive hyperkalaemia and hypocalcaemia which may induce further life-threatening complications. Therefore, early diagnosis of rhabdomyolysis is most important for prevention of its potentially life-threatening sequelae. Therapy of rhabdomyolysis consists of supportive and specific measures. Early diagnosis may help to prevent life-threatening sequelae like acute renal failure, electrolyte imbalance and shock. Withdrawal of the incriminated drug or detoxification in drug overdose should be followed by supportive measures including infusion therapy and correction of dehydration and electrolyte imbalances. Forced diuresis with sodium bicarbonate may protect the kidney function from acidosis and precipitation of myoglobin in tubules. Elimination of myoglobin from plasma may be enhanced by plasmapheresis. In patients with acute renal failure, haemodialysis is necessary. In malignant hyperthermia, immediate infusion of dantrolene sodium is required. This drug also seems to have a beneficial effect in neuroleptic malignant syndrome. The repair mechanisms of striated musculature function extremely well. The prognosis of muscular atrophy after the acute stage of rhabdomyolysis is excellent. The same is true for the prognosis of acute renal failure. However, the extent of complications or survival of the acute stage of rhabdomyolysis strongly depend on early diagnosis and start of adequate therapy.
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PMID:Clinical features, pathogenesis and management of drug-induced rhabdomyolysis. 265 42

Malignant hyperthermia (MH) is a pharmacogenetic disease in man and animals. It primarily involves skeletal muscle tissue, but other tissues might be affected to a lesser degree. Calcium homeostasis in muscle cells is upset in susceptible individuals, so that various agents and circumstances can increase the free, ionised intracellular calcium concentration to damaging levels. The primary defect is not known at present, but is believed to involve an abnormally sensitive calcium-induced calcium release mechanism. Thus small, localised increases in calcium concentration releases more calcium so that a vicious cycle is triggered. The increased calcium concentration causes multiple effects in the muscles by stimulating contraction and a hypermetabolic state, clinically observed as rigidity and fever. If demands on the homeostatic mechanisms to lower the calcium concentration become exhausted, and metabolism is insufficient to supply enough phosphocreatine and ATP, membrane potentials cannot be maintained, and permeability of the cell membranes increase. This causes loss of phosphate and H+ as well as K+ and Mg++, and later myoglobin and creatine kinase. Thereby oxidative metabolism is further impeded with formation of lactate as a result. The ensuing acidosis stimulates sympathetic innervation, resulting in tachycardia, high blood pressure, and vasoconstriction. Hyperkalemia causes arrhythmia. Dantrolene inhibits the release of calcium and can halt the process if given before depletion of the energy rich phosphates is too advanced.
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PMID:Pathophysiology of malignant hyperthermia. 269 55

We report on a patient with neuroleptic malignant syndrome (NMS) caused by a therapy for endogenous depression. The symptoms were hyperpyrexia (39.2 degrees C), rigidity, elevated creatine kinase (CK: 594 U/l) and coma. After transfer from an outside hospital, he was treated, at first without effect with dantrolene p.o. (80 mg q.i.d.) and i.v. (1 mg/kg-1/h-1). Clinical improvement and temperature reduction were noted when the levels of neuroleptic drugs fell during unspecific intensive care with mechanical ventilation, sedation (flunitrazepam, barbiturates), relaxation (pancuronium), and hydration. After uncomplicated weaning from the ventilator the patient became more cooperative and was returned to the psychiatric ward. Further treatment took the form of combined drug therapy with biperiden and flunitrazepam and in addition a series of 12 electroconvulsive therapies (ECT). The elevated CK levels initially decreased, serum potassium levels were found to be within normal limits, and myoglobinuria was not detected during the further course. Trigger agents for NMS are antipsychotic drugs such as thioxanthenes, phenothiazines and butyrophenones. Because the signs and symptoms are so similar to those of malignant hyperthermia (MH), it has been suggested that NMS and MH are related diseases. The postulated mechanisms of NMS become apparent in the CNS, whereas those of MH affect the muscle cell itself. An abnormal in vitro contraction test after NMS should suggest to triggering of MH crisis after succinylcholine administration in anaesthesia for ECT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The malignant neuroleptic syndrome and malignant hyperthermia]. 272 40

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

During the last 4 years different diagnostic procedures for the detection of malignant hyperthermia (MH) susceptibility have been used at the authors' clinical unit; this study was designed to compare the results of these tests. PATIENTS AND METHODS. Since March 1983, 158 patients have been referred for the following reasons: group A: probands (n = 17) who had had symptoms of MH during anesthesia; group B: patients of probands (n = 48) if the latter were not tested because of age (n = 24) or death (n = 2); group C: relatives from MH families (n = 86); group D: patients (n = 5) who developed fever during stress and/or physical activity (n = 3), had myotonia (n = 1), or developed rhabdomyolysis during intensive care (n = 1); group E: controls (n = 2). Two static halothane and two static caffeine tests according to the European protocol were performed in all patients (n = 158). Histological examinations of skeletal muscle (fixed in glutaraldehyde, stained with hematoxylin-eosin, Gieson, and toluidine blue) were done in the first 100 patients; all specimens were scored by the same investigator (E.S.). Score 0: normal; 1: increased number of sarcolemma cores; 2: 1+cores forming groups; 3: 1+2+fiber degeneration; 4: specific changes-myopathies. Plasma levels of creatine kinase (CK) were determined in the first 50 patients. Complete neurological examinations, including electromyography (EMG), were done in ten patients who had increased CK levels as well as histological scores of 3 or 4 (Table 1).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Malignant hyperthermia in Austria. II. A comparison of the results of diagnostic test procedures]. 341 55


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