Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant hyperthermia is a rare syndrome that occurs in genetically susceptible individuals who are exposed to frequently used inhalation anesthetics. The disorder is most common in children and young adults. It is triggered through a defect in the ability of skeletal muscles to concentrate and release calcium. Signs of malignant hyperthermia include hypercarbia, muscle rigidity and tachycardia. Temperature elevation is often a late sign of the syndrome. Treatment begins with stopping all inhaled anesthetics at the earliest sign of the syndrome. The use of dantrolene has significantly reduced mortality from malignant hyperthermia. No simple screening test exists. Family members or those with a suspicious history need to be counseled and should consider muscle biopsy and testing prior to surgery.
 ...
PMID:Malignant hyperthermia. 157 19

This retrospective study was undertaken to examine the management and outcome of children who developed isolated masseter muscle spasm (MMS) after the administration of intravenous succinylcholine during anesthetic induction. The inhalation anesthetics used for induction were continued in all of these cases. The medical records of 68 patients (male/female ratio, 1.7:1), identified from approximately 42,000 anesthetics given during the period 1980-1989, were reviewed. Fifty-seven children (2.3-12 yr old) were diagnosed as having isolated MMS, i.e., MMS without spasm of other muscles; 11 experienced generalized rigidity in combination with MMS. Anesthetic and postoperative management of these two groups differed. The overall incidence of MMS was 0.3% of inhalation anesthetics during which succinylcholine was given. Intraoperative arrhythmias occurred in 33% of the patients who developed isolated MMS and more frequently in older children. Most children experienced some degree of hypercarbia and/or metabolic acidosis, but the significance of these abnormalities in the spontaneously ventilating, fasting child is unknown. Serum creatine kinase levels when measured 18-24 h postoperatively were elevated in all but one child (n = 45). There was no long-term morbidity and no mortality. We conclude that failure of the masseter muscles to relax after succinylcholine is not uncommon in children. Based on our experience, and accepting that MMS may be part of the clinical spectrum of malignant hyperthermia, we believe that anesthesia can be continued safely in cases of isolated MMS when careful monitoring accompanies diagnostic evaluation. This differs from the current practice of discontinuing the anesthetic or switching to a nontriggering anesthetic technique.
 ...
PMID:Masseter muscle spasm in children: implications of continuing the triggering anesthetic. 186 39

The time course of changes in brain electrical activity during halothane anesthesia was examined in 12 malignant hyperthermia-susceptible (MHS) and 14 normal (nMHS) swine. Power densities in selected frequency bands were calculated from the electroen-cephalogram (EEG). EEG and systemic variables were determined over a period of 60 min after starting halothane (1% inspired). Malignant hyperthermia (MH) was triggered in all susceptible pigs. Initial changes in the EEG during development of MH consisted of a decrease in total power and a shift to lower frequencies (delta-theta activity) in all animals. These EEG alterations were noted when there was an increase in heart rate, but other systemic variables were still normal. EEG changes in all MHS animals started at an arterial oxygen tension (PaO2) greater than 90 mmHg and an arterial carbon dioxide tension (PaCO2) less than 50 mmHg. In 5 MHS animals EEG became isoelectric at a PaO2 of 61-82 mmHg and a PaCO2 of 53-68 mmHg. Mean arterial blood pressure at this time was 54-66 mmHg. To determine the effects of hypoxia on the EEG in 7 nMHS animals, oxygen was decreased over a period of 45-60 min to 7% inspired. In 7 other nMHS animals, hypercarbia was produced by admixture of carbon dioxide to the fresh gas supply to achieve incremental increases of PaCO2 to 110-120 mmHg. Significant EEG changes during hypoxia comparable to those seen at the onset of MH were noted at a PaO2 below 40 mmHg and during hypercarbia at a PaCO2 greater than 68 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Alterations in brain electrical activity may indicate the onset of malignant hyperthermia in swine. 224

It is generally assumed that the brain is not primarily involved in the development of a malignant hyperthermia syndrome (MH). However, spontaneous brain electrical activity (EEG) has not been related temporally to the development of haemodynamic, respiratory and metabolic changes during a fulminant MH crisis. In the present study cerebral blood flow (CBF) and spontaneous electroencephalogram (EEG) were recorded in 8 pigs susceptible (MHS) for the development of malignant hyperthermia and 8 non-susceptible pigs (nMHS) after exposure to 1% halothane. Power densities in selected frequency bands were calculated from the EEG. Additionally, body temperature and haemodynamic and blood gas parameters were studied over a period of 60 min. MH was triggered in all MHS animals. Following exposure to halothane initial EEG changes were noted after 20 to 30 min. They consisted of a decrease in total power and a shift to lower frequencies (delta-theta activity). At this time, CBF was significantly increased compared to control. In 4 animals an isoelectric EEG was noted at a PaO2 of 65-78 mmHg and PaCO2 of 52 to 64 mmHg. Characteristic changes for the development of an MH syndrome in haemodynamic and respiratory parameters as well as a rise in body temperature occurred after first EEG changes were seen. Our results do not support the hypothesis that early EEG changes during MH occur as a result of systemic hypotension, hypoxaemia, hypercapnia or cerebral ischaemia. Our data indicate that EEG monitoring in combination with monitoring of haemodynamic, respiratory and metabolic parameters may be of value for an early detection of an MH-crisis.
 ...
PMID:[Characteristics of cerebral blood flow and the electroencephalogram during experimental malignant hyperthermia]. 225 75

Two cases of malignant hyperthermia (MH) are presented. The first patient presented initially with tachyarrhythmia intraoperatively and rapid onset of MH crisis. Nasopharyngeal temperature of 43 degrees C was attained after 15-20 minutes of anaesthesia. The patient eventually died of myocardial failure despite external cardiac massage, inotropic support and ventricular pacing. The second patient presented with increasing endogenous hypercarbia following the administration of suxamethonium and isoflurane. The use of the end tidal carbon dioxide monitor led to an early diagnosis of MH. The early use of dantrolene may have contributed to the favourable outcome.
 ...
PMID:Malignant hyperthermia. 239 48

A 35-year-old 110 kg male developed marked hyperkalaemia, hyponatraemia, hypercapnia and hyperthermia during living-related renal transplantation under anaesthesia with oxygen-nitrous oxide, isoflurane and muscle relaxation with atracurium. This is the first report of successfully treated malignant hyperthermia triggered by isoflurane during renal transplantation with early appearance and persistent (to 12 hours after surgery) electrolyte abnormalities.
 ...
PMID:Atypical malignant hyperthermia with persistent hyperkalaemia during renal transplantation. 304 82

Expired carbon dioxide measurements (PeCO2) were used (1) to assess the adequacy of initial alveolar ventilation, and (2) to document intraoperative airway events and metabolic trends. Three hundred and thirty-one children were studied. Thirty-five intraoperative events were diagnosed by continuous PeCO2 monitoring; 20 were potentially life-threatening problems (malignant hyperthermia, circuit disconnection or leak, equipment failure, accidental extubation, endobronchial intubation, or kinked tube); only two of these were also diagnosed clinically. The duration of anaesthesia may be a factor: 3.9 hours for cases with events vs. 2.5 hours for cases without events (p less than 0.002). There was a higher incidence of hypercarbia (peak expired PeCO2 greater than or equal to 50) in children who were not intubated (29 per cent) compared to those who had an endotracheal tube in place (12 per cent) (p = 0.0001). Hypocarbia (peak expired PeCO2 less than or equal to 30) was more frequent in intubated cases (11 per cent) than in unintubated cases (three per cent) (p = 0.03). There was a high incidence of hypocarbia in infants less than one year of age (p = 0.02). We conclude: (1) life-threatening airway problems are common during anaesthesia in paediatric patients; (2) quantitative measurement of PeCO2 provides an early warning of potentially catastrophic anaesthetic mishaps; (3) the incidence of events increases with duration of anaesthesia.
 ...
PMID:Intraoperative events diagnosed by expired carbon dioxide monitoring in children. 308 6

Dantrolene sodium acts primarily by affecting calcium flux across the sarcoplasmic reticulum of skeletal muscle. Recently, dantrolene has been used very successfully in the treatment of several rare hypercatabolic syndromes which have previously been associated with high mortality rates. In malignant hyperthermia, where early diagnosis and treatment usually with intravenous dantrolene in association with other supportive measures (and often subsequent dantrolene therapy) is performed, recovery is seen in virtually 100% of patients. There is a rapid resolution of hyperthermia, dysrhythmias, muscle rigidity, tachycardia, hypercapnia, mottled or cyanotic skin, and metabolic acidosis, and a slower normalisation of myoglobinuria and elevated serum creatine phosphokinase levels. In patients with family history or previous episodes of malignant hyperthermia, prophylactic treatment with dantrolene prior to anaesthesia prevents the syndrome occurring in most cases. Where malignant hyperthermia has developed patients have been successfully treated with further dantrolene therapy. Dantrolene has also been used successfully in the treatment of a few cases of heat stroke and the neuroleptic malignant syndrome--both of which have many similarities to malignant hyperthermia. Dantrolene is well established in the treatment of patients with muscle spasticity where it generally improves at least some of the components of spasticity (i.e. hyper/hypotonia, clonus, muscle cramps and spasms, resistance to stretch and flexor reflexes, articular movement, neurological and motor functions and urinary control). However, in some patients, particularly those with multiple sclerosis, dantrolene may not be effective, and in many cases muscular strength may diminish. Long term dantrolene therapy has been associated with hepatic toxicity and may cause problems in patients treated for disorders of muscle spasticity. Thus, dantrolene offers a unique advance in the therapy available for the treatment of hypercatabolic disorders and is also useful in the treatment of muscle spasticity of various aetiology.
 ...
PMID:Dantrolene. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in malignant hyperthermia, the neuroleptic malignant syndrome and an update of its use in muscle spasticity. 352 59

Succinylcholine was administered by infusion to halothane-anesthetized ponies to determine dosage requirements for surgical relaxation up to 3 hours' duration. This was not possible to do, since 4 of 6 ponies studied developed severe reactions characterized by prolonged muscle fasciculations after the initial succinylcholine dose, muscle rigidity, hyperthermia, hypercapnia, tachycardia, increasing pulse pressure, and metabolic acidosis. The reactions resembled those associated with malignant hyperthermia, a disease recognized in persons and swine. Two ponies showed signs of the phase II or desensitization block of succinylcholine. All ponies recovered from anesthesia without signs of muscle injury.
 ...
PMID:Succinylcholine infusion associated with hyperthermia in ponies anesthetized with halothane. 666 Jun 17

Malignant hyperthermia is a potentially fatal condition inducible by volatile anaesthetics and/or suxamethonium in genetically susceptible individuals. A disturbed calcium homeostasis in skeletal muscle (possibly in the ryanodin receptor) results in elevated myoplasmatic calcium. The latter causes muscle contraction and a hypermetabolic state, clinically observed as rigidity, fever, hypercarbia, metabolic acidosis and hyperkalemia. Arythmia ensues. Dantrolene inhibits the release of calcium and can halt the process if the diagnosis is made early. A fatal incident of probable malignant hyperthermia in a 13 year old boy is described and evaluated according to a multifactorial clinical grading scale. The value of the in vitro contracture test to diagnose malignant hyperthermia is discussed. Suggestions concerning the treatment of masseterspasm rigidity, an acute episode of malignant hyperthermia, and safe anaesthesia for susceptible patients are presented.
 ...
PMID:[Malignant hyperthermia--still a current and dangerous problem]. 777 Aug 53


1 2 3 4 Next >>