malignant hyperthermia


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Related to malignant hyperthermia: Dantrolene

hyperthermia

 [hi″per-ther´me-ah]
1. greatly increased temperature; see also fever. Called also hyperpyrexia. adj., adj hyperther´mal, hyperther´mic.
2. a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as the state in which an individual's body temperature is elevated above his or her normal range.
malignant hyperthermia a syndrome affecting patients undergoing general anesthesia, marked by rapid rise in body temperature, signs of increased muscle metabolism, and usually rigidity. The sensitivity is inherited as an autosomal dominant trait.

ma·lig·nant hy·per·ther·mi·a

rapid onset of extremely high fever with muscle rigidity, precipitated by exogenous agents in genetically susceptible people, especially by halothane or succinylcholine. Compare: futile cycle.

malignant hyperthermia, susceptibility to, 1

An autosomal dominant (OMIM:145600) condition of variable penetration in which a patient, when subjected to certain anaesthetics (halothane, diethyl-ether, cyclopropane, enflurane and psychotropics), develops a potentially fatal reaction (up to 70% mortality in acute episodes), which occurs in 1/15,000 administrations of anaesthesics in children and 1/50–100,000 in adults; 1/2 of cases had not been previously sensitive to anaesthesia. Anaesthetised patients may develop high fever and muscle rigidity with rhabdomyolysis, release of myoglobin, renal damage and acute renal failure. 

Clinical findings
Tachycardia, tachypnoea, cyanosis, labile blood pressure, muscle rigidity, rapid and marked hyperpyrexia, acidotic, hyperkalemic, possibly DIC, renal failure; similar reactions may be evoked in these patients by warm weather, exercise, emotional stress or without known environmental cues, and are initiated by muscular hypermetabolism due to an idiopathic increase in sarcoplasmic calcium occurring under general anaesthesia. 

Diagnosis
Muscle contraction test with halothane or caffeine challenge.
 
Management
Hypothermia, hydration, sodium bicarbonate infusion, mechanical hyperventilation, diuretics to increased urine flow, dantrolene (an agent that blocks excitation-contraction coupling between T tubules and sarcoplasmic reticulum). 

Molecular pathology
Caused by defects in RYR1, which encodes ryanodine receptor 1, a calcium channel that mediates the release of Ca2+ from the sarcoplasmic reticulum and plays a key role in triggering muscle contraction.

ma·lig·nant hy·per·ther·mi·a

(mă-lig'nănt hī'pĕr-thĕr'mē-ă)
Rapid onset of extremely high fever with muscle rigidity, precipitated by exogenous agents in genetically susceptible people, especially by halothane or succinylcholine.

malignant hyperthermia

A rare inherited muscle disorder that leads to dangerously high fever from intense muscle contraction when the affected person is given a general anaesthetic drug such as halothane, cyclopropane or ethyl ether, or a muscle relaxant drug such as succinylcholine. Emergency treatment to cool the patient, to neutralize the rapid rise in blood lactic acid from the muscles, and to reverse the abnormal muscle response, is needed to save life.

Malignant hyperthermia

A type of reaction (probably with a genetic basis) that can occur during general anesthesia in which the patient experiences a high fever, the muscles become rigid, and the heart rate and blood pressure fluctuate.

ma·lig·nant hy·per·ther·mi·a

(mă-lig'nănt hī'pĕr-thĕr'mē-ă)
Rapid onset of extremely high fever with muscle rigidity, precipitated by exogenous agents in genetically susceptible people.
References in periodicals archive ?
Schuster, "Management of malignant hyperthermia: Diagnosis and treatment," Therapeutics and Clinical Risk Management, vol.
Dainese, "Calsequestrin-1: a new candidate gene for malignant hyperthermia and exertional/ environmental heat stroke," The Journal of Physiology, vol.
"A substitution of cysteine for arginine 614 in the ryanodine receptor is potentially causative of human malignant hyperthermia".
Tedeschi, "Sudden unexplained death in a patient with a family history of malignant hyperthermia," Journal of Clinical Anesthesia, vol.
Preparation of the Drager Fabius anesthesia machine for the malignant hyperthermia susceptible patient.
During a middle of the night laparoscopic appendectomy, Jan Palovik said words she never thought she would have to say: "Doctor, we have a Malignant Hyperthermia crisis." What happened next was just like we had practiced.
For example, before the early 1990's, pig malignant hyperthermia caused a two billion dollar loss each year in global pig production.
He wasn't sure of that when Steven flatlined for more than 30 minutes after a reaction to the general anesthesia - a rare syndrome called malignant hyperthermia, which creates a rapid breakdown and overheating of skeletal muscles.
Hollander and co-investigators (2003) first used the term malignant hyperthermia like syndrome (MHLS) when he identified six patients in hyperglycemic crisis without known exposure to an anesthetic.
A second similar syndrome is malignant hyperthermia, which also is characterized by muscle rigidity and hyperthermia that can reach 113[degrees]F.

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