Body temperature malignant hyperthermia

Body temperature Malignant hyperthermia occurred 3 hours after the start of an operation for esophageal resection in an 82-year-old man after anesthesia induced with propofol and suxamethonium and maintained with sevoflurane [6 ]. Masseter spasm was not a feature. End-tidal CO2 rose to 55 mmHg and body temperature exceeded 39.0°C. The patient responded promptly to dantrolene. Reports of malignant hyperthermia in patients over the age of 80 years are unusual. Both suxamethonium and sevofiur-ane are potent triggers. 

Malignant hyperthermia (MH) is an autosomal-dominant pharmacogenetic disorder that is triggered by exposure to inhalation of general anesthetics, such as halothane. In susceptible individuals, these drugs can induce tachycardia, a greatly increased body metabolism, muscle contracture and an elevated body temperature (above 40°C) with a rapid rate of increase. Many cases of MH are linked to a gene for type 1 ryanodine receptor (RyRl). 

Porphyria is not the only disorder that may he inadvertently precipitated by the administration of a drug. Malignant hyperthermia is a serious, life-threatening complication of general anesthesia with halothane, methoxyflurane, and succinylcholine. It occurs in 1 in 20,000 people. Clinically, it is characterized hy high body temperature (41°C), muscle rigidity, and cardiovascular collapse. 

The pharmacologic effects of Rohypnol include sedation, muscle relaxation, and anxiety reduction. The sedative effects are said to be seven to 10 times that of diazepam (Valium). In high doses, flunitrazepam can cause malignant hyperthermia, or a sharp increase in body temperature that can cause muscle breakdown and failure of the kidneys and cardiovascular system. 

Malignant hyperthermia An unusual adverse response to some inhalation anesthetics such as halothane in which there is an acute dramatic elevation in body temperature as well as tachypnea, muscle rigidity, and hyperkalemia. 

C. Malignant hyperthermia does not involve central brain control of temperature but is caused by metabolic alterations. Regardless of the source of energy—whether fatty acids or the utilization of ATP to support muscle contraction—the electron transport chain is involved. Uncoupling of oxidation from ADP phosphorylation is caused by uncoupling proteins that dissipate energy as heat. This causes the elevation of body temperature seen in this patient. 

Malignant hyperthermia is most likely, given that anesthetic agents stimulate a calcium release channel, leading to excessive Ca + release from the cistemae of the sarcoplasmic reticulum, in turn causing muscle contraction, an increase in body temperature, tachycardia, and subsequent metabolic acidosis. 

All of these anaesthetics (and suxamethonium, see page 235) have the potential to cause malignant hyperthermia. This is a rare but potentially lethal complication of anaesthesia. It is characterized by a rapid rise in body temperature, due to excessive muscle contractions, together with increased heart rate and acidosis. It is treated as an emergency with dantrolene, which causes muscle relaxation. 

The drug of choice in malignant hyperthermia is dantrolene, which prevents release of calcium from the sarcoplasmic reticulum of skeletal muscle cells. Appropriate measures must be taken to lower body temperature, control hypertension, and restore acid-base and electrolyte balance. The answer is (C). 

Prompt treatment is essential in malignant hyperthermia to control body temperature, correct acidosis, and prevent calcium release. Dantrolene blocks the release of activator calcium from its stores in the sarcoplasmic reticulum, preventing the tension-generating interaction of actin with myosin. The answer is (B). 

Body temperature Sevoflurane has once again been linked to malignant hyperthermia, in a 37-year-old man in whom the genetic link was found in the ryanodine receptor [10 ]. The current recommendations of the European Malignant Hyperthermia Group are to perform open muscle biopsy followed by an in vitro contracture test and molecular... 

Aimed to circmnvent, or at least alleviate, these problems, clinical hyperthermia - the therapeutic approach whereby elevated temperatures damage and/or kill malignant cancer cells within the body - is an attractive approach, given the relatively non-specific nature of heat treatment. It has already been used with some success as a adjunct to radiotherapy and chemotherapy, with some synergistic effects having been observed. That said, the design parameters of hyperthermia treatments inevitably do still rely in part on the cancer biology. In particular these include the therapeutic... 

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