Malignant hyperpyrexia

The susceptibility to MH can be identified with in vitro testing of muscle exposed to halothane and caffeine. It is a time-consuming technique, requiring an open muscle biopsy. It would therefore be desirable to develop a simpler method. The main disturbance of MH is hypermetabolism of muscle, however platelets also contain contractile elements and there have been descriptions of abnormalities of platelet metabolism and aggregation [103,104]. 

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Metabolic Myopathies Glycogen Storage Disease Disorders of Lipid Metabolism Respiratory Chain Disorders Mitochondrial DNA Abnormalities Myotonias, Periodic Paralyses, and Malignant Hyperpyrexia Myotonias... 

To cover these various disorders in an orderly and comprehensive manner, the following sections are devoted, respectively, to the muscular dystrophies the congenital myopathies the metabolic myopathies the myotonias, periodic paralyses, and malignant hyperpyrexia the neurogenic disorders the inflammatory muscle disorders the endocrine myopathies and the drug-induced and toxic myopathies. 

Denborough, M.A., Galloway, G.J., Hopkinson, K.C. (1982). Malignant hyperpyrexia and sudden infant death. Lancet 2, 1068-1069. 

Succinylcholine-induced hyperkalemia may lead to cardiac arrhythmia and arrest when plasma reaches 7 and 10 mM, respectively. The drug also may precipitate a fulminant attack of malignant hyperthermia in susceptible individuals (not to be confused with neuroleptic malignant hyperpyrexia, which involves dopamine and the CNS). Treatment in either case consists of cooling the body and administering oxygen and dantrolene sodium (discussed later). 

Procaine forms poorly soluble salts or conjugates with some drugs [12], and was reported to be a strong prostaglandin antagonist and a weak agonist [13]. It is used in the treatment of malignant hyperpyrexia [14-17]. Procaine hydrochloride was also used by intravenous injection for the relief of pain in acute pancreatitis [18-21],... 

No volatile anaesthetic drug should be given to a patient with known or suspected malignant hyperpyrexia syndrome. 

Desflurane has a marked depressant effect at the neuromuscular junction. At clinical concentrations it tends to reduce the train-of-four (TOP) ratio—possibly a prejunctional effect. It prolongs neuromuscular blockade by both non-depolarising and depolarising relaxants and may trigger malignant hyperpyrexia in susceptible patients. 

Increase in intraocular pressure Increase in intracranial pressure Masseter muscle spasm Hyperkalaemia in susceptible patients Cardiovascular effects Prolonged block Anaphylaxis Malignant hyperpyrexia... 

Idio ncrasy. This is a response that is qualitatively different from the action of the drug in normal individuals, again often genetically determined. Of importance to anaesthetists are abnormal responses to several drugs in patients with acute intermittent porphyria, and in those susceptible to the malignant hyperpyrexia syndrome. 

A Protocol for the Investigation of Malignant Hyperpyrexia (MH) Susceptibility. The European Malignant Hyperpyrexia Group. Br J Anaesth 56(11) 1267-9. 

Abnormality of calcium regulation Anesthetics, general, (halothane), muscle relaxants (succinylcholine) Malignant hyperpyrexia... 

The procedure was continued with a propofol infusion. No treatment for malignant hyperpyrexia was undertaken and no other markers for malignant hyperpyrexia were observed. She made a normal recovery from anesthesia. Creatine kinase activities were raised at 2370 U/1 intraoperatively and 18 046 U/1 at 20 hours postoperatively. 

The case is interesting in that although episodes of mass-eter spasm, rigidity, rhabdomyolysis, and malignant hyperpyrexia are well known after the use of halothane and suxamethonium, they have only rarely been reported when suxamethonium was not used. 

Malignant hyperpyrexia is a life-threatening condition that involves sustained muscle contraction, muscle damage, and the production of vast quantities of metabolic heat, carbon dioxide, and potassium. Although it is a rare complication of general anesthesia, it remains a topic of considerable interest (74). 

Genetic markers for malignant hyperpyrexia may soon make identification of risk groups simpler than the currently used muscle biopsy technique (75). 

Drury PM, Gilbertson AA. Malignant hyperpyrexia and anaesthesia. Two case reports. Br J Anaesth 1970 42(11) ... 

In one patient who took 900 mg of phenelzine, there was a marked excess of nrinary and plasma catecholamines, analogous to pheochromocjdoma, and the patient was successfully managed with alpha-adrenoceptor antagonists (44). In another patient, who probably took about 2000 mg of phenelzine, hyperpyrexia was prominent and responded to dantrolene sodium (45). The authors noted clinical similarities to malignant hyperpyrexia and neuroleptic malignant syndrome. 

Gronert GA, Milde JH. Hyperbaric nitrous oxide and malignant hyperpyrexia. Br J Anaesth 1981 53(11) 1238. 

Other cases of malignant hyperthermia have been reported in patients who received sevoflurane (50,51). Although it is highly likely that sevoflurane caused malignant hyperpyrexia in these cases, suxamethonium was also given and was also a suspect. 

Amide-based local anesthetic agents do not usually produce hypersensitivity reactions, although they may be re-spon.siblc for other unwanted effects and have been implicated in malignant hyperpyrexia. Families with a history of this disease should only be treated with cster-ba.scd local anesthetics. 

Please never write, fit for anaesthetic - it s ultimately the anaesthetist s call. I m often asked to assess notes for fimess for anaesthesia and can t take the history from the patient myself. Suxamethonium is commonly used for ECT, but can trigger malignant hyperpyrexia. It s greatly reassuring if the SHO s asked, Have any blood relatives had a problem with anaesthetic - and documented the answer in the notes. 

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