Glossary

Please find a list of useful terms linked to Malignant Hyperthermia.
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A

  • Acidosis: excess acid in the tissues
  • Allele: the form of a gene carried by an individual that determines the characteristic of the protein formed from that gene
  • Anaesthesia: a state of insensibility
  • Arrhythmia: an abnormal electrical rhythm of the heart.
  • ATP: the principal source of energy for immediate use within cells
  • Autosomes: the 22 pairs of chromosomes other than the X and Y chromosomes

B

C

  • Cardiac arrest: failure of the heart to produce a cardiac output.
  • Cardiac muscle: the highly specialised striated muscle of the heart
  • Central core disease: a congenital myopathy where demarcated cores are observed on microscopic examination of muscle tissue
  • Chromosome: The structures of the nucleus formed by DNA
  • Classical heatstroke: heatstroke resulting from high environmental temperature
  • Core myopathy: a congenital myopathy where there is a patch or patches with absence of enzyme staining on microscopic examination of the tissue
  • Creatine kinase: An enzyme originating in muscle tissue and measured in the blood as an indicator of muscle activity or muscle damage

D

  • Desflurane: a potent inhalational anaesthetic
  • DIC: disseminated intravascular coagulation, a disorder of clotting of the blood resulting in thrombosis within blood vessels and excessive bleeding from damaged blood vessels
  • DNA: deoxyribose nucleic acid, the chemical building blocks of genes
  • Dominant disorder: a genetic disorder requiring only one abnormal copy of the gene
  • Dynamic halothane test: in vitro contracture test in which muscle is exposed to halothane during a controlled stretch and relaxation manoeuver of the muscle

E

  • Excitation-contraction coupling: the process whereby an electrical signal arriving from a nerve at the muscle is converted into muscle contraction
  • Exertional heat illness: heat illness developing during physical activity or physical exertion
  • Exertional heatstroke: heatstroke associated with physical activity or physical exertion

F

G

  • General anaesthesia: A reversible drug induced coma with amnesia, insensibility to pain and muscle relaxation
  • Genes: the sequences of DNA that encode individual proteins
  • Genetic variant: A term used to indicate a change in the sequence of a gene which may or may not be of functional and/or disease significance.

H

  • Halothane: a potent inhalational anaesthetic used in the diagnostic tests for malignant hyperthermia
  • Heat illness: A disorder arising from the body’s inability to maintain a normal body temperature or as a consequence of maintaining a normal body temperature during heat stress.
  • Heat Stroke: A combination of markedly raised core body temperature and neurological dysfunction affecting the brain.
  • Hypercapnia: high concentration of carbon dioxide in the expired air
  • Hyperkalaemia: high serum potassium concentration
  • Hyperoxia: A lack of oxygen supply to the tissues
  • Hyperpyrexia: a severe pyrexia
  • Hyperthermia: high body temperature in the presence of a normal central thermoregulatory centre
  • Hypoxaemia: a lack of oxygen in the blood

I

  • In vitro contracture test: laboratory tests performed on muscle biopsy specimens for the diagnosis of malignant hyperthermia
  • Inhalational anaesthetics: drugs that cause general anaesthesia and are administered through the lungs
  • Intravenous anaesthetic: a drug with anaesthetic properties administered through the vein
  • Ion channels: protein structures within membranes that enable the movement of ions across the membrane
  • Ions: chemical elements or molecules that carry a positive or negative electrical charge
  • Isoflurane: a potent inhalational anaesthetic

J

K

L

M

  • Malignant hyperthermia susceptibility: The genetic predisposition to develop malignant hyperthermia under general anaesthesia
  • Malignant hyperthermia; a life threatening progressive hyperthermic and hypermetabolic reaction under general anaesthesia
  • Membrane pumps: the proteins that use energy to restore the balance of ions across a membrane
  • Membranes: in cell biology, the principally lipid envelopes of cells and compartments within cells
  • Mitochondria: the component of cells responsible for the main source of energy production within cells, often referred to as cellular batteries
  • Muscle: tissue that has the fundamental property of being able to contract (shorten) and relax (lengthen)
  • Muscular dystrophy: A disease of the muscle that is progressive and involves wasting and fibrosis of the muscle
  • Mutation: in the medical sense, a mutation is a change in the sequence of a gene that leads to a change in the protein of functional significance associated with a disease or condition
  • Myoglobin: an oxygen storage protein of muscle tissue that leaks from muscle that is damaged and can cause renal damage.
  • Myopathy: a clinical disorder of skeletal muscle where the predominant feature is muscle weakness
  • Myotonia: a disorder of skeletal muscle characterised by impaired relaxation of the muscle

N

  • Neuromuscular blocking drug: a drug that causes paralysis by preventing the normal transmission of messages from the nerves to skeletal muscles
  • Nitrous oxide: otherwise known as laughing gas, a week anaesthetic gas that does not trigger malignant hyperthermia
  • Nucleus: the compartment of cells that contains chromosomes

O

P

  • Periodic paralysis: a condition where the patient suffers from episodes of muscle weakness, sometimes preceded or followed by myotonia
  • Polymorphism: a common variant within a gene
  • Pyrexia: high body temperature resulting from abnormal central set-point temperature

Q

R

  • Recessive disorder: A genetic disorder requiring two abnormal copies of a gene for the condition or disease to be apparent
  • Rhabdomyolysis: skeletal muscle necrosis or breakdown
  • Ryanodine receptor: calcium release channels of the sarcoplasmic reticulum, originally characterised by their ability to bind ryanodine
  • Ryanodine: a naturally occurring plant alkaloid originally developed as a pesticide.

S

  • Sarcolemma: the cell membrane of muscle cells
  • Sarcoplasm: The main compartment within muscle cells
  • Sarcoplasmic reticulum: the internal storage compartment for calcium in muscle cells
  • Sevoflurane: a potent inhalational anaesthetic
  • Sex chromosome: either the X or Y chromosome. Females carry 2X chromosomes whereas males carry 1X and 1Y chromosome
  • Sex linked: a genetic disorder associated with the sex chromosomes
  • Skeletal muscle: the type of striated muscle that is responsible for control and movement of the skeleton. It is also known as voluntary muscle as the majority of skeletal muscle is under conscious control of the brain
  • Smooth muscle: muscle cells in which contractile elements are not arranged in a sufficiently organised fashion for them to appear striped under the microscope. Smooth muscle is under the involuntary control of the autonomic nervous system and their local chemical environment
  • Static caffeine test: in vitro contracture test in which muscle is exposed to caffeine.
  • Static halothane test: an in vitro contracture test in which muscle is exposed to halothane
  • Striated muscle: muscle in which the contractile elements are arranged in a highly organised way. The pattern of overlapping filaments gives the muscle a striped appearance when viewed under a microscope
  • Suxamethonium: a neuromuscular blocking drug that is implicated in the triggering of malignant hyperthermia

T

  • Tachycardia, a fast heart rate
  • Triggering drugs: drugs that initiate a malignant hyperthermia reaction

U

V

W

X

Y

Z