Hyperthermia - malignant
Key points
- Malignant hyperthermia is a group of inherited muscle problems characterized by muscle breakdown following certain stimuli - such as anesthesia, extremes of exercise (particularly in hot conditions), fever, or use of stimulant drugs.
- Malignant hyperthermia is inherited as an autosomal dominant trait (it requires only one affected parent for a child inherit the condition).
- Treatment The best course of action for this condition is prevention.
- Repeated episodes or untreated episodes can cause kidney failure.
Alternative names
Malignant hyperthermia; Hyperpyrexia - malignant
Definition
Malignant hyperthermia is a group of inherited muscle problems characterized by muscle breakdown following certain stimuli - such as anesthesia, extremes of exercise (particularly in hot conditions), fever, or use of stimulant drugs. The problems associated with this condition result from over-excitable muscles that contract uncontrollably, severe fever, abnormal heart rhythms, and kidney failure.
Causes, incidence, and risk factors
Malignant hyperthermia is inherited as an autosomal dominant trait (it requires only one affected parent for a child inherit the condition). It may be associated with muscular diseases such as muscular dystrophy and central core disease.
Malignant hyperthermia is often noted for the first time during administration of anesthesia. The anesthetized patient rapidly develops a high fever and muscle rigidity. During these episodes, muscle tissue is destroyed and break-down products of muscle may damage the kidneys and cause acute renal failure. The urine may turn dark due to released muscle pigments (see rhabdomyolysis).
Malignant hyperthermia can be fatal if not treated immediately. It can be prevented by administration of appropriate drugs before anesthesia.
Symptoms
- Rapid rise in temperature following administration of anesthesia
- Muscle rigidity and stiffness following administration of anesthesia
- Dark brown coloration to urine
- Muscle ache without obvious exercise to explain sore muscles
- Family history of malignant hyperthermia or unexplained death during anesthesia
Signs and tests
- Blood chemistry (see chem-20) shows increased blood levels of creatine phosphokinase (CPK), potassium, uric acid, phosphate.
- Myoglobin in the urine is elevated.
- Muscle biopsy using an in vitro contracture test may show abnormal results in response to certain drugs such as caffeine and halothane (an anesthetic).
- Muscle biopsy may show abnormal muscle, such as central cores, in some types.
- Genetic testing such as ryanodine receptor (RYR1) may show gene abnormalities.
- Phosphorus magnetic resonance spectroscopy, a research test, may show abnormal muscle function.
The best course of action for this condition is prevention. If a general anesthetic is to be given, pretreatment with dantrolene sodium is recommended. If you have a family history of anesthesia-induced problems it is imperative to alert your surgeon and anesthesiologist.
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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