Malignant Hyperthermia Flashcards
What type of disease is malignant hyperthermia?
A genetic disorder, hypothesised to cause abnormal regulation of muscle contraction
How many people are effected by malignant hyperthermia?
etween 1 in 10,000 and 1 in 50,000 individuals
What is the effect of malignant hyperthermia?
Affected individuals are at risk for a potentially life‐threatening syndrome on exposure to any of the various inhalation anesthetic agents, particularly halothane
What are the symptoms and onset of malignant hyperthermia?
Onset of the syndrome in the setting of the operating room is typified by the development of tachypnea (rapid breathing), low plasma [O2], high plasma [CO2], tachycardia (rapid heart rate), and hyperthermia (rising body temperature) as well as by rigidity, sweating, and dramatic swings in blood pressure.
The patient’s temperature may rise as rapidly as 1°C every 5 minutes. The onset of MH is usually during anesthesia, but it can occur up to several hours later
If untreated, what occurs to individuals experiencing malignant hyperthermia?
the patient will develop respiratory and lactic acidosis, muscle rigidity, and a breakdown of muscle tissue that leads to the release of K+ and thus profound hyperkalemia
What occurs in the muscle tissues during malignant hyperthermia?
a progressively severe hypermetabolic state
What may cause the uncontrolled muscle contraction in malignant hyperthermia?
the administration of halothane and succinylcholine‐causes excessive ATP hydrolysis to provide energy for contraction. The increased rate of ATP hydrolysis leads to an increased metabolic rate as muscle tries to replenish and to sustain its ATP stores. Hyperthermia develops because of the heat liberated by the hydrolysis of ATP.
How is malignant hyperthermia inherited?
Inheritance of MH follows a mendelian autosomal dominant pattern
Who else suffers from malignant hyperthermia
The poor pigs :’(
Farms = evil + unnecessary
Go vegan
What condition similar to MH may occur in patients treated with neuroleptic agents such as the phenothiazines or haloperidol?
neuroleptic malignant syndrome
What is the cause of neuroleptic malignant syndrome?
Abnormally high neuronal input to the muscle cells.
What is the treatment for malignant hyperthermia?
Administration of the drug dantrolene, cessation of anesthesia, and aggressive efforts aimed at cooling the body
Therapy also includes intravenous hydration and the judicious use of diuretics to keep the urine flowing; this lessens damage to the kidneys from the release of breakdown products, such as myoglobin from the damaged muscles.
Sodium bicarbonate is given to counter the lactic acidosis, and patients may be mechanically hyperventilated to blow off the excess CO2.
Why is dantrolene an effective therapeutic agent for malignant hyperthermia?
because it blocks EC coupling between T tubules and the SR, thus interrupting the otherwise uncontrolled progression of muscle contractions
When may dantrolene be given for a patient with malignant hyperthermia?
The drug can be given acutely in an effort to abort an ongoing attack, or in a person known to be at risk, it can be given before the initiation of anesthesia to prevent onset of the syndrome.
How may one test for malignant hyperthermia?
The relatives of a patient with a documented history of one episode of MH should be carefully screened to see whether they, too, carry the inherited trait; many of the affected relatives may demonstrate baseline elevations in muscle enzyme levels in their blood (e.g., an increase in creatine kinase levels).
