Malignant hyperthermia

Disease Description (Causes and Symptoms)

• Definition: An emergency condition (heat stroke) in which the core body temperature rises abnormally because the thermoregulatory center cannot cope with a hot environment or a sudden heat load, accompanied by dysfunction of the central nervous system.
• Pathophysiology: External heat or exercise raises body temperature → failure of thermoregulation despite sweating and redistribution of blood flow → protein denaturation, cell membrane damage, systemic inflammatory response (SIRS), and coagulation and organ damage caused by hyperthermia. Involvement of the central nervous system (decreased consciousness, confusion, seizures) is characteristic.
• Main causes and risk factors:
  • Prolonged exposure to a hot, humid environment (outdoor work, military training, marathons, etc.)
  • Hot, enclosed spaces (cars, jjimjilbangs)
  • Older adults, children, and people with chronic diseases (cardiovascular disease, diabetes, kidney disease, etc.)
  • Dehydration and use of medications that affect thermoregulation (such as anticholinergic drugs)
• Main symptoms:
  • High fever (elevated core body temperature); the skin is hot and red (hyperthermia), and in the classic type it is dry (anhidrosis), while the exertional type may be accompanied by sweating
  • Altered consciousness (confusion, fainting, coma), headache, dizziness, nausea and vomiting, visual disturbances
  • Difficulty breathing, tachycardia or hypotension, seizures
  • Signs of complications: muscle pain and changes in urine color (rhabdomyolysis), decreased urine output (acute kidney injury)

Treatment Methods (Standard Treatment · Medications · Procedures/Surgery · Lifestyle Management · Precautions)

• Emergency first aid (on site):
  • Immediately call 119 (emergency medical services).
  • Check the airway, breathing, and circulation; if the person is unconscious, maintain the airway and provide respiratory support (artificial ventilation if necessary).
  • Rapidly lower body temperature: remove clothing; evaporative cooling (spraying water + using a fan) is most effective. Continuously spray the skin with water at 20–25℃, then provide airflow.
  • For exertional heat stroke, cold water immersion is the fastest cooling method (use it if possible).
  • Apply cold compresses (ice packs) around large blood vessels, such as the neck, armpits, and groin.
  • If consciousness or breathing is unstable, prioritize stabilizing the airway, breathing, and hemodynamics before transporting the patient.
• Hospital treatment:
  • Continue active and sustained cooling (immersion, evaporative cooling, forced-cooling devices, etc.) while continuously monitoring core body temperature (such as rectal temperature).
  • Control seizures with anticonvulsants (for example, benzodiazepines).
  • In cases of hypotension, provide appropriate fluid replacement (such as normal saline) and, if necessary, vasopressors.
  • If rhabdomyolysis is suspected, maintain renal tubular perfusion with large-volume fluid administration; manage electrolytes such as uric acid and potassium as necessary and consider continuous renal replacement therapy when needed.
  • Monitor the liver, kidneys, and coagulation system in the emergency department or intensive care unit (including liver function, creatinine, CPK, electrolytes, and blood coagulation tests).
  • Antibiotics may be considered when infection is suspected as the cause of the fever. Antipyretics (acetaminophen, NSAIDs) are not basic cooling measures for heat stroke and have limited effectiveness.
• Lifestyle management and rehabilitation:
  • After recovery from the acute phase, gradually resume activities, maintain adequate fluid and electrolyte replacement, avoid hot environments, and gradually acclimatize to heat (acclimatization).
  • Review and adjust factors that increase the risk of recurrence (dehydration, certain medications).
• Precautions and risk of complications:
  • Delayed rapid cooling increases the risk of brain damage, rhabdomyolysis, acute kidney injury, acute liver injury, DIC, and death.
  • Incorrect cooling on site (for example, causing hypothermia through excessive use of cooling agents) should be avoided.
  • Antipyretic drugs are not the core treatment for failed thermoregulation and should not be relied on as an alternative measure.

Checklist Before an Outpatient Visit (Including Example Questions)

• Items to prepare:
  • A list of all medications currently being taken (including prescription drugs, OTC medications, and supplements)
  • Medical history (cardiovascular disease, kidney disease, epilepsy, metabolic diseases, etc.) and any previous history of heat-related illness
  • The time symptoms began, how symptoms progressed (changes in consciousness, whether seizures occurred), and the activity at the time of onset (exercise, indoor exposure, etc.)
  • Temperature measurement records (if available), including the type of measurement and readings; changes in urine color and output; and recent fluid intake
  • Recent test results (if available) and copies of hospital records
• Questions to write down in advance for the outpatient visit (examples):
  • When did the symptoms first begin? In what situation (exercise, outdoor exposure) did they occur?
  • What are the current urine output and color like? Do you have muscle pain or stiffness?
  • What medications are you currently taking (especially anticholinergic drugs, diuretics, and psychiatric medications)?

Examples of General Questions to Ask the Doctor

• How severe is this condition (heat stroke), and is hospitalization necessary?
• What cooling method is currently being used, and what is the target body temperature?
• How will the risks of complications (kidney injury, rhabdomyolysis, liver injury, neurological injury) be assessed and prevented?
• After recovering at home, what activity restrictions, fluid intake, and monitoring (body temperature, urine color, etc.) should be followed?
• Are there any medications I am taking that should be stopped or adjusted?

Examples of Condition-Specific Questions

• If it occurred during exercise: "How long should I wait before participating in games or training again, and what steps should I follow for rehabilitation (heat acclimatization) when returning?"
• Regarding the risk of rhabdomyolysis and kidney injury: "At what CPK (muscle enzyme) or creatinine test results would additional treatment or hospitalization be necessary?"

If you have any additional questions (for example, emergency first-aid methods in a specific situation or the relationship with medications you are currently taking), please let us know, and we will provide a more customized checklist and list of questions.