From the Research
Malignant hyperthermia (MH) from succinylcholine and volatile anesthetics requires immediate treatment with dantrolene sodium, with an initial dose of 2.5 mg/kg IV, which can be repeated as needed until symptoms resolve, with a total dose not exceeding 10 mg/kg, as recommended by the most recent and highest quality study 1.
Key Considerations
- MH is a pharmacogenetic disorder affecting ryanodine receptors in skeletal muscle, causing uncontrolled calcium release, hypermetabolism, and potentially fatal hyperthermia 2.
- The incidence of MH reactions ranges from 1:10,000 to 1:250,000 anesthetics, with a prevalence of genetic abnormalities as high as one in 400 individuals 2.
- Prompt recognition and treatment of MH are crucial for averting life-threatening complications and ultimately for the patient's survival, with a knowledgeable anesthesiologist playing a pivotal role in the successful management of MH 3.
Treatment and Management
- At the first sign of MH, discontinue triggering agents and administer dantrolene sodium, with each 20 mg vial reconstituted with 60 mL sterile water 1.
- Simultaneously, hyperventilate with 100% oxygen, actively cool the patient using ice packs and cold IV fluids, treat hyperkalemia with calcium, insulin/glucose, and sodium bicarbonate, and manage acidosis.
- Monitor core temperature, end-tidal CO2, electrolytes, creatine kinase, myoglobin, and coagulation studies, and continue dantrolene 1 mg/kg IV every 4-6 hours for 24-48 hours to prevent recurrence.
Genetic Testing and Screening
- Patients who experience MH should undergo genetic testing, receive MH-susceptible medical alert identification, and have family members screened, as MH is inherited in an autosomal dominant pattern in humans 2.
- The risk of dying from MH has decreased significantly over the past few years, from 80% to less than 5%, due to increased understanding of the clinical manifestation and pathophysiology of the syndrome, and the introduction of DNA testing for susceptibility to MH 2.