Probably the leading cause of anesthesia-related death in healthy patients
Incidence
Anesthetized Adults: 1 in 50k-100k patients
Anesthetized Children: 1 in 3k-15k patients
Inheritance: autosomal dominant
Etiology
Halogenated Inhalational Anesthetics
Enflurane
Halothane
Isoflurane
Aminoamide Local Anesthetics (less clearly etiologic)
Lidocaine
Prilocaine
Etidocaine
Mepivacaine
Bupivacaine
Other
Succinylcholine
Surgical Stress: reported to be etiologic in some cases
Physiology
Sarcoplasmic Reticulum Calcium Channel Defect: impaired ability of skeletal muscle to uptake myoplasmic calcium released from sarcoplasmic reticulum (SR)
Elevated Myoplasmic Calcium During Event: causes increased muscle metabolism and contraction
Intact Hypothalamic Thermoregulation
Diagnosis
ABG: may demonstrate hypoxemia and hypercapnia
May demonstrate metabolic acidosis (due to lactate)
CHEM
Hyperglycemia
Hyperkalemia
Hypernatremia
Hypercalcemia
Hypermagnesemia
Hyperphosphatemia
Lactate: may be elevated
CK: may be elevated
Clinical Manifestations
Timing of Onset
Symptom onset usually within 30 min of start of anesthesia (or may occur several hours later), with rapid progression
Neuro Manifestations
Muscle Stiffness
Rigidity
Other Manifestations
Fever (see Fever, [[Fever]]): may rise as fast as 1°C q5min
