Management of malignant hyperthermia: diagnosis and treatment

Figures & data

Figure 1 Pathophysiologic changes during a malignant hyperthermia crisis.

Abbreviations: Ca²⁺, calcium; DHP receptor, dihydropyridine receptor; MH, malignant hyperthermia; RYR1, ryanodine receptor subtype 1.

Table 1 Clinical signs of malignant hyperthermia

Early	Late
Masseter spasm	Hyperthermia
Generalized muscular rigidity (50%–80%)	Rhabdomyolysis
Tachycardia (>80%)	Acute renal failure
Hypercapnia	Cardiac arrhythmia
Hypoxia	Hypotension
Combined metabolic-respiratory acidosis	Circulatory failure

Table 2 Possible differential diagnoses of acute malignant hyperthermia crisis

Differential diagnoses of malignant hyperthermia

Inadequate depth of anesthesia

Sepsis

Insufficient ventilation or spontaneous breathing

Malfunction of anesthesia machine

Anaphylactic reaction

Pheochromocytoma

Thyroid crisis

Neuromuscular disease

CO2 increase due to laparoscopic procedure

Drug intoxication

Serotonin syndrome

Malignant neuroleptic syndrome

Table 3 Immediate causative and symptomatic treatment of acute malignant hyperthermia crisis

Causative treatment	Symptomatic treatment
Stop trigger agent, disconnect vaporizer	Inform surgeon, aim for termination of surgery as soon as possible
Increase respiratory minute volume 2–4-fold with 100% oxygen at maximum fresh gas flow	Stabilize hemodynamics and start antiarrhythmic therapy if appropriate
Administer dantrolene 2 mg/kg initially	Apply internal and external cooling
Continue anesthesia with nontriggering drugs	Extend hemodynamic monitoring, insert arterial line and central venous line if needed
Repeat dantrolene application until clinically stable (maximum 20 mg/kg)	Treat metabolic acidosis, perform forced diuresis