A 3-year-old Thai boy underwent open reduction and internal fixation with K-wire of condylar fracture of humerus under general anesthesia. The patients developed generalized muscle regidity, masseter muscle spasm, elevated creatinine kinase, high temperature (39.3 C), inappropriate tachycardia, and arterial base excess was more than-8 mEq/L. The clinical grading scale of diagnosis of malignant hyperthermia was 58 (grade D6; almost certain malignant hyperthermia). Succinylcholine has been identified as the trigger agent, as other possible trigger agents were not involved. The treatment included hyperventilation, external cooling and cold IV fluids without administration of dantrolene. The patient fully recovered and discharged on day 12. This case report showed an incidence of malignant hyperthermia of approximated 1:150,000 in Thai Anesthesia Incidents Study (THAI Study).

Keywords : Malignant hyperthermia, Complication, Adverse event, Succinylcholine