Anesthetic management of delayed malignant hyperthermia during scheduled right frontotemporal craniotomy

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Malignant hyperthermia is a critical complication that arises when certain anesthetics are administered to susceptible patients, posing a significant risk of mortality if not promptly identified and treated. We present a case of a 48-year-old male admitted for the excision of an intracranial tumor. The patient underwent orotracheal intubation under total intravenous anesthesia and non-depolarizing muscle relaxants. After intubation, anesthetic maintenance was achieved through the administration of sevoflurane and intravenous agents. During the initial stage, there was a gradual increase in the patient’s heart rate and end-tidal carbon dioxide pressure (PetCO 2 ). Five hours after anesthesia, sevoflurane administration was ceased, resulting in effective control of the condition. However, a subsequent episode of elevated blood pressure led to the re-administration of sevoflurane, causing a sharp rise in heart rate, PetCO 2 levels, and body temperature. The patient’s oropharynx temperature peaked at 39.4 ℃, axillary temperature at 45.1 ℃, PetCO 2 level at 69 mmHg, and heart rate at 115 bpm. Due to no dantrolene, we used physical cooling through rapid infusion of ice-cold saline, which initiated a downward trend in core temperature, PetCO 2 levels, and heart rate within 1 h. Throughout the anesthesia process, no significant acidosis or hyperkalemia was observed. After completion of the surgery, the patient was admitted to the ICU with a stabilized oropharynx temperature of 37.8 ℃. Subsequently, the patient experienced febrile symptoms in the following days but was discharged safely on the third postoperative day. Genetic testing revealed homozygous mutations in the RYR1 gene, both in the patient and his son, confirming the occurrence of malignant hyperthermia during the operation. This case report details the diagnosis and management of a 48-year-old male patient with a homozygous RYR1 gene mutation who developed delayed malignant hyperthermia (MH) following sevoflurane anesthesia. Despite the absence of the specific antagonist dantrolene, the condition was successfully controlled through active symptomatic management. Postoperative genetic testing further confirmed that both the patient and his son carried the pathogenic RYR1 mutation, definitively establishing their MH susceptibility.