術後悪性高熱症を疑い悪性高熱症関連遺伝子検査を施行した1症例

A Suspected Case of Postoperative Malignant Hyperthermia Examined with Malignant Hyperthermia-related Genes

要旨

　全身麻酔終了後に悪性高熱症様症状を呈した患者に対しダントロレン投与などの治療が奏効した。臨床所見から術後劇症型悪性高熱症と診断した。青年期に頻回に熱中症を発症していた既往がのちに判明した。悪性高熱症関連遺伝子検査を施行したが既報の悪性高熱症原因遺伝子には変異を認めず，悪性高熱症素因は確定できなかった。

　An elderly male patient underwent lung surgery under general anesthesia. Immediately after extubation, he suffered abnormal hyperthermia reaching 39.7°C. We suspected postoperative malignant hyperthermia（PMH）and treated him with re-intubation, high flow-rate oxygen, intravenous dantrolene, and body surface cooling. His general condition rapidly improved and he was extubated the next day. After his recovery, we found out that he used to get heat strokes repeatedly during his youth.

　Next-generation panel sequencing for malignant hyperthermia（MH）did not reveal any pathogenic variants in causative MH genes（RYR1, CACNA1S, STAC3）. We identified a ITPR2 heterozygous missense variant, but the relationship between the variant and MH is not disclosed yet.