A Rare Case of Suspected Malignant Hyperthermia in a Three-Day-Old Neonate: A Case Report

Malignant hyperthermia (MH) is a rare, life-threatening pharmacogenetic disorder of skeletal muscle calcium regulation, most commonly triggered by volatile anesthetics and depolarizing muscle relaxants. While pediatric patients are at increased risk compared to adults, MH is exceedingly rare in neonates, and its clinical presentation may differ by age group, with hyperthermia and generalized rigidity more prominent in the youngest patients. This report describes a three-day-old female who developed a rapid rise in end-tidal CO2, tachycardia, metabolic acidosis, and hyperthermia intraoperatively during emergent laparotomy, despite cessation of active warming and stable ventilator settings. These findings, in the context of volatile anesthetic exposure, are consistent with the clinical diagnostic criteria for MH, including unexplained hypercarbia, temperature elevation, and hemodynamic instability. Prompt recognition led to immediate discontinuation of triggering agents, initiation of active cooling, and administration of intravenous dantrolene, resulting in gradual clinical improvement. This case underscores the importance of early recognition and intervention in suspected MH, even in neonates, highlighting the need for perioperative vigilance, rapid multidisciplinary response, and referral for confirmatory contracture and genetic testing in survivors.