Anaesthetic considerations for delivery in an obstetric patient with a RYR1 gene variant: a case report

Malignant hyperthermia (MH) is a rare, potentially life-threatening pharmacogenetic disorder most commonly associated with variants in the ryanodine receptor 1 gene (RYR1). Obstetric patients with undetermined risk of MH present distinct challenges, as the potential need for urgent delivery limits opportunities for anaesthetic preparation and necessitates a high level of multidisciplinary readiness. We describe the perioperative management of a 32-year-old woman heterozygous for a RYR1 splicing variant who underwent an elective caesarean delivery at 39 weeks' gestation following an in vitro fertilisation pregnancy. Her partner is a heterozygous carrier of the same pathogenic RYR1 variant, giving the fetus a 25% risk of severe autosomal-recessive myopathy, 50% chance of being an asymptomatic carrier, and an undetermined risk of malignant hyperthermia susceptibility. The patient had an undetermined risk of MH, in the absence of confirmatory testing. Early antenatal anaesthetic assessment enabled comprehensive risk evaluation and multidisciplinary planning. A detailed perioperative management strategy was implemented, incorporating early communication pathways, preparation of a trigger-free theatre, and development of a patient-specific MH prevention pack. Simulation-based multidisciplinary training was undertaken to enhance team preparedness and streamline trigger-free anaesthetic setup. An uncomplicated caesarean delivery was performed under spinal anaesthesia in a pre-prepared trigger-free environment. The patient was discharged home on the third post-operative day with a baby boy. This case underscores the importance of early antenatal identification, multidisciplinary collaboration, and simulation-based training in developing structured emergency and personalised anaesthetic strategies. Given the rarity of such cases, and the absence of obstetric specific UK or Irish guidelines, proactive institutional preparedness remains essential to ensure safe obstetric outcomes in patients with undetermined risk of MH.