Transient neurological deterioration after patent foramen ovale closure associated with nitrous oxide exposure in an adolescent with homozygous MTHFR polymorphism

INTRODUCTION: Transient ischaemic attack after patent foramen ovale closure presents diagnostic challenges. PATIENT INFORMATION: polymorphism underwent successful patent foramen ovale closure under nitrous oxide anaesthesia. CLINICAL FINDINGS: Post-procedure, he experienced neurological deterioration and loss of consciousness with elevated homocysteine levels (43 mmol/L). CONCLUSION: Nitrous oxide-induced methionine synthase inhibition may precipitate transient ischaemic events in genetically susceptible patients.