Ketogenic diet: rapid onset of selenium deficiency-induced cardiac decompensation.

Selenium-deficiency cardiomyopathy is a known secondary complication from long-term treatment with a ketogenic diet for medical refractory epilepsy. Our patient, a 5-year-old boy on a ketogenic diet for intractable seizures, had a normal selenium level before starting the diet, but he shortly thereafter developed acute reversible cardiomyopathy and ventricular tachycardia, which was unmasked during a hospitalization for an elective operative procedure. His cardiomyopathy was suspected to be secondary to a selenium-deficient state and was confirmed by way of a markedly low serum selenium level and supported by rapid improvement with the initiation of selenium supplementation and cessation of the ketogenic diet. For patients being initiated on a ketogenic diet, current screening guidelines call for baseline and follow-up selenium levels every 3 months during the first year along with RDA selenium supplementation, which is 30 mcg/day. Most of the new ketogenic diet formulas meet this requirement. Our patient underwent elective surgery before his planned 3-month selenium level check and had potentially preventable complications. Secondary to this experience, we suggest that all patients initiated on a ketogenic diet should have a preoperative electrocardiogram (EKG), an echocardiogram, and selenium level determined before any elective surgery. These steps would prevent unnecessary perioperative morbidity and mortality.