Hypercalcaemia may occur years after initiating ketogenic diet in children

Children starting the ketogenic diet, particularly in the setting of renal impairment, are at risk of developing ketotic hypercalcaemia in subsequent years, suggests a study.

“The mechanism is unknown but appears to be due to reduced osteoblast activity and impaired bone formation,” the investigators said. “We recommend close attention to optimizing bone health in these children, and screening for the development of ketotic hypercalcaemia.”

This multicentre case series was conducted to describe the clinical characteristics of acute hypercalcaemia in children on the ketogenic diet by analysing the presentation, response to treatment, and natural history in a large cohort of patients.

Fourteen children (median age, 6.3 years) who developed acute hypercalcaemia 2.1 years (range, 0.2–12) after starting the ketogenic diet were enrolled. The investigators then collected information on clinical presentation, treatment, and course of complication.

All participants had low levels of parathyroid hormone. Levels of 1,25-dihydroxyvitamin D were also low except in one child. Seven children (50 percent) had impaired renal function at presentation and 12 had low alkaline phosphatase levels for age.

Normocalcaemia was achieved, but two patients had hypercalcaemia recurrence over observation up to 9.8 years. One child discontinued the ketogenic diet prior to achieving normocalcaemia, while four more stopped the diet during follow-up after resolution of hypercalcaemia.

“The ketogenic diet is associated with progressive skeletal demineralization, hypercalciuria, and nephrolithiasis,” the investigators said. “Acute hypercalcaemia has been described as a newly recognized complication of this treatment.”