Introduction: An association between the ketogenic diet (KD) and hypercalcaemia has been suggested in one case series of three children1, where hypercalcaemia occurred within 12 months of starting KD. We describe a case where severe hypercalcaemia occurs after four years on KD.
Case: A 5.5-year-old boy is referred for hypercalcaemia in context of early sepsis and a background of Dynamin-1 gene mutation causing infantile epileptic encephalopathy and developmental delay. He had been commenced on KD at 18 months of age due to drug-resistant seizures. A Deep Brain Stimulator (DBS) was inserted at three years for refractory hyperkinetic movements. He has since been on intermittent long-term antibiotics for recurrent DBS infections without systemic symptoms.
There were no recent changes to his medications: sodium valproate, gabapentin, clobazam, clonidine, and intravenous flucloxacillin and azithromycin.
|Corrected calcium||4.07 (High)||2.19-2.69mmol/L|
|Alkaline phosphatase (ALP)||99 (Low)||139-347IU/L|
|Parathyroid hormone (PTH)||6 (Low)||10-65ng/L|
|Urine Calcium:Creatinine Ratio||1.3 (High)||0.05-0.60|
|1,25 Vitamin D||24 (Low)||48-192pmol/L|
|Chest/hand/wrist Xrays||Low bone mineral density, otherwise normal|
|Full Blood Count||Normal|
|Thyroid Function Tests|
Calcium was normal six months prior to presentation (2.57mmol/L), but intermittent mild hypercalcaemia was noted over the last 12 months (highest 2.83mmol/L). ALP had been low over the past three years.
Hypercalcaemia persisted despite hyperhydration and two pamindronate infusions. He subsequently became unstable due to DBS infection and was managed with surgical intervention and antibiotics. Calcium normalised after two weeks of hyperhydration, but increased after cessation of hyperhydration.
KD was gradually weaned and replaced with low calcium milk. Once KD was ceased, serum calcium normalized and remained normal after hyperhydration was discontinued. Calcium remained stable and PTH increased after one week to 73ng/L. Calcium was gradually re-introduced into his diet to 500mg/day with no recurrence of hypercalcaemia and normalization of PTH.
Conclusion: This case suggests that severe hypercalcaemia may occur several years after commencement of KD and can be refractory to standard management. In this case, the hypercalcaemia may have been caused by the combination of long-term KD and sepsis with acute kidney injury. However, despite resolution of sepsis and acute kidney injury, his hypercalcaemia did not fully resolve until KD was ceased.
19 Sep 2019 - 21 Sep 2019