Endocrine Abstracts

Hypercalcaemia has been previously described in association with ketogenic diet (KD), occurring within 12 months of starting KD. We present a case where severe hypercalcaemia occured after four years on KD.

Case: A 5.5-year-old boy referred for hypercalcaemia in context of early sepsis and background of Dynamin-1 gene mutation causing infantile epileptic encephalopathy. He had been commenced on KD at 18 months of age for drug-resistant seizures. A Deep Brain Stimulator (DBS) was inserted at 3 years for refractory hyperkinetic movements. He has since had intermittent antibiotics for recurrent DBS infections without systemic symptoms. There were no recent changes to medications: sodium valproate, gabapentin, clobazam, clonidine, intravenous flucloxacillin and azithromycin (Table 1).

Calcium was normal 6 months prior to presentation (2.57 mmol/l). Intermittent mild hypercalcaemia was noted over the last 12 months (highest 2.83 mmol/l). ALP had been low for 3 years. Patient became unstable due to DBS infection, managed surgically and with antibiotics. Hypercalcaemia persisted despite hyperhydration and 2 pamindronate infusions. While serum calcium eventually normalised after two weeks, hypercalcaemia recurred with hyperhydration cessation. KD was gradually weaned and replaced with low calcium milk. Once KD was ceased, serum calcium normalized and remained normal after hyperhydration was discontinued. PTH increased after one week to 73 ng/l. Calcium was gradually re-introduced into his diet to 550 mg/day with no recurrence of hypercalcaemia and normalization of PTH.

Conclusion: This case suggests hypercalcaemia may occur years after KD commencement and can be refractory to standard management. In this case, hypercalcaemia may have been caused by the combination of long-term KD and sepsis with acute kidney injury. Despite clinical improvement, hypercalcaemia only resolved with cessation of KD.