MON-074 Ketotic Hypercalcemia; A Possible Side Effect of Managing Refractory Epilepsy with Ketogenic Diet

Abstract

Background: Patients with epilepsy have multiple risk factors for low bone mass, including immobility, reduced muscle mass, and use of multiple anticonvulsant medications. The ketogenic diet (KD) has been used as an effective treatment of refractory epilepsy for decades, with multiple reports in medical literature describing adverse effects on bone and mineral metabolism including gradual loss of bone mineral density. There has been only one report of hypercalcemia in three children on the KD for refractory seizures. We now describe another case, highlighting the importance of considering the KD as a cause of hypercalcemia.. Case presentation: A 14-year-old girl with Rett syndrome, epilepsy, global developmental delay and gastrostomy tube dependency presented to the emergency room with marked dehydration. She had been on the KD for several years due to refractory epilepsy. Her parents had recently noticed thick oral secretions. The only change in her management plan was the recent change of her formula from Ketocal 3:1 to Ketocal 2.5:1. Lab studies showed hypercalcemia 15 mg/dL (ref 9.2-10.7) with ionized calcium of 7.99 mg/dL (ref, 4.8-5.2). She had normal serum calcium levels on multiple previous occasions, including 10.2 mg/dL 4 months prior to presentation. Other studies included increased BUN 37 mg/dL (ref, 7-21) and Creatinine 2.31 mg/dL (ref, 0.53-0.8). She had a low normal PTH 14 pg/ml (ref, 8-72), PTH-related peptide 0.6 pmol/l (ref, < 4.2), and 25-hydroxyvitamin D 66 ng/ml (30-100). 1,25-dihydroxyvitamin D level was low at 12.5 pg/ml (ref, 19.9-79.3), with increased urine calcium/creatinine ratio 1.00 mg/mg creat (Ref, 0.02-0.26). Beta Hydroxybutyrate was 3.45 mmol/l (ref, 0.02 - 0.27), without major change over the last year. Renal US was normal. She received IV hydration with improvement in serum calcium, BUN, and creatinine and was discharged on increased intake of free water and adjustment of KD to maintain Beta Hydroxybutyrate around 2 mmol/l. Her serum calcium currently ranges 10.5- 12 mg/dl, and will soon begin therapy with subcutaneous calcitonin. Conclusion: The KD has adverse effects on bone and mineral metabolism, and can lead to severe hypercalcemia and/or hypercalciuria as well as decreased bone density. Agents that decrease bone resorption are highly effective. Providers caring for children on this diet should be aware of such potential association. Reference: Hawkes CP, Levine MA. Ketotic hypercalcemia: a case series and description of a novel entity.J Clin Endocrinol Metab. 2014 May;99(5):1531-6.