Kidney Stones in Epileptic Children Receiving Ketogenic Diet: Frequency and Risk Factors

Although it is a valuable option for children with drug-resistant epilepsy, ketogenic diet (KD) therapy is associated with several side effects. The frequency of kidney stones and risk factors for their development in epileptic children receiving KD is unclear. The aim of this study was to determine the frequency and risk factors for the development of renal stones in children receiving KD therapy.

A total of 95 patients receiving KD were identified. Of these, seven patients were excluded from the study due to the duration of KD being less than 12 months. The remaining 88 children were enrolled in the study.

Renal stones were detected in 15 patients (17%), of which 12 (73.3%) received potassium citrate treatment. Two (13.3%) patients needed lithotripsy despite receiving potassium citrate treatment, and one of these, who received potassium citrate treatment for 5 months, developed acute vesicourethral reflux and underwent surgery. No patient discontinued KD due to renal stone development. The serum uric acid concentrations and urine calcium/creatinine ratio did not change significantly over the 24-month follow-up period. Age, gender, etiology, age at seizure onset, duration of KD, mobility status, use of topiramate or zonisamide, and the number of antiepileptic drugs used were not significantly different between patients with and without kidney stones.

Renal stone appears to be a common adverse effect of KD therapy. Although adequate hydration and potassium citrate treatment are effective in most patients, lithotripsy and surgery may be required in a minority of patients.