Modified Atkins diet for drug-resistant epilepsy and the risk of urolithiasis

Ketogenic diet (KD) is widely used for drug-resistant epilepsy (DRE). The study was designed to evaluate one of the risk factors for development of renal calculi with KD.

Twenty patients with DRE on Modified Atkins diet (MAD) were subjected to full history and laboratory investigations, including microscopic urine analysis, urinary calcium after overnight fasting, and calcium/creatinine ratio, as well as pelviabdominal ultrasound. Frequency and severity of seizures assessed by Chalfont severity score were recorded. All assessment measures were repeated after 3 and 6 months of KD therapy.

There were significant reductions in both frequency and severity of seizures, yet 2 patients (10%) developed renal stones after 6 months on KD. Gross hematuria was reported in 1 of those 2 patients (50%), but microscopic hematuria was detected in both patients. The urine calcium and the urine calcium/creatinine ratio were elevated in both patients having renal calculi after 6 months.

KD increases the risk of renal stones with hypercalciuria among the causes. We recommend initiation of prophylactic measures once KD is commenced by maximizing fluid intake and urine alkalinization with regular urinary studies including calcium/creatinine ratio and renal ultrasound for patients with symptoms.

KD has been increasingly used in epilepsy management and beyond. The potential side effects of such diet should be highlighted while valuing the merits. KD increases the risk of renal stones because of hypercalciuria among other causes. We recommend initiation of prophylactic measures once KD is commenced by maximizing fluid intake and urine alkalinization with estimation of urinary calcium/creatinine ratio and renal ultrasound in patients with relevant symptoms.