title: Urolithiasis on the ketogenic diet with concurrent topiramate or zonisamide therapy.
abstract: Children with refractory epilepsy who are co-treated with the ketogenic diet (KD) and carbonic anhydrase inhibitor (CA-I) anti-epileptic medications including topiramate (TPM) and zonisamide (ZNS) are at risk for urolithiasis. Retrospective chart review of all children treated with ketogenic therapy at our institution was performed in order to estimate the minimal risk of developing signs or symptoms of stone disease. Children (N=93) were classified into groups according to KD+/-CA-I co-therapy. Fourteen patients had occult hematuria or worse, including 6 with radiologically confirmed stones. Three of 6 calculi developed in the KD+ZNS group of 17 patients who were co-treated for a cumulative total of 97 months (3.1 stones per 100 patient months). One confirmed stone was in the KD+TPM group of 22 children who were co-treated for a cumulative total of 263 months (0.4 stones per 100 patient months). All six patients had at least three of five biochemical risk factors including metabolic acidosis, concentrated urine, acid urine, hypercalciuria and hypocitraturia. Standard of care interventions to minimize hypercalciuria, crystalluria and stone formation used routinely by pediatric nephrologists should also be prescribed by neurologists treating patients with combination anti-epileptic therapy. Non-fasting KD initiation, fluid liberalization, potassium citrate prophylaxis as well as regular laboratory surveillance are indicated in this high risk population.
authors.affiliation: Pediatric Nephrology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA. epaul@partners.org
authors.forename: Elahna
authors.initials: E
authors.lastname: Paul
authors.forename: Kerry D
authors.initials: KD
authors.lastname: Conant
authors.forename: Irie E
authors.initials: IE
authors.lastname: Dunne
authors.forename: Heidi H
authors.initials: HH
authors.lastname: Pfeifer
authors.forename: David A
authors.initials: DA
authors.lastname: Lyczkowski
authors.forename: Michael A
authors.initials: MA
authors.lastname: Linshaw
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Thiele
mesh_terms: D000927:Anticonvulsants / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy / Q000009:adverse effects; D055423:Diet, Ketogenic / Q000009:adverse effects*; D004827:Epilepsy / Q000178:diet therapy / Q000188:drug therapy; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives*; D006801:Humans; D007223:Infant; D007555:Isoxazoles / Q000009:adverse effects*; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D000077236:Topiramate; D052878:Urolithiasis / Q000139:chemically induced*; D000078305:Zonisamide
chemical_list: D000927:Anticonvulsants; D007555:Isoxazoles; D000077236:Topiramate; D005632:Fructose; D000078305:Zonisamide
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