Silicate Urolithiasis during Long-Term Treatment with Zonisamide

Satoru Taguchi,Akira Ishikawa,Kanami Takaya,Teruaki Kobayashi,Toshikazu Sato,Yukio Homma,Yorito Nose

doi:10.1155/2013/629381

Satoru Taguchi, Akira Ishikawa + Show 5 more

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https://doi.org/10.1155/2013/629381

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Abstract

Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.

Highlights

Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi [1]
The supposed mechanism is that zonisamide induces urine alkalinization and promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells [5]
Urinary silicate calculi are common in herbivorous animals such as ovine and cattle but rare in humans with an incidence of 0.2% of all urinary calculi [1, 6]

Summary

Introduction

Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi [1]. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for gastric and duodenal ulcers over a long period of time [2, 3]. Zonisamide, a newer antiepileptic drug, is one of important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells [5]. There has been no report of silicate urolithiasis supposed to be associated with zonisamide. We report a case of silicate urolithiasis during long-term treatment with zonisamide for epilepsy and discuss the etiology of the disease by examining the silicate concentration in his urine

Case Presentation

Findings

Discussion