Urolithiasis associated with topiramate

OBJECTIVE: Topiramate is a sulfamate-substituted monosaccharide anticonvulsant used as adjunctive therapy for intractable refractory seizures. It is report a case of topiramate-induced urolithiasis. CASE REPORT: A 35-year-old man presented with acute, right-sided, colicky flank pain. He denied hematuria or dysuria. He was in use of phenytoin, risperidone, phenobarbital, and topiramate. The total daily dose of topiramate was 375 mg. A CT scan showed a 7 x 1 mm curvilinear density at the right ureterovesical junction with proximal hydrouretronephrosis. He was managed with rigid ureteroscopic stone extraction and the calculus metabolic analysis revealed the stone was composed of carbonate apatite (70 percent), calcium oxalate dihydrate (20 percent), and calcium oxalate monohydrate (10 percent). COMMENTS: The present case typifies many features of topiramate-induced urolithiasis. Those who care for patients with urinary stone disease should be aware of this association.

Effect of uric acid on sodium oxalate-induced urolithiasis in rats--biochemical and histological evidences.

Effect of uric acid on sodium oxalate-induced biochemical and histological changes were studied in rats. Rats injected with sodium oxalate (0.7 mg/100 g body wt, ip) show calcium deposits in the lumen of kidney tubules. Uric acid administration was found to potentiate calcium oxalate calculi formation. Lipid peroxide formation was increased up to 100% in kidney and 28% in liver by sodium, oxalate treatment. Uric acid administration was found to reduce lipid peroxide level up to 12% in liver and 20% in kidney. From this study it is concluded that lipid peroxidation may not be the cause of sodium oxalate-induced urolithiasis and the results are discussed with reference to the epitaxic nature of uric acid on kidney stone formation.

Djenkol bean as a cause of urolithiasis.

An 8-year-old boy was admitted into the hospital with symptoms of anuria after consumption of 12 djenkol beans. Laparotomy showed a urethral calculus, size 2.0 x 0.4 cm, which was found to contain djenkolic acid 65 gm/100 gm stone with a small amount of protein, sodium, potassium and uric acid. This calculus contained no calcium, magnesium, phosphorus, ammonium salt, oxalate, carbonate, cystine and fibrin. The solubility of L-djenkolic acid in urine at 37 degrees C was found to be pH dependent, i.e., the higher the pH, the increase in solubility of djenkolic acid. D-pencillamine also showed similar effect, increasing the solubility of L-djenkolic acid in the urine at pH 5.7 in vitro. The cause and mechanism of formation of djenkolic acid crystals and calculi were discussed.