BLADDER CALCULUS

JAY B. HOLLANDER, M.D.

From the Section of Urology, Department of Surgery, University of Michigan, Ann Arbor, Michigan

ABSTRACT-A case report of triamterene bladder calculus is presented. Triamterene containing antihypertensiues should be used with caution in patients with predisposition to farm stones.

Triamterene is a commonly used potassium- urinary tracts; the calcification was in the blad- sparing natriuretic used alone (Dyrenium) or in der (Fig. 1). The patient underwent cystolitho- combination with hydrochlorothiazide lapaxy of a large, multifaceted bladder stone. (Dyazide) to treat hypertension. Triamterene Stone analysis was performed with 4.1 g of and its metabolites are excreted in the urine. stone analyzed. It was composed of Triamterene can be a cause of urolithiasis with monohydrate and surrounding an estimated incidence of 0.5 cases per 1,000 a nidus of triamterene and its two major metab- persons taking the medication.’ Reported is a olites, parahydroxytriamterene and parahy- case of a bladder calculus in a Dyazide user, droxytriamterene sulfate. The nidus of triam- Stone analysis revealed a nidus of triamterene terene represented 20 per cent of the total stone and its two major metabolites. The patient had weight. On subsequent follow-up, obstructive continued symptoms of prostatism with ele- voiding symptoms persisted as did elevated vated post-void residuals after cystolitholapaxy post-void residuals. Transurethral resection of Incomplete emptying may have been a factor in the prostate was performed with an unre- the formation of his bladder calculus. Despite markable postoperative course. The patient’s the rarity of triamterene urolithiasis, it is rec- blood pressure has been managed without ommended that Diazide users who may be at triamterene since his cystolitholapaxy and has risk for stone formation be screened periodi- had no further problems. cally with an abdominal roentgenogram and urinalysis.

Case Report A sixty-five-year-old white man presented with a five-month history of intermittent dis- comfort in the right and left lower abdominal quadrants which was not associated with void- ing. There was a history of intermittency, de- creased force of stream, and nocturia twice nightly. There was no past history of urinary tract infeetion, hematuria, or urolithiasis. He had a twenty-five-year history of hyperten- sion and was taking hydralazine hydrochloride (Apresoline), 15 mg PO q day, metoprolol tartrate (Lopressor), 15 mg PO q day, and FIGURE 1. Supìne plaìn film of pelvis showìng Diazide I PÖ q da’y. Urinalysis was acéilular, calcific shadow near rìght bladder wall, and con- and excretory urogram showed normal upper firmed a.slarge bladder calculus at cystoscopy.

154 UROLOGY / AUGUST 1987 / VOLUMEXXX,NUMBER2 Comment tion.* There is no evidente, however, that the incidence of calcium oxalate stones is higher in Triamterene is a diuretic which exerts its ef- triamterene users. fect on the distal renal tubule to inhibit the The actual risk of stone formation while on reabsorption of sodium in exchange for potas- triamterene therapy is unknown. As men- sium and hydrogen ions. It is, therefore, a po- tioned, it has been estimated there is an inci- tassium-sparing natriuretic. It is most com- dence of 0.5 stones per 1,000 persons taking monly prescribed in combination with Dyazide. Frequency of urolithiasis in the hydrochlorothiazide. Triamterene is rapidly United States has been estimated at 16.4 stones metabolized to parahydroxytriamterene and per 10,000 population which would be greater then to parahydroxytriamterene sulfate. It is ex- than the incidence of triamterene stone forma- creted in both bile and urine with urinary me- tion in patients taking the medication5 Never- tabolites in much higher concentration than the theless, it would seem prudent to recommend parent compound. The t% for triamterene is that those patients who are at risk for stone for- one and one-half to two and one-half hours with mation be screened at least once if they have urinary excretion diminishing within six to been on chronic triamterene therapy. A simple eight hours.2 abdominal plain film and urinalysis would According to Louis C. Herring & Co., based seem to be appropriate. We believe our patient on their extensive stone analysis experience, ap- was at risk for bladder stone formation because proximately 1,450 stones containing some of urinary stasis associated with his prostatism triamterene are being passed each year in the and high post-void residual. Patients with the nation.’ It was also estimated that there are 3 diagnosis of triamterene stone formation, once million people taking triamterene in one form stone free, should be cured by discontinuing the or another giving an annual triamterene stone medication . incidence of 0.5 per 1,000 persons taking the drug. The Herring Co. found 436 cases of triamterene urolithiasis in the eighteen-month Department of Urology period following the initial case report of triam- St. Paul-Ramsey Medical Center terene-induced nephrolithiasis in 1979, 3 640 Jackson Street Though increased dosage of triamterene may be St. Paul, Minnesota 55101 related to stone formation, many cases have been found on a dosage of only one Diazide per References day (50 mg of triamterene). Triamterene stones 1. Oldroyd N, Ettinger B, and Sorgel F: Renal calculi in are gold-mustard colored, can be smooth sur- triamterene users, in Smith LH, Rohertson WC, and Finlayson B (Eds): Urolithiasis-Clinical and Basic Research, New York, faced but irregular in shape. If broken, they Plenum Press, 1981, pp 131-137. may show concentric lamellae. Triamterene 2. Pruitt AW, Winkel JS, and Dayton PG: Variations in the fate also may be found in combination with calcium of triamterene, Clin Pharmacol Ther 21: 610 (1977). 3. Ettinger B, Weil E, Mandel NS, and Darling S: Triam- oxalate monohydrate and uric acid. It is almost terene-induced nephrolithiasis, Ann Intern Med 91: 745 (1979). never associated with calcium phosphate or 4. White DJ, and Nancollas GH: ‘Ikiamterene and renal stone magnesium ammonium phosphate.’ Some in- formation, J Urol 127: 593 (1982). 5. Sierakowski, R, et al: The frequency of urolithiasis in hospi- vestigators believe triamterene and its metabo- tal discharge diagnoses in the United Sta&, Invest Urol 15: 438 lites may catalyze calcium oxalate stone forma- (1978).

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