MP80-08 METABOLIC CHARACTERISTICS OF BRUSHITE STONE FORMERS

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You have accessJournal of UrologyStone Disease: Evaluation II1 Apr 2015MP80-08 METABOLIC CHARACTERISTICS OF BRUSHITE STONE FORMERS Tracy Marien, S. Duke Herrell, and Nicole Miller Tracy MarienTracy Marien More articles by this author , S. Duke HerrellS. Duke Herrell More articles by this author , and Nicole MillerNicole Miller More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.2844AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Brushite nephrolithiasis is an especially aggressive form of stone disease associated with larger stone burden, more frequent stone episodes and kidney injury. In addition to surgical intervention most brushite stone formers require medical management. Several recent studies have shown the number of brushite stone formers to be increasing. It is important for urologists to be aware of the implications of this stone type and the consequences of untreated metabolic derangements. The aim of this study is to characterize the metabolic abnormalities of brushite stone formers. METHODS A retrospective chart review was performed of all patients at our institution who have a history of brushite stones. Twenty-four hour urine studies done prior to being placed on medical therapy were captured. Patient demographics and stone event history was also reviewed. RESULTS Of 118 brushite stone formers, 49 patients were identified who completed a 24 hour urine analysis prior to starting medical therapy. These patients' stone disease characteristics are presented in Table 1. Every patient had at least one metabolic abnormality. The most common abnormality was elevated urinary pH (73%), followed by elevated urinary sodium (71%), hypercalciuria (67%), hypocitraturia (65%), and low urinary volume (61%) (see Table 1). Fourteen (88%) of the 16 patients who did not have hypercalciuria had hypocitraturia. Both of the patient who did not have hypercalciuria or hypocitraturia had a very high urinary pH (6.4 and 6.7) in addition to a urinary sodium of 310 mmol/d in one and low urine volume in the other. All patients were counseled on dietary preventative measures and 28 patients (57%) were started on medical therapy. CONCLUSIONS All brushite stone formers have significant metabolic derangements on 24 hour urine testing. The most commonly abnormalities in this series were elevated urine pH and high urinary sodium. We recommend metabolic evaluation in all of these patients with aggressive dietary modifications and medical therapy to decrease incidence of recurrent stone episodes and long-term kidney damage. The role of citrate replacement remains uncertain in the hypocitraturic brushite stone former due to concern for further raising urine pH. Table 1. Brushite Stone Former Characteristics Patients (n = 49) Spontaneous passage∗ 30 (79%) Surgical intervention 49 (100%) No. of surgical interventions/pt, average (range) Total 8.5 (1-57) PCNL 1.0 (0-7) Ureteroscopy 3.8 (0-17) ESWL 3.7 (0-40) Pyelithotomy (2 patients) 0.4 (0-1) Family history∗ 26 (59%) Age at first stone event ∗ (yo) 26.1 (6-51) Gender Female 23 (47%) Male 26 (53%) BMI (kg/mˆ2) 29.5 (20-43) Serum creatinine (mg/dL) 0.91 (0.51-1.36) Length of follow-up (mo) 47.1 (1-221) 24 hour urine Hypercalciuria∗∗ 33 (67%) Hypocitraturia∗∗ 32 (65%) Hyperoxaluria (> 40 mg/d) 9 (18%) Hyperuricosuria∗∗ 15 (31%) Elevated sodium (> 150 mmol/d) 35 (71%) Elevated phosphate (> 1.2 mmol/d) 21 (43%) Low volume (< 2L) 30 (61%) Elevated urine pH (> 6.2) 36 (73%) Patients started on medical therapy Total 28 (57%) Thiazide diuretic 20 (41%) Citrate therapy 4 (8%) Combined therapy 4 (8%) Elevated serum calcium 4 (8%) Elevated parathyroid hormone 3/22 (14%) Abbreviations: Pt, patient; PCNL, percutaneous nephrolithotomy; ESWL, extracorporeal shockwave lithotripsy; yo, years old; BMI, body mass index; kg, kilograms; m, meters; mg, milligrams; dL, deciliter; mo, months; d, day; mmol, millimoles; L, liter; g, grams. ∗ History of stone passage was available for 38 patients, family history was available for 44 patients, and age at first stone event was known for 35 patients. ∗∗ Hypercalciuria was defined as greater than 250 mg/d in men and greater than 200 md/d in women. Hypocitraturia was defined as less than 450 mg/d in men and less than 550 mg/d in women. Hyperuricosuria was defined as greater then 0.80 g/d in men and greater than 0.75 g/d in women. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e1021-e1022 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Tracy Marien More articles by this author S. Duke Herrell More articles by this author Nicole Miller More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...