Sonali Sheth

Ureteral Stone Location at Emergency Room Presentation With Colic

PURPOSE It is thought that the 3 narrowest points of the ureter are the ureteropelvic junction, the point where the ureter crosses anterior to the iliac vessels and the ureterovesical junction. Textbooks describe these 3 sites as the most likely places for ureteral stones to lodge. We defined the stone position in the ureter when patients first present to the emergency department with colic. MATERIALS AND METHODS We retrospectively reviewed the records of 94 consecutive patients who presented to the emergency department with a chief complaint of colic and computerized tomography showing a single unilateral ureteral calculus. Axial, coronal and 3-dimensional reformatted computerized tomography scans were evaluated, and stone position and size (maximal axial and coronal diameters) were recorded, as were the position of the ureteropelvic junction, the iliac vessels (where the ureter crosses anterior to the iliac vessels) and the ureterovesical junction. Patients with a history of nephrolithiasis, shock wave lithotripsy, ureteroscopy or percutaneous nephrolithotripsy were excluded from study. Statistical analysis was performed using Students t test and Pearsons correlation coefficient. RESULTS At the time of emergency department presentation for colic ureteral stone position was the ureteropelvic junction in 10.6% cases, between the ureteropelvic junction and the iliac vessels in 23.4%, where the ureter crosses anterior to the iliac vessels in 1.1%, between the iliac vessels and the ureterovesical junction in 4.3% and at the ureterovesical junction in 60.6%. Proximal calculi had a greater axial diameter than distal calculi (mean 6.1 vs 4.0 mm) and a greater coronal diameter than distal calculi (6.8 vs 4.1 mm, each p <0.001). Axial and coronal diameters moderately correlated with stone position (r = -0.47 and -0.55, respectively, each p <0.001). CONCLUSIONS Proximal ureteral stones were larger in axial and coronal diameter than distal ureteral stones. At emergency department presentation for colic most stones were at the ureterovesical junction and in the proximal ureter between the ureteropelvic junction and the iliac vessels. A few stones were at the ureteropelvic junction and only 1 lodged at the level where the ureter crosses anterior to the iliac vessels, despite the literature stating that these locations are 2 of the 3 most likely places for stones to become lodged.

Abnormalities of 24-Hour Urine Composition in First-time and Recurrent Stone-formers

OBJECTIVE To examine differences in 24-hour urine composition between recurrent and first-time stone-formers. METHODS A retrospective review of patients evaluated in 2 metabolic stone clinics was performed. Recurrent stone formation was defined as patients with a history of more than 1 stone episode and first-time stone-formers were those with a history of a single-stone episode. Frequencies of urine metabolic abnormalities were noted. Multivariate linear regression was performed to evaluate the likelihood of abnormalities of 24-hour urine composition. RESULTS Three-hundred eleven patients met inclusion criteria: 71 (22.8%) were first-time stone-formers and 240 (77.1%) were recurrent stone-formers. On univariate analysis, the likelihood of having a single abnormality of 24-hour urine composition (ie, hypercalciuria, hyperoxaluria, hyperuricosuria, or hypocitraturia) was similar between the 2 groups (83.1% for first-time vs 88.8% for recurrent, P = NS). In addition, there were similar rates of hypercalciuria (39.4% vs 43.3%, P = NS), hyperoxaluria (32.4% vs 33.3%, P = NS), hyperuricosuria (29.6% vs 23.3%, P = NS), and hypocitraturia (45.0% vs 45.0%, P = NS). On multivariate logistic regression, there was no difference in detection of any urine abnormality (ie, hypercalciuria or hyperoxaluria or hypocitraturia or hyperuricosuria) between first-time (referent) or recurrent stone-formers (OR 1.68, 95% CI .8-3.5, P = .2). CONCLUSION In this study, detection of urine abnormalities was similar in first-time and recurrent stone-formers. Given the strong patient preference for stone prevention and the high success of directed therapy in the literature, we believe it is not unreasonable to offer comprehensive metabolic evaluation to first-time stone-formers who express a desire to undergo evaluation.

Relationship Between Serum Vitamin D and 24-Hour Urine Calcium in Patients With Nephrolithiasis

OBJECTIVE To examine the relationship between serum 25-OH vitamin D and 24-hour urine calcium in patients with nephrolithiasis. METHODS A retrospective review was performed. Patients evaluated in 2 metabolic stone clinics were included for analysis. Multivariate linear regression models were adjusted for known risk factors for stone disease (age, gender, body mass index, hypertension, diabetes mellitus, gout, relevant medications, and 24-hour urine composition). RESULTS One-hundred sixty-nine patients were included in the study. Female to male ratio was 69:100, mean age was 50.9 years (SD 13.7), and mean body mass index was 27.4 (SD 6.4). Vitamin D deficiency (25-OH vitamin D <20 ng/mL) was present in 18.9% of patients, vitamin D insufficiency (>20, <30 ng/mL) was present in 34.9% of patients, and vitamin D was within normal limits (≥ 30 ng/mL) in 46.1% of patients. On age-adjusted and multivariate linear regression, serum 25-OH vitamin D was not related to 24-hour urine calcium (age adjusted β = -0.31 m 95% CI -1.9 to 1.3; multivariate adjusted β = 0.08, 95% CI -1.3 to 1.5). CONCLUSION Although 25-OH vitamin D is involved in the bodys calcium homeostasis, our study does not show a relationship between serum vitamin D level and 24-hour urine calcium excretion in stone-formers. This information may have implications regarding the safety of vitamin D repletion in patients with nephrolithiasis.

The effects of ambient temperature, humidity and season of year on urine composition in patients with nephrolithiasis

Study Type – Prognosis (cohort series)

Relationship between glomerular filtration rate and 24-hour urine composition in patients with nephrolithiasis.

OBJECTIVE To examine the relationship between GFR and 24-hour urine composition in patients with nephrolithiasis to understand how renal function may affect stone risk. Alterations in glomerular filtration rate (GFR) are associated with a number of physiological changes. METHODS A retrospective, institutional review board-approved review of patients from 2 metabolic stone clinics was performed. One-way analysis of variance and multivariate linear regression models were used to evaluate the relationship between GFR quintile and 24-hour urine composition. RESULTS A total of 403 patients (241 male, 162 female) with a mean age of 52.6 ± 14.2 years were included in the study. On univariate analysis, decreasing GFR by quintile was associated with significant reductions in urine calcium, citrate, supersaturation of calcium oxalate, and supersaturation of calcium phosphate (P < .05 for each). In multivariate linear regression models, decreasing GFR by quintile was associated with significant decreases in urine calcium (β = -11.2, 95% CI = -18.3 to 4.01), urine citrate (β = -32.4, 95% CI = -54.1 to 10.8), oxalate (β = -1.83, 95% CI = -2.85 to 0.81), supersaturation of calcium oxalate (β = -0.58, 95% CI = 0.84 to 0.33) and supersaturation of calcium phosphate (β = -0.09, 95% CI = 0.17 to 0.02), as well as an increase in urine magnesium (β = 3.40, 95% CI = 0.7 to 6.1). CONCLUSION Reduction in GFR is associated with decreased urine calcium, oxalate, and citrate, and increased urine magnesium. These findings have implications for treatment of patients with stone disease and impaired renal function.

Effect of Socioeconomic Status on 24-Hour Urine Composition in Patients With Nephrolithiasis

OBJECTIVE To examine the relationship between the poverty and education levels and 24-hour urine composition in patients with nephrolithiasis because little is known about the relationship between socioeconomic status and kidney stone risk. METHODS A retrospective review was performed of patients evaluated at 2 metabolic stone clinics. The poverty level (ie, percentage of those living below the poverty level) and education level (ie, percentage of those with a high school education or greater) for each postal code were determined from the U.S. Census Bureau data. Multivariate linear regression analysis was used to examine the relationship between the poverty and education levels and 24-hour urine composition. RESULTS A total of 435 patients were included in the present study. Of the 435 patients, 173 were women and 262 were men (40% women), the mean age was 52.5 ± 14.4 years, and the mean body mass index was 28.6 ± 6.5 kg/m(2). The mean percentage of those below the poverty level was 8.2% ± 6.2%, and the mean percentage of those with a high school education or greater was 87.4% ± 7.4%. On multivariate linear regression analysis, an increasing local poverty level was associated with significant increases in urine calcium (β = 1.51, 95% confidence interval [CI] 0.16-2.86). A decreasing local level of education (ie, decreasing percentage of those with a high school diploma or greater) was associated with significant increases in urine calcium (β = 1.26, 95% CI 0.10-2.42), supersaturation of calcium oxalate (β = 0.04, 95% CI 0.006-0.09), and supersaturation of calcium phosphate (β = 0.013, 95% CI 0.0002-0.03). No other associations were found between the poverty and education levels and any urine constituents or supersaturations. CONCLUSION In the present study of patients with stone formation, increasing poverty was associated with increased urine calcium, and increasing education appeared to be protective by decreasing urine calcium and the supersaturation of calcium oxalate and calcium phosphate. Additional studies are important to elucidate the mechanisms underlying these findings.

Ureteral stenting and retrograde pyelography in the office: clinical outcomes, cost effectiveness, and time savings.

OBJECTIVES To examine the clinical outcomes and cost-effectiveness of endourologic procedures performed in the office using standard fluoroscopy and topical anesthesia. METHODS We performed a retrospective review of all patients who underwent primary ureteral stent placement, ureteral stent exchange, or ureteral catheterization with retrograde pyeolography or Bacillus Calmette-Guerin (BCG) instillation under fluoroscopic guidance in the office. For an evaluation of potential time savings, we compared this to a cohort of similar procedures performed in the operating room during the same time period. RESULTS Procedures were attempted in 65 renal units in 38 patients (13 male, 25 female) with a mean age of 62.2 years (range 29.1-95.4 years). Primary ureteral stent placement was successful in 23/24 (95.8%) renal units. Ureteral stent exchange was successful in 19/22 (86.4%) renal units. Ureteral catheterization with retrograde pyelography or BCG instillation was successful in 19/19 (100%) renal units. The total cost savings for the 38 patients in this study, including excess cost from failure in the office, was approximately

2235 SHOULD 25-OH VITAMIN D BE CHECKED IN ALL STONE-FORMERS WITH HYPERCALCIURIA AND ELEVATED PTH?

91,496, with an average cost savings of

Gender differences in subcutaneous and perirenal fat distribution

1,551 per procedure. Office-based procedures were associated with a nearly three-fold reduction in total hospital time as a result of reduced periprocedure waiting times. CONCLUSIONS Ureteral stent placement, ureteral stent exchange, and ureteral catheterization can be performed safely and effectively in the office in both men and women. This avoids general anesthesia and provides significant savings of time and cost for both patients and the health care system.

2245 THE EFFECTS OF AMBIENT TEMPERATURE, HUMIDITY, AND SEASON OF YEAR ON URINE COMPOSITION IN PATIENTS WITH NEPHROLITHIASIS

INTRODUCTION AND OBJECTIVES: Secondary hyperparathyroidism (i.e. elevated parathyroid hormone NOT due to a parathyroid adenoma or hyperplasia) may occur in patients with renal leak hypercalciuria and also in patients with low 25-OH vitamin D. Patients with the former condition may benefit from treatment with a thiazide diuretic, while those with the latter may also benefit from vitamin D repletion. METHODS: A retrospective review was performed of patients with hypercalciuria. Patients evaluated in two metabolic stone clinics were included for analysis. Serum 25-OH Vitamin D, PTH, and calcium values were normalized to account for variations in laboratory assays. RESULTS: 79 patients were included in the study. F:M ratio was 40:39, mean age was 48.4 years (SD 13.1) and mean BMI was 26.8 (SD 6.8). Vitamin D deficiency (i.e. vitamin D level lower than the lower limit of normal for a given laboratory) was present in 38/79 patients (48.1%). Mean 24-hour urine calcium was 242.3 mg/day (SD 117.6). In total, 11/79 patients (13.9%) demonstrated PTH values above normal limits and 5 of these 11 patients (45.4%) demonstrated vitamin D deficiency. CONCLUSIONS: In nearly half of stone-patients with elevated PTH, 25-OH vitamin D was below normal. For those patients, the source of secondary hyperparathyroidism may be renal leak hypercalciuria or vitamin D deficiency. We believe it is worthwhile to check vitamin D in stone-formers with elevated PTH as this may lead to the unanticipated diagnosis of vitamin D deficiency.