Usefulness of measuring renal papillae in Hounsfield units in stone - forming patients.

INTRODUCTION: The aim of this work is to study the density of the renal papillae in stone-forming patients and to determine its usefulness. MATERIALS AND METHODS: This study included a total of 79 patients diagnosed with renal stones and on whom a computed tomography without contrast was performed from June 2014 to May 2015. The patients were divided into two groups: Group 1 (single ep¬isode) included 43 patients, and Group 2 (recurrent episodes) included 36 patients. The density of six renal papillae (3 per kidney) was measured, and the means obtained were compared between Groups 1 and 2. Statistical analysis was performed using SPSS 20.0. RESULTS: The mean papillary density in Group 1 was 32.26 (SD 4.07) HU compared to 42.36 (SD 8.03) HU in Group 2 (P=00001). A ROC curve was constructed, obtaining an optimal cut-off point of 36.8HU [area under the curve, 0.881 (95% CI; 0.804-0.958); P=0001], with a sensitivity of 80% and a specificity of 90%. The relative risk was estimated at 40.3 (95% CI; 10.8-151.1), meaning that a patient with a mean papillary density greater than 36.8HU would have a 40 times greater risk of having recurrent renal stones. The positive predictive value (PPV) was 81% and the negative predictive value (NPV) was 90%. CONCLUSION: The measurement of renal papillary density could be useful in predicting recurrent stone-formers. These results need to be confirmed in future studies with a greater number of patients and a longer follow-up.

Usefulness of measuring renal papillae in Hounsfield units in stone - forming patients

ABSTRACT Introduction: The aim of this work is to study the density of the renal papillae in stone-forming patients and to determine its usefulness. Materials and Methods: This study included a total of 79 patients diagnosed with renal stones and on whom a computed tomography without contrast was performed from June 2014 to May 2015. The patients were divided into two groups: Group 1 (single episode) included 43 patients, and Group 2 (recurrent episodes) included 36 patients. The density of six renal papillae (3 per kidney) was measured, and the means obtained were compared between Groups 1 and 2. Statistical analysis was performed using SPSS 20.0. Results: The mean papillary density in Group 1 was 32.26 (SD 4.07) HU compared to 42.36 (SD 8.03) HU in Group 2 (P=00001). A ROC curve was constructed, obtaining an optimal cut-off point of 36.8HU [area under the curve, 0.881 (95% CI; 0.804-0.958); P=0001], with a sensitivity of 80% and a specificity of 90%. The relative risk was estimated at 40.3 (95% CI; 10.8-151.1), meaning that a patient with a mean papillary density greater than 36.8HU would have a 40 times greater risk of having recurrent renal stones. The positive predictive value (PPV) was 81% and the negative predictive value (NPV) was 90%. Conclusion: The measurement of renal papillary density could be useful in predicting recurrent stone-formers. These results need to be confirmed in future studies with a greater number of patients and a longer follow-up.

Catéter ureteral desintegrado / Ureteral stent disintegrated

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Uso de las concentraciones urinarias en mg/dl en relación a los valores absolutos en 24 h para la evaluación de factores litogénicos en pacientes litiásicos / Use of urinary concentrations in mg/dl in relation to absolute values in 24-hour samples for the evaluation of lithogenic factors in stone forming patients

OBJETIVO: El objetivo de este estudio es analizar las concentraciones en orina (mg/dl) de diferentes factores litogénicos en una muestra de 24 h como predictor de estas alteraciones en lugar de valores absolutos que dependen del volumen de diuresis. MÉTODOS: Desde junio 2014 a mayo 2015 se incluyen un total de 131 pacientes, pertenecientes al Área de Gestión Sanitaria Norte de Almería, con litiasis a los que se indica estudio metabólico. Se realiza estudio de concentraciones de calcio, oxalato, úrico y citrato en orina, junto con cociente calcio/citrato. Se tiene en cuenta la clasificación de hipercalciuria (> 260 mg/24h), hiperuricosuria (> 750 mg/24 h), hiperoxaluria (> 40 mg/24h), hipocitraturia (< 320 mg/24h), hipomagnesuria (< 35 mg/24h). Análisis estadístico con SPSS 17.0. RESULTADOS: Para la concentración de calcio en orina se estima un punto de corte de 12,55 mg/dl con sensibilidad 90% y especificidad 85% con RR de 51,2 (13,9-188,4). En relación a la concentración de oxalato se estima un punto de corte de 1,86 mg/dl con sensibilidad del 91% y especificidad del 84%, con un RR estimado de 67,2 (8,3-540,6). En cuanto a la concentración de úrico en orina se estima un punto de corte de 31,2 mg/dl con una sensibilidad 85% y especificidad 70%, con un RR estimado de 12 (3,8-37,6). En cuanto al citrato, el punto de corte estimado para su concentración fue de 18,8 mg/dl con una sensibilidad y especificidad del 82% y 74% respectivamente, estimando un RR de 13,7 (4,4-42,6). El punto de corte para el magnesio fue de 2,26 mg/dl con sensibilidad 95% y especificidad 78% y RR de 67,6 (11,4-398,3). CONCLUSION: La determinación de concentraciones en orina, en lugar de valores absolutos que dependen en gran medida de la diuresis, parece ser útil a la hora de estimar alteraciones metabólicas clásicas, por lo que deben ser tenidos en cuenta en la evaluación de los pacientes con litiasis

OBJECTIVE: The aim of this study is to analyze urine concentrations (mg/dl) of different lithogenic factors in a sample of 24 h as a predictor of these changes rather than absolute values depend on the volume of diuresis. METHODS: A total of 131 patients from the North Almeria Health Management Area (Spain) with urinary stone disease in whom a metabolic study was indicated were included from June 2014 to May 2015. The concentrations of calcium, oxalate, uric acid, citrate and magnesium were measured in the urine, and the calcium/citrate ratio was calculated. The classifications used were: hypercalciuria (> 260 mg/24h), hyperuricosuria (> 750 mg/24h), hyperoxaluria (> 40 mg/24h), hypocitraturia (> 320 mg/24h) and hypomagnesuria (< 35 mg/24h). The statistical analysis was performed using SPSS 17.0. RESULTS: A cut-off point of 12.55 mg/dl, with a sensitivity of 90% and a specificity of 85% and a relative risk (RR) of 51.2 (13.9-188.4), was estimated for urinary calcium. For oxalate the cut-off point was 1.86 mg/dl, with a sensitivity of 91% and a specificity of 84% with an estimated RR of 67.2 (8.3-540.6). As regards the uric acid concentration in urine, a cut-off point of 31.2 mg/dl was estimated, with a sensitivity of 85% and a specificity of 70% and a RR of 12 (3.8-37.6). For citrate the cut-off point was 18.8 mg/dl, with a sensitivity and specificity of 82% and 74%, respectively, with a RR of 13.7 (4.4- 42.6). The cut-off point for magnesium was 2.26mg/dl with a sensitivity of 95% and specificity of 78%, with a RR of 67.6 (11.4-398.3). CONCLUSION: The determination of urine concentrations, instead of absolute values, depends to a large extent on urine output, appears to be useful when estimating classic metabolic alterations and should be taken into account in the evaluation of patients with urinary stone disease