Citrato y litiasis renal / Citrate and renal stones

El citrato es un potente inhibidor de la cristalización de sales de calcio. La hipocitraturia es una alteración bioquímica frecuente en la formación de cálculos de calcio en adultos y especialmente en niños. El pH ácido (sistémico, tubular e intracelular) es el principal determinante de la excreción de citrato en la orina. Si bien la mayoría de los pacientes con litiasis renal presentan hipocitraturia idiopática, hay un número de causas para esta anormalidad que incluyen acidosis tubular renal distal, hipokalemia, dietas ricas en proteínas de origen animal y/o dietas bajas en álcalis y ciertas drogas, como la acetazolamida, topiramato, IECA y tiazidas. Las modificaciones dietéticas que benefician a estos pacientes incluyen: alta ingesta de líquidos y frutas, especialmente cítricos, restricción de sodio y proteínas, con consumo normal de calcio. El tratamiento con citrato de potasio es efectivo en pacientes con hipocitraturia primaria o secundaria y en aquellos desordenes en la acidificación, que provocan un pH urinario persistentemente ácido. Los efectos adversos son bajos y están referidos al tracto gastrointestinal. Si bien hay diferentes preparaciones de citrato (citrato de potasio, citrato de sodio, citrato de potasio-magnesio) en nuestro país solo está disponible el citrato de potasio en polvo que es muy útil para corregir la hipocitraturia y el pH urinario bajo, y reducir marcadamente la recurrencia de la litiasis renal.(AU)

Citrate is a powerful inhibitor of the crystallization of calcium salts. Hypocitraturia is a biochemical common alteration in calcium stone formation in adults and especially in children. The acid pH (systemic, tubular and intracellular) is the main determinant of citrate excretion in the urine. While the etiology of hypocitraturia is idiopathic in most patients with kidney stones, there are a number of causes for this abnormality including distal renal tubular acidosis, hypokalemia, diets rich in animal protein and / or diets low in alkali and certain drugs, such as acetazolamide, topiramate, ACE inhibitors and thiazides. Dietary modifications that benefit these patients include high intake of fluids and fruits, especially citrus, sodium and protein restriction, with normal calcium intake. Treatment with potassium citrate is effective in patients with primary or secondary hypocitraturia and acidification disorders, which cause unduly acidic urine pH persistently. Adverse effects are low and are referred to the gastrointestinal tract. While there are various preparations of citrate (potassium citrate, sodium citrate, potassium citrate, magnesium) in our country is available only potassium citrate powder that is useful to correct both the hypocitraturia and the low urinary pH and reduce markedly the recurrence of kidney stones.(AU)

La dieta en el tratamiento de la litiasis renal. Bases fisiopatológicas / [Diet in the treatment of renal lithiasis. Pathophysiological basis].

The composition of urine is influenced by diet and changes in dietary factors have been proposed to modify the risk of recurrent nephrolithiasis. Nutrients that have been implicated include calcium, oxalate, sodium, animal protein, magnesium and potassium. There is significant evidence showing that a high calcium diet is associated with a reduction of lithogenic risk. One of the possible mechanisms to explain this apparent paradox is that the higher intake of calcium in the intestine binds with dietary oxalate, reducing its absorption and urinary excretion. Oxalate from the diet seems to provide only a small contribution to excretion and dietary restriction is appropriate only in those with hyperoxaluria and hyperabsorption. Observational studies have shown a positive and independent association between sodium intake and the formation of new kidney stones. Consumption of animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate, all factors that could participate in the genesis of stones. Potassium-rich foods increase urinary citrate because of its alkali content. In prospective observational studies, diets rich in magnesium were associated with a lower risk of kidney stone formation in men. In conclusion, diet is a key element in the management of the patient with kidney stones but always subordinated to present metabolic risk factors.

Long term effect of thiazides on bone mass in women with hypercalciuric nephrolithiasis / Efecto a largo plazo de tiziadas sobre la masa ósea en mujeres con hipercalciuria nefrolitiasis

Background: Decreased bone mineral density and increased prevalence of bone fractures have been found in patients with idiopathic hypercalciuria. It is not yet clear if thiazide treatment prevent these events. Methods: We retrospectively evaluated bone mass and biochemical markers of bone turnover in response to thiazide therapy in 52 consecutive female patients with idiopathic hypercalciuria and nephrolithiasis. Patients were divided in two subgroups according to their menopausal status: 25 were pre-menopausal (Group I) and 27 were postmenopausal (Group II). Results: Osteoporosis was found in 12 patients at baseline, 9 at the lumbar spine and 6 at the femoral neck. Two were pre-menopausal and 10 were postmenopausal. Patients with osteoporosis were analyzed separately (Group III). There was a significant and persistent reduction in urinary calcium with preservation of bone mass in all the groups after a median follow-up of 51 months. Few adverse effects were found using low doses of hydrochlorothiazide / amiloride. Only in the group III we found a statistcally significant an increase in BMD at the lumbar spine of 9.5% and an increase in BMD at femoral neck of 4.4% that did not reach statistical significance. Conclusions: We conclude that correction of hypercalciuria during long term treatment with low-dose hydrochlorothiazide//amiloride in women with nephrolithiasis prevents bone loss and in those with osteoporosis can lead to a significant increase in bone mineral density at the lumbar spine. Few adverse effects were seen during treatment and no interruption of therapy was necessary.(AU)

Introducción: Reducción de la densidad mineral ósea y aumento de la prevalencia de fracturas óseas se han encontrado en pacientes con hipercalciuria idiopática. Aún no está claro si el tratamiento con tiazidas prevenir estos eventos. Métodos: Evaluamos retrospectivamente la masa ósea y los marcadores bioquímicos de recambio óseo en respuesta a la terapia con tiazidas en 52 pacientes femeninos consecutivos con hipercalciuria idiopática y nefrolitiasis. Los pacientes fueron divididos en dos subgrupos de acuerdo a su estado de la menopausia : 25 fueron pre-menopáusicas (Grupo I) y 27 eran posmenopáusicas (Grupo II). Resultados: La osteoporosis se encontró en 12 pacientes al inicio del estudio, 9 en la columna lumbar y 6 en el cuello femoral. Dos eran premenopáusicas y 10 eran posmenopáusicas. Los pacientes con osteoporosis se analizaron por separado (Grupo III). Hubo una reducción significativa y persistente en el calcio urinario con la preservación de la masa ósea en todos los grupos después de una mediana de seguimiento de 51 meses. Pocos efectos adversos se encuentran utilizando dosis bajasde hidroclorotiazida / amilorida. Sólo en el grupo III encontramos un aumento estadísticamente significativo en la DMO de la columna lumbar del 9,5% y un aumento de la densidad mineral ósea en el cuello femoral de 4,4% que no alcanzó significación estadística. Conclusión: Llegamos a la conclusión de que la corrección de la hipercalciuria durante el tratamiento a largo plazo con dosis bajas de hidroclorotiazida / / amilorida en mujeres con nefrolitiasis previene la pérdida ósea y en aquellos con osteoporosis puede conducir a un aumento significativo en la densidad mineral ósea en la columna lumbar. Pocos se observaron efectos adversos durante el tratamiento y no hay interrupción de la terapia era necesario.(AU)

Litiasis renal: modificaciones bioquimicas durante el seguimiento / Renal lithiasis: biochemical changes in the follow-up

Con el objeto de evaluar si se producen modificaciones bioquímicas durante el seguimiento de pacientesnefrolitiásicos, se estudiaron 237 pacientes (115 mujeres y 122 hombres con una edad promediode 39 ± 8 y 42 ± 7 años respectivamente) controlados durante 23.7 ± 19.3 meses. A todos se les realizó un estudio metabólico de litiasis renal inicial y como mínimo uno o más posteriormente con las mismas características que el basal. No fueron incluidos pacientes con los diagnósticos de riñón en esponja, acidosis renotubular, hiperparatiroidismo primario, malformaciones renales o infecciones urinarias. Del total de pacientes, 139 (Grupo I) presentaron en el seguimiento una modificación metabólica no evidenciada en el estudio inicial, mientras que 98 (Grupo II) no. El tiempo de seguimiento de los primeros, no fue significativamente diferente de aquellos que no modificaron el diagnóstico basal. Las alteraciones bioquímicas agregadas más frecuentes fueron, hipocitraturia en el 43.1%, hipercalciuria idiopática en 20.8% y alteraciones del ácido úrico en 16.5%. De 110 pacientes seguidos más de 3 años, 37 (33%) recurrieron. De éstos, 25 (23%) modificaron el diagnóstico metabólico basal vs. 12 (11%) que mantuvieron el mismo diagnóstico (p < 0.002). Cambios en las alteraciones bioquímicas fueron observados con frecuencia en el seguimiento de pacientes con nefrolitiasis. Estos cambios no se asocian necesariamente a la dieta o a las drogas administradas. La hipocitraturia fue el diagnóstico bioquímico más frecuentemente agregado. Observamos mayor recurrencia en aquellos que modificaron el diagnóstico inicial y cuya modificación no fue corregida durante el seguimiento.(AU)

With the aim of assessing if biochemicalchanges occur in the follow up of patients with renal lithiasis, 237 patients were studied (115 womenand 122 men, mean age 39 ± 8 and 42 ± 7 years, respectively) and controlled during 27.3 ± 19.3 months. All ofthem had previously undergone metabolic evaluations at baseline and one or more than one control studies afterwards. Patients with a diagnosis of sponge kidney, renal tubular acidosis, primary hyperparathyroidism, anatomical malformations of the urinary tract, or urinary infections were not included. Two populations were identified: those who presented changes in the baseline diagnosis (139 patients, Group I) and those who presentedno changes (98 patients, Group II). In these groups, no differences were observed in baseline metabolic diagnoses or in the follow-up period. Hypocitraturia was the additional diagnosis most frequently observed (43.1%), followed by Idiopatic hypercalciuria (20.8%) and abnormalities of uric acid (16.5%). In the group of 110 patients followed up for more than 3 years, 37 patients recurred (33%). Among the latter, 25 (23%) changed the baseline metabolic diagnosis vs. 12 (11%) that maintained the same diagnosis (p < 0.002). Changes in metabolic disorders were frequently observed in the follow up of patients with nephrolithiasis. These changes are not necessarily associated with the diet indicated or drug treatment. Hypocitraturia was the additional metabolic disorder mostfrequently found. In general, there is a higher recurrence rate in those patients who present changes in their biochemical parameters and undergo no treatment.(AU)

Litiasis renal: modificaciones bioquimicas durante el seguimiento / Renal lithiasis: biochemical changes in the follow-up

Con el objeto de evaluar si se producen modificaciones bioquímicas durante el seguimiento de pacientesnefrolitiásicos, se estudiaron 237 pacientes (115 mujeres y 122 hombres con una edad promediode 39 ± 8 y 42 ± 7 años respectivamente) controlados durante 23.7 ± 19.3 meses. A todos se les realizó un estudio metabólico de litiasis renal inicial y como mínimo uno o más posteriormente con las mismas características que el basal. No fueron incluidos pacientes con los diagnósticos de riñón en esponja, acidosis renotubular, hiperparatiroidismo primario, malformaciones renales o infecciones urinarias. Del total de pacientes, 139 (Grupo I) presentaron en el seguimiento una modificación metabólica no evidenciada en el estudio inicial, mientras que 98 (Grupo II) no. El tiempo de seguimiento de los primeros, no fue significativamente diferente de aquellos que no modificaron el diagnóstico basal. Las alteraciones bioquímicas agregadas más frecuentes fueron, hipocitraturia en el 43.1%, hipercalciuria idiopática en 20.8% y alteraciones del ácido úrico en 16.5%. De 110 pacientes seguidos más de 3 años, 37 (33%) recurrieron. De éstos, 25 (23%) modificaron el diagnóstico metabólico basal vs. 12 (11%) que mantuvieron el mismo diagnóstico (p < 0.002). Cambios en las alteraciones bioquímicas fueron observados con frecuencia en el seguimiento de pacientes con nefrolitiasis. Estos cambios no se asocian necesariamente a la dieta o a las drogas administradas. La hipocitraturia fue el diagnóstico bioquímico más frecuentemente agregado. Observamos mayor recurrencia en aquellos que modificaron el diagnóstico inicial y cuya modificación no fue corregida durante el seguimiento.(AU)

With the aim of assessing if biochemicalchanges occur in the follow up of patients with renal lithiasis, 237 patients were studied (115 womenand 122 men, mean age 39 ± 8 and 42 ± 7 years, respectively) and controlled during 27.3 ± 19.3 months. All ofthem had previously undergone metabolic evaluations at baseline and one or more than one control studies afterwards. Patients with a diagnosis of sponge kidney, renal tubular acidosis, primary hyperparathyroidism, anatomical malformations of the urinary tract, or urinary infections were not included. Two populations were identified: those who presented changes in the baseline diagnosis (139 patients, Group I) and those who presentedno changes (98 patients, Group II). In these groups, no differences were observed in baseline metabolic diagnoses or in the follow-up period. Hypocitraturia was the additional diagnosis most frequently observed (43.1%), followed by Idiopatic hypercalciuria (20.8%) and abnormalities of uric acid (16.5%). In the group of 110 patients followed up for more than 3 years, 37 patients recurred (33%). Among the latter, 25 (23%) changed the baseline metabolic diagnosis vs. 12 (11%) that maintained the same diagnosis (p < 0.002). Changes in metabolic disorders were frequently observed in the follow up of patients with nephrolithiasis. These changes are not necessarily associated with the diet indicated or drug treatment. Hypocitraturia was the additional metabolic disorder mostfrequently found. In general, there is a higher recurrence rate in those patients who present changes in their biochemical parameters and undergo no treatment.(AU)

Fósforo oculto: identificación de aditivos a base de fósforo en alimentos procesados según la información brindada en sus rótulos nutricionales / Hidden phosphorus: identification of phosphorus-based additives in processed foods according to the information present in its nutritional labels

En forma creciente se están agregando aditivos que contienen fósforo a los productos alimenticios. Este agregado a alimentos procesados se produce por una variedad de razones, tales como preservativos, como agentes leudantes, como mejora dores de sabor, etc. Dado que estos aditivos son agregados a alimentos que naturalmente contienen fósforo así como a otros que no lo contienen, la estimación de contenido total de fósforo por tablas se hace dificultosa, considerándose como una fuente oculta de fósforo.(AU)

La dieta en el tratamiento de la litiasis renal. Bases fisiopatológicas. / [Diet in the treatment of renal lithiasis. Pathophysiological basis].

The composition of urine is influenced by diet and changes in dietary factors have been proposed to modify the risk of recurrent nephrolithiasis. Nutrients that have been implicated include calcium, oxalate, sodium, animal protein, magnesium and potassium. There is significant evidence showing that a high calcium diet is associated with a reduction of lithogenic risk. One of the possible mechanisms to explain this apparent paradox is that the higher intake of calcium in the intestine binds with dietary oxalate, reducing its absorption and urinary excretion. Oxalate from the diet seems to provide only a small contribution to excretion and dietary restriction is appropriate only in those with hyperoxaluria and hyperabsorption. Observational studies have shown a positive and independent association between sodium intake and the formation of new kidney stones. Consumption of animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate, all factors that could participate in the genesis of stones. Potassium-rich foods increase urinary citrate because of its alkali content. In prospective observational studies, diets rich in magnesium were associated with a lower risk of kidney stone formation in men. In conclusion, diet is a key element in the management of the patient with kidney stones but always subordinated to present metabolic risk factors.

Citrato y litiasis renal. / [Citrate and renal stones].

Citrate is a powerful inhibitor of the crystallization of calcium salts. Hypocitraturia is a biochemical common alteration in calcium stone formation in adults and especially in children. The acid pH (systemic, tubular and intracellular) is the main determinant of citrate excretion in the urine. While the etiology of hypocitraturia is idiopathic in most patients with kidney stones, there are a number of causes for this abnormality including distal renal tubular acidosis, hypokalemia, diets rich in animal protein and / or diets low in alkali and certain drugs, such as acetazolamide, topiramate, ACE inhibitors and thiazides. Dietary modifications that benefit these patients include high intake of fluids and fruits, especially citrus, sodium and protein restriction, with normal calcium intake. Treatment with potassium citrate is effective in patients with primary or secondary hypocitraturia and acidification disorders, which cause unduly acidic urine pH persistently. Adverse effects are low and are referred to the gastrointestinal tract. While there are various preparations of citrate (potassium citrate, sodium citrate, potassium citrate, magnesium) in our country is available only potassium citrate powder that is useful to correct both the hypocitraturia and the low urinary pH and reduce markedly the recurrence of kidney stones.