Risk factors evaluation for urolithiasis among children / Evaluación de factores de riesgo para urolitiasis en niños

Abstract: Background: The prevalence of pediatric urolithiasis varies from 0.01-0.03%. Urolithiasis may be caused by anatomical, metabolic and environmental factors. Recurrence varies between 16 to 67%, and it is frequently associated with metabolic abnormalities. The objective of the present work was the identification of risk factors that promote urolithiasis in a child population. Methods: This study included 162 children with urolithiasis and normal renal function (mean age 7.5 years). Risk factors were investigated in two stages. In the first stage, 24-hour urine, and blood samples were analyzed to assess metabolic parameters and urinary tract infection. During the second stage, the effect of calcium restriction and a calcium load on renal Ca excretion were evaluated. Data were statistically analyzed. Results: Urolithiasis was observed in 0.02% of children, 50% of them with family history of urinary stones. There were multiple risk factors for urolithiasis including hypocitraturia (70%), hypomagnesuria (42%), hypercalciuria (37%; in 11/102 was by intestinal hyperabsorption, in 13/102 was unclassified. Ca resorption or renal Ca leak were not detected). We also detected alkaline urine (21%), systemic metabolic acidosis (20%), urinary infections (16%), nephrocalcinosis with urolithiasis (11%), oliguria (8%), urinary tract anomalies, hyperuricosemia and hypermagnesemia (7% each one), hypercalcemia (6%), hyperoxaluria (2%) and hypercystinuria (0.61%). Conclusions: Hypocitraturia and hypomagnesuria were the most frequent risk factors associated with urolithiasis, followed by hypercalciuria. High PTH values were excluded. Children presented two or more risk factors for urolithiasis.

Resumen: Introducción: La prevalencia de urolitiasis pediátrica varía de 0.01-0.03%. Las causas de urolitiasis pueden ser anatómicas, metabólicas o ambientales. Las recurrencias varían entre 16 a 67%, y están frecuentemente asociadas con alteraciones metabólicas. El objetivo del presente trabajo fue la identificación de factores de riesgo que promueven la urolitiasis en una población infantil. Métodos: Se incluyeron 162 niños con urolitiasis y función renal normal, cuya edad media fue de 7.5 años. Los factores de riesgo fueron investigados en dos etapas. En la primera, con la muestras de orina de 24 h y sangre, se investigaron parámetros metabólicos e infecciones del tracto urinario. En una segunda etapa se valoró la calciuria, previa restricción seguida de carga de Ca. Los hallazgos fueron analizados estadísticamente. Resultados: Se presentó urolitiasis en el 0.02% de los niños con historia familiar en el 50%. Se observó hipocitraturia (70%); hipomagnesuria (42%); hipercalciuria (37%; en 11/102 fue por hiperabsorción intestinal; en 13/102 fue inclasificable; no se observó hipercalciuria por resorción o pérdida renal). También se observó orina alcalina (21%); acidosis metabólica sistémica (20%); infecciones urinarias (16%); nefrocalcinosis con urolitiasis (11%); oliguria (8%); anomalías urinarias congénitas, hiperuricosemia e hipermagnesemia (7% cada una); hipercalcemia (6%); hiperoxaluria (2%); e hipercistinuria (0.61%). Conclusiones: La hipocitraturia e hipomagnesemia fueron los factores de riesgo con mayor frecuencia, seguidos de hipercalciuria. Se excluyeron los valores de hiperparatiroidismo. Los niños exhibieron dos o más factores de riesgo para el desarrollo de urolitiasis.

Clinical and demographic factors associated with compliance and subsequent urinary metabolic changes in first-time ureteral stone formers / 동물의과학연구지

Dietary and lifestyle modifications are widely prescribed to prevent recurrence of urolithiasis, although little is known about the clinical and demographic factors associated with patient compliance and urinary metabolic changes. The present study assessed the clinical and demographic factors influencing compliance with a modified diet and lifestyle in first-time ureteric stone formers as well as determined the effects of compliance on urinary stone risk factors. We retrospectively reviewed the medical records of 53 patients presenting with ureteric calcium stones. Using a self-completed questionnaire, patients were classified according to compliance with seven recommendations for modifying diet and lifestyle into good compliance group (complied with > or = three recommendations) and poor compliance group. Before (on a random diet) and after prescribing the modifications, 24 hour urine samples were collected from those in the good and poor compliance group. The stone size at presentation and initial treatment modality were closely associated with patient compliance (P=0.019, P=0.027, respectively). Citrate excretion significantly increased in the good compliance group after adopting modifications (P=0.012), whereas the poor compliance group did not show a statistically significant difference. Moreover, patients in the poor compliance group showed significantly increased urinary calcium excretion by the end of the study (P=0.040). After adjustments for age, sex, body mass index, and metabolic abnormality status, poor compliance was found to be an independent risk factor for persistence or development of hypocitraturia (OR: 3.885; 95% CI: 1.102~13.694; P=0.035). In conclusion, our results imply that patient education programs regarding diet and lifestyle should be tailored to the individual's clinical and demographic characteristics.

Clinical Significance of Hypocitraturia in Patients with Nephrolithiasis / 대한비뇨기과학회지

PURPOSE: Hypocitraturia is cited as one of the risk factors promoting stone formation or recurrence of nephrolithiasis. We estimated the relationship between hypocitraturia and other metabolic abnormalities, such as hypercalciuria, hyperuricosuria and hyperoxaluria. The effects of potassium citrate medication were also investigated. MATERIALS AND METHODS: We selected 706 renal stone patients with hypocitraturia (<320mg/day), who had received extracorporeal shock wave lithotripsy (ESWL) treatment, and examined the relationship between hypocitraturia and other metabolic abnormalities according to sex and age. We also examined the increment effect of urinary citrate and stone-free rate following potassium citrate (Urocitra(R)) medication. RESULTS: Complicated hypocitraturia (coexistence with other metabolic abnormalities) was found in 332 of the 706 patients (47.0%). Of the 706 patients, 242 (34.3%), 112 (15.9%) and 33 (4.7%) had hyperoxaluria, hyperuricosuria and hypercalciuria, respectively. Complicated hypocitraturia was higher in the male than female subjects, and was statistically significant (50.4% vs. 39.8%). In 287 (77%) of the 373 patients who received potassium citrate treatment, the urinary citrate level was increased. The mean urinary citrate level was significantly increased (142.5 vs. 336.2 mg/day) (p<0.01), but the stone free rate was not following the citrate treatment. CONCLUSIONS: Potassium citrate was effective in increasing the urinary citrate level. However, prophylactic effects of potassium citrate against recurrent nephrolithiasis must be proved by appropriate comparative studies.

A Case of Type 1 Renal Tubular Acidosis Accompanying Renal Stone and Nephrocalcinosis Caused by Hypocitraturia / 대한신장학회잡지

Renal stone and nephrocalcinosis are common clinical manifestations of type 1 renal tubular acidosis. In normal state, citrate plays the most critical role in suppressing stone formation as it combines with calcium. In type 1 RTA, increased reabsorption of citrate in proximal tubule results in low citrate excretion, which precipitates renal stone formation. We report a case of type 1 RTA accompanying renal stone and nephrocalcinosis caused by hypocitraturia. A 16-year-old male patient who had renal stone and nephrocalcinosis showed hypocitraturia. Incomplete type 1 RTA was proved as the cause of hypocitraturia by bicarbonate and ammonium loading test in the patient.

The Physiologic Effects of the Urocitra in Patients with Urolithiasis / 대한비뇨기과학회지

PURPOSE: To investigate the biochemical change in serum and 24-hour urine after therapy with Urocitra(R) in patients affected by urolithiasis, who had hypocitraturia alone or associated with other metabolic disorder. MATERIALS AND METHODS: One hundred eighteen patients with evidence of 1 or more stone attacks within the last 3 years participated in the present study. They were 78 men and 40 women (6 to 78 years old, with a mean age of 47.01 12.95 years). All of the patients received 15 to 20ml of Urocitra(R)-solution or 5 g of Urocitra(R)-C powder, three or four times daily for 3 months. Before treatment, 24-hour urine and venous blood samples were obtained, while patients were maintained on a random diet, and analyzed for various stone risk factors. After 1 week, 1 month and 3 months of treatment, samples were again obtained and analyzed in the same manner. Thereafter, we compared the biochemical values before and after treatment. RESULTS: In all three follow-up periods Urocitra(R) induced a significant increase in urinary citrate (p<0.001) level. Urinary potassium (p<0.001), pH (p<0.001) and total volume (p<0.05) also increased significantly after 1 and 3 months of therapy, as did urinary citrate excretion in patients with hypocitraturia and normocitraturia. Urocitra(R) did not alter calcium, sodium or phosphorus urinary excretion. There was no significant change of serum chemistry after administration. CONCLUSIONS: Urocitra(R) was effective in increasing urinary pH and citrate. Furthermore, it was relatively free of side effects, except for minor gastrointestinal distress. Thus, our study provides physiological and clinical validation for the use of Urocitra(R) in patients affected by urolithiasis, who have hypocitraturia alone or associated with another metabolic disorder.

Change of Na~+/dicarboxylate cotransporter-1 expression in rats with nephrolithiasis induced by ethylene glycoi and mechanism of potassium citrate prevention / 中华肾脏病杂志

Objective To investigate the change of Na+ /dicarboxylate cotransporter (SDCT) 1 expression in renal tissues of rats with nephrolithiasis induced by ethylene glycol (EG) and the mechanism of potassium citrate prevention. Methods Male Wistar rats were divided into control, nephrolithiasis and potassium citrate treated groups. Calcium oxalate crystal deposition and histological changes in kidney were examined by anatomical and light microscope. The plasma and urinary biochemical parameters, such as citrate, oxalate etc., were analyzed by routine biochemical method. The expression of SDCT1 mRNA in kidneys was determined by Northern blot, and the change of SDCT1 protein abundance was detected by immunohistochemistry. Results On day 3, the animals in the nephrolithiasis group had a higher level of SDCT1 mRNA and protein abundance in kidneys, as well as a lower level of citrate in the urine when compared with the control group. However none of the rats in this group had obviously calcium oxalate crystal deposition in kidneys. On day 7 and 14, the expression of SDCT1 mRNA and protein abundance were shown further increase, when the urinary citrate concentration was decreased progressively, and 87. 5% to 100% of the rats in this group displayed a large quantity of calcium crystal deposition in the kidney. In the potassium citrate treated group, both the expression of SDCT1 mRNA and protein abundance were shown almost complete inhibited during the whole experiment time, meanwhile the urinary citrate level was significantly elevated with time; furthermore, the occurrence of the renal crystal deposition decreased to 37. 5% on day 14, and the pathologic changes such as tubular dilation and inflammatory cells infiltration were shown to be alleviated. Conclusions The upregulation of SDCT1 mRNA and protein abundance in kidney has a close relationship with hypocitraturia, which may play an important role in the development of nephroliathisis. The treatment with potassium citrate has a beneficial effect on the experimental nephrolithiasis rats through inhibiting the expression of SDCT1 in the renal tissue.

Biochemical evaluation of 24-hour urine in stone patients / 대한비뇨기과학회지

The fifty four patients with urinary stones(38 men. 16 women) and nine controls on usual constant diet were evaluated with the measurement of urinary minerals. electrolytes, citrate and calculation or net gastrointestinal absorption or alkali by recently devised simple method, i.e., (Na+K+ Ca + Mg)-(CI +1.8P) of urine, to evaluate prevalence of either hypo-or hyper-excretion of each items as well as to see possible correlation between citraturia and net gastrointestinal absorption of alkali. In 24-hour urine measurement, the stone patients in comparison with controls showed hyperexcretion of calcium(p<0.05), oxalate(p<0.05) and sodium(p<0.05) and hypoexcretion of phosphorus( p<0.05), potassium(p<0.001) and citrate(p <0.05). Hypocilraturia(less than 320mg/ dl) was noted in 64.8% of all stone patients though mean urine citrate levels were higher in women compared to men without statistical significance. In view of gender difference, all 24-hour urine analysis except citrate in stone patients were higher in men than women. of which calcium, creatinine, potassium and chloride were statistically significant(p<0.05). A retrograde analysis between citraturia and net gastrointestinal absorption of alkali in both stone patients and controls didn`t reveal any significant correlation. In conclusion, 24-hour urine biochemistries are an influential factor or the stone formation and this study regarding to relation between hypocitraturia and reduced net gastrointestinal absorption of alkali shows no correlation."