RESUMO
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.
RESUMO
The aim of this study was to evaluate the preventive effect of sodium bicarbonate on systemic acidosis due to ruminal acidosis, which was induced by ingestion of concentrate after prolonged fasting. Fourteen sheep were divided into three experimental groups: control group (Cg), with four sheep, submitted to fasting without development of ruminal acidosis; no-treated group (NTg), with five sheep with rumen acidosis without preventive treatment; and treated group (Tg), with five sheep with rumen acidosis and preventively treated with sodium bicarbonate. Assessments of ruminal pH and arterial hemogasometry were performed for 48 hours after ingestion of the concentrate. There was a reduction in the ruminal pH in all groups, whereas the Cg showed a reduction only after 24 hours. A reduction in the arterial pH, bicarbonate and base excess in all groups was also noted, indicating systemic metabolic acidosis, but the NTg presented the greatest alteration. It is concluded that sodium bicarbonate prevents systemic metabolic acidosis, reducing its severity in sheep subjected to ruminal acidosis.(AU)
O objetivo deste estudo foi avaliar o efeito preventivo do bicarbonato de sódio sobre a acidose sistêmica em decorrência da acidose ruminal, a qual foi induzida pelo fornecimento de concentrado após jejum prolongado. Foram utilizados 14 ovinos, divididos em três grupos experimentais: grupo controle (Cg), contendo quatro ovinos, submetidos a jejum sem desenvolvimento de acidose ruminal; grupo não tratado (NTg), contendo cinco ovinos submetidos a acidose ruminal sem tratamento preventivo; e grupo tratado (Tg), contendo cinco ovinos, submetidos a acidose ruminal e tratados preventivamente com bicarbonato de sódio. Foram realizadas avaliações do pH ruminal e hemogasometria arterial, durante 48 horas após o fornecimento do concentrado. Houve redução do pH ruminal em todos os grupos, sendo que o Cg apresentou a redução apenas às 24 horas. Notou-se redução do pH arterial, bicarbonato e excesso de base em todos os grupos, indicando acidose metabólica sistêmica; no entanto, o NTg apresentou o quadro mais grave. Conclui-se que o bicarbonato de sódio possui efeito preventivo da acidose metabólica sistêmica, reduzindo a sua gravidade em ovinos submetidos à acidose ruminal.(AU)