Principais distúrbios metabólicos em adolescentes portadores de nefrolitíase / Main metabolic disorders in adolescents with nephrolithiasis

Introdução: Os cálculos renais compreendem uma das mais comuns patologias do trato urinário e têm apresentado maior incidência em adolescentes nos últimos anos. Objetivos: Identificar os distúrbios metabólicos causadores de cálculo renal mais prevalentes em adolescentes. Métodos: Foram analisados os prontuários de 135 indivíduos portadores de nefrolitíase, com idade entre 12 e 18 anos, de ambos os sexos. Na análise laboratorial, incluiu-se: duas amostras de urina de 24 horas, contendo cálcio, citrato, oxalato e ácido úrico; uma amostra sanguínea, contendo creatinina, paratormônio, ácido úrico e cálcio; pH urinário após 12 horas de restrição hídrica e jejum; urocultura e cistinúria qualitativa. Resultados: 88 pacientes apresentaram hipercaIciúria (65,2%), 42 apresentaram hipocitratúria (31,1%) e 29 hiperuricosúria (21,5%). As demais alterações observadas foram: volume urinário reduzido (14,8%), infecções do trato urinário (9,6%), hiperoxalúria (5,2%), hiperparatireoidismo (1,5%) e acidose tubular renal (1,5%). Os distúrbios metabólicos mais frequentemente observados nos adolescentes portadores de cálculo renal foram hipercalciúria, hipocitratúria e hiperuricosúria

Introduction: Kidney stones are one of the most common pathologies of the urinary tract and have had a higher incidence in adolescents in recent years. Objectives: To identify the most prevalent metabolic disorders that cause kidney stones in adolescents. Methods: The medical records of 135 individuals with nephrolithiasis, aged between 12 and 18 years, of both sexes, were analyzed. The laboratory analysis included: two 24-hour urine samples containing calcium, citrate, oxalate and uric acid; a blood sample, containing creatinine, parathyroid hormone, uric acid, and calcium; urinary pH after 12 hours of fluid restriction and fasting; uroculture and qualitative cystinuria. Results: 88 patients had hyperuricosuria (65.2%), 42 had hypocitraturia (31.1%) and 29 had hyperuricosuria (21.5%). The other changes observed were: reduced urinary volume (14.8%), urinary tract infections (9.6%), hyperoxaluria (5.2%), hyperparathyroidism (1.5%) and renal tubular acidosis (1.5 %). Conclusions: The metabolic disorders most frequently observed in adolescents with kidney stones were hypercalciuria, hypocitraturia and hyperuricosuria.

Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation.

Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.

Hiperoxaluria primaria tipo 2 y oxalosis sistémica: Reporte de caso / Primary hyperoxaluria type 2 and systemic oxalosis: A case report

La hiperoxaluria primaria tipo 2 es una enfermedad rara caracterizada por sobreproducción de oxalato por una deficiencia enzimática intrahepática, lo que lleva a litiasis renal, nefrocalcinosis y daño renal crónico. Varón de 17 años con antecedentes de infecciones urinarias, y litiasis renal desde los 6 años. Desarrolló insuficiencia renal crónica terminal a los 11 años ingresando a terapia de diálisis peritoneal crónica ambulatoria. Durante su evolución presentó dolor a nivel de la columna vertebral y grandes articulaciones como tobillos, rodillas y hombros, deformación progresiva de las articulaciones distales de las manos. La resonancia magnética de columna reporto aplastamiento de cuerpos vertebrales en D8 y D9. La biopsia ósea de vértebra mostró depósito de cristales de oxalato de calcio. El estudio genético confirmó el diagnóstico de hiperoxaluria primaria tipo 2, esta enfermedad debe sospecharse en niños que forman cálculos a temprana edad, sería el primer caso reportado en Perú.

Primary hyperoxaluria type 2 is a rare disease characterized by over production of oxalate due to a deficiency of an intra hepatic enzyme leading to renal lithiasis, nephrocalcinosis and chronic kidney damage. We report the case of 17-year-old male patients with history of urinary tract infections and renal lithiasis since the age of 6 years. The patient developed end-stage kidney disease at the age of 11 years receiving chronic ambulatory peritoneal dialysis. He developed back pain and polyarthralgia of the ankles, knees, shoulders and progressive deformity of the hands. The magnetic resonance of the spine revealed flattening of D9-D9. Bone biopsy of the affected area showed presence of calcium oxalate. A genetic study confirmed the diagnosis of primary hyperoxaluria type 2. This entity should be suspected in children with renal stones at an early age, this may be the first case in Peru.

Association between glomerular filtration rate (measured by high-performance liquid chromatography with iohexol) and plasma oxalate / Associação entre taxa de filtração glomerular (medida por cromatografia liquida de alto desempenho com iohexol) e oxalato plasmático

ABSTRACT Introduction: Secondary hyperoxalemia is a multifactorial disease that affects several organs and tissues in patients with native or transplanted kidneys. Plasma oxalate may increase during renal failure because it is cleared from the body by the kidneys. However, there is scarce evidence about the association between glomerular filtration rate and plasma oxalate, especially in the early stages of chronic kidney disease (CKD). Methods: A case series focuses on the description of variations in clinical presentation. A pilot study was conducted using a cross-sectional analysis with 72 subjects. The glomerular filtration rate (GFR) and plasma oxalate levels were measured for all patients. Results: Median (IQR) GFR was 70.50 [39.0; 91.0] mL/min/1.73 m2. Plasma oxalate was < 5.0 µmol/L in all patients with a GFR > 30 mL/min/1.73m2. Among the 14 patients with severe CKD (GFR < 30 mL/min/1.73 m2) only 4 patients showed a slightly increased plasma oxalate level (between 6 and 12 µmol/L). Conclusion: In non-primary hyperoxaluria, plasma oxalate concentration increases when GFR < 30mL/min/1.73 m2 and, in our opinion, values greater than 5 µmol/L with a GFR > 30 mL/min/1.73 m2 are suggestive of primary hyperoxaluria. Further studies are necessary to confirm plasma oxalate increase in patients with low GFR levels (< 30mL/min/1.73 m2).

RESUMO Introdução: A hiperoxalemia secundária é uma doença multifatorial que afeta vários órgãos e tecidos em pacientes com rins nativos ou transplantados. O oxalato plasmático pode aumentar durante a insuficiência renal porque é eliminado do corpo pelos rins. No entanto, há evidências escassas sobre a associação entre taxa de filtração glomerular e oxalato plasmático, especialmente nos estágios iniciais da doença renal crônica (DRC). Métodos: uma casuística centrada na descrição das variações na apresentação clínica. Foi realizado um estudo piloto a partir da análise transversal com 72 indivíduos. As taxas de filtração glomerular (TFG) e os níveis plasmáticos de oxalato foram medidos para todos os pacientes. Resultados: A TFG mediana (IIQ) foi de 70,50 [39,0; 91,0] mL/min/1,73 m2. O nível plasmático de oxalato foi < 5,0 µmol/L em todos os pacientes com TFG > 30 mL/min/1,73 m2. Entre os 14 pacientes com DRC grave (TFG < 30 mL/min/1,73 m2), apenas quatro apresentaram ligeiro aumento do nível plasmático de oxalato (entre 6 e 12 µmol/L). Conclusão: Na hiperoxalúria não primária, a concentração plasmática de oxalato aumenta quando TFG < 30 mL/min/1,73 m2 e, em nossa opinião, valores superiores a 5 µmol/L com TFG > 30 mL/min/1,73 m2 sugerem presença de hiperoxalúria primária. Estudos adicionais são necessários para confirmar o aumento do oxalato plasmático em pacientes com níveis baixos de TFG (< 30 mL/min/1,73 m2).

Primary hiperoxaluria diagnosed after kidney transplantation: report of 2 cases and literature review / Hiperoxalúria primária diagnosticada após transplante renal: relato de dois casos e revisão da literatura

Abstract Primary hyperoxaluria (PH) is a very rare genetic disorder; it is characterized by total or partial deficiency of the enzymes related to the metabolism of glyoxylate, with an overproduction of calcium oxalate that is deposited in different organs, mainly the kidney, leading to recurrent lithiasis, nephrocalcinosis and end stage renal disease (ESRD). In patients with ESRD that receive kidney transplantation alone, the disease has a relapse of 100%, with graft loss in a high percentage of patients in the first 5 years of transplantation. Three molecular disorders have been described in PH: mutation of the gene alanin glioxalate aminotransferase (AGXT); glyoxalate reductase/hydroxy pyruvate reductase (GRHPR) and 4-OH-2-oxoglutarate aldolase (HOGA1). We present two cases of patients with a history of renal lithiasis who were diagnosed with primary hyperoxaluria in the post-transplant period, manifested by early graft failure, with evidence of calcium oxalate crystals in renal biopsy, hyperoxaluria, hyperoxalemia, and genetic test compatible; they were managed with proper diet, abundant oral liquids, pyridoxine, hydrochlorothiazide and potassium citrate; however, they had slow but progressive deterioration of their grafts function until they reached end-stage chronic renal disease.

Resumo A hiperoxalúria primária (HP) é um distúrbio genético muito raro, caracterizado por deficiência total ou parcial das enzimas relacionadas ao metabolismo do glioxilato, superprodução de oxalato de cálcio que se deposita em vários órgãos (principalmente os rins) resultando em litíase recorrente, nefrocalcinose e doença renal terminal (DRT). Nos pacientes com DRT que recebem transplante renal, a doença apresenta recidiva em 100% dos casos, com perda do enxerto nos primeiros cinco anos após o transplante num elevado percentual de pacientes. Três distúrbios moleculares foram descritos na HP: mutação dos genes da alanina-glioxilato aminotransferase (AGXT), glioxilato redutase/hidroxipiruvato redutase (GRHPR) e 4-OH-2-oxoglutarato aldolase (HOGA1). Apresentamos dois casos de pacientes com histórico de litíase renal diagnosticados com hiperoxalúria primária no período pós-transplante, manifestada na forma de perda precoce do enxerto com evidências de cristais de oxalato de cálcio na biópsia renal, hiperoxalúria, hiperoxalemia e testes genéticos compatíveis. Os pacientes foram tratados com abordagem nutricional, líquidos orais em abundância, piridoxina, hidroclorotiazida e citrato de potássio. Contudo, os pacientes apresentaram deterioração lenta e gradual da função do enxerto e evoluíram para doença renal terminal.

Hyperoxaluria in a Model of Mini-Gastric Bypass Surgery in Rats.

BACKGROUND: Bariatric surgery is associated with hyperoxaluria hence predisposing to nephrolithiasis. The present study aimed to investigate the underlying mechanisms contributing to increased urinary oxalate in a mini-gastric bypass (MGB) surgery model in rats under different dietary conditions. The expression of intestinal oxalate transporters was also evaluated. METHODS: Male rats underwent MGB (n = 21) or Sham procedure (n = 21) and after recovery were fed a standard or high-fat diet with or without oxalate for 8 weeks. Stool and urine were collected before surgery (baseline) and at the end of protocol (final), when intestinal fragments were harvested for expression of Slc26a3 and Slc26a6 oxalate transporters. RESULTS: MGB groups fed with fat, irrespective of oxalate supplementation, presented steatorrhea. In MGB animals fed with fat and oxalate (Fat + Ox), final values of urinary oxalate and calcium oxalate supersaturation risk were markedly and significantly increased versus baseline or Sham animals under the same diet, as well as MGB groups under other diets. Slc26a3 was decreased in biliopancreatic limbs of MGB rats, probably reflecting a physiological adaptation to the restriction of food passage. Slc26a6 was not altered in any harvested intestinal fragment. CONCLUSIONS: A high-fat and oxalate diet induced hyperoxaluria and elevation in calcium oxalate supersaturation risk in a MGB rat model. The presence of fat malabsorption and increased dietary oxalate absorption, but not modifications of Slc26a3 and Slc26a6 oxalate transporters, accounted for these findings, suggesting that bariatric patients may benefit from a low-fat and low-oxalate diet.

Pediatric primary urolithiasis: Symptoms, medical management and prevention strategies.

In the past few decades pediatric urolithiasis has become more frequent. The reason for this increase is not completely clear but has been attributed to changes in climate, nutritional habits and possibly other environmental factors. Although less frequent than adult stone disease, urolithiasis in the pediatric age group is also related to significant morbidity, particularly since stones tend to recur, and, thus, should not be underestimated. Most children with idiopathic stone disease have an underlying metabolic abnormality substantiating the importance of metabolic evaluation already following initial diagnosis of urolithiasis. Identification of the metabolic abnormality allows for more specific prescription of non pharmacological and pharmacological interventions aimed at preventing recurrent stone formation. A better understanding of the causes of kidney stone disease will provide better strategies for stone prevention in children.

Metabolic and endocrinological factors related to nephrolithiasis pre and post multiple techniques of bariatric surgery: a sistematic review / Fatores endócrinos e metabólicos relacionados à nefrolitíase pré e pós técnicas diversas de cirurgia bariátrica: uma revisão sistemática

INTRODUCTION: Despite of benefits of bariatric surgery for obesity treatment, the procedure may be related to some complications. AIM: Analyze studies to address the relation between nephrolithiasis and bariatric surgery. METHODS: Ten papers about this theme were selected from 2005-2013 in Pubmed, describing the relation of nephrolithiasis or their risk factors with several types of bariatric surgery. RESULTS: Retrospective studies with minimal follow-up of three years demonstrated 7,65% in surgery patients and 4,63% non-surgery with nephrolithiasis (p<0,05). Prospective studies (8 of 10) revealed large percentage of calculi appearing and significant increase in oxaluria. CONCLUSION: There is correlation between obesity surgery and nephrolithiasis. .

INTRODUÇÃO: Apesar dos benefícios das operações bariátricas para o tratamento da obesidade, elas podem acompanhar algumas complicações. OBJETIVO: Analisar estudos que enfoquem a relação entre nefrolitíase e procedimentos cirúrgicos bariátricos. MÉTODOS: Foram selecionados 10 estudos de 2005 a 2013 no PubMed que descreviam a relação de nefrolitíase ou seus fatores de risco com diversas técnicas de cirurgia bariátrica. RESULTADOS: Estudos retrospectivos, com seguimento por no mínimo três anos, demonstraram que 7,65% dos pacientes operados e 4,63% dos não operados apresentaram nefrolitíase (p<0,05). Estudos prospectivos (8 dos 10) verificaram grande porcentagem de aparecimento de nefrolitíase ou aumento significativo na oxalúria. CONCLUSÃO: Os estudos mostraram que há relação entre operações para obesidade e nefrolitíase. .

Nephrocalcinosis induced by hyperoxaluria in rats

PURPOSE: To investigate nephrocalcinosis due to hyperoxaluria induced by two different inducing agents in rats. METHODS: Forty Sprague-Dawley male rats were randomly distributed into four groups: Group1 (Clinical control, n = 10); Group 2 (0.5% Ethylene Glycol + Vitamin D3, n = 10); Group 3 (1.25% Ethylene Glycol, n = 10); and Group 4 (5%Hydroxy L-proline, n = 10). Five animals from each group were euthanized after one week of follow-up (M1 Moment) and the remaining, after four weeks (M2 Moment). All animals underwent 24h urine dosages of calcium, oxalate, uric acid, citrate and serum creatinine. Histology and histomorphometric analyses were performed using Image J program in the hematoxylin-eosin stains. Calcium deposits in the renal parenchyma were quantified by PIXE technique (Proton Induced X-Ray Emission). RESULTS: 24h urinary parameters did not show any significant variations after 28 days of experiment except by hyperoxaluria that was significantly higher in Group 3. Histomorphometric analyses showed a significantly higher nephrocalcinosis in Group 2 (p<0.01). The calcium deposits in the renal parenchyma were 10 and 100 times higher in Group 2 in comparison to other groups in the M1 and M2 moments, respectively. CONCLUSION: The Group 2 (vitamin D3+Ethylene Glycol 0.5%) was the best model to induce nephrocalcinosis in rats after 28 days.

Nephrocalcinosis induced by hyperoxaluria in rats

PURPOSE: To investigate nephrocalcinosis due to hyperoxaluria induced by two different inducing agents in rats. METHODS: Forty Sprague-Dawley male rats were randomly distributed into four groups: Group1 (Clinical control, n = 10); Group 2 (0.5% Ethylene Glycol + Vitamin D3, n = 10); Group 3 (1.25% Ethylene Glycol, n = 10); and Group 4 (5%Hydroxy L-proline, n = 10). Five animals from each group were euthanized after one week of follow-up (M1 Moment) and the remaining, after four weeks (M2 Moment). All animals underwent 24h urine dosages of calcium, oxalate, uric acid, citrate and serum creatinine. Histology and histomorphometric analyses were performed using Image J program in the hematoxylin-eosin stains. Calcium deposits in the renal parenchyma were quantified by PIXE technique (Proton Induced X-Ray Emission). RESULTS: 24h urinary parameters did not show any significant variations after 28 days of experiment except by hyperoxaluria that was significantly higher in Group 3. Histomorphometric analyses showed a significantly higher nephrocalcinosis in Group 2 (p<0.01). The calcium deposits in the renal parenchyma were 10 and 100 times higher in Group 2 in comparison to other groups in the M1 and M2 moments, respectively. CONCLUSION: The Group 2 (vitamin D3+Ethylene Glycol 0.5%) was the best model to induce nephrocalcinosis in rats after 28 days.(AU)

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

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.

Hiperoxaluria primaria en tres hermanos / Primary hyperoxaluria in three brothers

La hiperoxaluria es responsable de 2%-20% de las causas metabólicas de litiasis en niños y adolescentes. Esta puede ser secundaria o primaria(HP), en este último caso es tipo I o tipo II, de herencia autosómica recesiva. El objetivo es analizar diagnóstico y evolución en dos hermanos con HP tipo I y un tercero con alta probabilidad. El primer caso presentó a los 9 años un cólico nefrítico con litiasis múltiples bilaterales y una IRA leve. Presentaba hiperoxaluria de 214 mg/1,73 m2. Se descartaron causas secundarias. El estudio genético demostró dos copias de la mutación IIe244Thr. Los otros dos pacientes se presentaron en forma similar, a edades de 8 y 17 años. La piridoxina a altas dosis descendió los niveles de oxaluria como está descrito en un tercio de los casos. El tiempo de evolución es 7,3 y 1 año respectivamente. Persisten actualmente con litiasis bilaterales, sin nefrocalcinosis ni alteraciones del medio interno. La severidad de la HP tipo I es variable, hay formas de presentación temprana con litiasis recurrente y falla renal crónica en la infancia o en la adolescencia; otras de inicio tardío en edad adulta. Se trata de una enfermedad grave, progresiva, cuyo diagnóstico temprano con estudio metabólico completo puede mejorar el pronóstico,fundamentalmente en aquellos que responden a la piridoxina. El manejo de la litiasis y sus complicaciones es fundamental para evitar la IRC. Cuando ésta se desarrolla, la diálisis agresiva y el trasplante hepatorrenal son las opciones terapéuticas. Es el primer informe de casos confirmados de hiperoxaluria primaria en nuestro país...

Hiperoxaluria primaria en tres hermanos / Primary hyperoxaluria in three brothers

La hiperoxaluria es responsable de 2%-20% de las causas metabólicas de litiasis en niños y adolescentes. Esta puede ser secundaria o primaria(HP), en este último caso es tipo I o tipo II, de herencia autosómica recesiva. El objetivo es analizar diagnóstico y evolución en dos hermanos con HP tipo I y un tercero con alta probabilidad. El primer caso presentó a los 9 años un cólico nefrítico con litiasis múltiples bilaterales y una IRA leve. Presentaba hiperoxaluria de 214 mg/1,73 m2. Se descartaron causas secundarias. El estudio genético demostró dos copias de la mutación IIe244Thr. Los otros dos pacientes se presentaron en forma similar, a edades de 8 y 17 años. La piridoxina a altas dosis descendió los niveles de oxaluria como está descrito en un tercio de los casos. El tiempo de evolución es 7,3 y 1 año respectivamente. Persisten actualmente con litiasis bilaterales, sin nefrocalcinosis ni alteraciones del medio interno. La severidad de la HP tipo I es variable, hay formas de presentación temprana con litiasis recurrente y falla renal crónica en la infancia o en la adolescencia; otras de inicio tardío en edad adulta. Se trata de una enfermedad grave, progresiva, cuyo diagnóstico temprano con estudio metabólico completo puede mejorar el pronóstico,fundamentalmente en aquellos que responden a la piridoxina. El manejo de la litiasis y sus complicaciones es fundamental para evitar la IRC. Cuando ésta se desarrolla, la diálisis agresiva y el trasplante hepatorrenal son las opciones terapéuticas. Es el primer informe de casos confirmados de hiperoxaluria primaria en nuestro país.