The natural history of solitary post-nephrectomy kidney in a pediatric population

ABSTRACT Introduction: Children with a solitary post-nephrectomy kidney (SNK) are at potential risk of developing kidney disease later in life. In response to the global decline in the number of nephrons, adaptive mechanisms lead to renal injury. The aim of this study was to determine the prevalence and time of onset of high blood pressure (HBP), proteinuria, glomerular filtration rate (GFR) disruption and renal tubular acidosis (RTA) in children with SNK. Materials and methods: After obtaining the approval from our institution's ethics committee, we reviewed the medical records of patients under 18 years of age who underwent unilateral nephrectomy between January 2005 and December 2015 in three university hospitals. Results: We identified 43 patients, 35 (81.4%) cases of unilateral nephrectomy (UNP) were due to a non-oncologic pathology and Wilm's tumor was identified in 8 (18.6%) cases. In patients with non-oncologic disease, 9.3% developed de novo hypertension, with an average time of onset of 7.1 years, 25% developed proteinuria de novo, with an average time of onset of 2.2 years. For GFR, 21.8% presented deterioration of the GFR in an average time of 3.4 years. Ten (43.5%) patients developed some type of de novo renal injury after UNP. Patients with oncologic disease developed the conditions slowly and none of them developed proteinuria. Conclusions: Taking into account the high rate of long term postoperative renal injury, it can be considered that nephrectomy does not prevent this disease. The follow-up of children with SNK requires a multidisciplinary approach and long-term surveillance to detect renal injury.

A physiology-based approach to a patient with hyperkalemic renal tubular acidosis / Abordagem diagnóstica de um paciente com acidose tubular renal hipercalêmica

ABSTRACT Hyperkalemic renal tubular acidosis is a non-anion gap metabolic acidosis that invariably indicates an abnormality in potassium, ammonium, and hydrogen ion secretion. In clinical practice, it is usually attributed to real or apparent hypoaldosteronism caused by diseases or drug toxicity. We describe a 54-year-old liver transplant patient that was admitted with flaccid muscle weakness associated with plasma potassium level of 9.25 mEq/L. Additional investigation revealed type 4 renal tubular acidosis and marked hypomagnesemia with high fractional excretion of magnesium. Relevant past medical history included a recent diagnosis of Paracoccidioidomycosis, a systemic fungal infection that is endemic in some parts of South America, and his outpatient medications contained trimethoprim-sulfamethoxazole, tacrolimus, and propranolol. In the present acid-base and electrolyte case study, we discuss a clinical approach for the diagnosis of hyperkalemic renal tubular acidosis and review the pathophysiology of this disorder.

RESUMO A acidose tubular renal hipercalêmica é uma acidose metabólica de ânion gap normal que invariavelmente indica anormalidade na secreção de íons potássio, amônio e hidrogênio. Na prática clínica, está geralmente atribuída a um estado de hipoaldosteronismo real ou aparente, causado por doenças ou toxicidade por drogas. Descrevemos um paciente de 54 anos, transplantado hepático, que foi admitido com fraqueza muscular associada à hipercalemia, potássio plasmático de 9,25 mEq/L. A investigação adicional revelou acidose tubular renal tipo 4 e importante hipomagnesemia com elevada fração de excreção de magnésio. A história patológica pregressa incluía um diagnóstico recente de Paracoccidioidomicose - uma infecção sistêmica fúngica endêmica que ocorre em algumas partes da América do Sul -, e as medicações de uso habitual continham sulfametoxazol-trimetoprim, tacrolimus e propranolol. No presente relato de caso, discutiremos uma abordagem clínico-laboratorial para o diagnóstico da acidose tubular renal hipercalêmica, assim como da hipomagnesemia, revisando a fisiopatologia desses transtornos.

Acidose tubular renal tipo IV no pronto atendimento / Renal tubular acidosis type IV in emergency medical services

No Hospital de Base de São José do Rio Preto, uma paciente com diabetes melito tipo 2, apresentando quadro de acidose metabólica, foi tratada na emergência da clínica médica. Foi seguido inicialmente protocolo de cetoacidose diabética. Após um dia sem melhora clínica, com a hipótese diagnóstica de acidose tubular renal tipo IV, confirmada pela acidose metabólica hipercalêmica e hiperclorêmica, foi optado por introduzir fludrocortisona no tratamento. Devido à melhora clínica e laboratorial fechou-se o diagnóstico e a paciente encontra-se em acompanhamento no ambulatório.

At the Hospital de Base hospital in São José do Rio Preto, a type II diabetic patient presenting metabolic acidosis was treated at the internal medicine ER. Initially the diabetic ketoacidosis treatment protocol was followed. Due to no improvement after one day of treatment, the diagnostic hypothesis of renal tubular acidosis type IV was confirmed by the hyperkalemic and hyperchloremic metabolic acidosis. We treated the patient with fludrocortisone. Due to clinical recovery and improvement of laboratory results, the patient was discharged and is now an outpatient in our institution.

Mecanismos fisiopatológicos del desbalance glomérulo-tubular en la hipertensión arterial / Pathophysiological mechanisms of the lack of glomerulus-tubule balance in arterial high blood pressure

Las actuales tendencias e hipótesis para interpretar los mecanismos etiopatogénicos de la hipertensión arterial esencial, involucran al sistema renal como mecanismo preponderante en la regulación a largo plazo de la presión arterial y la existencia en él de algún fenómeno que puede conllevar a desbalance glomérulo-tubular, con preponderancia tubular Aunque el análisis de este último hecho no ha sido como tal abordado en la patogénesis del síndrome hipertensivo. Con el objetivo de interpretar el papel del desbalance glomérulo-tubular, con preponderancia tubular en la fisiopatología de la hipertensión arterial como fenómeno en el que confluyen múltiples mecanismos fisiopatológicos renales ya descritos, se revisaron estos últimos, de forma integrada y su relación causal con el desbalance glomérulo-tubular, con preponderancia tubular. La preponderancia tubular, punto común de los mecanismos que se discuten, favorece la disminución de la excreción fraccional de Na+, la retención hidrosalina y la elevación de la presión arterial

The current trends and hypotheses to know the etiopathogenesis mechanisms of the essential arterial high blood pressure involved the renal system as a prevailing mechanism in the long-term regulation of arterial pressure and the existence in it of some phenomenon that could lead to a glomerulus-tubule lack of balance with tubular preponderance. Although the analysis of this latter fact, has not been approached as such in pathogenesis of hypertensive syndrome. With the aim of to interpret the role of glomerulus-tubule lack of balance with tubular preponderance in pathophysiology of arterial high blood pressure as a phenomenon in which converging multiple renal pathophysiological mechanisms already described, these latter were reviewed in a integrated way and its causal relation with the above mentioned lack of balance with tubular preponderance. This preponderance, a common point of discussed mechanisms, favors the decrease of a fractional releasing of Na+, the hydrosaline retention and the raise of arterial pressure

Study of urinary acidification in patients with idiopathic hypocitraturia

Hypocitraturia (HCit) is one of the most remarkable features of renal tubular acidosis, but an acidification defect is not seen in the majority of hypocitraturic patients, whose disease is denoted idiopathic hypocitraturia. In order to assess the integrity of urinary acidification mechanisms in hypocitraturic idiopathic calcium stone formers, we studied two groups of patients, hypocitraturic (HCit, N = 21, 39.5 + or - 11.5 years, 11 females and 10 males) and normocitraturic (NCit, N = 23, 40.2 + or - 11.7 years, 16 females and 7 males) subjects, during a short ammonium chloride loading test lasting 8 h. During the baseline period HCit patients showed significantly higher levels of titratable acid (TA). After the administration of ammonium chloride, mean urinary pH (3rd to 8th hour) and TA and ammonium excretion did not differ significantly between groups. Conversely, during the first hour mean urinary pH was lower and TA and ammonium excretion was higher in HCit. The enhanced TA excretion by HCit during the baseline period and during the first hour suggests that the phosphate buffer mechanism is activated. The earlier response in ammonium excretion by HCit further supports other evidence that acidification mechanisms react promptly. The present results suggest that in the course of lithiasic disease, hypocitraturia coexists with subtle changes in the excretion of hydrogen ions in basal situations

Acidosis tubular renal tipo I y parálisis periódica hipopotasémica / Tubular acidosis type 1 with hypotassemic periodic paralysis

Mujer de 25 años de edad con el diagnóstico de acidosis tubular renal distal o tipo 1 con acidosis metabólica hiperclorémica o de brecha aniónica normal persistente, pH urinario mayor de 6.5, excreción urinaria de calcio elevada a hipopotasemia. La frecuencia de la acidosis tubular renal distal tipo 1 asociada a parálisis periódica hipopotasémica es rara. En la literatura los reportes con escasos

Alimentación en el niño con padecimientos renales / Feeding children with renal diseases

La alimentación en el niño con padecimientos renales, al igual que en un niño sano, tiene por objeto mantener un crecimiento adecuado y bienestar general, de acuerdo con las características propias de cada enfermedad renal. Para esto hay que conocer la fisiopatología de cada una de las enfermedades, y adecuar la alimentación al estado metabólico presente. Al hacer la prescripción dietética, hay que calcular siempre las calorías, proteínas, agua y electrolitos, de acuerdo con las pérdidas sufridas. Durante la insuficiencia renal, el paciente no puede excretar los productos finales del metabolismo, por lo cual las proteínas se deben restringir pensando siempre en su valor biológico. En el síndrome nefrótico, cuando las proteínas se pierden en exceso, su ingesta debe aumentar para compensar la pérdida. Otros elementos, se debe manejar de una manera similar; por ejemplo, el sodio se debe restringir en pacientes con edema o hipertensión arterial, y se debe aumentar en pacientes con tubulopatías que pierden este elemento de manera exagerada por la orina. Se hace énfasis en las diferentes metabólicas de las diferentes edades y la repercusión que tienen al prescribir la dieta.

Tubulopatías: I parte / Tubular pathology: I part

El ultrafiltrado glomerular, que tiene las mismas características que el plasma, es modificado por el túbulo hasta llegar a la obtención de orina. Para ello se requiere reabsorción de agua, de sodio y de bicarbonato. Las tubulopatías son trastornos funcionales primarios o adquiridos, que afectan los mecanismos de trasporte (secreción o reabsorción) tubular de agua y electrólitos y que no se acompañan de compromiso glomerular significativo. Hay diversos tipos de tubulopatías, pero en esta revisión sólo se analizan las que se caracterizan por alteraciones del intercambio de Na-H y que dan lugar a las acidosis tubulares, entre las cuales se distinguen: tipo I o distales, tipo II o proximales, tipo III o mixtas y tipo IV o hiperkalémicas entre las que señalan 5 subtipos. Se describen las principales características fisiopatológicas de estas diversas formas de acidosis tubular así como la manera de estudiarlas y de manejarlas

Baja estatura como forma de presentación de una acidosis tubular renal tipo III / Low body height as a form of presentation of a renal tubular acidosis type III

Se presenta una paciente de 13 años de edad cuyo motivo de consulta fue baja estatura. Se confirma por el examen clínico, la radiología y el laboratorio, acidosis tubular renal tipo III. Se instituye terapéutica específica con buena respuesta. Se discute la fisiopatología del trastorno y se enfatiza la importancia de investigar esta patología frente a niños con retraso del crecimiento, acidosis sistémica, pH urinario elevado y función renal conservada

Acidosis tubular renal / Renal tubular acidosis

Se actualiza el concepto de ATR, haciéndose una diferenciación fisiopatológica y clínica de las formas proximal y distal. Se señala asimismo la distinta necesidad de bicarbonato para el tratamiento de las mismas. Se presenta ena clasificación de la ATR.