RESUMEN La disfunción miccional es un trastorno del llenado o vaciado de la vejiga en niños sin alteraciones neurológicas o anatómicas. Los síntomas del tracto urinario inferior (LUTS, por la sigla en inglés de Lower urinary tract symptoms) son un motivo frecuente de consulta con el pediatra, el nefrólogo o el urólogo pediatra, e incluso con el neurólogo y el psicólogo infantil. Se le considera una enfermedad relativamente benigna lo que en ocasiones genera desinterés entre médicos y familiares y lleva a consultas tardías e interpretación inadecuada de los síntomas. Manifestaciones como urgencia, incontinencia, enuresis, goteo posmiccional, infecciones urinarias, vulvovaginitis recurrente y constipación, en un niño sin enfermedad neurológica, deben hacer pensar al médico en disfunción miccional para enfocar oportunamente el diagnóstico, restablecer la calidad de vida del paciente, evitar las infecciones urinarias y el daño renal subsecuente e irreversible secundario a un diagnóstico tardío. Las recomendaciones actuales hacen énfasis en un enfoque menos invasivo, tratamiento conservador, manejo de la constipación y reentrenamiento vesical. Este artículo discute la evaluación, el diagnóstico y el tratamiento correctos de niños con LUTS.

SUMMARY Voiding dysfunction is a disorder of the bladder filling or emptying in children without neurological or anatomical disorders. Lower urinary tract symptoms (LUTS) are a frequent reason for consulting the pediatrician, nephrologist or pediatric urologist, and even the neurologist and child psychologist. It is considered a relatively benign disease that sometimes generates disinterest among doctors and families, leading to late consultation and inadequate interpretation of symptoms. Urgency, incontinence, enuresis, post-void dribbling, urinary tract infections, recurrent vulvovaginitis and constipation in children without neurological disease should lead to consider the possibility of voiding dysfunction, in order to recognize it timely, restore the quality of life, prevent urinary tract infection and the irreversible kidney damage secondary to delayed diagnosis. Current recommendations emphasize on a less invasive approach, conservative treatment, management of constipation and bladder retraining. This article discusses the correct assessment, diagnosis and management of children with LUTS.

Introducción: el rechazo agudo mediado por anticuerpos es una complicación que se presenta luego del trasplante renal y es una causa importante de pérdida del injerto. La plasmaféresis es una de las terapias utilizadas para su tratamiento, algunos estudios sugieren mejor supervivencia del injerto renal con el uso de plasmaféresis; sin embargo su evidencia es débil. Objetivo: este estudio tiene como objetivo describir la experiencia del uso de plasmaféresis en el rechazo agudo mediado por anticuerpos. Materiales y Métodos: estudio descriptivo retrospectivo realizado en el Hospital Pablo Tobón Uribe entre agosto de 2005 y junio de 2015 en pacientes con diagnóstico de rechazo agudo mediado por anticuerpos, quienes recibieron entre tres y nueve sesiones de plasmaféresis. Resultados: se realizaron un total de 769 trasplantes renales; de los cuales 26 pacientes presentaron rechazo agudo mediado por anticuerpos y recibieron plasmaféresis como parte del tratamiento. Todos los pacientes recibieron terapia de inducción al momento del trasplante y en el 80,8% la terapia de mantenimiento utilizada fue tacrolimus-micofenolato-prednisolona. El rechazo mediado por anticuerpos se presentó en forma temprana en el 61,5% de los pacientes. A seis y doce meses el 44% y 53,8% de los pacientes respectivamente presentaron pérdida del injerto renal; las complicaciones se presentaron en el 53,8% de los pacientes, las cuales fueron hipocalcemia, hipotensión y anafilaxia. Conclusión: en esta cohorte el uso de plasmaféresis en el rechazo agudo mediado por anticuerpos no logró evitar la pérdida del injerto renal en el 50% de los pacientes; se sugiere adicionar a esta terapia otras alternativas de tratamiento entre ellas, la inmunoglobulinas intravenosas, rituximab, eculizumab y bortezomib. MÉD.UIS. 2016;29(2):41-8.

Background: antibody-mediated renal allograft rejection is a complication after kidney transplantation, and it has poor prognosis for graft survival. Plasmapheresis has been used with controversial results; few trials indicate a trend towards superior graft survival in patients receiving this treatment; however, the evidence remains weak. Objetive: the aim of this study was to describe the experience in treating Antibody-mediated renal allograft rejection with plasmapheresis in kidney transplant recipients. Methods: retrospective and descriptive study of the patients that underwent three to nine session of plasmapheresis as a treatment of severe Antibody-mediated renal allograft rejection in Pablo Tobón Uribe Hospital. Results: between August 2005 and June 2015, 769 patients underwent kidney transplantation at our institution; 26 patients received plasmapheresis as part of the treatment for Antibody-mediated renal allograft rejection. All patients received induction therapy. Maintenance therapy used was tacrolimus, mycophenolic acid and steroids in 80,8% of the patients and cyclosporine, micophenolic acid and steroids in 19,2%. Antibody mediated rejection had an early onset in 61,5% of the cases. At six and 12 months after therapy, 44% and 53,8% patients respectively were back on dialysis. Complications were reported in 53,8% of the patients (hypocalcaemia, hypotension and anaphylaxis). Conclusion: in this cohort, 50% of patients who received Plasmapheresis as therapy for severe Antibody-mediated renal allograft rejection presented loss graft after one year of follow up. It is necessary adding to this therapy new treatment alternatives, among them intravenous immunoglobulin, rituximab, eculizumab and bortezomib. MÉD.UIS. 2016;29(2):41-8.

No es clara la repercusión clínica de la hidronefrosis. Este estudio busca determinar las características de las imágenes diagnósticas de los pacientes con hidronefrosis prenatal y determinar si el valor del diámetro anteroposterior de la pelvis renal puede identificar la presencia de malformaciones urológicas posnatales y la necesidad de cirugía. Materiales y métodos: estudio transversal en el que se revisaron las historias clínicas de todos los pacientes con edades entre 0 y 5 años de edad, con diagnóstico prenatal de hidronefrosis, quienes consultaron a un hospital de cuarto nivel de complejidad en la ciudad de Medellín - Colombia. Cada unidad renal se evaluó en forma independiente. Resultados: en total se estudiaron 135 unidades renales de 97 pacientes. No se encontró hidronefrosis posnatal en el 17,8 %. Al seguimiento, el 85 % de los pacientes con estenosis pieloureteral y 90 % de los pacientes con valvas de uretra posterior fueron clasificados prenatalmente como hidronefrosis moderada a grave. Por el contrario, el 41,4 % de los riñones con diagnóstico de reflujo vesico-ureteral fueron clasificados como hidronefrosis leve, 34,5 % moderada y 24,1 % grave. El 56,3 % de los riñones necesitaron algún tipo de cirugía. El 26 % de las hidronefrosis clasificadas como leves necesitaron algún procedimiento quirúrgico. Un diámetro anteroposterior de la pelvis renal de 10,5 mm tuvo una sensibilidad de 67 % y una especificidad de 71,2 % para la detección de malformaciones nefro-urológicas. Conclusión: la hidronefrosis prenatal, independiente de su grado, puede ser indicativa de malformaciones del tracto genitourinario. Se recomienda un seguimiento estricto en los pacientes con hidronefrosis, incluso en los casos leves, para así detectar tempranamente la presencia o no de malformaciones nefro-urológicas que requieran algún tipo de intervención.

Currently, we do know the clinical repercussions of prenatal hydronephrosis. This study aims to assess the imaging features of hydronephrosis patients and to determine whether the renal pelvis value in the prenatal ultrasound correlates with the presence of urologic malformations and the need for surgery. Materials and methods: Cross sectional study. We evaluated the medical records of all patients almost 5 years old with prenatal hydronephrosis who had consulted during 2006-2010. Results: we analyzed 97 patients, for a total of 135 kidneys. 17.8 % had not hydronephosis; 85.1 % of the patients with pyeloureteral junction stenosis and 90 % of those with posterior urethral valves had been prenatally classified as having mild to severe hydronephrosis. Conversely, 41.4 % of kidneys with vesicouretral reflux were classified as having mild hydronephrosis, 34.5 % moderate and 24.14 % severe. Furthermore, 56.3 % of the evaluated kidneys needed some type of surgery. It is also worth mentioning that it was necessary to perform surgical procedures on 26 % of the kidneys with mild hydronephrosis. Finally, the analysis of the ROC curve made it possible to find that, when the pelvis has an anteroposterior diameter of 10.5 mm, the sensitivity for the detection of nephro-urologic malformations is 67 % and the specificity 71.2 %. Conclusion: prenatal hydronephrosis, regardless of its degree, may be an indication of malformations in the urinary tract. We recommend performing strict follow-ups on the patients to determine the presence of nephro-urologic malformations requiring some kind of intervention.

Introducción: los esteroides son el tratamiento de elección del síndrome nefrótico con tasas de éxito hasta del 90%. En pacientes que no responden adecuadamente a ellos, se han usado diferentes esquemas de inmunosupresión. Objetivo y métodos: describir la respuesta terapéutica en un grupo de siete niños con síndrome nefrótico córtico-dependiente (SNCD) o córtico-resistente (SNCR) que recibieron tratamiento con rituximab y micofenolato mofetil en un hospital universitario de la ciudad de Medellín durante los años 2010-2012. Resultados: dos pacientes tenían SNCD y cinco, SNCR; la mediana de edad en el momento del diagnóstico fue de 2 años (p25-75: 1-5); seis meses después de la aplicación del rituximab se encontró disminución de la proteinuria en el 93% de los pacientes; los esteroides se lograron suspender en el 100%; además, disminuyó el número de recaídas; sin embargo, la proteinuria reapareció un año después de dicho tratamiento. Conclusión: con el rituximab disminuyen la proteinuria y la dosis de esteroides, pero la enfermedad recurre 12 meses después de usarlo. Se sugiere hacer otro estudio evaluando el efecto de una segunda dosis de rituximab al año de la primera.

Introduction: Steroids are the cornerstone of therapy for nephrotic syndrome (NS) with a remission rate as high as 90%. In patients who do not respond to them or are steroid dependent, other immunosuppressive drugs have been used. Although rituximab use in NS is off-label, many authors have published their experience with it. Objective and methods: To describe retrospectively a group of seven children with nephrotic syndrome, either steroid-dependent (SDNS) or steroid- resistant (SRNS), treated with rituximab and mycophenolate, at Pablo Tobón Uribe Hospital, in Medellín, Colombia. Results: Two patients with SDNS and five with SRNS were evaluated; median age at diagnosis was 2 years (p25-75: 1-5); six months after treatment with rituximab there was reduction in proteinuria (93%), in the steroid dose (100%) and in the relapse episodes. However, proteinuria reappeared 12 months after treatment. Conclusion: During the first year after rituximab treatment of NS there is reduction in proteinuria and in the steroid dose, but thereafter there is relapse. It is suggested to carry out another study using a second dose of rituximab one year after the first one.

Introdução: os esteroides são o tratamento de eleição da síndrome nefrótica com taxas de sucesso até da 90%. Em pacientes que não respondem adequadamente a eles, usaram-se diferentes esquemas de imunossupressão. Não está aprovado o uso do rituximab em pacientes com síndrome nefrótica, mas alguns grupos publicaram sua experiência com ele nesta doença. Objetivo e métodos: descrever a resposta terapêutica num grupo de sete meninos com síndrome nefrótica córtico-dependente (SNCD) ou córtico -resistente (SNCR) que receberam tratamento com rituximab e micofenolato mofetil num hospital universitário da cidade de Medellín durante os anos 2010-2012. Resultados: dois pacientes tinham SNCD e cinco, SNCR; a idade no momento do diagnóstico foi de 2 anos (p25-75: 1-5); seis meses depois da aplicação do rituximab se encontrou diminuição de 93% da proteinúria e de 100% na dose de prednisolona; ademais, diminuiu o número de recaídas; no entanto, a proteinúria reapareceu um ano depois de dito tratamento. Conclusão: com o rituximab diminuem a proteinúria e a dose de esteroides, mas a doença recorre 12 meses depois de usá-lo. Sugere-se fazer outro estudo avaliando o efeito de uma segunda dose de rituximab no ano seguinte da primeira dose.

Introdução: A tuberculose é uma infecção oportunista comum em pacientes transplantados renais. Objetivo: Oferecer uma descrição clínica e laboratorial de pacientes transplantados com diagnóstico de tuberculose e sua resposta ao tratamento durante o período entre 2005 e 2013 no Hospital Pablo Tobón Uribe. Métodos: Estudo retrospectivo descritivo. Resultados: Em 641 transplantes renais, a tuberculose foi confirmada em 12 pacientes. Destes, 25% tinham histórico de rejeição aguda e 50% apresentaram níveis de creatinina superiores a 1,5 mg/dl antes da infecção. A patologia geralmente se apresentava como pulmonar (50%) e disseminada (33,3%). A primeira fase do tratamento consistiu de três meses de HZRE (isoniazida, pirazinamida, rifampicina e etambutol) em 75% dos casos e HZME (isoniazida, pirazinamida, moxifloxacina e etambutol) em 25% dos pacientes. Durante a segunda fase do tratamento, 75% dos pacientes receberam isoniazida e rifampicina e 25% isoniazida e etambutol. A duração do tratamento variou entre seis e 18 meses. Em 41,7% dos pacientes, hepatotoxicidade foi associada ao início do tratamento da tuberculose. Durante o seguimento de um ano a função renal manteve-se estável e a taxa de mortalidade foi de 16,7%. Conclusão: A tuberculose foi responsável por diversos sintomas inespecíficos na população de transplantados renais estudada. Tuberculose pulmonar e disseminada foram as formas mais frequentes de acometimento e necessitaram de tratamento prolongado. Medicamentos contra a tuberculose apresentaram alta toxicidade e mortalidade. Esta infecção deve ser considerada quando o paciente apresenta síndrome febril de origem desconhecida, especialmente durante o primeiro ano após o transplante renal.

Introduction: Tuberculosis is a common opportunistic infection in renal transplant patients. Objective: To obtain a clinical and laboratory description of transplant patients diagnosed with tuberculosis and their response to treatment during a period ranging from 2005 to 2013 at the Pablo Tobón Uribe Hospital. Methods: Retrospective and descriptive study. Results: In 641 renal transplants, tuberculosis was confirmed in 12 cases. Of these, 25% had a history of acute rejection, and 50% had creatinine levels greater than 1.5 mg/dl prior to infection. The disease typically presented as pulmonary (50%) and disseminated (33.3%). The first phase of treatment consisted of 3 months of HZRE (isoniazid, pyrazinamide, rifampicin and ethambutol) in 75% of the cases and HZME (isoniazid, pyrazinamide, moxifloxacin and ethambutol) in 25% of the cases. During the second phase of the treatment, 75% of the cases received isoniazid and rifampicin, and 25% of the cases received isoniazid and ethambutol. The length of treatment varied between 6 and 18 months. In 41.7% of patients, hepatotoxicity was associated with the beginning of anti-tuberculosis therapy. During a year-long follow-up, renal function remained stable, and the mortality rate was 16.7%. Conclusion: Tuberculosis in the renal transplant population studied caused diverse nonspecific symptoms. Pulmonary and disseminated tuberculosis were the most frequent forms and required prolonged treatment. Antituberculosis medications had a high toxicity and mortality. This infection must be considered when patients present with a febrile syndrome of unknown origin, especially during the first year after renal transplant.

Introducción: la hidronefrosis es una de las malformaciones congénitas detectadas comúnmente en la ecografía prenatal. Los casos moderados y graves frecuentemente se asocian a anomalías de la vía urinaria. Objetivo: describir las causas de la hidronefrosis, la frecuencia de su diagnóstico prenatal y la de enfermedad renal crónica (ERC) en una serie de pacientes pediátricos. Materiales y métodos: estudio descriptivo, retrospectivo de 924 pacientes atendidos entre 1960 y 2010 en un hospital universitario de Medellín. Resultados: hubo predominio de hombres (64,3%); en el 14,4% el diagnóstico fue prenatal. En el 18,3% no se encontraron anomalías urológicas asociadas. Siete de estos (4,2%) llegaron a la ERC. La estenosis pieloureteral fue la anomalía hallada con mayor frecuencia (28,6%) seguida por el reflujo vesicoureteral (21,5%) y las valvas de la uretra posterior (9,4%); el 10,2% de los pacientes llegaron a la enfermedad renal crónica; al agrupar los pacientes de acuerdo con el método utilizado para el diagnóstico de hidronefrosis, el grupo en que se hizo por urografía excretora tuvo ERC en el 11,3%, en contraste con el 8,4% en quienes el diagnóstico se hizo por ecografía renal; por otro lado. al agrupar los pacientes con diagnóstico ecográfico de hidronefrosis prenatal o posnatal, el porcentaje de ERC fue de 4,8% frente a 10,8%, respectivamente. Conclusión: el diagnóstico temprano de la hidronefrosis permite detectar anomalías urológicas susceptibles de seguimiento o corrección quirúrgica. Todavía existe mucha controversia acerca del mejor seguimiento imaginológico para estos pacientes.

Introduction: Hydronephrosis is one of the most common congenital malformations detected on prenatal ultrasounds. Moderate and severe cases are often associated with urological abnormalities. Objective: To describe the causes of hydronephrosis, and the frequency of its prenatal diagnosis and of chronic kidney disease (CKD) in a series of pediatric patients. Materials and methods: A descriptive, retrospective study of 924 patients under 18 years of age seen at a university hospital in Medellín, Colombia, between 1960 and 2010. Results: 64.3% were male. Diagnosis was prenatal in 133 (14.4%). Hydronephrosis was bilateral in 198 patients (28.5%). In 169 (18.3%) no associated urological abnormality was found; 7 of these (4.2%) reached CKD. Ureteropelvic stenosis was diagnosed in 216 (23.3%) followed by vesicoureteral reflux in 199 (21.5%) and posterior urethral valves in 87 (9.4%); 93 (10.2%) reached CKD. When hydronephrosis was diagnosed by urography, patients developed CKD in 11.3% vs. 8.4% in those whose diagnosis was made by ultrasound; frequency of CKD was 4.8% when diagnosis by ultrasound was prenatal, and 10.8% when it was postnatal. Conclusion: Early diagnosis of hydronephrosis allows the detection of urologic abnormalities susceptible to treatment. There is controversy about the best imaginological method for the follow-up of these patients.

Hydronephrosis is one of the most common congenital malformations detected on prenatal ultrasounds. Moderate and severe cases are often associated with urological abnormality. OBJECTIVE To describe a series of pediatric patients diagnosed with hydronephrosis determining their etiology, prenatal diagnosis and frequency of chronic kidney disease (CKD). MATERIALS AND METHODS A descriptive, retrospective study. RESULTS The records of 924 patients between the ages of 0 and 18 years were evaluated, 35.7% female and 64.3% male. In 14.4% (133) the diagnosis was prenatal. Hydronephrosis was bilateral in 198 patients (28.5%). In 18.3% (169) no associated urological abnormality was found, reaching 4.2% in CKD (7). Ureteropelvic stenosis was diagnosed in 23.3% (216) followed with 21.5% VUR (199) and posterior urethral valves in 9.4% (87), reaching 10.2% ERC (93). When the hydroneprhosis was diagnosed by urography, those patients presented 11.3% of chronic kidney disease vs. 8.4% in whom the diagnosis was made by ultrasound, when the hydronephosis diagnosed was by prenatal vs postnatal ultrasound, the percentage of CKD was 4.8% vs 10.8%, respectively. CONCLUSION Early diagnosis of hydronephrosis allows the detection of urologic abnormalities susceptible of treatment. Although there are still many questions about which one is the ideal strategy of follow up; the ultrasonography, voiding cystourethrogram, urography, scintigraphy and magnetic resonance urography in selected patients are the most useful tools in order to evaluate urinary tract anomaly.

Introduction: It is well known that the incidence of malignancy is significantly higher in transplanted patients than in general population. The incidence of lymphoproliferative disease post-transplantation (PTLD) is approximately of 1% to 2% in kidney transplantation recipients. The main objective of this study was to evaluate the PTLD incidence when monitoring kidney transplanted patients between the years 2005 and 2010. Material and Methods: Kidney transplanted patients data was retrospectively taken between the years 2005 to 2010 in order to determine the number of PTLD cases according to the inductor scheme used. Results: 425 patients were transplanted between 2005 and 2010. They received alemtuzumab 76.2%,daclizumab 10.7%, basiliximab 3.6% and thymoglobulin 2.4%. The 7% did not receive antibody induction. During this period 2 cases of PTLD ocurred: One with multiple myeloma and the other with lymphoma. One of them had been treated with alemtuzumab and the other with thymoglobulin. Conclusions: The PTLD incidence in our group, where alemtuzumab was used predominantly as inductor, was very low; this might suggest that alemtuzumab is a medication that does not increase the risk of this kind of neoplasia.

Introducción: Se conoce que la incidencia de malignidad es significativamente mayor en los pacientes trasplantados que en la población general. La incidencia de enfermedad linfoproliferativa post trasplante (PTLD) es aproximadamente de 1% a 2% en los receptores de trasplante renal. El objetivo principal de este estudio fue evaluar la incidencia de PTLD en el seguimiento de pacientes trasplantados de riñón entre el 2005 y el 2010. Material y Métodos: Se tomaron de forma retrospectiva los datos de pacientes trasplantados de riñón entre los años 2005 a 2010 para determinar el número de casos de PTLD según el esquema inductor usado. Resultados: Se trasplantaron 425 pacientes en el periodo 2005 - 2010. Recibieron alemtuzumab 76.2%, daclizumab 10.7%, basiliximab 3.6% y timoglobulina 2.4%. No recibieron inducción con anticuerpos el 7 %. Durante este tiempo se presentaron 2 casos de PTLD: 1 con mieloma múltiple y otro con linfoma. Uno de ellos recibió alemtuzumab y otro timoglobulina. Conclusiones: En esta cohorte de pacientes donde se usó predominantemente alemtuzumab, la incidencia de PTLD fue más baja que lo reportado en estudios previos.

INTRODUÇÃO: A síndrome nefrótica é uma das mais frequentes doenças glomerulares em crianças e o tratamento com corticosteróides ainda é o tratamento de escolha. Apesar disso, 10 a 15% dos pacientes são resistentes a corticosteróides, e o melhor tratamento para tais casos ainda não foi definido. O ácido micofenólico (AM) é um dos tratamentos usados em tais situações. OBJETIVO: Descrever o comportamento clínico de crianças diagnosticadas com síndrome nefrótica resistente a corticosteróide (SNRC) e avaliar a resposta terapêutica ao AM. MÉTODOS: Esse foi um estudo retrospectivo e descritivo. RESULTADOS: 26 registros de pacientes com SNRC; 70% homens e 30% mulheres. Todos os pacientes foram submetidos a biópsias renais, o que mostrou predominância de glomeruloesclerose segmentar focal (GESF). Os medicamentos imunossupressores utilizados foram: Mofetil Micofenolato (MMF) 100%; Ciclosporina 69,2%; Ciclosfosfamida 23,1%; e Rituximabe 23%. Um mês após início do tratamento com MMF, 61,5% tiveram remissão. A mediana das recidivas por ano para os pacientes foi de 3 (p25: 2,75 - p75: 4). Essa mediana se tornou 1 (p25: 1 - p75: 3,25) após o uso da medicação (p = 0,08). Além disso, antes do início do tratamento com MMF, a mediana da dose de corticosteróide foi de 1 (p25: 0.5 - p75: 1.62) mg/k/ dia. Após a utilização do MMF, essa mediana se tornou 0,07 (p25: 0 - p75: 0,55) mg/k/dia (p < 0,001), em 8 pacientes a prednisolona foi interrompida. CONCLUSÃO: em nossa casuística, o tratamento com MMF mostrou resultados positivos, tais como a redução na frequência de recidivas, menos proteinúria, e redução da dose de corticosteróide administrada sem deterioração nas taxas de filtração glomerular. Entretanto, mais estudos são necessários para se avaliar a eficácia, segurança e otimização da dosagem.

INTODUCTION: Nephrotic syndrome is one of the most frequent glomerular diseases among children, and steroid therapy remains as the treatment choice. In spite of this, 10 to 15% of the patients are steroidresistant, and the best therapy for such cases has never been defined. Mycophenolate acid (MA) is one of the treatments used in such situations. OBJECTIVE: To describe the clinical behavior of children diagnosed with steroid-resistant nephrotic syndrome (SRNS) and to assess the therapeutic response to MA. METHODS: This was a retrospective and descriptive study. RESULTS: 26 clinical records of patients with SRNS; 70% male and 30% female. All patients underwent kidney biopsies, which showed a predominance of focal segmental glomerulosclerosis (FSGS). The immunosuppresive drugs used were: Mycophenolate mofetil (MMF) 100%, Cyclosporine 69.2%, Cyclophosphamide 23.1%, and Rituximab 23%. One month after treatment initiation with MMF 61.5% achieved remission. The median of relapses per year for the patients was 3 (p25: 2.75 - p75: 4). This median became 1 (p25: 1 - p75: 3.25) after using this medication (p = 0.08). Furthermore, prior to the start of the MMF treatment, the median of the steroid dose was 1 (p25: 0.5- p75: 1.62) mg/k/day. After using MMF, this median became 0.07 (p25: 0 - p75: 0.55) mg/k/day (p < 0.001), in 8 patients prednisolone was stopped. CONCLUSION: In our experience, treatment with MMF showed positive results such as decrease in the frequency of relapses, less proteinuria, and reduction in the dose of steroids administered without deterioration of glomerular filtration rates. However, more studies are needed to assess efficacy, safety, and optimal dosage.

Introducción: el síndrome nefrótico (SN) es una de las enfermedades glomerulares más frecuentes en la infancia y son pocos los estudios realizados en Colombia sobre esta enfermedad. Objetivo: describir las características clínicas y epidemiológicas de los niños con SN atendidos en el Hospital Universitario San Vicente de Paúl, de Medellín, Colombia, entre los años 1960-2009. Metodología: estudio descriptivo retrospectivo. Resultados: el 87,9% de los pacientes fueron corticosensibles, entre 1,7%-5,4% se tornaron corticorresistentes. La histopatología predominante fue la del síndrome nefrótico con cambios mínimos (43,6%) seguida por la glomeruloesclerosis focal y segmentaria (37,3%). El 40% requirieron inmunosupresión adicional; en 88,8% de estos se utilizó ciclofosfamida con remisión en 85,7%. Se presentaron complicaciones en 56% y 52% de ellas fueron infecciosas. El 9% de los pacientes llegaron a la insuficiencia renal crónica. La tasa de mortalidad fue del 5,7%. Discusión: esta es una de las series más grandes de pacientes con SN reportadas hasta el momento y con un período de seguimiento de hasta 35 años, lo que aporta información valiosa sobre el comportamiento local de la enfermedad y la respuesta al tratamiento inmunosupresor, El seguimiento a largo plazo de estos pacientes es fundamental para ofrecer el mejor tratamiento disponible y nos plantea nuevos interrogantes sobre la evolución del SN en nuestra población.

Introduction: Nephrotic syndrome (NS) is a glomerular disease that frequently affects children. There have been few studies on it in Colombia. Objective: To describe the clinical and epidemiological features of children with SN treated at HUSVP between 1960 and 2009. Methodology: Retrospective and descriptive study. Results: Steroid-sensitive nephrotic syndrome was diagnosed in 87.9% of the patients, and between 1.7%-5.4% turned steroid-resistant. Biopsies revealed disease with minimal changes in 43.6% and focal segmental glomerulosclerosis in 37.3%. Additional immunosuppressive therapy was required by 40% of the patients; in 88.8% of these, cyclophosphamide was used, and remission was achieved in 85.7%. In 56% of the cases there were complications that were infectious in 52%. Nine percent of the patients progressed to end-stage renal disease. Mortality rate was 5.7%. Discussion: The large number of patients with nephrotic syndrome studied in this series and the long period of follow-up (up to 35 years) provide valuable information about the clinical behavior of this syndrome in Colombia and on its response to immunosuppressive therapy.

Introducción: una de las principales infecciones bacterianas en la población pediátrica es la infección urinaria (ITU). Factores asociados como reflujo vesicoureteral (RVU), valvas de la uretra posterior, vejiga neurogénica y otras malformaciones anatómicas aumentan la probabilidad de desarrollar cicatrices renales y displasia/hipoplasia, lo que a su vez eleva el riesgo de hipertensión arterial (HTA), proteinuria y enfermedad renal crónica (ERC) a largo plazo. Objetivo: describir las malformaciones asociadas a ITU y la frecuencia de desarrollo de ERC en pacientes pediátricos que consultaron al Hospital Universitario San Vicente de Paúl entre 1960 y 2010. Metodología: estudio descriptivo, retrospectivo, en el que se evaluaron 4.476 registros de pacientes con diagnóstico de ITU. Resultados: los pacientes con anomalías de las vías urinarias correspondieron al 78,3% (con predominio de mujeres: 52,8%). Se encontró RVU primario en 29,9%; de estos 5,1% evolucionaron a ERC. La vejiga neurogénica se diagnosticó en 8,1%, de los cuales 70,8% fueron secundarios a mielomeningocele y 4,9% desarrollaron ERC. Las valvas de la uretra posterior se presentaron en 3,5% de la muestra total, de los cuales el 28,5% llegaron a ERC. Conclusión: la ITU en la población pediátrica es un marcador de malformación de la vía urinaria y su pronóstico está determinado por la presencia de RVU, anomalías obstructivas y/o displasia renal que favorecen la aparición de cicatrices renales y aumentan el riesgo de HTA, proteinuria y ERC. Un enfoque diagnóstico adecuado permitiría establecer estrategias de manejo con el objetivo de evitar el deterioro de la función renal.

Introduction: Urinary tract infection (UTI) is a major cause of bacterial disease in the pediatric population. Associated factors such as vesicoureteral reflux (VUR), posterior urethral valves, neurogenic bladder and other anatomical malformations increase the likelihood of developing renal scarring and dysplasia/ hypoplasia, which at the same time increase in the long term the risk of hypertension (HT), proteinuria and chronic kidney disease (CKD). Objective: To describe the malformations associated with the frequency of UTI and development of CKD in pediatric patients who consulted San Vicente de Paúl Hospital, in Medellin, Colombia, between 1960 and 2010. Methods: A descriptive, retrospective study in which the clinical records of 4.476 patients with UTI were evaluated. Results: Patients with urinary tract anomalies corresponded to 78.3% of the total (predominance of women: 52.8%). Primary VUR was found in 29.9%; out of these, 5.1% progressed to CKD. Neurogenic bladder was diagnosed in 8.6%, of which 70.8% were secondary to myelomeningocele and 4.9% developed CKD. The posterior urethral valves were present in 3.5% of the total sample, of which 28.5% developed CKD. Conclusion: UTI in the pediatric population is a marker of urinary tract malformation and the prognosis is determined by the presence of VUR, obstructive anomalies and/or renal dysplasia favoring renal scarring, and increasing the risk of hypertension, proteinuria and CKD. An appropriate diagnostic approach would be the basis to implement management strategies to prevent deterioration of renal function.

La insuficiencia renal crónica es el resultado del deterioro progresivo e irreversible de la función renal, que genera incapacidad del riñón para remover los productos de desecho y mantener el equilibrio ácido básico. El objetivo de este estudio fue identificar las causas de insuficiencia renal crónica en nuestros pacientes y su importancia relativa en este desenlace. Se hizo un estudio descriptivo retrospectivo de corte transversal, basado en la revisión de 367 registros pertenecientes al Servicio de Nefrología Infantil, de pacientes con diagnóstico de insuficiencia renal crónica (IRC), que acudieron al Servicio de Consulta Externa del Hospital Universitario San Vicente de Paúl, de Medellín, entre el 01 de enero de 1960 y el 30 de agosto de 2010. De los 367 pacientes, 199 (54,2%) fueron hombres y 168 (45,8%), mujeres; las enfermedades predominantes como causa de la IRC fueron: reflujo vésico-ureteral (37,1%), hidronefrosis (24,0%), valvas de la uretra posterior (13,4%), glomerulonefritis aguda (12,3%), síndrome nefrótico (11,2%) e hipoplasia renal (9,3%).

Chronic renal failure (CRF) results from progressive and irreversible deterioration of kidney function; it manifests as the inability to remove waste products and to maintain acid-base balance. The objectives of this study were to identify the diseases responsible for CRF in our patients and their relative importance in such outcome. A descriptive retrospective study was carried out, based on the review of the charts of 367 children with the diagnosis of CRF treated at the Pediatric Nephrology Service (Hospital Universitario San Vicente de Paúl, Medellín, Colombia) between 01 January 1960 and August 30, 2010. One hundred and ninety nine patients (54,2%) were males, and 168 (45,8), females. The predominant diseases as cause of CRF were: vesico-ureteral reflux (37.1%), hydronephrosis (24.0%), posterior urethral valves (13.4%), acute glomerulonephritis (12.3%), nephrotic syndrome (11.2%), and kidney hypoplasia (9.3%).

Los síndromes de Bartter y Gitelman son trastornos hereditarios caracterizados por una reducción marcada del transporte de sales por el asa ascendente gruesa de Henle. Los pacientes con el síndrome de Bartter presentan grandes pérdidas renales de agua, hipotensión arterial, alcalosis metabólica, hipokalemia e hipercalciuria y tienen un riesgo alto de sufrir nefrolitiasis. Estudios recientes han permitido subdividir el síndrome de Bartter en cinco tipos de acuerdo con el defecto genético y el fenotipo. El tipo 1 es causado por una mutación en el gen que codifica para el cotransportador cloro-sodio-potasio; el tipo 2 se debe a una mutación en el gen que codifica para el canal de potasio ROMK. Estas dos variantes genéticas se denominan conjuntamente síndrome de Bartter neonatal por el comienzo temprano de los síntomas, con polihidramnios materno, prematuridad, poliuria grave y nivel elevado de prostaglandina E2. El tipo 3, conocido como síndrome de Bartter clásico, es causado por mutaciones en el gen que codifica para el canal de cloro CLC-Kb; se detecta desde la niñez con retardo del crecimiento, poliuria, polidipsia y anorexia. El tipo 4 se asocia a sordera neurosensorial y se caracteriza por una mutación en el gen que codifica para la proteína Barttin la cual hace parte de los canales de cloro CLC-Kb y CLC-Ka; el tipo 5 se debe a una mutación en el gen que codifica para un receptor de calcio ubicado en la membrana basolateral del asa ascendente de Henle; estos pacientes, además de los síntomas comunes a los de otros tipos, presentan déficit de paratohormona. El síndrome de Gitelman tiene un fenotipo más leve y una presentación más tardía que el de Bartter; se diferencia de este porque los pacientes tienen hipomagnesemia e hipocalciuria; pueden ser asintomáticos o presentar debilidad muscular transitoria, parestesias, parálisis e incluso alteraciones del ritmo cardíaco. Los avances en genética molecular han permitido la clasificación adecuada de estos síndromes y han abierto puertas para diferentes opciones terapéuticas. Esta revisión incluye aspectos genéticos, fisiopatológicos y clínicos de estos síndromes.

Bartter and Gitelman syndromes are hereditary disorders characterized by a remarkable reduction of salt transportation by the thick ascending limb of the Henle's loop. Consequently, patients suffering from Bartter syndrome present with renal salt wasting, low blood pressure, hypokalemic metabolic alkalosis and hypercalciuria, and are at risk of developing renal stones. Based on recent studies, the Bartter syndrome has been subdivided into five types according to the genetic defect involved and the phenotype: type 1 is caused by a mutation in the gene coding for the chloride, sodium, and potassium co-transporter; type 2 is due to a mutation in the gene coding for the ROMK potassium channel. These two genetic variations are jointly denominated neonatal Bartter syndrome, because of their early clinical presentation, with maternal polyhydramnios, prematurity, severe polyuria and high levels of E2 prostaglandine. Type 3, also known as classic Bartter syndrome, is produced by mutations in the gen that codes for the chloride CLC-Kb channel; this type is detected since childhood with growth delay, polyuria, polydipsia and anorexia. Type 4, which is associated with neurosensorial deafness, is characterized by a mutation in the gen that codes for the Barttin protein which is a part of the CLC-Kb and CLC-Ka chloride channels. Type 5 appears because of a mutation in the gene that codes for a calcium receptor located at the basolateral membrane of the ascending limb of Henle's loop; patients with this type develop parathormone deficit, as well as the symptoms that are common to all types of the syndrome. The phenotype of Gitelman syndrome is less severe and its clinical presentation is delayed; it differs from the Bartter syndrome in that patients have hypomagnesemia and hipocalciuria. They may be asymptomatic or show transitory muscular weakness, paresthesias, paralysis and even cardiac rhythm alterations. Recent advances in molecular genetics have made it possible to distinguish between the different clinical types and are the basis for several therapeutic options. This review includes genetic, physiopathological and clinical aspects of the Bartter and Gitelman syndromes.