[Microalbuminuria in pediatric patients diagnosed with hemolytic uremic syndrome]. / Microalbuminuria en Pacientes Pediátricos Con Diagnóstico de síndrome Hemolítico Urémico.

INTRODUCTION: Hemolytic uremic syndrome (HUS) is characterized by the presence of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney failure. It is the leading cause of acute kidney failure in children under 3 years of age. A variable number of patients develop proteinuria, hypertension, and chronic renal failure. OBJECTIVE: To evaluate the renal involvement in pediatric patients diagnosed with HUS using the microalbumin/creatinine ratio. PATIENTS AND METHODS: Descriptive concurrent cohort study that analyzed the presence of microalbuminuria in patients diagnosed with HUS between January 2001 and March 2012, who evolved without hypertension and normal renal function (clearance greater than 90ml/min using Schwartz formula). Demographic factors (age, sex), clinical presentation at time of diagnosis, use of antibiotics prior to admission, and need for renal replacement therapy were evaluated. RESULTS: Of the 24 patients studied, 54% were male. The mean age at diagnosis was two years. Peritoneal dialysis was required in 45%, and 33% developed persistent microalbuminuria. Antiproteinuric treatment was introduce in 4 patients, with good response. The mean follow-up was 6 years (range 6 months to 11 years). The serum creatinine returned to normal in all patients during follow up. CONCLUSIONS: The percentage of persistent microalbuminuria found in patients with a previous diagnosis of HUS was similar in our group to that described in the literature. Antiproteinuric treatment could delay kidney damage, but further multicenter prospective studies are necessary.

Pharmacokinetics of eculizumab in adult and pediatric patients with atypical hemolytic uremic syndrome and C3 glomerulopathy. / Farmacocinética de eculizumab en pacientes adultos y pediátricos con síndrome hemolítico urémico atípico y glomerulopatía C3.

OBJECTIVE: The objective of the study was to analyze and describe the concentrations of eculizumab and the complement blockade in patients with atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy, and to define a therapeutic margin where there is a high probability of achieving therapeutic efficacy. METHODS: Observational, ambispective and multicenter study that included adult and pediatric patients diagnosed with aHUS and C3 glomerulopathy from September 2020 to October 2022 in five hospitals in Spain. Eculizumab was administered at the doses recommended by the data sheet according to the European Medicines Agency (EMA). Pre-dose and post-dose concentrations of eculizumab were determined, as well as blockade of the classical complement pathway (CH50). Sociodemographic and clinical data were collected, and pharmacokinetic parameters were calculated. To establish the cut-off point for eculizumab concentrations that predicted complement blockade, Receiver Operating Characteristic (ROC) curve analysis was performed. Lastly, the Kruskal-Wallis test was used to contrast the differences in different parameters according to eculizumab concentrations. RESULTS: Twenty-five patients were included, 19 adults (76.0%) and 6 pediatrics (24.0%), with median ages of 43.4 (IQR 35.7-48.8) and 10.1 (IQR 9.6-11.3) years, respectively. Of these, 22 (88.0%) patients were diagnosed with aHUS and 3 (12.0%) with C3 glomerulopathy. A total of 111 eculizumab concentrations were determined. Mean pre-dose and post-dose concentration values detected during the maintenance phase were 243.8 (SD 240.6) µg/mL and 747.4 (SD 444.3) µg/mL, respectively. Increased complement blockade was observed at higher pre-dose concentrations (p=0.002) and decreased serum creatinine at both higher pre- and post-dose concentrations (p=0.001 and p=0.017, respectively). Using ROC curves, it was determined that a pre-dose concentration >149.0 µg/mL was optimal to achieve complement blockade, with an AUC of 0.87 (0.78-0.95). Finally, high inter-individual (48.9% CV) with low intra-individual variabilities (11.9% CV) in eculizumab clearance were observed. CONCLUSIONS: The present study reports supratherapeutic concentrations of eculizumab in patients with aHUS, and defines higher concentrations than those described in the data sheet to achieve blockade, thus encouraging the personalization of treatment with eculizumab.

[Translated article] Pharmacokinetics of eculizumab in adult and pediatric patients with atypical hemolytic uremic syndrome and C3 glomerulopathy.

OBJECTIVE: The objective of the study was to analyze and describe the concentrations of eculizumab and the complement blockade in patients with atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy, and to define a therapeutic margin where there is a high probability of achieving therapeutic efficacy. METHODS: Observational, ambispective, and multicenter study that included adult and pediatric patients diagnosed with aHUS and C3 glomerulopathy from September 2020 to October 2022 in 5 hospitals in Spain. Eculizumab was administered at the doses recommended by the data sheet according to the European Medicines Agency (EMA). Pre- and post-dose concentrations of eculizumab were determined, as well as blockade of the classical complement pathway (CH50). Sociodemographic and clinical data were collected, and pharmacokinetic parameters were calculated. To establish the cut-off point for eculizumab concentrations that predicted complement blockade, Receiver Operating Characteristic (ROC) curve analysis was performed. Lastly, the Kruskal-Wallis test was used to contrast the differences in different parameters according to eculizumab concentrations. RESULTS: Twenty-five patients were included, 19 adults (76.0%) and 6 pediatrics (24.0%), with median ages of 43.4 (interquartile range (IQR) 35.7-48.8) and 10.1 (IQR 9.6-11.3) years, respectively. Of these, 22 (88.0%) patients were diagnosed with aHUS and 3 (12.0%) with C3 glomerulopathy. A total of 111 eculizumab concentrations were determined. Mean pre- and post-dose concentration values detected during the maintenance phase were 243.8 (SD 240.6) µg/mL and 747.4 (standard deviation (SD) 444.3) µg/mL, respectively. Increased complement blockade was observed at higher pre-dose concentrations (P = .002) and decreased serum creatinine at both higher pre- and post-dose concentrations (P = .001 and P = .017, respectively). Using ROC curves, it was determined that a pre-dose concentration >149.0 µg/mL was optimal to achieve complement blockade, with an AUC of 0.87 (0.78-0.95). Finally, high inter-individual (48.9% variation coefficient (CV)) with low intra-individual variabilities (11.9% CV) in eculizumab clearance were observed. CONCLUSIONS: The present study reports supratherapeutic concentrations of eculizumab in patients with aHUS, and defines higher concentrations than those described in the data sheet to achieve blockade, thus encouraging the personalization of treatment with eculizumab.

Thrombotic microangiopathies in critically ill children: The MATUCIP registry in Spain.

INTRODUCTION: Thrombotic microangiopathies (TMA) are rare diseases usually presenting with renal, haematological, neurologic and cardiovascular involvement and nonspecific but severe symptoms. A registry of TMA cases managed in Spanish paediatric intensive care units (the MATUCIP Registry) was established with the aim of gaining knowledge on their clinical characteristics, diagnosis and acute-phase treatment. METHODS: We conducted a prospective multicentre observational study in 20 paediatric intensive care units (PICUs) in Spain from January 2017 to December 2021 in children aged more than 1 month with TMAs, who were followed up through the discharge from the PICU. RESULTS: The sample included 97 patients (51.5% female) with a median age of 2.6 years (interquartile range [IQR], 1.6-5.7). The initial manifestations were gastrointestinal (74.2%), respiratory (14.4%), fever (5.2%), neurologic (3.1%) and other (3.1%). At admission, 75.3% of patients had microangiopathic haemolytic anaemia, 95.9% thrombocytopenia and 94.8% acute kidney injury. Of the total sample, 57.7% of patients received a diagnosis of Shiga toxin-associated haemolytic uraemic syndrome (HUS), 14.4% of Streptococcus pneumoniae-associated HUS, 15.6% of atypical HUS, 10.3% of secondary TMA and 2.1% of thrombotic thrombocytopenic purpura. Eighty-seven patients (89.7%) developed arterial hypertension, and 49.5% gastrointestinal, 22.7% respiratory, 25.8% neurologic and 12.4% cardiac manifestations. Also, 60.8% required renal replacement therapy and 2.1% plasma exchange. Twenty patients received eculizumab. The median PICU stay was 8.5 days (IQR, 5-16.5). Two children died. CONCLUSIONS: The MATUCIP registry demonstrates the clinical variability of TMA cases requiring admission to the PICU. Knowledge of the presentation and outcomes of TMAs can facilitate early aetiological diagnosis. This registry can help improve our understanding of the clinical spectrum of these diseases, for which there is a dearth of published data.

Management of atypical uremic hemolytic syndrome in pregnant patient.

Atypical uremic haemolytic syndrome is a variant of thrombotic micro-andiopathy characterized by non-autoimmune hemolytic anemia, thrombocytopenia and acute renal failure as a result of excessive activation of the complement. Up to 60% of patients have mutations in the genes that encode the complement system. A disensing factor is required for its manifestation, including gestation. It is an entity with a high morbidity, which can decrease drastically if an early diagnosis is made and appropriate treatment is initiated. Administration of ecuilizumab has demonstrated rapid process disruption, reducing the need for extrarenal purification therapies and improving renal function and patient prognosis.

Diagnostic-therapeutic algorithm for thrombotic microangiopathy. A report of two cases.

Thrombotic microangiopathies (TMA) are a group of clinical syndromes associated with haemolytic anaemia, thrombocytopenia and organ dysfunction, mainly renal or neurological. They are associated with significant morbidity and mortality, so early diagnosis and treatment are essential. In this article we report two cases of TMA; a patient with thrombotic thrombocytopenic purpura (TTP) and a patient with atypical haemolytic uraemic syndrome (aHUS).

Management of atypical uremic hemolytic syndrome in pregnant patient. / Manejo de síndrome hemolítico urémico atípico en la paciente gestante.

Atypical uremic haemolytic syndrome is a variant of thrombotic micro-andiopathy characterized by non-autoimmune hemolytic anemia, thrombocytopenia and acute renal failure as a result of excessive activation of the complement. Up to 60% of patients have mutations in the genes that encode the complement system. A disensing factor is required for its manifestation, including gestation. It is an entity with a high morbidity, which can decrease drastically if an early diagnosis is made and appropriate treatment is initiated. Administration of ecuilizumab has demonstrated rapid process disruption, reducing the need for extrarenal purification therapies and improving renal function and patient prognosis.

Diagnostic-therapeutic algorithm for thrombotic microangiopathy. A report of two cases. / Algoritmo diagnóstico-terapéutico de las microangiopatías trombóticas. A propósito de 2 casos.

Thrombotic microangiopathies (TMA) are a group of clinical syndromes associated with haemolytic anaemia, thrombocytopenia and organ dysfunction, mainly renal or neurological. They are associated with significant morbidity and mortality, so early diagnosis and treatment are essential. In this article we report two cases of TMA; a patient with thrombotic thrombocytopenic purpura (TTP) and a patient with atypical haemolytic uraemic syndrome (aHUS).

Síndrome urémico hemolítico: reporte de dos casos pediátricos con nexo epidemiológico / Hemolytic uremic syndrome: report of two pediatric clinical cases with epidemiologic link / Síndrome urémico hemolítico: reporte de casos pediátricos con nexo epidemiológico

Introducción: el síndrome hemolítico urémico (SHU) es en muchos países, de las causas más frecuentes de insuficiencia renal aguda. La mayoría de los casos ocurre luego de un episodio de gastroenteritis aguda (GEA) por Escherichia coli productora de toxina Shiga (STEC). En Uruguay a pesar de ser una enfermedad de notificación obligatoria, existe subregistro. Objetivo: describir dos casos clínicos de SHU asociados a GEA con nexo epidemiológico. Casos clínicos: se trata de dos varones de 4 y 5 años, sanos. En los días previos, ingesta de carne en el mismo local comercial. Consultaron por dolor abdominal, deposiciones líquidas y vómitos reiterados. El niño de 4 años presentaba fiebre y deposiciones líquidas con sangre. El niño de 5 años dolor abdominal. El estado de hidratación y las constantes vitales eran normales en ambos. Fueron admitidos a cuidados moderados. A las 48 horas y a los 5 días, respectivamente, agregan palidez cutáneo-mucosa intensa, edemas y oliguria. Estudios complementarios: anemia, plaquetopenia e insuficiencia renal. Ingresaron a cuidados intensivos y se realizó diálisis peritoneal. La investigación de STEC fue negativa y la evolución favorable. Conclusiones: en menores de 5 años el SHU asociado a GEA es la forma de enfermedad más frecuente. En Uruguay predominan las cepas STEC no-O157. En estos casos no se pudo identificar el agente. La existencia de un nexo epidemiológico alerta sobre la necesidad de extremar los cuidados en la preparación y cocción de la carne. Debido a la asociación con una enfermedad prevalente, es necesario tener presente esta complicación para poder sospecharla e iniciar el tratamiento en forma precoz y oportuna.

Introduction: hemolytic uremic syndrome (HUS) is one of the most frequent causes of acute renal failure in many countries. Most cases occur after an episode of acute gastroenteritis (GEA) due to the Shiga toxin producing Escherichia Soli (STEC). In Uruguay, despite being a disease that requires mandatory notification, it is under reported. Objective: to describe two clinical cases of HUS associated with GEA with an epidemiological link. Clinical cases: these are two healthy boys aged 4 and 5 years. In the previous days, they reported meat intake in the same commercial premises. They consulted for abdominal pain, liquid stools and repeated vomiting. The 4 year old boy had a fever and bloody stools. The 5 year old boy had abdominal pain. They both showed normal hydration levels and vital signs. They were admitted to moderate care. At 48 hours and 5 days, respectively, they showed intense skin and mucosal paleness, edema and oliguria. Complementary studies: anemia, thrombocytopenia and renal failure. They were admitted to intensive care and peritoneal dialysis was performed. The STEC's investigation was negative and the evolution favorable. Conclusions: in children under 5 years of age, HUS associated with GEA is the most frequent form of the disease. In Uruguay, non-O157 STEC strains predominate. In these cases, the agent could not be identified. The existence of an epidemiological link warns us about the need for extreme care in the preparation and cooking of meat. Due to the association with a prevalent disease, it is necessary to keep this complication in mind in order to suspect it and initiate early and timely treatment.

Introdução: a síndrome hemolítico urêmica (SHU) é uma das causas mais frequentes de insuficiência renal aguda em muitos países. A maioria dos casos ocorre após um episódio de gastroenterite aguda (GEA) devido à Escherichia Coli, a toxina produtora de Shiga (STEC). No Uruguai, apesar de ser uma doença de notificação compulsória, há subnotificação. Objetivo: descrever dois casos clínicos de SHU associada à AGE com vínculo epidemiológico. Casos clínicos: dois meninos saudáveis com idades entre 4 e 5 anos. Nos dias anteriores, eles reportaram consumo de carne nos mesmos estabe- lecimentos comerciais. Eles consultaram para dor abdominal, fezes líquidas e vômitos repetidos. O menino de 4 anos teve febre e fezes com sangue. O menino de 5 anos teve dores abdominais. O estado de hidratação e os sinais vitais foram normais em ambos meninos. Foram internados em cuidados moderados. Às 48 horas e 5 dias, respectivamente, apresentaram aliás palidez intensa da pele e mucosas, edema e oligúria. Realizaramse estudos complementares: anemia, trombocitopenia e insuficiência renal. Eles foram internados em terapia intensiva e realizouse diálise peritoneal. A investigação do STEC foi negativa e a evolução favorável. Conclusões: em crianças menores de 5 anos, a SHU associada à GEA é a forma mais frequente da doença. No Uruguai, predominam cepas STEC não-O157. Nesses casos, o agente não pôde ser identificado. A existência de um nexo epidemiológico alerta para a necessidade de extremo cuidado no preparo e cozimento da carne. Devido à associação com doença prevalente, é necessário considerar essa complicação para suspeitar e iniciar o tratamento precoce e oportunamente.

Frecuencia de hospitalizaciones por síndrome urémico hemolítico en niños de 0 a 14 años en el Perú, periodo 2015 a 2022

Introducción. Existen limitados reportes epidemiológicos del síndrome urémico hemolítico (SUH) en Latinoamérica. Objetivo. Describir la frecuencia y características de las hospitalizaciones por SUH en niños de 0 a 14 años. Métodos. Se realizó un estudio descriptivo de análisis secundario con datos de hospitalizaciones por SUH de instituciones de salud de Perú en el periodo 2015-2022. Resultados. Se registraron 228 hospitalizaciones. El 52,2% fueron varones. El 88,6% fue menor de cinco años y el 11% menor de un año. Los departamentos con más hospitalizaciones fueron Lima y Arequipa con 133 y 46 casos. Las instituciones del Ministerio de Salud (MINSA) y del Seguro Social (EsSalud) reportaron el 42,5% y 27,6% de las hospitalizaciones. Del 2015 al 2022, la incidencia varió de 0,42 a 1,13 casos/100 000 niños menores de cinco años. Conclusiones. Las hospitalizaciones por SUH fueron más frecuentes en menores de cinco años y en las instituciones del MINSA.

Introduction. There are limited epidemiological reports of hemolytic uremic syndrome (HUS) in Latin America. Objective. To describe the frequency and characteristics of hospitalizations due to HUS in children aged 0 to 14 years. Methods. Descriptive study of secondary analysis was performed with data on hospitalizations due to HUS from healthcare institutions from Peru, 2015-2022. Results. Two hundred twenty-eight hospitalizations were registered, 52.2% were male, 88.6% were under five years old, and 11% were under one year old. The departments with more hospitalizations were Lima (133 cases) and Arequipa (46 cases). The institutions of the Ministry of Health (MINSA) and Social Security (EsSalud) reported 42.5% and 27.6% of hospitalizations. From 2015 to 2022, the incidence ranged from 0.42 to 1.13 cases/100,000 children under five years of age. Conclusions. Hospitalizations due to HUS were more frequent in children under five years of age and MINSA institutions.

Successful kidney transplant with eculizumab, thymoglobulin and belatacept therapy in a highly-sensitised patient with atypical haemolytic uraemic syndrome due to factor H mutation. / Trasplante renal exitoso con protocolo de eculizumab, timoglobulina y belatacept en paciente altamente sensibilizada con síndrome hemolítico urémico atípico por mutación del factor H.

Atypical haemolytic uremic syndrome is a disease caused by complement regulation abnormalities that generally progresses to chronic end-stage renal disease with a high rate of recurrence in kidney transplantation and a high risk of graft loss. Anti-complement therapy has improved the prognosis of these patients, achieving disease remission in most cases, increasing the likelihood of a successful kidney transplant and increasing patient and graft survival. Drugs with low risk of induction of thrombotic microangiopathies such as belatacept and mycophenolate have also been used with satisfactory results. We present the case of a young patient at high immunological risk, with atypical haemolytic uraemic syndrome due to factor H mutation, who underwent a successful kidney transplantation with eculizumab, thymoglobulin, belatacept, mycophenolate and steroids, to date preserving excellent graft function without disease recurrence.

Características del síndrome urémico hemolítico en pacientes de un hospital pediátrico de Perú, 2010-2020 / Characteristics of hemolytic uremic syndrome in patients from a pediatric hospital in Peru, 2010-2020

RESUMEN El propósito del presente estudio fue describir las características clínicas, epidemiológicas, laboratoriales, tratamiento y seguimiento de pacientes con síndrome urémico hemolítico (SUH). Se revisaron las historias clínicas de los pacientes con SUH hospitalizados en el Instituto Nacional de Salud del Niño-Breña (INSN-B) de Lima, Perú. Se incluyeron a 83 pacientes. La mediana de edad fue de 22 meses. El 71,1% (n=59) registró uso previo de antibióticos. El 86,8% (n=72) tuvieron oligoanuria y el 74,6% (n=62) diarrea. Cinco cultivos fueron positivos (dos Escherichia coli enterohemorrágica). Cuarenta y nueve (59%) requirieron terapia de reemplazo renal. Ningún paciente falleció durante la hospitalización. Al año del seguimiento, siete pacientes presentaron nefropatía pos-SUH. En conclusión, en el INSN-B, la mediana de edad fue similar que años anteriores y hubo una mayor frecuencia de oligoanuria y terapia de reemplazo renal en comparación con reportes previos.

ABSTRACT This study aimed to describe the clinical-epidemiological, laboratory, treatment, and follow-up characteristics of patients with hemolytic uremic syndrome (HUS). The medical records of patients with HUS hospitalized at the Instituto Nacional de Salud del Niño-Breña (INSN-B) (Lima, Peru) were reviewed. We evaluated 83 patients. The median age was 22 months (interquartile range: 14 to 30 months). Of the sample, 71.1% (59) registered previous use of antibiotics. Seventy-two (86.8%) had oligoanuria and 62 (74.6%) had diarrhea. Five cultures were positive (two enterohaemorrhagic Escherichia coli). Forty-nine (59%) required renal replacement therapy. No patient died during hospitalization. At one year of follow-up, seven patients developed post-HUS nephropathy. In conclusion, in INSN-B, the median age was like previous years and there was a higher frequency of oligoanuria, and renal replacement therapy compared to previous reports.

Síndrome hemolítico urémico secundario a Streptococcus pneumoniae. Reporte de un caso clínico / Streptococcus pneumoniae associated hemolytic uremic syndrome. Case report

El síndrome hemolítico urémico secundario a Streptococcus pneumoniae (SHU-Sp) es una complicación poco frecuente de las enfermedades invasoras por S. pneumoniae. Presenta una alta morbimortalidad, con requerimiento de transfusiones de glóbulos rojos y plaquetas, terapia de sustitución de la función renal de inicio precoz y más prolongada, así como mayores complicaciones a largo plazo, comparado con las formas secundarias a infección entérica por Escherichia coli productora de toxina Shiga. Presentamos el caso clínico de una preescolar de dos años, previamente sana, vacunada con tres dosis de PCV13, que desarrolló una insuficiencia renal aguda, anemia hemolítica y plaquetopenia, en el contexto de una neumonía con empiema y bacteriemia por S. pneumoniae.

Streptococcus pneumoniae associated hemolytic uremic syndrome (Sp-HUS) is an uncommon complication of invasive pneumococcal infections. Patients with Sp-HUS have a higher mortality and long term morbidity than those due to HUS from Shiga toxin-producing Escherichia coli infections (STEC-HUS). They often require more red blood cells and platelet transfusions, and early initiation of renal substitution therapy, presenting a higher rate of arterial hypertension and chronic renal disease in the long term, compared to STEC-HUS. We report a healthy 2 year-old infant, vaccinated with three doses PCV13, that developed acute renal failure, hemolytic anemia and thrombocytopenia in the course of a complicated pneumococcal pneumonia with empyema and bacteremia.

Where are we with haemolytic uremic syndrome? / Síndrome hemolítico urémico: estado actual.

Haemolytic uremic syndrome (HUS) is characterised by microangiopathic haemolytic anaemia with acute kidney injury. It is currently classified into two main categories: Shiga-toxin producing E. coli-hemolytic uremic syndrome (STEC-HUS) and atypical haemolytic uremic syndrome (aHUS). Endothelial cell damage is the common pathway in HUS to developing thrombotic microangiopathy. Atypical HUS includes primary, secondary and aHUS due to metabolic diseases. In the majority of aHUS cases, hyperactivity of the alternative complement pathway plays a central role. Therefore, treatment is based on complement inhibitors like eculizumab, a drug that has revolutionised the natural history of the disease. Relapses are frequent after kidney transplant and thus confer a poor prognosis.

[Thrombotic microangiopathy/haemolytic uraemic syndrome. Histopathology update]. / Microangiopatía trombótica/síndrome hemolítico urémico. Actualización de sus características histopatológicas.

Thrombotic microangiopathy (TMA) encompasses different entities known as haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). The histopathological characteristics have remained constant since the initial description and consist in glomerular-type affectation with the presence of double contours, mesangiolysis and microthrombi. It is generally accepted that the vascular damage is related to the prognosis. Ultrastructure, together with conventional histology, shows notable changes in both capillaries and endothelial cells. A comprehensive histopathological study of the renal biopsy, using electronmicroscopy, is useful in the confirmation of a clinical suspicion and demonstrates the pathogenetic mechanisms in the microcirculatory damage. The close resemblance between the ultrastructural appearance and that seen with the light microscope of TMA and transplant glomerulopathy (TG) is precisely what suggests that both entities are subject to the same etiopathogenetic mechanism in which the endothelial cell is targeted. Recent advances in the pathology of atypical HUS, its relation with complement system and the discovery of specific therapeutic targets, has rekindled an interest in the study of TMA and the importance of renal biopsy.

[The pathology of renal transplants]. / Anatomía patológica del trasplante renal.

In order to make an objective assessment of the histopathology of a renal biopsy during a kidney transplant, all the various elements involved in the process must be understood. It is important to know the characteristics of the donor organ, especially if the donor is older than 65. The histopathological features of the donor biopsy, especially its vascular status, are often related to an initial poor function of the transplanted kidney. The T lymphocyte inflammatory response is characteristic in acute cellular rejection; the degree of tubulitis, together with the amount of affected parenchyme, are important factors. The proportion of cellular sub-populations, such as plasma cells and macrophages, is also important, as they can be related to antibody-mediated humoral rejection. Immunofluorescent or immunohistochemical studies are necessary to rule out C4d deposits or immunogloblulins. The presence of abundant deposits of C4d in tubular basement membranes supports a diagnosis of humoral rejection, as does the presence of capillaritis, glomerulitis which, together with vasculitis, are typical diagnostic findings in C4d negative cases. Interstitial fibrosis, tubular atrophy and glomerular sclerosis, although non-specific, imply a chronic phase. Transplant glomerulopathy and multilamination in more than 6 layers of the tubular and glomerular basement membranes are quasi-specific characteristics of chronic humoral rejection. Electron microscopy is essential to identify of these pathologies as well as to demonstrate the presence of other glomerular renal diseases.

Síndrome hemolítico urémico atípico en lactantes con mutaciones genéticas: Reporte de 3 casos / Atypical hemolytic uremic syndrome (aHUS) in infants, with genetic mutations, about three cases

RESUMEN El síndrome hemolítico urémico atípico (SHUa) es una entidad clínica considerada rara; sin embargo, es la causa más común de insuficiencia renal aguda en niños. Esta enfermedad se acompaña de anemia hemolítica microangiopática, trombocitopenia, retención nitrogenada y afectación de la función renal, por lo que representa alta morbilidad y compromiso sistémico. Se reportan tres casos de SHUa en lactantes que presentaron pródromos respiratorios, diarrea, anemia hemolítica y trombocitopenia, con pérdida de función renal. Estos casos mostraron que dicha patología está asociada a mutaciones en los genes: CFH (Complemento Factor H), MCP (Membrana Cofactor Proteín), CFHR1 (Complemento Factor H-Related Proteín1), CFHR5 (Complemento factor H-Related Protein 5) y el gen C3 (Complemento component 3). Los genes CFH y MCP se encontraron afectados en dos de los casos, mientras que el tercer caso mostró una mutación nueva no reportada en el gen C3. Estos resultados evidencian que estas mutaciones están presentes en el Perú, por lo que se debe investigar y establecer medidas de prevención para reducir el alto riesgo de morbilidad y mortalidad que presentan los niños portadores SHUa.

SUMMARY The atypical hemolytic uremic syndrome (aHUS) is a rare clinical entity, but it is the most common cause of acute kidney failure in kids. The disease is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure, and it is associated with high morbidity and systemic involvement. We report here three cases of aHUS in infants presenting with prodromal respiratory symptoms, diarrhea, hemolytic anemia, thrombocytopenia and acute renal failure. aHUS cases depict mutations in several genes: membrane cofactor protein (MCP) and complement factor H related proteins 1 and 5 (CFH, RP1 and PR5. Two our patients showed mutations in the genes CFH and MCP, and one presented a new non-previously reported mutation in the gen C3. Our results emphasize the existence of these aHUS mutations and underscore the need to study them to prevent morbidity and mortality.

Chronic gemcitabine-induced thrombotic microangiopathy in the kidneys / Microangiopatía trombótica crónica localizada en riñones asociada al uso de gemcitabina

Abstract Thrombotic microangiopathies (TMAs) are characterized by microvascular occlusion secondary to diffuse endothelial damage which produces inflammation, platelet aggregation and red blood cell destruction, causing ischemic injury to the affected organ. They are clinically characterized by Coombs-negative microangiopathic hemolytic anemia, and multiple organ damage (mainly of the kidneys, central nervous system, cardiovascular apparatus and gastrointestinal tract). They may occur systemically or locally, and they have multiple etiologies. In patients with cancer, determining the cause of thrombotic microangiopathy is a great diagnostic challenge, with the most frequent etiologies being active malignant neoplasms, disseminated intravascular coagulation, infections and antineoplastic drugs. We present the clinical case of a patient with unresectable pancreatic adenocarcinoma on chronic gemcitabine treatment, and highlight the importance of suspecting and distinguishing chemotherapy-induced TMAs from neoplasm-induced TMAs, as their prognosis and treatment are very different. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2249).

Resumen Las microangiopatías trombóticas (MAT) se caracterizan por la oclusión microvascular como consecuencia de una lesión endotelial difusa que produce inflamación, agregación plaquetaria y destrucción de glóbulos rojos, causando daño isquémico del órgano afectado. Se caracterizan clínicamente por anemia hemolítica microangiopática, Coombs negativo, daño multiorgánico (principalmente de riñones, sistema nervioso central, aparato cardiovascular y tracto gastrointestinal). Su presentación puede ser sistémica o localizada y sus etiologías son múltiples. En los pacientes con cáncer es un gran reto diagnóstico establecer la causa de la microangiopatía trombótica, siendo las etiologías más frecuentes la neoplasia maligna activa, la coagulación intravascular diseminada, infecciones y medicamentos antineoplásicos. Se presenta el caso clínico de una paciente con adenocarcinoma cáncer de páncreas irresecable, en manejo crónico con gemcitabina y se resalta la importancia de sospechar y distinguir la MAT inducida por quimioterapia, de la causada por la neoplasia ya que el pronóstico y tratamiento son muy diferentes. (Acta Med Colomb 2022; 47. DOI:https://doi.org/10.36104/amc.2022.2249).

Manifestaciones hepatopancreáticas en síndrome hemolítico urémico atípico

Introducción: el síndrome hemolítico urémico atípico es una enfermedad severa y huérfana, la cual en su variedad atípica se presenta con manifestaciones clínicas extrarrenales y sistémicas. La presencia de afectación gastrointestinal es infrecuente, pero en los pacientes en los que se manifiesta el pronóstico desfavorable, dado que estos cursan con más recaídas y mayor mortalidad, por lo cual se hace indispensable que el personal de salud esté entrenado en detectar y reconocer las manifestaciones menos frecuentes de esta patología, para así impactar positivamente en el desenlace de estos pacientes. Objetivo: se busca ilustrar un caso singular en cuanto a la sintomatología presentada infrecuente por el paciente y sobre una etiología no descrita previamente en la literatura. Presentación del caso: se reporta el caso de un escolar masculino de 8 años que presentó fiebre, ictericia, dolor abdominal y lumbar, diarrea, hematemesis y hematuria, al cual se le diagnosticó síndrome hemolítico urémico atípico. El paciente presentó un rápido deterioro clínico con compromiso multiorgánico, documentándose hipertensión arterial y lesión renal aguda, que recibió manejo con cristaloides y diurético de asa sin mejoría, por lo que requirió inicio de terapia de reemplazo renal e incluso múltiple soporte transfusional; sin embargo, continuó sin mejoría clínica, por lo que se indicó inicio de anticuerpo monoclonal IgG humanizado recombinante con buenos resultados. Discusión y conclusión: este caso es un claro ejemplo de que la afectación extrarrenal y multiorgánica puede ser la manifestación principal de esta enfermedad, por lo que es importante que el clínico se encuentre sensibilizado y conozca los signos y los síntomas de la presentación atípica de esta patología, con el fin de evitar retrasos diagnósticos y terapéuticos. Asimismo, el abordaje etiológico es de suma importancia para brindar un pronóstico más preciso al paciente y su familia.

Introduction: Atypical hemolytic uremic syndrome is a severe and orphan disease, in its atypical variety courses with extrarenal clinical manifestations. The presence of gastrointestinal compromise is infrequent, but the prognosis is unfavorable, since they have more relapses and higher mortality. Therefore, it is important that physicians are trained in recognizing the rare manifestations of this pathology, in order to improve the outcome in these patients. Purpose: This case illustrates a unique case in terms of symptoms and etiology not previously described. Case presentation: We report the case of an 8-year-old male who presented with fever, jaundice, abdominal and lumbar pain, diarrhea, hematemesis, and hematuria. Atypical hemolytic uremic syndrome was diagnosed. He presented clinical deterioration with multiple organ involvement, documenting high blood pressure and acute kidney injury, who received management with crystalloids and diuretics without improvement, requiring renal replacement therapy and multiple transfusional support. However, there was still no clinical improvement, so the start of recombinant humanized IgG monoclonal antibody was indicated, with satisfactory outcomes. Discussion and conclusions: This case is a clear example that extrarenal and multi-organ involvement can be the main manifestation of this disease, so it is important that clinicians are aware of the clinical course that may develop a patient with atypical presentations, in order to avoid diagnostic and therapeutic delays. Likewise, the etiological approach is important in order to provide an accurate prognosis to the patient and his family.

Ocular involvement in atypical haemolytic uraemic syndrome. / Afectación ocular en un síndrome hemolítico urémico atípico.

CASE REPORT: The case is presented of a young man with an atypical haemolytic-uraemic syndrome (aHUS), complicated with bilateral serous retinal detachment, cotton wool spots, and a branch artery occlusion. Treatment with plasmapheresis, haemodialysis and systemic eculizumab led to the blood and urine parameters returning to normal, as well as resolution of the retinal anomalies. Genetic analysis show both mutations in complement factor H and C3. DISCUSSION: Haemolytic-uraemic syndrome (HUS) is a thrombotic microangiopathy characterised by microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal failure. Atypical HUS is caused by genetic mutation of complement system. Ocular involvement is an unusual manifestation of this rare syndrome.