Acute kidney injury: the experience of a tertiary center of Pediatric Nephrology / Insuficiência renal aguda: experiência de um centro terciário de Nefrologia Pediátrica

ABSTRACT Introduction: Acute kidney injury (AKI) is an abrupt deterioration of kidney function. The incidence of pediatric AKI is increasing worldwide, both in critically and non-critically ill settings. We aimed to characterize the presentation, etiology, evolution, and outcome of AKI in pediatric patients admitted to a tertiary care center. Methods: We performed a retrospective observational single-center study of patients aged 29 days to 17 years and 365 days admitted to our Pediatric Nephrology Unit from January 2012 to December 2021, with the diagnosis of AKI. AKI severity was categorized according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The outcomes considered were death or sequelae (proteinuria, hypertension, or changes in renal function at 3 to 6 months follow-up assessments). Results: Forty-six patients with a median age of 13.0 (3.5-15.5) years were included. About half of the patients (n = 24, 52.2%) had an identifiable risk factor for the development of AKI. Thirteen patients (28.3%) were anuric, and all of those were categorized as AKI KDIGO stage 3 (p < 0.001). Almost one quarter (n = 10, 21.7%) of patients required renal replacement therapy. Approximately 60% of patients (n = 26) had at least one sequelae, with proteinuria being the most common (n = 15, 38.5%; median (P25-75) urinary protein-to-creatinine ratio 0.30 (0.27-0.44) mg/mg), followed by reduced glomerular filtration rate (GFR) (n = 11, 27.5%; median (P25-75) GFR 75 (62-83) mL/min/1.73 m2). Conclusions: Pediatric AKI is associated with substantial morbidity, with potential for proteinuria development and renal function impairment and a relevant impact on long-term prognosis.

RESUMO Introdução: Insuficiência renal aguda (IRA) é uma deterioração abrupta da função renal. A incidência de IRA pediátrica está aumentando em todo o mundo, em ambientes críticos e não críticos. Nosso objetivo foi caracterizar apresentação, etiologia, evolução e desfechos da IRA em pacientes pediátricos internados em um centro de atendimento terciário. Métodos: Realizamos estudo retrospectivo observacional de centro único de pacientes com idade entre 29 dias a 17 anos e 365 dias internados em nossa Unidade de Nefrologia Pediátrica, de janeiro de 2012 a dezembro de 2021, com diagnóstico de IRA. A gravidade da IRA foi categorizada de acordo com os critérios do Kidney Disease Improving Global Outcomes (KDIGO). Os desfechos considerados foram óbito ou sequelas (proteinúria, hipertensão ou alterações na função renal em avaliações de acompanhamento de 3 a 6 meses). Resultados: Incluímos 46 pacientes com idade mediana de 13,0 (3,5-15,5) anos. Cerca de metade (n = 24; 52,2%) apresentou um fator de risco identificável para o desenvolvimento de IRA. Treze pacientes (28,3%) eram anúricos; todos foram classificados como IRA KDIGO 3 (p < 0,001). Quase um quarto (n = 10; 21,7%) dos pacientes necessitaram de terapia renal substitutiva. Aproximadamente 60% (n = 26) apresentou pelo menos uma sequela, sendo proteinúria a mais comum (n = 15; 38,5%; mediana (P25-75) da relação proteína/creatinina urinária 0,30 (0,27-0,44) mg/mg), seguida de taxa de filtração glomerular (TFG) reduzida (n = 11; 27,5%; mediana (P25-75) da TFG 75 (62-83) mL/min/1,73 m2). Conclusões: A IRA pediátrica está associada à morbidade substancial, com potencial para desenvolvimento de proteinúria e comprometimento da função renal e impacto relevante no prognóstico de longo prazo.

Acute kidney injury: the experience of a tertiary center of Pediatric Nephrology.

INTRODUCTION: Acute kidney injury (AKI) is an abrupt deterioration of kidney function. The incidence of pediatric AKI is increasing worldwide, both in critically and non-critically ill settings. We aimed to characterize the presentation, etiology, evolution, and outcome of AKI in pediatric patients admitted to a tertiary care center. METHODS: We performed a retrospective observational single-center study of patients aged 29 days to 17 years and 365 days admitted to our Pediatric Nephrology Unit from January 2012 to December 2021, with the diagnosis of AKI. AKI severity was categorized according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The outcomes considered were death or sequelae (proteinuria, hypertension, or changes in renal function at 3 to 6 months follow-up assessments). RESULTS: Forty-six patients with a median age of 13.0 (3.5-15.5) years were included. About half of the patients (n = 24, 52.2%) had an identifiable risk factor for the development of AKI. Thirteen patients (28.3%) were anuric, and all of those were categorized as AKI KDIGO stage 3 (p < 0.001). Almost one quarter (n = 10, 21.7%) of patients required renal replacement therapy. Approximately 60% of patients (n = 26) had at least one sequelae, with proteinuria being the most common (n = 15, 38.5%; median (P25-75) urinary protein-to-creatinine ratio 0.30 (0.27-0.44) mg/mg), followed by reduced glomerular filtration rate (GFR) (n = 11, 27.5%; median (P25-75) GFR 75 (62-83) mL/min/1.73 m2). CONCLUSIONS: Pediatric AKI is associated with substantial morbidity, with potential for proteinuria development and renal function impairment and a relevant impact on long-term prognosis.

Genetic atypical hemolytic uremic syndrome in children: a 20-year experience from a tertiary center / Síndrome hemolítica urêmica atípica genética em crianças: uma experiência de 20 anos a partir de um centro terciário

Abstract Introduction: Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, which primarily affects preschool-aged children. This study's aim was to describe the clinical profile, management, and long-term outcome of the genetic aHUS patients admitted to a tertiary care pediatric nephrology center during 20 years. Methods: We performed a retrospective analysis of the clinical records of all aHUS patients younger than 18 years with identified genetic mutations. Data on clinical features, genetic study, therapeutic interventions, and long-term outcomes were reviewed. Results: Five cases of aHUS with an identified genetic mutation were included; all were inaugural cases with the youngest being 4 months old. Complement factor H gene mutation was identified in four patients. Therapeutic plasma exchange was performed for acute management in 4 patients, one of whom also needed acute renal replacement therapy (peritoneal dialysis). All patients went on complete remission, 2 had more than one relapse but only 1 of these progressed to chronic kidney disease during the follow-up period (median (25th-75th percentile), 136 (43.5-200.5) months). Conclusion: In children, the prognosis of renal function seems to be strongly dependent on the genetic background, thus being crucial to perform genetic study in all aHUS cases. In our cohort, 2 patients presented genetic mutations not previously described. Recent innovations on the genetic field leading to the identification of new mutations has lead to a better understanding of aHUS pathogenesis, but further studies, focusing on the genotype-phenotype correlation, with longer follow-up periods, are needed.

Resumo Introdução: A síndrome hemolítica urêmica atípica (SHUa) é um distúrbio raro caracterizado pela tríade de anemia hemolítica microangiopática, trombocitopenia e lesão renal aguda, afetando principalmente crianças em idade pré-escolar. O objetivo deste estudo foi descrever perfil clínico, manejo e desfecho em longo prazo dos pacientes com SHUa genética admitidos em um centro terciário de nefrologia pediátrica durante 20 anos. Métodos: Realizamos análise retrospectiva dos registros clínicos de todos os pacientes com SHUa menores de 18 anos com mutações genéticas identificadas. Revisaram-se dados sobre características clínicas, estudo genético, intervenções terapêuticas e desfechos em longo prazo. Resultados: Incluíram-se cinco casos de SHUa com uma mutação genética identificada; sendo todos casos inaugurais, o mais jovem tendo 4 meses de idade. A mutação no gene do fator H do complemento foi identificada em quatro pacientes. Plasmaférese terapêutica foi realizada para tratamento agudo em 4 pacientes, um dos quais também necessitou terapia renal substitutiva aguda (diálise peritoneal). Todos os pacientes tiveram remissão completa, 2 mais de uma recidiva, mas apenas 1 evoluiu para doença renal crônica durante acompanhamento (mediana (percentil 25°-75°), 136 (43,5-200,5) meses). Conclusão: Em crianças, o prognóstico da função renal parece ser fortemente dependente do histórico genético, sendo crucial realizar estudo genético em todos os casos de SHUa. Em nossa coorte, 2 pacientes apresentaram mutações genéticas não descritas anteriormente. Inovações recentes no campo genético que levaram à identificação de novas mutações conduziram a um melhor entendimento da patogênese SHUa, mas são necessários mais estudos, focando na correlação genótipo-fenótipo, com períodos de acompanhamento mais longos.

Genetic atypical hemolytic uremic syndrome in children: a 20-year experience from a tertiary center.

INTRODUCTION: Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, which primarily affects preschool-aged children. This study's aim was to describe the clinical profile, management, and long-term outcome of the genetic aHUS patients admitted to a tertiary care pediatric nephrology center during 20 years. METHODS: We performed a retrospective analysis of the clinical records of all aHUS patients younger than 18 years with identified genetic mutations. Data on clinical features, genetic study, therapeutic interventions, and long-term outcomes were reviewed. RESULTS: Five cases of aHUS with an identified genetic mutation were included; all were inaugural cases with the youngest being 4 months old. Complement factor H gene mutation was identified in four patients. Therapeutic plasma exchange was performed for acute management in 4 patients, one of whom also needed acute renal replacement therapy (peritoneal dialysis). All patients went on complete remission, 2 had more than one relapse but only 1 of these progressed to chronic kidney disease during the follow-up period (median (25th-75th percentile), 136 (43.5-200.5) months). CONCLUSION: In children, the prognosis of renal function seems to be strongly dependent on the genetic background, thus being crucial to perform genetic study in all aHUS cases. In our cohort, 2 patients presented genetic mutations not previously described. Recent innovations on the genetic field leading to the identification of new mutations has lead to a better understanding of aHUS pathogenesis, but further studies, focusing on the genotype-phenotype correlation, with longer follow-up periods, are needed.