ABSTRACT We present a case of a 69-year-old man who presented for routine check-up and was incidentally found to have kidney failure with an initially unrevealing history and bland urinary sediment. He was diagnosed with oxalate nephropathy in the setting of chronic turmeric supplementation and chronic antibiotic therapy with associated diarrhea. Our case provides several key insights into oxalate nephropathy. First, the diagnosis requires a high index of clinical suspicion. It is uncommonly suspected clinically unless there is an obvious clue in the history such as Roux-en-Y gastric bypass or ethylene glycol poisoning. Diagnosis can be confirmed by histopathologic findings and corroborated by serum levels of oxalate and 24-hour urinary excretion. Second, the diagnosis can often be missed by the pathologist because of the characteristics of the crystals unless the renal pathologist has made it a rule to examine routinely all H&E sections under polarized light. This must be done on H&E, as the other stains dissolve the crystals. Third, one oxalate crystal in a routine needle biopsy is considered pathologic and potentially contributing to the AKI or to the CKD in an important way. Fourth, secondary oxalosis can be largely mitigated or prevented in many cases, especially iatrogenic cases. This can come through the surgeon or the gastroenterologist providing proper instructions to patients on an oxalate-restricted diet or other specific dietary measures. Lastly, this case highlights the success that results from cooperation and communication between the pathologist and the treating physician.

RESUMO Relatamos o caso de um homem de 69 anos que se apresentou para exame de rotina e descobriu-se incidentalmente que ele tinha insuficiência renal, com histórico inicialmente não revelador e sedimento urinário brando. Ele foi diagnosticado com nefropatia por oxalato no contexto de suplementação crônica de cúrcuma e antibioticoterapia crônica com diarreia associada. Nosso caso fornece diversas sugestões importantes sobre nefropatia por oxalato. Primeiro, o diagnóstico requer elevado índice de suspeita clínica. A suspeita clínica é incomum, a menos que haja evidência óbvia no histórico, como bypass gástrico em Y de Roux ou envenenamento por etilenoglicol. O diagnóstico pode ser confirmado por achados histopatológicos e corroborado por níveis séricos de oxalato e excreção urinária de 24 horas. Segundo, o diagnóstico pode passar despercebido pelo patologista devido às características dos cristais, a menos que o patologista renal estabeleça como regra examinar rotineiramente todas as seções coradas com H&E sob luz polarizada. Isso deve ser feito com H&E, pois, outras colorações dissolvem os cristais. Em terceiro lugar, um cristal de oxalato em biópsia por agulha de rotina é considerado patológico, contribuindo potencialmente para LRA ou para DRC de maneira significativa. Em quarto lugar, a oxalose secundária pode ser amplamente mitigada ou prevenida em muitos casos, especialmente casos iatrogênicos. Isso pode ser feito pelo cirurgião ou pelo gastroenterologista, fornecendo instruções adequadas aos pacientes sobre uma dieta restrita em oxalato ou outras medidas dietéticas específicas. Por fim, esse caso destaca o sucesso que resulta da cooperação e comunicação entre o patologista e o médico assistente.

Resumen Introducción: el mayor inconveniente del uso de contrastes yodados en la práctica clínica es la nefropatía por contraste, que aumenta la morbimortalidad y los costes hospitalarios. El preacondicionamiento isquémico remoto (PCIR) es una técnica de protección tisular no invasiva que ha demostrado ser capaz de disminuir la afectación renal tras la administración de contraste intravascular. Objetivo: el objetivo principal del estudio es valorar el impacto del PCIR en la incidencia de la nefropatía inducida por contraste en pacientes intervenidos de reparación aórtica endovascular (EVAR). Material y métodos: se incluyeron pacientes intervenidos de EVAR electivo asignados de manera secuencial en grupo control y de preacondicionamiento (C y P, respectivamente). Se analizaron parámetros bioquímicos pre- y posoperatorios (a las 24 y a las 72 horas y a los 30 días). Resultados: el 98,3 % de los pacientes incluidos en el estudio fueron varones, sobre una muestra total de 120 pacientes. La media de edad fue de 73 años (rango: 56-87). La diabetes y la insuficiencia renal crónica preoperatoria (entendida como filtrado glomerular < 60 ml/min) estuvieron presentes en el 29,16 % y en el 38,33 % de los pacientes, respectivamente. La mitad de la muestra recibió preacondicionamiento en el preoperatorio. Un total de 24,17 % pacientes desarrollaron nefropatía a pesar de sueroterapia con o sin preacondicionamiento. En el posoperatorio (24-72 h) el preacondicionamiento no modificó la incidencia de nefropatía, creatinina y urea sérica o tasa de filtrado glomerular (eFG). Sin embargo, a los 30 días el grupo preacondicio-nado mostró una mejoría significativa de las cifras de creatinina y de ureas séricas (1,46 ± 0,3 frente a 1,03 ± 0,5; p < 0,001; 61,06 ± 27,5 mg/dl frente a 43,78 ± 12,9 mg/dl; p = 0,003) y aumento de eFG (56,37 ± 23,4 ml/min /1,73 m2 frente a 72,85 ± 17,7ml/min/ 1,73 m2; p = 0,004). Conclusiones: el PCIR parece efectivo en reducir los efectos del contraste yodado sobre el riñón en pacientes intervenidos de EVAR a corto plazo (30 días).

Abstract Introduction: the biggest drawback of using iodinated contrasts in clinical practice is contrast nephropathy, which increases morbidity and mortality and hospital costs. Remote ischemic preconditioning (RIPC) is a non-invasive tissue protection technique that has proven to be able to reduce renal involvement after intravascular contrast administration. Objective: the main goal of this study was to assess the impact of RIPC on the incidence of contrast-induced nephropathy in patients undergoing endovascular aortic repair (EVAR). Material and methods: patients who underwent elective EVAR were included, and then sequentially assigned to the control and preconditioning groups (groups C and p, respectively). Pre- and postoperative hematocrit (at 24, 72 hours, and 30 days) was analyzed. Results: a total of 98.3 % of the patients included in the study were men out of a total sample of 120 patients. The mean age was 73 years (range, 56-87). Diabetes and preoperative chronic kidney disease (understood as glomerular filtration rates < 60 mL/min) were present in 29.16 % and 38.33 % of the patients, respectively. Half of the sample received preconditioning in the preoperative period. A total of 24.17 % of the patients developed nephropathy despite fluid therapy with or without preconditioning. At the postoperative period (24 h-72 h), preconditioning did not modify the incidence rate of nephropathy, serum creatinine and urea, or even the estimated glomerular filtration rate (eGFR). However, at the 30-day follow-up the preconditioned group showed a significant improvement in serum creatinine and urea levels (1.46 ± 0.3 vs 1.03 ± 0.5; p < 0.001; 61.06 ± 27.5 mg/dL vs 43 .78 ± 12.9 mg/dL; p = 0.003) and eGFR increase (56.37 ± 23.4 mL/min/1.73 m2 vs 72.85 ± 17.7mL/min/1.73 m2; p = 0.004). Conclusions: RIPC seems effective in alleviating the effects of iodinated contrast on the kidneys of patients undergoing EVAR in the short term follow up (30 days).

ABSTRACT Introducción: Anti-C1q autoantibodies have been proposed as useful marker in systemic lupus erythematosus due to their association with lupus nephritis. Objective: To determine the prevalence of anti-C1q in patients with systemic lupus erythematosus and other rheumatic diseases to evaluate the association with lupus nephropathy. Methods: One hundred seventy-nine patients with systemic lupus erythematosus and 82 with other rheumatic diseases were included. Lupus nephritis was diagnosed in 70 (39%) of patients with systemic lupus erythematosus. Anti-C1q IgG antibodies were determined by ELISA. Associations were evaluated by logistic regression analysis. Results: The prevalence of anti-C1q was 37% (66/179) in patients with systemic lupus erythematosus and 9% (7/82) in controls (OR = 6.3; 95% CI 2.8-14). .1; p < 0.001). Anti-C1q was associated with proteinuria (OR = 2.6; 95% CI 1.2-6.0; p < 0.022); elevated erythrocyte sedimentation rate (OR = 3.2; 95% CI 1.5-6.7; p < 0.003) and anti-dsDNA (OR = 3.9; 95% CI 1.7-9.1; p < 0.002). In the logistic regression model adjusted for demographics and anti-dsDNA, although the OR of anti-C1q for nephritis was 2-fold higher than in the absence of anti-C1q, it only approached statistical significance. Simultaneous positivity of anti-C1q and anti-dsDNA was associated with lupus nephritis (OR = 4.3; 95% CI 1.9-9.5; p < 0.001). Conclusions: Anti-C1q occurred more frequently in patients with systemic lupus erythematosus than in controls. Anti-C1q combined with anti-dsDNA was strongly associated with lupus nephritis.

RESUMEN Introducción: Los autoanticuerpos anti-C1q han sido propuestos como un marcador útil en el lupus eritematoso sistémico por su asociación con la nefritis lúpica. Objetivo: Determinar la prevalencia de anti-C1q en pacientes con lupus eritematoso sistémico y otras enfermedades reumáticas para la evaluar la asociación con la nefropatía lúpica. Métodos: Se incluyeron 179 pacientes con lupus eritematoso sistémico y 82 con otras enfermedades reumáticas. La nefritis lúpica fue diagnosticada en 70 (39 %) de los pacientes con lupus eritematoso sistémico. Los anticuerpos anti-C1q IgG se determinaron por ELISA. Las asociaciones se evaluaron por análisis de regresión logística. Resultados: La prevalencia de anti-C1q fue de 37 % (66/179) en los pacientes con lupus eritematoso sistémico y de 9 % (7/82) en controles (OR = 6,3; IC 95 % 2,8-14,1; p < 0,001). El anti-C1q fue asociado con proteinuria (OR = 2,6; IC 95 % 1,2-6,0; p < 0,022); eritrosedimentación elevada (OR = 3,2; IC 95 % 1,5-6,7; p < 0,003) y anti-DNAdc (OR = 3,9; IC 95 % 1,7-9,1; p < 0,002). En el modelo de regresión logística ajustado para demografía y anti-DNAdc, aunque la OR del anti-C1q para la nefritis fue 2 veces más alta que en ausencia del anti-C1q, solo se aproximó a la significación estadística. La positividad simultánea de anti-C1q y anti-DNAdc estuvo asociada a la nefritis lúpica (OR = 4,3; IC 95 % 1,9-9,5; p < 0,001). Conclusiones: El anti-C1q se presentó con mayor frecuencia en pacientes con lupus eritematoso sistémico que en los controles. El anti-C1q combinado con anti-DNAdc resultó fuertemente asociado a la nefritis lúpica.

ABSTRACT Introduction: Hypokalemia is a frequent hydroelectrolytic disorder, associated with systemic and multifactorial diseases, whose acute form can be complicated and cause death, but in its chronic presentation it can be a marker of nephropathy. Objective: To characterize the profile of the patient with non-drug hypokalemia seen in an emergency. Methods: The records of patients older than 18 years diagnosed with hypokalemia, admitted to the hospital from June 2018 to December 2019, were reviewed. Demographic data, medical history, and post-treatment evolution were collected. It was compared with 108 patients without hypokalemia seen in the same period. Results: 87 cases with mean age of 38.5 years were studied. 90.8% were men under 50 years of age, who worked as farmers (29.9%), with history of exposure to pesticides and high ambient temperatures. Most of them had no history of previous cardiometabolic or renal disease. 48.3% of all patients with hypokalemia (n = 42) had creatinine higher than 1.2 mg/dL and 63% had hyponatremia. Hypokalemia was moderate in 39% and severe in 12%, and it was found that men were affected 4.7 times more than women. Regarding the group without hypokalemia and abnormal creatinine, they had higher frequency of chronic disease (92.5% versus 8%). Conclusions: Non-drug hypokalemia was found in male farmers, without chronic disease, but with evidence of early nephropathy and hyponatremia. The possibility of Mesoamerican nephropathy was suggested. A regional epidemiological alert and a prevention and control program should be established.

RESUMEN Introducción: La hipopotasemia es un trastorno hidroelectrolítico frecuente, asociado a enfermedades sistémicas y multifactoriales, cuya forma aguda puede complicarse y causar la muerte, pero en su presentación crónica puede ser un marcador de nefropatía. Objetivo: Caracterizar el perfil del paciente con hipopotasemia no medicamentosa atendidos de emergencia. Métodos: Se revisaron los registros de pacientes mayores de 18 años con diagnóstico de hipopotasemia, ingresados en el hospital en el período de junio 2018 a diciembre de 2019. Se colectaron datos demográficos, antecedentes médicos y evolución postratamiento. Se comparó con 108 pacientes sin hipopotasemia atendidos en el período de estudio. Resultados: Se encontraron 87 casos con edad media de 38,5 años. El 90,8 % eran hombres menores de 50 años, de oficio agricultor (29,9 %), con historia de exposición a plaguicidas y a altas temperaturas ambientales. La mayoría de ellos no tenía historia de enfermedad cardiometabólicas o renal previa. El 48,3 % de todos los pacientes con hipopotasemia (n = 42) tenía creatinina mayor a 1,2 mg/dL y 63 % tenía hiponatremia. La hipopotasemia fue moderada en 39 % y severa en 12 %, los hombres 4,7 veces más afectados que las mujeres. Respecto al grupo sin hipopotasemia y creatinina anormal, tenían mayor frecuencia de enfermedad crónica (92,5 % versus 8 %). Conclusiones: Se encontró hipopotasemia no medicamentosa en varones agricultores, sin enfermedad crónica, pero con datos de nefropatía temprana e hiponatremia, se sugirió la posibilidad de nefropatía mesoamericana. Debe establecerse una alerta epidemiológica regional y un programa de prevención y control.

Abstract Introduction: IgA nephropathy (IgAN) is the most common glomerular disease globally, and its susceptibility and the risk for the development of end-stage kidney disease are related to genetic and environmental factors. IgAN recurrence after kidney transplantation is relatively common, impacting graft function and survival. This study evaluated the risk factors and the clinical, laboratory, and histological characteristics of post-transplant IgAN recurrence based on the Oxford classification. Material and methods: Retrospective single-center cohort study including kidney transplant recipients with biopsy-proven pre-transplantation IgAN, with analysis of risk factors and clinical, laboratory, and histological characteristics of the IgAN recurrence cases. Results: 53 patients fulfilled the inclusion criteria and were included in the study. The majority was male, white, eutrophic, with a mean age of 27 ± 9 years at IgAN diagnosis. Systemic arterial hypertension and proteinuria were frequent in the pretransplant period. Four recipients (7.5%) presented IgAN recurrence in a period of 6 to 122 months post-transplant. According to the Oxford classification, they had high scores of mesangial hypercellularity and segmental glomerulosclerosis in the native kidney biopsies and there was mesangial hypercellularity in all analyzed graft biopsies. None of these patients had received induction immunosuppression and all of them presented graft failure in the follow-up. Conclusions: In this series, there was a high prevalence of mesangial hypercellularity and segmental glomerulosclerosis on native kidney biopsies, and mesangial hypercellularity occurred in all IgAN recurrence graft biopsies. Despite the lower incidence of recurrence of IgAN post-transplant compared to previous reports, progression to graft loss was of 100%.

Resumo Introdução: Nefropatia por IgA (NIgA) é a doença glomerular mais comum mundialmente. Sua suscetibilidade e risco para desenvolvimento de doença renal em fase terminal estão relacionados a fatores genéticos e ambientais. A recidiva de NIgA pós-transplante é relativamente comum, impactando na função e sobrevida do enxerto. Este estudo avaliou fatores de risco e características clínicas, laboratoriais e histológicas da recidiva de NIgA pós-transplante, com base na classificação de Oxford. Material e métodos: Estudo de coorte retrospectivo de centro único, incluindo receptores de transplante renal com NIgA pré-transplante comprovada por biópsia, com análise dos fatores de risco e características clínicas, laboratoriais e histológicas dos casos de recidiva de NIgA. Resultados: 53 pacientes preencheram critérios de inclusão e foram incluídos no estudo. A maioria era homem, branco, eutrófico, com idade média de 27 ± 9 anos no diagnóstico de NIgA. Hipertensão arterial sistêmica e proteinúria foram frequentes no período pré-transplante. Quatro receptores (7,5%) apresentaram recidiva de NIgA entre 6-122 meses pós-transplante. Segundo a classificação de Oxford, eles apresentaram altos escores de hipercelularidade mesangial e glomeruloesclerose segmentar nas biópsias de rins nativos. Houve hipercelularidade mesangial em todas as biópsias de enxerto analisadas. Nenhum destes pacientes recebeu imunossupressão de indução. Todos apresentaram falência do enxerto no acompanhamento. Conclusões: Nesta série, houve alta prevalência de hipercelularidade mesangial e glomeruloesclerose segmentar em biópsias de rins nativos, e hipercelularidade mesangial ocorreu em todas as biópsias do enxerto de recidiva da NIgA. Apesar da menor incidência de recidiva de NIgA pós-transplante comparada a relatos anteriores, a progressão para perda do enxerto foi de 100%.

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.

RESUMEN Antecedentes: Además de las nefropatías diabéticas (DNP), también se conoce la prevalencia frecuente de nefropatías no diabéticas (NDNP) en pacientes diagnosticados con Diabetes mellitus tipo 2 (DM). El diagnóstico precoz de estas condiciones es importante para el tratamiento y pronóstico de estos pacientes. Objetivo: Este estudio tuvo como objetivo investigar las relaciones entre los hallazgos clínicos y de laboratorio de las biopsias renales de pacientes diabéticos tipo 2. Material y Métodos: Revisamos retrospectivamente las historias clínicas de 140 pacientes que tenían diagnóstico de DM tipo 2, desde julio de 2020 hasta agosto de 2022, y se les realizó biopsia renal en las clínicas de nefrología del Hospital Umraniye. Se revisaron los resultados de biopsia renal, presencia de hipertensión arterial, retinopatía diabética, hematuria y proteinuria así como también la duración de la enfermedad, las indicaciones de la biopsia, la hemoglobina glucosilada (HbA1c), la creatinina sérica, el nitrógeno ureico en sangre, la albúmina y los niveles de proteinuria en orina de 24 h. El nivel de significación estadística se determinó como p<0,05. Resultados: se detectaron NDNP en el 43,7% de los pacientes. Entre estos, el diagnóstico más común fue la nefritis intersticial (20%). La indicación de biopsia más frecuente resultó ser la proteinuria en rango nefrótico (30,7%). La diferencia entre las indicaciones de biopsia renal de los pacientes DNP y NDNP fue estadísticamente significativa (p<0,001). Los pacientes con DNP tuvieron una mayor incidencia de retinopatía (60%, 11%, p<0,001). Se detectó una diferencia estadísticamente significativa entre la duración de la enfermedad de los grupos DNP y NDNP (11,23 +5,74 años, p:0,002). De acuerdo con el análisis de regresión multivariado, la presencia de DR y el valor de HbA1c en más del 7% tienen 4,482 y 4,591 veces mayor riesgo de incidencia de DNP (p = 0,021, p: 0,024). Conclusión: El diagnóstico precoz de DNP y NDNP de pacientes diabéticos mediante la realización de biopsias renales afecta el tratamiento y pronóstico de los pacientes. Por lo tanto, al evaluar pacientes diabéticos, es necesario no pasar por alto los hallazgos sugestivos de NDNP.

ABSTRACT Background: In addition to diabetic nephropathies (DNP), prevalence of nondiabetic nephropathies (NDNP) is also known to be frequent in patients diagnosed with type 2 Diabetes mellitus (DM). Early diagnosis of these conditions is important for the treatment and prognosis of these patients. Aim: This study aimed to investigate the relationships between clinical and laboratory findings of type 2 diabetic patients’ renal biopsies. Material and Methods: We retrospectively reviewed the medical records of 140 patients who had diagnosis of type 2 DM and underwent renal biopsy from July 2020- August 2022 at nephrology clinics of Hospital Umraniye. Renal biopsy results, presence of hypertension, diabetic retinopathy, hematuria, proteinuria; duration of the disease, biopsy indications, glycated hemoglobin (HbA1c), serum creatinine, blood urea nitrogen, albumin, and proteinuria levels in 24h urine were measured. The statistical significance level was determined as p<0,05. Results: NDNP were detected in 43,7% of the patients. Among these the most common diagnosis was interstitial nephritis (20%). The most common biopsy indication was found to be nephrotic range proteinuria (30,7%). The difference between the DNP and NDNP patients’ renal biopsy indications was statistically significant (p<0,001). DNP patients had a higher retinopathy incidence (60%,11%, p<0,001). A statistically significant difference was detected between the disease duration of DNP and NDNP groups (11,23 +5,74 years, p:0,002). According to multivariate regression analysis DR and HbA1c value, more than 7% have 4, 482 and 4,591-fold increased the risk of DNP incidence (p=0,021, p:0,024). Conclusion: Early diagnosis of DNP and NDNP of diabetic patients by performing renal biopsies affects the treatment and prognosis of the patients. Therefore, when evaluating diabetic patients, its necessary not to overlook the findings suggestive of NDNP.

RESUMEN Introducción: Los estudios han demostrado que la frecuencia de insuficiencia renal aguda (IRA) aumenta en pacientes con COVID-19. Se ha informado que la necrosis tubular aguda es el daño más común en estos pacientes, probablemente debido a la alteración de la perfusión renal. Por otro lado, pueden estar involucrados diferentes procesos fisiopatológicos complejos, debido a los efectos directos de la infección viral sobre el sistema renina-angiotensina-aldosterona, la activación de la coagulopatía, la tormenta de citoquinas y la activación del sistema inmunológico. En estos pacientes se pueden observar muchas enfermedades glomerulares, como vasculitis asociada a anca, glomerulonefritis membranosa y nefropatía por IgA. Caso clínico: Presentamos un caso de nefropatía IgA extracapilar (NIgA) de nuevo diagnóstico tras una infección por SARS-CoV-2 y vacunación. Un hombre de 31 años sin antecedentes médicos presentó hematuria macroscópica 24 horas después de la infección por SARS-CoV-2. La hematuria remitió espontáneamente en 3 días. Fue vacunado con dos dosis de CoronaVac (Sinovac) tres meses después de haber sido infectado por el SARS-CoV-2. Luego fue vacunado con la vacuna Pfizer-BioNTech COVID-19, un mes después de la segunda dosis de la vacuna CoronaVac (Sinovac). Presentó hematuria macroscópica y proteinuria no nefrótica 24 horas después de la primera dosis de la vacuna Pfizer-BioNTech COVID-19. Se realizó una biopsia renal que mostró NIgA extracapilar. Comenzó con metilprednisolona y bloqueador del receptor de angiotensina. Los pacientes que reciben vacunas basadas en ARNm demuestran anticuerpos contra el dominio de unión al receptor (RBD) de la proteína S1. De manera similar a la infección natural, debido a la fuerte estimulación de la respuesta inmunitaria de las vacunas basadas en ARNm en comparación con otras vacunas, los pacientes pueden producir anticuerpos de novo, lo que lleva a depósitos de complejos inmunitarios que contienen IgA. Conclusiones: Este caso destaca los efectos inmunológicos de las nuevas vacunas contra el SARS-CoV-2 basadas en ARNm. Los nefrólogos deben estar al tanto de la aparición de hematuria o proteinuria luego de la infección por SARS-CoV-2 o la vacuna contra el SARS CoV-2 basada en ARNm.

ABSTRACT Introduction: Studies have shown that the frequency of acute kidney injury (AKI) increases in patients with COVID-19. Acute tubular necrosis has been reported to be the most common damage in these patients, probably due to impaired renal perfusion. On the other hand, different complex pathophysiological processes may be involved due to viral infection's direct effects on the renin-angiotensin-aldosterone system, the activation of coagulopathy, the cytokine storm, and the activation of the immune system. Many glomerular diseases may be seen in these patients, like anca-associated vasculitis, membranous glomerulonephritis, and IgA nephropathy. Clinical case: We present a newly diagnosed crescentic IgA nephropathy (IgAN) case after a SARS-CoV-2 infection and vaccination. A 31-year-old man with no medical history presented with gross hematuria 24 hours after SARS-CoV-2 infection. Hematuria regressed spontaneously within three days. He was vaccinated with two doses of CoronaVac (Sinovac) three months after he had been infected by SARS-CoV-2. Then he was vaccinated with the Pfizer-BioNTech COVID-19 vaccine one month after the second dose of CoronaVac (Sinovac) vaccine. He presented with gross hematuria and subnephrotic proteinuria 24 hours after the first dose of the Pfizer-BioNTech COVID-19 vaccine. A kidney biopsy was performed and showed crescentic IgA nephropathy (IgAN). He was started on methylprednisolone and angiotensin receptor blocker. Patients who receive mRNA-based vaccines demonstrate robust antibody production against the receptor-binding domain (RBD) of the S1 protein. Similar to natural infection, due to the intense stimulation of immune response from mRNA-based vaccines compared to other vaccines, the patients may produce de novo antibodies, leading to IgA-containing immune-complex deposits. Conclusions: This case highlights the immunological effects of the novel mRNA-based SARS-CoV-2 vaccines. Nephrologists should be aware of new-onset hematuria or proteinuria after SARS-CoV-2 infection or mRNA-based SARS-CoV-2 vaccine.

ABSTRACT Introduction: Rheumatologic diseases are not unusual in general population. This group of patients usually requires hospitalization for various causes and up to a third of them may be admitted to the Intensive Care Unit (ICU). The prognosis can be unfavorable, especially in the presence of renal involvement. Objective: To characterize rheumatologic patients admitted to Intensive Care and determi- ne their mortality. Methods: We conducted a descriptive, retrospective cross-sectional study. Data were collec- ted from medical records of patients with rheumatic diseases admitted to the ICU of the Hospital de Clínicas from January 2021 to December 2022. Results: Twenty-nine patients with rheumatic diseases were admitted in the two years of the study. Twenty-three (79.31%) were women. The median age was 37 years (IQR 22.5). Twenty patients (68.9%) had Systemic Lupus Erythematosus, five (17.2%) rheumatoid arthri- tis and there maining four patients (3.44%) had mixed connective tissue disease, Sjogren‘s Syndrome, Overlap Syndrome and Churg Strauss Vasculitis. The most frequent comorbidi- ties were: arterial hypertension (55%) and nephropathy (41.3%). The causes of admission to the ICU were medical (62%) and surgical (38%). Between medical causes, respiratory failure was the main reason (44%), followed by shock (27%) and intercurrent infections (11.1%). The mean APACHE II (Assessment of Age and Chronic Health) score was 17 ± 10; SOFA on admission (Sequential Organ Failure Assessment): 6 ± 8.5 and the SLEDAI Scale (Systemic Lupus Erythematosus Disease Activity Measure) in lupus patients: 10.6 ± 8.3. Nineteen patients (65.5%) received mechanical ventilation (MV) with a median number of days on MV of 6 (IQR 9). Vasoactive drugs were used by 65.5% and hemodialysis by 17.2%. Methylprednisolone was administered to 10 of the patients (37.9%), in addition 4 of them required cyclophosphamide and 3 immunoglobulins. During hospitalization thirteen patients (44.8%) developed acute renal failure and twelve of them (41.3%) intercurrent in- fections; 6 of them with blood stream Gram Positive isolation. The median length of stay in the ICU was 6 days (IQR: 10) and mortality was 37.9% (eleven patients). Conclusions: In our study, the population was mainly young women with several comorbidities, who were admitted in serious condition to the ICU, most of them for medical reasons. Two-thirds required MV and vasoactive drugs. They presented complications such as acute renal failure and intercurrent infections. Mortality was 38%, only a little higher than that corresponding to the gravity score of income.

RESUMEN Introducción: Las enfermedades reumatológicas no son infrecuentes en la población general. Este grupo de pacientes suele requerir hospitalización por diversas causas y hasta un tercio puede ingresar a la Unidad de Cuidados Intensivos (UCI). El pronóstico puede ser desfavorable, sobretodo en presencia de compromiso renal. Objetivo: Caracterizar a los pacientes reumatológicos ingresados a Cuidados Intensivos y determinar la mortalidad. Métodos: Se realizó un estudio descriptivo, retrospectivo de corte transversal. Los datos fueron obtenidos de las historias clínicas de los pacientes con enfermedades reumatológicas ingresados al Departamento de Cuidados Intensivos Adultos del Hospital de Clínicas desde enero de 2021 hasta diciembre de 2022. Resultados: Veintinueve pacientes con enfermedades reumatológicas ingresaron en los dos años de estudio. Con una mediana de edad de 37 años (RIC 22,5), veintitrés fueron mujeres (79,31%). Tenían lupus eritematoso sistémico veinte pacientes (68,9%); cinco con artritis reumatoide (17,2%) y los cuatros pacientes restantes tenían enfermedad mixta del tejido conectivo, Síndrome de Sjogren, Síndrome de Superposición y Vasculitis de Churg Strauss (3,44%). Las comorbilidades más frecuentes fueron: hipertensión arterial (55%) y nefropatía (41,3%). Las causas de ingreso a la UCI fueron médicas (62%) y quirúrgicas (38%). Entre las médicas, la insuficiencia respiratoria aguda fue el principal motivo (44%), seguido por shock (27%) e infecciones sobre agregadas (11,1%). La puntuación media de APACHE II (Age and Chronic Health Evaluation) fue 17 ± 10; SOFA al ingreso (Sequential Organ Failure Assessment): 6 ± 8,5 y en los pacientes lúpicos la Escala de SLEDAI (Systemic Lupus Erythematosus Disease Activity Measure): 10,6 ± 8,3. Recibieron asistencia respiratoria mecánica (ARM) 19 pacientes (65,5%) con una mediana de días de ARM de 6 (RIC 9). Utilizaron drogas vasoactivas 65,5% y hemodiálisis 17,2%. Se administró metil- prednisolona a 10 de los pacientes (37,9%), además 4 de ellos requirieron ciclofosfamida y 3 inmunoglobulinas. Durante su hospitalización desarrollaron falla renal aguda 13 (44,8%) y sobreinfecciones12 pacientes (41,3%), de los cuales en 6 se aislaron Gram positivos en sangre. La mediana de estancia fue de 6 días (RIC:10) y la mortalidad en UCI fue del 37,9% (11 pacientes). Conclusiones: En nuestro estudio la población fue principalmente de mujeres jóvenes con comorbilidades, que ingresaron graves a terapia intensiva, la mayoría por causas médicas. Dos tercios requirieron ARM y drogas vasoactivas. Presentaron complicaciones como la falla renal aguda y sobreinfecciones bacterianas. La mortalidad fue del 38%, solo un poco mayor que la correspondiente al escore de gravedad del ingreso.

ABSTRACT Membranous nephropathy is a glomerulopathy, which main affected target is the podocyte, and has consequences on the glomerular basement membrane. It is more common in adults, especially over 50 years of age. The clinical presentation is nephrotic syndrome, but many cases can evolve with asymptomatic non-nephrotic proteinuria. The mechanism consists of the deposition of immune complexes in the subepithelial space of the glomerular capillary loop with subsequent activation of the complement system. Great advances in the identification of potential target antigens have occurred in the last twenty years, and the main one is the protein “M-type phospholipase-A2 receptor” (PLA2R) with the circulating anti-PLA2R antibody, which makes it possible to evaluate the activity and prognosis of this nephropathy. This route of injury corresponds to approximately 70% to 80% of cases of membranous nephropathy characterized as primary. In the last 10 years, several other potential target antigens have been identified. This review proposes to present clinical, etiopathogenic and therapeutic aspects of membranous nephropathy in a didactic manner, including cases that occur during kidney transplantation.

RESUMO A nefropatia membranosa é uma glomerulopatia, cujo principal alvo acometido é o podócito, e acarreta consequências na membrana basal glomerular. Tem maior frequência em adultos, principalmente acima dos 50 anos. A apresentação clínica é a síndrome nefrótica, mas muitos casos podem evoluir com proteinúria não nefrótica assintomática. O mecanismo consiste na deposição de complexos imunes no espaço subepitelial da alça capilar glomerular com subsequente ativação do sistema do complemento. Grandes avanços na identificação de potenciais antígenos alvo têm ocorrido nos últimos vinte anos, e o principal é a proteína “M-type phospholipase-A2 receptor” (PLA2R) com o anticorpo anti-PLA2R circulante, o que possibilita avaliar a atividade e o prognóstico dessa nefropatia. Essa via de lesão corresponde aproximadamente a 70% a 80% dos casos da nefropatia membranosa caracterizada como primária. Nos últimos 10 anos vários outros antígenos alvo potenciais têm sido identificados. Esta revisão se propõe a apresentar de modo didático aspectos clínicos, etiopatogênicos e terapêuticos da nefropatia membranosa, incluídos os casos com ocorrência no transplante renal.

ABSTRACT Introduction: Juvenile systemic lupus erythematosus (JSLE) is a multisystem autoimmune disease characterized by the production of autoantibodies and the frequent development of immune complex-mediated glomerulonephritis. Lupus nephritis is a frequent and serious complication of JSLE, has a high associated morbidity rate, and is the cause of end-stage renal failure in many of these patients. IgA Nephropathy represents the most common etiology in the general population and is rarely associated with JSLE. Clinical case: a female adolescent with JSLE who was diagnosed with non-lupus nephritis (IgA nephropathy). Conclusions: The anatomopathological diagnosis is key to establish the prognosis and plan the treatment.

RESUMEN Introducción: El lupus eritematoso sistémico juvenil (LESJ) es una enfermedad autoinmunitaria, multisistémica, caracterizada por la producción de autoanticuerpos y el desarrollo frecuente de glomerulonefritis mediada por inmunocomplejos. La nefritis lúpica es una complicación frecuente y grave del LESJ, con alta morbilidad, siendo causa de insuficiencia renal terminal en muchos de estos pacientes. La nefropatía por IgA representa la etiología más común en la población general y raramente se asocia con LESJ. Caso clínico: adolescente femenino con LESJ en quien se diagnosticó nefritis no lúpica (nefropatía por IgA). Conclusiones: El diagnóstico anatomopatológico es clave para establecer el pronóstico y planificar el tratamiento.

Abstract Background: hypovitaminosis D is frequent in kidney transplant recipient (KTR) patients and is associated with deleterious effects both at the bone and extraosseous levels. Treatment with cholecalciferol is effective for the normalization of 25(OH)D, demonstrating a beneficial effect on the calcium-tropic axis in other populations; however, its effect on the PTH/vitamin D/calcium and FGF23/klotho/phosphorus axis in RTR has not been reported. The aim of this study was to evaluate the effect of normalization of serum 25(OH)D concentrations on the PTH/vitamin D/calcium-FGF23/klotho/phosphorus axis in KTR treated with cholecalciferol, as well as the association between the components of this axis. Methods: a prospective study in 23 KTR with hypovitaminosis D, with evolution from 1 to 12 months post-transplantation, an estimated glomerular filtration rate > 60 mL/min/1.73 m2 and a history of primary nephropathy treated with cholecalciferol, in whom the PTH/vitamin D/calcium and FGF23/klotho/phosphorus axis was evaluated during the state of hypovitaminosis D and at normalization of 25(OH)D. Results: at the normalization of 25(OH)D, a reduction in PTH [103 (58.5-123.9) vs 45.6 (30.1-65.1) pg/mL; p = 0.002] and an increase in serum phosphorus [3.1 (2.3-3.5) vs 3.3 (3-3.6) mg/dL; p = 0.01] were evident, with no differences in calcium, klotho and FGF23 concentrations. The time to achieve normalization of 25(OH)D was 12 weeks (RIC, 4-12), with a dose of 5000 IU/day (RIC, 4000-6000). A positive association between klotho and PTH was corroborated (r = 0.54; p = 0.008; linear regression, β = 0.421; B = 0.004; 95 % CI, 0.003-0.007; p = 0.045). Conclusions: treatment with cholecalciferol is effective for the normalization of 25(OH)D, with a beneficial effect on calcium-phosphotropic metabolism characterized by a reduction in PTH concentration, without significant changes in calcemia or calciuria, as well as an increase in phosphatemia, without modifications in FGF23 or klotho concentrations.

Resumen Introducción: la hipovitaminosis D es frecuente en los receptores de trasplante renal (RTR) y se asocia con efectos deletéreos tanto a nivel óseo como extraóseo. El tratamiento con colecalciferol es eficaz para la normalización de la 25(OH)D, demostrándose un efecto benéfico sobre el eje calciotrópico; sin embargo, su efecto sobre el eje fosfotrópico no se ha reportado. El objetivo de este estudio fue evaluar el efecto de la normalización de las concentraciones séricas de 25(OH)D sobre el eje PTH/vitamina D/calcio-FGF23/klotho/fósforo en RTR tratados con colecalciferol, así como la asociación entre sus componentes. Métodos: estudio prospectivo en 23 RTR con hipovitaminosis D y antecedente de nefropatía primaria tratados con colecalciferol, en quienes se evaluó el eje PTH/vitamina D/calcio y FGF23/klotho/fósforo durante el estado de hipovitaminosis D y a la normalización de la 25(OH)D. Resultados: a la normalización de la 25(OH)D se evidenció una reducción de la PTH [103 (58,5-123,9) vs. 45,6 (30,1-65,1) pg/mL; p = 0,002] y un aumento del fósforo sérico [3,1 (2,3-3,5) vs. 3,3 (3-3,6) mg/dL; p = 0,01], sin diferencias en las concentraciones de calcio, klotho y FGF23. El tiempo para lograr la normalización de la 25(OH)D fue de 12 semanas (4-12), con una dosis de 5000 UI/día (4000-6000). Se corroboró una asociación positiva entre klotho y PTH (r = 0,54; p = 0,008; regresión lineal, β = 0,421; IC 95 %: 0,003-0,007; p = 0,045). Conclusiones: el tratamiento con colecalciferol es eficaz para la normalización de la 25(OH)D con un efecto benéfico sobre el metabolismo calcio-fosfotrópico caracterizado por una reducción de la PTH y un incremento de la fosfatemia, sin modificaciones de calcemia, calciuria, FGF23 o klotho.

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.

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 Background Kidney disease is a rare manifestation of ankylosing spondylitis (AS) and its pathological alterations remain poorly described. The aim of this study was to investigate the clinical presentation and pathological alterations on kidney biopsy of AS patients and review and discuss the current literature on the issue. Methods: We retrospectively studied the clinical presentation and kidney pathological alterations of 15 Caucasian AS patients submitted to kidney biopsy between October 1985 and March 2021. Results: Patients were predominantly male (66.7%) with median age at the time of kideney biopsy of 47 years [IQR 34 - 62]. Median serum creatinine at presentation was 1.3 mg/dL [IQR 0.9 - 3] and most patients also had either proteinuria (85.7%) and/or hematuria (42.8%). The most common indication for kidney biopsy was nephrotic syndrome (33.3%), followed by acute or rapidly progressive kidney injury (20%) and chronic kidney disease of unknown etiology (20%). Chronic interstitial nephritis (CIN) (n=3) and AA amyloidosis (n=3) were the most common diagnosis. Others included IgA nephropathy (IgAN) (n=2), focal segmental glomerulosclerosis (n=2), membranous nephropathy (n=1), and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN)(n=1). Conclusions: We present one of the largest series of biopsy-proven kidney disease in Caucasian AS patients. We found a lower prevalence of IgAN than previously reported in Asian cohorts. We found a higher prevalence of CIN and a lower prevalence of AA amyloidosis than that described in previous series of Caucasian patients. We also present the first case of AS-associated IC-MPGN.

Resumo Antecedentes: A doença renal é uma manifestação rara de espondilite anquilosante (EA) e as suas alterações patológicas permanecem pouco descritas. O objetivo deste estudo foi investigar a apresentação clínica e alterações patológicas na biópsia renal de doentes com EA bem como rever e discutir a literatura atual sobre o assunto. Métodos: Estudamos retrospectivamente a apresentação clínica e alterações patológicas renais de 15 doentes caucasianos com EA submetidos a biópsia renal entre Outubro de 1985 e Março de 2021. Resultados: Os doentes eram predominantemente homens (66,7%) com idade mediana no momento da biópsia de 47 anos [IIQ 34 - 62]. A creatinina sérica mediana na apresentação foi de 1,3 mg/dL [IIQ 0,9 - 3] e a maioria dos pacientes apresentava também proteinúria (85,7%) e/ou hematúria (42,8%). A indicação mais comum para biópsia renal foi a síndrome nefrótica (33,3%), seguida de lesão renal aguda ou rapidamente progressiva (20%) e doença renal crónica de etiologia desconhecida (20%). A Nefrite intersticial crónica (NIC) (n=3) e a amiloidose AA (n=3) foram os diagnósticos mais comuns. Outros incluíram nefropatia por IgA (NIgA) (n=2), glomeruloesclerose segmentar focal (n=2), nefropatia membranosa (n=1) e glomerulonefrite membranoproliferativa mediada por imunocomplexos (GNMP-IC) (n=1). Conclusões: Apresentamos uma das maiores séries de doenças renais comprovadas por biópsia em doentes caucasianos com EA. Encontramos uma prevalência de NIgA menor do que a relatada anteriormente em coortes asiáticas. Encontramos uma maior prevalência de NIC e uma prevalência menor de amiloidose AA do que a descrita em séries anteriores de pacientes caucasianos. Também apresentamos o primeiro caso de GNMP-IC associada à EA.

Resumen La nefropatía obstructiva se considera una manifestación inusual en las vasculitis ANCA. Se presenta el caso de un masculino de 38 años, con granulomatosis con poliangitis e hidronefrosis unilateral, y revisión de la literatura. Masculino de 38 años, sano, quien consulta por cuadro subagudo de odinofagia, síntomas constitucionales y lesión renal aguda anúrica. Inicialmente con hallazgo de hidronefrosis izquierda, manejado como nefropatía obstructiva, que eventualmente desarrolla hemorragia alveolar difusa, distrés respiratorio y fallece debido a un síndrome de distrés respiratorio agudo severo refractario asociado a su granulomatosis con poliangitis. La nefropatía obstructiva es una manifestación inusual de las vasculitis ANCA asociadas. Es importante la sospecha diagnóstica en estos cuadros multisistémicos para no dilatar el tratamiento inmunosupresor conjunto con el resto de las terapias requeridas.

Abstract Obstructive nephropathy is considered an unusual presentation in ANCA-associated vasculitis. The following case describes a 38-year-old male with granulomatosis with polyangiitis and unilateral hydronephrosis, as well as a literature review. A 38-year-old male with an unremarkable medical background presents with a 3-week history of odynophagia, constitutional symptoms and anuric kidney injury. Initially managed as an obstructive nephropathy due to a left hydronephrosis finding, the patient eventually develops a diffuse alveolar hemorrhage, acute respiratory distress and perishes due to granulomatosis with polyangiitis. Obstructive nephropathy is an unusual manifestation of ANCA-associated vasculitis. Diagnostic suspicion is important in these multisystem pictures so as not to delay immunosuppressive treatment together with the rest of the required therapies.