Síndrome hemolítico urémico atípico secundario a infección neumocócica invasiva / Atypical hemolytic uremic syndrome secondary to invasive pneumococcal infection

Introducción: El síndrome hemolítico urémico (SHU) es una patología infrecuente y grave en pediatría. Se clasifica en SHU “típico” o “atípico” en función de su etiopatogenia. Se caracteriza por la triada: anemia hemolítica microangiopática, trombopenia e insuficiencia renal, siendo característica la presencia de esquistocitos en sangre periférica. Caso clínico: Varón de 13 meses sin antecedentes personales ni familiares de interés. Consulta por fiebre alta de 5 días, sintomatología catarral, astenia, ictericia, vómitos, diarrea y oliguria. Exploración física: mal estado general, HTA estadio I, coloración pálido-ictérica, taquicardia, polipnea, hipoventilación basal pulmonar derecha y edemas pretibiales. Pruebas complementarias: analítica sanguínea: Hb 8,4 g/dl, 20.000/mm3 plaquetas, leucocitosis con desviación izquierda, urea 186 mg/dl, creatinina 3,27 mg/dl [FGe(Schwartz_2009): 10,5 ml/min/1,73 m2], PCR, PCT y LDH elevadas, haptoglobina baja. Sistemático/sedimento urinario: proteinuria 0,95 mg/mg, hematuria glomerular. Frotis sangre periférica: 5% Esquistocitos. Test de Coombs directo: positivo. Radiografía torácica: condensación basal pulmonar derecha. Ante presencia de la triada: anemia hemolítica microangiopática, trombopenia e insuficiencia renal es diagnosticado de SHU en contexto de neumonía, iniciando tratamiento de soporte en UCIP, furosemida y antibioterapia empírica. Actividad ADAMTS13 y determinación de Shiga-toxina: negativas. Hemocultivo: + Streptococcus pneumoniae. Estudio de complemento normal. Empeoramiento funcional renal, precisando hemodialfiltración veno-venosa continua y administración de eculizumab. Presentó mejoría progresiva y alta con diagnóstico final de SHU secundario a sepsis neumocócica. Seguimiento en consulta de Nefrología Pediátrica, actualmente padece enfermedad renal crónica en estadio G3A2. Conclusiones: Es importante realizar un diagnóstico y tratamiento precoces para mejorar su pronóstico vital y funcional renal, estableciendo protocolos de manejo inicial y seguimiento multidisciplinar.(AU)

Introduction. Hemolytic uremic syndrome (HUS) is a rare and serious pathology in pediatrics. It is classified as “typical” or “atypical” HUS depending on its etiopathogenesis. It is characterized by the triad: microangiopathic hemolytic anemia, thrombopenia and renal failure, with the presence of schistocytes in peripheral blood being characteristic. Case report: 13-month-old male with no personal or family history of interest. Consultation due to high fever for 5 days, catarrhal symptoms, asthenia, jaundice, vomiting, diarrhea and oliguria. Physical examination: Poor general condition, Stage-I arterial hypertension, pale-jaundiced muco-cutaneous, tachycardia, polypnea, hypoventilation at the right lung base and pretibial edema. Complementary tests: Blood analysis: Hb 8.4 g/dl, platelets 20,000/mm3, leukocytosis with left deviation, urea 186mg/dl, creatinine 3.27 mg/dl [eGFR(Schwartz_2009): 10.5 ml/min/1.73 m2], elevated CRP, PCT and LDH, low haptoglobin. Systemic/urinary sediment: proteinuria 0.95 mg/mg, glomerular hematuria. Peripheral blood smear: 5% Schistocytes. Direct Coombs test: positive. Chest x-ray: right pulmonary basal condensation. In the presence of the triad: microangiopathic hemolytic anemia, thrombopenia and renal failure, HUS was diagnosed in the context of pneumonia, initiating supportive treatment in the PICU, furosemide and empirical antibiotic therapy. ADAMTS13 activity and Shiga-toxin determination: negative. Blood culture: + Streptococcus pneumoniae. Worsening renal function, requiring continuous veno-venous hemodiafiltration and administration of eculizumab. He showed progressive improvement and was discharged with diagnosis of HUS secondary to pneumococcal sepsis. Follow-up in Pediatric Nephrology consultation, currently suffering from chronic kidney disease (stage G3A2). Conclusions: It is important to carry out early diagnosis and treatment to improve vital and renal functional prognosis, establishing initial management protocols and multidisciplinary follow-up.(AU)

[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.