[Focal segmental glomerulosclerosis related to BK virus in a child with nephrotic syndrome. A case report]. / Glomerulopatía colapsante asociada a virus BK en un niño con síndrome nefrótico idiopático. Informe de un caso.

BACKGROUND: focal segmental glomerulosclerosis (FSGS) is observed in about 10 % of children with idiopathic nephrotic syndrome; this disorder is usually resistant to corticoid therapy. In the last few years, five histological types of FSGS have been recognized; the collapsing nephropathy type is characterized by a rapid evolution to chronic renal failure. CLINICAL CASE: a four-year-old boy presented with an irrelevant past history; eight months before admission he developed idiopathic nephrotic syndrome. He was treated with steroids without improvement, and a renal biopsy was performed in which minimal glomerular changes were found. Despite combined immunosuppressive treatment, he developed renal failure, septic shock and death. Collapsing nephropathy was demonstrated by immunohistochemistry, light and electron microscopy; renal new human papovirus (BK) infection was also found in the postmortem study. CONCLUSIONS: collapsing nephropathy is an aggressive disorder resistant to immunosuppressive treatment, as occurred in our patient. Although some viral diseases have been associated with collapsing nephropathy, to our knowledge, BK infection has not been previously described in those patients.

Aplasia adquirida de la serie roja por infección por parvovirus B19 en una adolescente con trasplante renal / Pure red cell aplasia caused by parvovirus B19 infection in a female adolescent after renal transplantation

Introducción. El parvovirus B19 ha sido identificado como el agente etiológico del eritema infeccioso o quinta enfermedad, de las crisis aplásicas transitorias en niños con enfermedades hemolíticas, y de la aplasia adquirida de la serie roja en pacientes inmunocomprometidos, incluyendo los pacientes que reciben un trasplante de un órgano sólido o de médula ósea. Caso clínico. Adolescente femenina de 15 años de edad con insuficiencia renal crónica terminal de causa desconocida, quien recibió trasplante renal de donador cadavérico. Dos meses después del trasplante presentó anemia grave arregenerativa que requirió transfusiones de sangre, sin responder a la suspensión del tratamiento con mofetil micofenolato. Aunque la investigación de anticuerpos IgM e IgG contra el parvovirus B19 fue negativa, se encontró positividad en la investigación del DNA viral por medio de la prueba de reacción en cadena de la polimerasa. El estudio de la médula ósea mostró el patrón característico de pronormoblastos con cambios megaloblásticos y vacuolas en el citoplasma y detención en la maduración a nivel de los normoblastos. El tratamiento con inmunoglobulina intravenosa por 10 días se acompañó de respuesta reticulocitaria adecuada y corrección de la anemia. Conclusiones. En los pacientes con trasplante renal y anemia grave arregenerativa debe investigarse la presencia de parvovirus B19, preferentemente a través de la prueba de reacción en cadena de la polimerasa. El tratamiento con inmunoglobulina intravenosa es el más adecuado para eliminar la infección y corregir el cuadro anémico.

Introduction. Parvovirus B19 can present in children as erythema infectious rash, aplastic anemia in patients with hemolytic diseases and pure red cell aplasia in immunocompromised patients, such as in bone marrow and solid organ transplant recipients. Case report. A 15-year-old female with end stage renal disease of unknown origin received a renal transplant from a cadaveric donor. Two months after the transplant, she presented severe arregenerative anemia despite mofetil micofenolate withdrawal and required blood transfusions. IgM and IgG titers for parvovirus B19 were negative, but DNA polymerase chain reaction was positive. Bone marrow showed the characteristic pattern of pronormoblasts with megaloblastic changes and cytoplasmic vaculations, with maturation arrest at normoblast level. The patient was treated with intravenous immunoglobulin for 10 days with adequate reticulocyte response and resolution of her anemia. Conclusions. Parvovirus B19 should be investigated in renal transplant patients with severe arregenerative anemia; DNA polymerase reaction test is the diagnostic test of choice. Treatment with intravenous immunoglobulin is the recommended therapy for the control and elimination of the infection and anemia resolution.