title: [Focal segmental glomerulosclerosis related to BK virus in a child with nephrotic syndrome. A case report].
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Departamento de Nefrología, Hospital Infantil de México "Federico Gómez," Distrito Federal, México.
authors.forename: Luis
authors.initials: L
authors.lastname: Velásquez-Jones
authors.forename: Lillian
authors.initials: L
authors.lastname: Romero-Silva
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ramón-García
authors.forename: Martha
authors.initials: M
authors.lastname: Portillo-Carrillo
authors.forename: Saúl
authors.initials: S
authors.lastname: Valverde-Rosas
authors.forename: Benjamín
authors.initials: B
authors.lastname: Romero-Navarro
authors.forename: Pedro
authors.initials: P
authors.lastname: Valencia-Mayoral
mesh_terms: D001739:BK Virus; D002675:Child, Preschool; D005923:Glomerulosclerosis, Focal Segmental / Q000821:virology*; D006801:Humans; D008297:Male; D009404:Nephrotic Syndrome / Q000150:complications*; D027601:Polyomavirus Infections / Q000150:complications*; D014412:Tumor Virus Infections / Q000150:complications*