title: Acute focal bacterial nephritis, pyonephrosis and renal abscess in children.
abstract: OBJECTIVE
  Acute focal bacterial nephritis (AFBN), renal abscess and pyonephrosis are uncommon and not fully addressed forms of urinary tract infection (UTI) which may be underdiagnosed without the appropriate imaging studies. Here, we review the characteristics and outcome of these renal entities in children managed at a single medial centre.
  
  
  METHODS
  The medical files of all children hospitalized for episodes of AFBN, renal abscess and pyonephrosis during a 10-year period (2003-2012) were reviewed.
  
  
  RESULTS
  Among the 602 children hospitalized for UTI, 21 presented with AFBN, one with abscess and three with pyonephrosis. All 25 children (13 girls), ranging in age from 0.06 to 13.4 years, were admitted with fever and an impaired clinical condition, and 18 had urological abnormalities. More than one lesion, often of different types, were identified in 11 episodes. Urine cultures from 13 episodes grew non-Escherichia coli pathogens and those from two episodes were negative. Antibiotics were administered for 14-60 days, and emergency surgery was required in three cases. During follow-up, 13 patients underwent corrective surgery. Permanent renal lesions were identified in 16 patients.
  
  
  CONCLUSIONS
  AFBN, renal abscess and pyonephrosis should be suspected in children with severe presentation and urological history. Appropriate imaging is crucial for management planning. Prognosis is often guarded despite appropriate treatment. Based on the results of this study we propose a management algorithm.
authors.affiliation: Department of Paediatrics, Heraklion University Hospital, POB 2208, Heraklion, 71003, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Bitsori
authors.affiliation: Department of Radiology, Heraklion University Hospital, Heraklion, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Raissaki
authors.affiliation: Department of Clinical Microbiology, Heraklion University Hospital, Heraklion, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Maraki
authors.affiliation: Department of Paediatrics, Heraklion University Hospital, POB 2208, Heraklion, 71003, Greece. emmgalan@med.uoc.gr.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Galanakis
mesh_terms: D000038:Abscess / Q000175:diagnosis* / Q000628:therapy; D000293:Adolescent; D001424:Bacterial Infections / Q000150:complications; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007674:Kidney Diseases / Q000175:diagnosis / Q000628:therapy; D008297:Male; D009393:Nephritis / Q000175:diagnosis* / Q000628:therapy; D053018:Pyonephrosis / Q000175:diagnosis* / Q000628:therapy; D012189:Retrospective Studies; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy
keywords: Acute focal bacterial nephritis; Magnetic resonance urography; Non-E. coli pathogens; Pyonephrosis; Renal abscess