title: Isolated hematuria and sterile pyuria may indicate systemic lupus erythematosus activity.
abstract: OBJECTIVE
  To identify patients presenting with isolated hematuria and/or pyuria in the absence of other systemic lupus erythematosus (SLE) disease activity, describe their demographics, and determine whether they present with evidence of SLE flare in a period adjacent to the presentation.
  
  
  METHODS
  We studied patients followed at the University of Toronto Lupus Clinic between 1970 and 2012. An episode of isolated hematuria (> 5 red blood cells per high power field) and/or pyuria (> 5 white blood cells per high power field) was defined as 2 consecutive visits with these findings in the absence of other concurrent SLE manifestations such as proteinuria, casts, or azotemia. We then excluded patients whose findings might be explained by urinary tract infections, menstruation, urolithiasis, and/or anticoagulation. Only patients presenting with no other SLE disease activity were included.
  
  
  RESULTS
  Isolated hematuria and/or pyuria were identified in 49 patients, of whom 17 were excluded according to the criteria above, leaving 32. Twenty-four patients had another renal manifestation 1 year before and/or after the occurrence; 27 had a non-renal manifestation 1 year before and/or after the occurrence; 3 patients had a biopsy in the same time frame, all with evidence of active lupus nephritis. Therefore the majority of patients with an occurrence of isolated hematuria and/or pyuria had evidence of renal or other non-renal SLE disease activity at a time adjacent to this presentation.
  
  
  CONCLUSIONS
  Although not proven, our results suggest that these manifestations were associated with SLE activity, either before or after the episode, and therefore may represent a phase of active disease.
authors.affiliation: From the University of Toronto Lupus Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada.Jonathan Y.C. Ding was the recipient of the Canadian Rheumatology Association Roche Summer Studentship.J.Y.C. Ding, BSc, Medical Student, University of Toronto; D. Ibañez, MSc, Biostatistician, Centre for Prognosis Studies in the Rheumatic Diseases; D.D. Gladman, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto; M.B. Urowitz, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto.
authors.forename: Jonathan Y C
authors.initials: JY
authors.lastname: Ding
authors.affiliation: From the University of Toronto Lupus Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada.Jonathan Y.C. Ding was the recipient of the Canadian Rheumatology Association Roche Summer Studentship.J.Y.C. Ding, BSc, Medical Student, University of Toronto; D. Ibañez, MSc, Biostatistician, Centre for Prognosis Studies in the Rheumatic Diseases; D.D. Gladman, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto; M.B. Urowitz, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto.
authors.forename: Dominique
authors.initials: D
authors.lastname: Ibañez
authors.affiliation: From the University of Toronto Lupus Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada.Jonathan Y.C. Ding was the recipient of the Canadian Rheumatology Association Roche Summer Studentship.J.Y.C. Ding, BSc, Medical Student, University of Toronto; D. Ibañez, MSc, Biostatistician, Centre for Prognosis Studies in the Rheumatic Diseases; D.D. Gladman, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto; M.B. Urowitz, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto.
authors.forename: Dafna D
authors.initials: DD
authors.lastname: Gladman
authors.affiliation: From the University of Toronto Lupus Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada.Jonathan Y.C. Ding was the recipient of the Canadian Rheumatology Association Roche Summer Studentship.J.Y.C. Ding, BSc, Medical Student, University of Toronto; D. Ibañez, MSc, Biostatistician, Centre for Prognosis Studies in the Rheumatic Diseases; D.D. Gladman, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto; M.B. Urowitz, MD, FRCPC, Professor of Medicine, Senior Scientist, University of Toronto. m.urowitz@utoronto.ca.
authors.forename: Murray B
authors.initials: MB
authors.lastname: Urowitz
mesh_terms: D000328:Adult; D005260:Female; D006417:Hematuria / Q000209:etiology* / Q000473:pathology; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011776:Pyuria / Q000209:etiology* / Q000473:pathology; D055815:Young Adult
keywords: HEMATURIA; LUPUS NEPHRITIS; PYURIA; SYSTEMIC LUPUS ERYTHEMATOSUS