title: Thrombocytosis accompanying urinary tract infection suggests obstruction or abscess.
abstract: OBJECTIVE
  Reactive thrombocytosis can be found in patients with different types of infections, including upper urinary tract infection (UTI). In this study, we determined whether thrombocytosis in patients with upper UTI is a random phenomenon or is related to complications associated with the UTI.
  
  
  METHODS
  We reviewed the charts of patients admitted to the urology department with a diagnosis of upper UTI and thrombocytosis (platelet count >500 x 10(9)/L) in the years 1991 to 2003 (study group). Patients admitted to the urology department in the year 2003 with a diagnosis of upper UTI without thrombocytosis served as the control group.
  
  
  RESULTS
  The study group consisted of 83 patients admitted to the urology department with a diagnosis of upper UTI and thrombocytosis (mean platelet count, 593 x 10(9)/L; SD, 88; range, 501-949). The control group consisted of 99 patients. An obstructed kidney was found in 54 patients (65%) of the study group and in 18 patients (18%) of the control group (P < .00001). Perinephric abscess was found in 7 patients (8%) in the study group compared with none in the control group (P < .003). The positive predictive value of thrombocytosis for kidney obstruction or abscess in patients with upper UTI was 71%. Nephrectomy of a nonfunctioning infected kidney was required in 6 patients of the study group (7%) and 2 of the control group (P = .14). In 26 patients (31%) of the study group, the finding of thrombocytosis preceded the diagnosis of the complication (by a median period of 3 days). In these patients, thrombocytosis was essentially an early marker for the complication.
  
  
  CONCLUSIONS
  Thrombocytosis in a patient with upper UTI is not a random phenomenon. It is a marker of kidney obstruction or perinephric abscess. The finding of thrombocytosis in a patient with upper UTI should alert the attending physician to actively search for these complications. Cross-sectional imaging study (abdominal ultrasonography or computed tomography) should be performed.
authors.affiliation: Department of Urology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. ong1000@netvision.net.il
authors.forename: Ofer N
authors.initials: ON
authors.lastname: Gofrit
authors.forename: Amos
authors.initials: A
authors.lastname: Shapiro
authors.forename: Deborah
authors.initials: D
authors.lastname: Rund
authors.forename: Antony G
authors.initials: AG
authors.lastname: Verstandig
authors.forename: Ezekiel H
authors.initials: EH
authors.lastname: Landau
authors.forename: Ran
authors.initials: R
authors.lastname: Katz
authors.forename: Ofer Z
authors.initials: OZ
authors.lastname: Shenfeld
authors.forename: Yehoshuah
authors.initials: Y
authors.lastname: Gdor
authors.forename: Dov
authors.initials: D
authors.lastname: Pode
mesh_terms: D000038:Abscess / Q000097:blood / Q000150:complications*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000097:blood / Q000150:complications*; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000150:complications*; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000150:complications*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D013922:Thrombocytosis / Q000209:etiology*; D014552:Urinary Tract Infections / Q000097:blood / Q000150:complications*