OBJECTIVES:

To determine the prevalence of and to identify risk factors for sterile cerebrospinal fluid (CSF) pleocytosis in a large sample of febrile young infants with urinary tract infections (UTIs) and to describe the clinical courses of those patients.

DESIGN:

Secondary analysis of a multicenter retrospective review.

SETTING:

Emergency departments of 20 North American hospitals. Patients Infants aged 29 to 60 days with temperatures of 38.0°C or higher and culture-proven UTIs who underwent a nontraumatic lumbar puncture from January 1, 1995, through May 31, 2006.

MAIN EXPOSURE:

Febrile UTI.

OUTCOME MEASURES:

Presence of sterile CSF pleocytosis defined as CSF white blood cell count of 10/μL or higher in the absence of bacterial meningitis and clinical course and treatment (ie, presence of adverse events, time to defervescence, duration of parenteral antibiotic treatment, and length of hospitalization).

RESULTS:

A total of 214 of 1190 infants had sterile CSF pleocytosis (18.0%; 95% confidence interval, 15.9%-20.3%). Only the peripheral white blood cell count was independently associated with sterile CSF pleocytosis, and patients with a peripheral white blood cell count of 15/μL or higher had twice the odds of having sterile CSF pleocytosis (odds ratio, 1.97; 95% confidence interval, 1.32-2.94; P = .001). In the subset of patients at very low risk for adverse events (ie, not clinically ill in the emergency department and without a high-risk medical history), patients with and without sterile CSF pleocytosis had similar clinical courses; however, patients with CSF pleocytosis had longer parenteral antibiotics courses (median length, 4 days [interquartile range, 3-6 days] vs 3 days [interquartile range, 3-5 days]) (P = .04).

CONCLUSION:

Sterile CSF pleocytosis occurs in 18% of young infants with UTIs. Patients with CSF pleocytosis at very low risk for adverse events may not require longer treatment with antibiotics.