Introduction

Urinary tract infection (UTI) is a common infection in childhood. It occurs in approximately 7 % of infants with fever and 7.8% of both febrile and afebrile older children with urinary symptoms¹. In newborn infants, it has been shown that fever and total white blood cell count lack sensitivity in identifying UTI². Urine culture is recommended in febrile young infants². Therefore, we set out to determine whether peripheral blood tests correlate with urinary culture. The link between blood finding and the LOS in children and adolescents with UTI has also been examined.

 

Methods

We studied 135 patients admitted to paediatric ward with UTI. All patients underwent blood tests including serum WCC, neutrophil count and CRP values. The link between urinary culture and serum WCC, normal neutrophil count and CRP values was investigated. The relationship between peripheral blood findings and the LOS was also examined.

 

Results

In this group of patients, mean (SD) age 3.0 (4.1) years. Mean (SD) LOS was 2.5 (1.3) days. In these patients, Escherichia coli (E. coli) was documented in 126 (93.3%) patients, Enterobacter [2 (1.5%)], Klebsiella [2 (1.5%)], Proteus [1 (0.7%)], Pseudomonas [2 (1.5%)], Staphylococcus aureus 1 (0.7%)] and Streptococcus pyogenes [1 (0.7%)]. Blood culture was performed in 126 of 135 patients (93.3%), of whom123 (91.1%) had negative blood culture; 3 (2.2%) patients experienced E. coli in both urine and blood culture.

Of 135 patients, 121 (89.6%) had > 50 WCC/cm³ in urine and 13 (9.6%) experienced 10- 50 WCC/cm³. However one patients had < 10 WCC/cm³ in urine, this was 10- 50 WCC/cm³ in repeated sample on the same day. In this group of patients, 95 of 135 (70.4%) experienced leukocytosis [mean (SD) serum WCC 17.41 (6.9) X10⁹/l] and 102 of 135 (75.6%)] had neutrophilia [mean (SD) neutrophil values 10.9 (6.0)] X10⁹/l. The majority of patients [118 (87.4%)] experienced CRP > 5 mg/L [mean (SD) 69.4 (65.7)]. Of 135 patients, 16 (11.9%) had combined normal serum WCC, normal neutrophil count and CRP < 5 mg/L. In this group of patients, no link has been reported between LOS and serum WCC, serum neutrophil values, E. coli infection or CRP values (p value 0.51, 0.98, 0.87, 0.82, respectively).

In this group of patients, leukocytosis was documented in 89 of 126 (70.6 %) patients with UTI caused by E. coli infection and in 6 of 9 (66.7%) individuals with UTI due to other organisms (p value 0.80). Similarly, neutrophilia was reported in 96 of 126 (76.2%) patients with E. coli infection and in 6 of 9 (66.7%) individuals with other organisms (p value 0.52). Of 135 patients, 111 of 126 (88.1%) with E. coli infection and 6 of 9 (66.7%) with non E. coli infection had CRP values more than 5 mg/L (p value 0.068).

Approximately 1 in 8 patients with UTI have combined normal serum WCC, normal serum neutrophil values and CRP <5 mg/L. The majority of patients (89.6%) with UTI had > 50 WCC/cm³ in urine, however, approximately, 1 in 10 patients with UTI experienced 10-50 WCC/cm³ in urine. In children and adolescents, urine should be tested for UTI in those with clinical signs and symptoms suggested UTI, even in presence of combined normal serum WCC, normal neutrophil and CRP <5 mg/L.

 

Conflict of Interest:

The authors report no conflicts of interest associated with this article

 

Correspondence:

Montasser Nadeem, Paediatric consultant, NCH, Tallaght, Dublin 24

Email: [email protected]

 

 

References

1. Shaikh N, Morone NE, Bost JE, Farrell MH. Prevalence of urinary tract infection in childhood: a meta-analysis. Pediatr Infect Dis J 2008; 27:302.

2. Bonadio W1, Maida G. Urinary tract infection in outpatient febrile infants younger than 30 days of age: a 10-year evaluation. Pediatr Infect Dis J. 2014;33(4):342-4.

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