Diagnostic performance of urine dipstick testing in children with suspected UTI: a systematic review of relationship with age and comparison with microscopy

Background: Prompt diagnosis of urinary tract infection (UTI) in children is needed to initiate treatment but is difficult to establish without urine testing, and reliance on culture leads to delay. Urine dipsticks are often used as an alternative to microscopy, although the diagnostic performance of dipsticks at different ages has not been established systematically. Method: Studies comparing urine dipstick testing in infants versus older children and urine dipstick versus microscopy were systematically searched and reviewed. Meta‐analysis of available studies was conducted. Results: Six studies addressed these questions. The results of meta‐analysis showed that the performance of urine dipstick testing was significantly less in the younger children when compared with older children (p < 0.01). Positive likelihood ratio (LR) of both nitrite and leucocyte positive 38.54 [95% confidence interval (CI) 22.49–65.31], negative LR for both negative 0.13 (95% CI 0.07–0.25) are reasonably good, and those for young infants are less reliable [positive LR 7.62 (95% CI 0.95–51.85) and negative LR 0.34 (95% CI 0.66–0.15)]. Comparing microscopy and urine dipstick testing, using bacterial colony count on urine culture showed no significant difference between the two methods. Conclusion: Urine dipstick testing is more effective for diagnosis of UTI in children over 2 years than for younger children.     

A head-to-head comparison: "clean-void" bag versus catheter urinalysis in the diagnosis of urinary tract infection in young children

OBJECTIVE: To compare the validity of the urinalysis on clean-voided bag versus catheter urine specimens using the catheter culture as the "gold" standard. STUDY DESIGN: This is a cross-sectional study of 303 nontoilet-trained children under age 3 years at risk for urinary tract infection (UTI) who presented to a children's hospital emergency department. Paired bag and catheter specimens were obtained from each child and sent for dipstick and microscopic urinalysis. Sensitivity and specificity were compared using McNemar's chi2 test for paired specimens and the ordinary chi2 test for unpaired comparisons. RESULTS: The bag dipstick was more sensitive than the catheter dipstick for the entire study sample: 0.85 (95% confidence interval [CI]=0.78 to 0.93) versus 0.71 (95% CI=0.61 to 0.81), respectively. Both bag and catheter dipstick sensitivities were lower in infants < or =90 days old (0.69 [95% CI=0.44 to 0.94] and 0.46 [95% CI=0.19 to 0.73], respectively) than in infants >90 days old (0.88 [95% CI=0.81 to 0.96] and 0.75 [95% CI=0.65 to 0.86], respectively). Specificity was consistently lower for the bag specimens than for the catheter specimens: 0.62 (95% CI=0.56 to 0.69) versus 0.97 (95% CI=0.95 to 0.99), respectively. CONCLUSIONS: Urine collection methods alter the diagnostic validity of urinalysis. These differences have important implications for the diagnostic and therapeutic management of children with suspected UTI.     

Sterile cerebrospinal fluid pleocytosis in young infants with urinary tract infection

BACKGROUND: During the first 3 months of life febrile infants are subjected to sepsis workup, which includes evaluation for urinary tract infection (UTI) and meningitis. We investigated the existence of concomitant meningeal inflammation in infants younger than 90 days old affected with UTI. METHODS: We reviewed the medical records of all infants younger than 90 days old, who were hospitalized for UTI from January, 1990, to January, 2001. For the diagnosis of sterile cerebrospinal fluid (CSF) pleocytosis, the child's age, the CSF total white blood cell (WBC) count and the CSF absolute neutrophil count were taken into consideration. CSF pleocytosis was defined as the presence of > or = 35, > or = 21 and > or = 15 WBC/mm3 of CSF during the first, second and third month of life, respectively. The CSF Gram-stained smear, latex agglutination test and bacterial culture were negative. RESULTS: Sterile CSF pleocytosis was found in 15 (12.8%) of 117 infants with UTI who had had a lumbar puncture included in their initial laboratory evaluation. The 15 infants had a median age +/- semiinterquartile range of 40 +/- 25 days (range, 4 to 75 days). In these infants the median CSF WBC count +/- semiinterquartile range was 55 +/- 125/mm3 (range, 21 to 1,270/mm3). CONCLUSIONS: Sterile CSF pleocytosis was found in 12.8% of infants younger than 90 days old with UTI. The pathogenesis of this meningeal inflammation is not fully understood. Although bacterial infection of the subarachnoid space, with low bacterial seeding, cannot be excluded, at least in some cases, it is possible that CSF pleocytosis in some of the infants with UTI is mainly caused by the endotoxin of Gram-negative or other inflammation-inducing molecules of Gram-positive urine pathogens.     

Test characteristics and interpretation of cerebrospinal fluid gram stain in children

BACKGROUND: Few data exist regarding the test characteristics of cerebrospinal fluid (CSF) Gram stain among children at risk for bacterial meningitis, especially the rate of false positive Gram stain. METHODS: We conducted a retrospective cohort study of children seen in the emergency department of Children's Hospital Boston who had CSF obtained between December 1992 and September 2005. Patients who had ventricular shunts, as well as those who received antibiotics before CSF was obtained were excluded. Test characteristics of CSF Gram stain were assessed using CSF culture as the criterion standard. Patients were considered to have bacterial meningitis if there was either: (1) growth of a pathogen, or (2) growth of a possible pathogen noted on the final CSF culture report and the patient was treated with a course of parenteral antibiotics for 7 days or more without other indication. RESULTS: A total of 17,569 eligible CSF specimens were collected among 16,036 patients during the 13-year study period. The median age of study subjects was 74 days. Seventy CSF specimens (0.4%) had organisms detected on Gram stain. The overall sensitivity of Gram stain to detect bacterial meningitis was 67% [42 of 63; 95% confidence interval (CI): 54-78] with a positive predictive value of 60% (42 of 70; 95% CI: 48-71). Most patients without bacterial meningitis have negative Gram stain [specificity 99.9% (17,478 of 17,506; 95% CI: 99.8-99.9)] with a negative predictive value of 99.9 (17,478 of 17,499; 95% CI: 99.8-99.9). CONCLUSIONS: CSF Gram stain is appropriately used by physicians in risk stratification for the diagnosis and empiric treatment of bacterial meningitis in children. Although a positive Gram stain result greatly increases the likelihood of bacterial meningitis; the result may be because of contamination or misinterpretation in 40% of cases and should not, by itself, result in a full treatment course for bacterial meningitis.     

Comparison of hemocytometer leukocyte counts and standard urinalyses for predicting urinary tract infections in febrile infants

OBJECTIVES: To compare the accuracy of standard and hemocytometer white blood cell (WBC) counts and urinalyses for predicting urinary tract infection (UTI) in febrile infants. METHODS: Enrolled were 230 febrile infants < 12 months of age. All urine specimens were obtained by suprapubic bladder aspiration and microscopically analyzed by the standard urinalysis (UA) and by hemocytometer WBC counts simultaneously, and quantitative urine cultures were performed. Receiver-operating characteristic (ROC) curves were constructed for each method of UA. The optimal cutoff point of the UA test in predicting UTI was determined by ROC analysis. RESULTS: There were 37 positive urine cultures of at least 1,000 CFU/ml. Of these 37 patients, 9 females and 28 males, 1 had a positive blood culture (Escherichia coli). Thirty (81%) of the positive urine cultures had a bacterial colony count > or = 100,000 colony-forming units/ml, whereas the remaining had between 1,000 and 50,000 colony-forming units/ml. The area under the ROC curve for standard UA was 0.790 +/- 0.053, compared with 0.900 +/- 0.039 for hemocytometer WBC counts (P < 0.05). For hemocytometer WBC counts, the presence of < or =10 WBC/microl appeared to be the most useful cutoff point, yielding a high sensitivity (83.8%) and specificity (89.6%). Standard UA, with a cutoff point of 5 WBC/high power field, had a lower sensitivity (64.9%) and similar specificity (88.1%). The hemocytometer WBC counts showed significantly greater sensitivity and positive predictive value (83.8 and 60.8%, respectively) than the standard urinalysis (64.9 and 51.1%, respectively) (P < 0.05). The accuracy, specificity and likelihood ratio of hemocytometer WBC counts were also greater than that of standard UA (88.7, 89.6 and 8.08% vs. 84.3, 88.1 and 5.44%). CONCLUSION: Hemocytometer WBC counts provide more valid and precise prediction of UTI in febrile infants than standard UA. The presence of > or =10 WBC/microl in suprapubic aspiration specimens is the optimum cutoff value for identifying febrile infants for whom urine culture is warranted.     

A comparison of the initial to the later stream urine in children catheterized to evaluate for a urinary tract infection

BACKGROUND: To avoid potential contamination, it is recommended that the first few drops of urine be discarded when obtaining a catheterized urine sample from a child being evaluated for a urinary tract infection (UTI). The existing evidence to make such a recommendation is scant. Our goal, therefore, was to determine whether the urinalysis, Gram stain, and culture results were significantly different from the initial and later urine samples collected from catheterized children. METHODS: A prospective diagnostic discrimination between early and later urine samples was conducted on a convenience sample of pediatric patients being evaluated for a UTI in an urban emergency department. Results of the urinalysis, Gram stain, and quantitative culture were compared between the early and later stream urine samples. RESULTS: Data from 86 children were analyzed. Four of 80 patients had a false identification of low colony count bacteruria from the early but not from the later stream. For patients with negative cultures, the early stream was also more likely to falsely identify > or =5 wbc/hpf (P<0.01) or bacteruria (P<0.05) on urinalysis than the later stream. CONCLUSIONS: There is a small but potentially meaningful contamination of the early stream urine compared with the later stream in young children catheterized to evaluate for a urinary tract infection.     

Test characteristics of the respiratory syncytial virus enzyme-linked immunoabsorbent assay in febrile infants < or = 60 days of age

The test characteristics of rapid tests for respiratory syncytial virus (RSV) in infants may differ from older children secondary to a lower likelihood of previous illness with RSV. Our main goal was to establish the test characteristics of the RSV Abbott Testpack (TP) enzyme-linked immunoabsorbent assay (EIA) in febrile infants < or = 60 days of age. Our secondary goal was to determine the likelihood of RSV given a particular clinical syndrome and a negative or positive EIA. A prospective sample of infants with a temperature > or = 38.0 degrees C was evaluated during 2 successive RSV seasons. Conventional tissue and shell vial viral cultures were utilized as the reference standard. The RSV Abbott Testpack EIA had a sensitivity of 75% (95% CI 60-90%), a specificity of 98% (95% CI 96-100%), a positive predictive value of 89% (95% CI 77-100%), a negative predictive value of 95% (95% CI 91-98%), a likelihood ratio for a positive test of 35.5 (95% CI 11.4-110.7), and a likelihood ratio for a negative test of 0.26 (95% CI 0.14-0.47). Even with a negative EIA, patients with lower and upper respiratory tract illness still had a 22.3% and 5.5% chance of harboring RSV, respectively. The RSV Abbott Testpack is a useful diagnostic tool in the detection of RSV in febrile infants but has limitations. During months typically associated with RSV disease, a positive RSV TP indicates a high likelihood of illness, but clinicians should be wary of false negatives.     

Procalcitonin and C-reactive protein as diagnostic markers of severe bacterial infections in febrile infants and children in the emergency department

OBJECTIVE: To assess the value of procalcitonin (PCT) and C-reactive protein (CRP), compared with that of total white-blood cell count (WBC) and absolute neutrophil count (ANC), in predicting severe bacterial infections (SBIs) in febrile children admitted to Emergency Department. METHODS: A prospective study was conducted in 408 children aged 7-days to 36-months, admitted with fever without source, at a tertiary care Pediatric Emergency Department. PCT, CRP, WBC, and ANC were determined upon admission and compared. Specificity, sensitivity, multilevel likelihood ratios, receiver operating characteristic (ROC) analysis, and multivariate stepwise logistic regression were carried out. RESULTS: SBI was diagnosed in 94 children (23.1%). PCT, CRP, WBC, and ANC were significantly higher in this group than in non-SBI patients. The area under the ROC (AUC) obtained was 0.82 (95% CI: 0.78-0.86) for PCT, 0.85 (95% CI: 0.81-0.88) for CRP (P = 0.358), 0.71 (95% CI: 0.66-0.75) for WBC, and 0.74 (95% CI: 0.70-0.78) for ANC. Only PCT (OR: 1.32; 95% CI: 1.11-1.57; P < 0.001) and CRP (OR: 1.02; 95% CI: 1.01-1.03; P < 0.001) were retained as significant predictors of SBI in a multiple regression model. For infants with fever <8 hours (n = 45), AUC for PCT and CRP were 0.92 (95% CI: 0.80-0.98) and 0.75 (95% CI: 0.60-0.87), respectively (P = 0.056). CONCLUSION: Both PCT and CRP are valuable markers in predicting SBI in children with fever without source and they perform better than WBC and ANC. PCT appears more accurate at the beginning of infections, but overall CRP may be the most convenient marker for its better sensitivity and feasibility.     

Urine testing and urinary tract infections in febrile infants seen in office settings: the Pediatric Research in Office Settings' Febrile Infant Study.

OBJECTIVE: To determine the predictors and results of urine testing of young febrile infants seen in office settings. DESIGN: Prospective cohort study. SETTING: Offices of 573 pediatric practitioners from 219 practices in the American Academy of Pediatrics Pediatric Research in Office Settings' research network. SUBJECTS: A total of 3066 infants 3 months or younger with temperatures of 38 degrees C or higher were evaluated and treated according to the judgment of their practitioners. MAIN OUTCOME MEASURES: Urine testing results, early and late urinary tract infections (UTIs), and UTIs with bacteremia. RESULTS: Fifty-four percent of the infants initially had urine tested, of whom 10% had a UTI. The height of the fever was associated with urine testing and a UTI among those tested (adjusted odds ratio per degree Celsius, 2.2 for both). Younger age, ill appearance, and lack of a fever source were associated with urine testing but not with a UTI, whereas lack of circumcision (adjusted odds ratio, 11.6), female sex (adjusted odds ratio, 5.4), and longer duration of fever (adjusted odds ratio, 1.8 for fever lasting > or = 24 hours) were not associated with urine testing but were associated with a UTI. Bacteremia accompanied the UTI in 10% of the patients, including 17% of those younger than 1 month. Among 807 infants not initially tested or treated with antibiotics, only 2 had a subsequent documented UTI; both did well. CONCLUSIONS: Practitioners order urine tests selectively, focusing on younger and more ill-appearing infants and on those without an apparent fever source. Such selective urine testing, with close follow-up, was associated with few late UTIs in this large study. Urine testing should focus particularly on uncircumcised boys, girls, the youngest and sickest infants, and those with persistent fever.     

Reliability of the urinalysis for predicting urinary tract infections in young febrile children

BACKGROUND: Urinary tract infections (UTIs) are a common source of bacterial infection among young febrile children. Clinical variables affecting the sensitivity of the urinalysis (UA) as a screen for UTI have not been previously investigated. The limited sensitivity of the UA for detecting a UTI requires that a urine culture be obtained in some children regardless of the UA result; however, a proper urine culture requires an invasive procedure, so the criteria for its use should be optimized. OBJECTIVES: To determine how the sensitivity of the standard UA as a screening test for UTI varies with age, and to determine the clinical situation that necessitates the collection of a urine culture regardless of the UA result. METHODS: Retrospective medical record review of patients younger than 2 years with fever (>/=38 degrees C) seen in the emergency department during a period of 65 months. All urine cultures were reviewed for the collection method, isolates, and colony counts. A UA result was considered positive if the presence of 1 of the following was detected: leukocyte esterase, nitrite, or pyuria (>/=5 white blood cells per high power field). Patients who had a paired UA and urine culture were used to calculate the sensitivity, specificity, and likelihood ratios of the UA. The prevalence of UTIs was also subcategorized by age, race, sex, and fever. RESULTS: Medical records of 37 450 febrile children younger than 2 years were reviewed. Forty-four percent were girls. Median age and temperature were 10.6 months and 38.8 degrees C. A total of 11 089 patients (30%) had urine cultures obtained. The sensitivity of the UA was 82% (95% confidence interval [CI], 79%-84%) and did not vary by age subgroups. The specificity of UA was 92% (95% CI, 91%-92%). The likelihood ratios for a positive UA and negative UA were 10.6 (95% CI, 10.0-11.2) and 0.19 (95% CI, 0.18-0.20), respectively. Prevalence of UTI was 2.1% overall (2.9% for girls and 1.5% for boys, respectively). Among girls, the prevalence of UTI was 5.0% in white patients, 2.1% in Hispanic patients, and 1.0% in black patients. Among boys, the prevalence was 2.2% in Hispanic patients, 1.4% in white patients, and 0.8% in black patients. Higher prevalence was also seen among patients with a temperature at or above 39 degrees C compared with those whose temperature was between 38.0 degrees C and 38.9 degrees C. The greatest prevalence of UTI (13%) was found among white girls younger than 6 months with a temperature at or greater than 39 degrees C. The posttest probability of a UTI in the presence of a negative UA can be calculated using the negative likelihood ratio and the patient-specific prevalence of UTI. When the prevalence of UTI is 2%, 1 UA among 250 will produce a false-negative test result. CONCLUSIONS: The sensitivity of the standard UA is 82% (95% CI, 79%-84%) and does not vary with age in febrile children younger than 2 years. The prevalence of UTI varies by age, race, sex, and temperature. A negative likelihood ratio and estimates of prevalence can be used to calculate the risk of missing a UTI due to a false-negative UA result.     

Clinical predictors of positive urine cultures in young children at risk for urinary tract infection

BACKGROUND:

Urinary tract infections (UTIs) are a common source of bacterial infection among young febrile children. The diagnosis of UTI is challenging because the clinical presentation is not specific.

OBJECTIVE:

To describe clinical predictors to identify young children needing urine culture for evaluation of UTI.

METHODS:

Retrospective cohort study of all children younger than two years of age (719 hospital visits for 545 patients) suspected of having a UTI during a 12-month period. The outcome was UTI, defined as a catheterized urine culture with pure growth of 10⁴ colonies/mL or greater, or suprapubic aspiration culture with 10³ colonies/mL or greater. Candidate predictors included demographic, historical and physical examination variables.

RESULTS:

The medical records of 545 children younger than two years of age were reviewed. Forty-six per cent were girls. Mean age was 9.1 months (SD 7 months). Four variables were found to predict UTI: absence of another source of fever on examination (odds ratio [OR]=41.6 [95% CI, 8.8 to 197.4]), foul smelling urine (OR=19.7 [95% CI, 5.7 to 68.2]), white blood cell count greater than 15,000/mm³ (OR=4.3 [95% CI, 2.0 to 9.3]), younger than six months old (OR=3.1 [95% CI, 1.3 to 7.1]). The sensitivity of an abnormal urine analysis was 0.77 (95% CI, 0.66 to 0.88) and the specificity was 0.31 (95% CI, 0.2 to 0.42).

CONCLUSION:

An incremental increase in risk for UTI is associated with younger age (younger than six months), having a white blood cell count higher than 15,000/mm³, parental report of malodorous or foul smelling urine and the absence of an alternative source of fever. In the present patient population, obtaining a urine culture from children with at least one of these clinical predictors would have resulted in missing one UTI (2%), and 111 negative cultures (20%) would have been avoided.     

Prevalence of urinary tract infection in childhood: a meta-analysis

BACKGROUND: Knowledge of baseline risk of urinary tract infection can help clinicians make informed diagnostic and therapeutic decisions. We conducted a meta-analysis to determine the pooled prevalence of urinary tract infection (UTI) in children by age, gender, race, and circumcision status. METHODS: MEDLINE and EMBASE databases were searched for articles about pediatric urinary tract infection. Search terms included urinary tract infection, cystitis, pyelonephritis, prevalence and incidence. We included articles in our review if they contained data on the prevalence of UTI in children 0-19 years of age presenting with symptoms of UTI. Of the 51 articles with data on UTI prevalence, 18 met all inclusion criteria. Two evaluators independently reviewed, rated, and abstracted data from each article. RESULTS: Among infants presenting with fever, the overall prevalence (and 95% confidence interval) of UTI was 7.0% (CI: 5.5-8.4). The pooled prevalence rates of febrile UTIs in females aged 0-3 months, 3-6 months, 6-12 months, and >12 months was 7.5%, 5.7%, 8.3%, and 2.1% respectively. Among febrile male infants less than 3 months of age, 2.4% (CI: 1.4-3.5) of circumcised males and 20.1% (CI: 16.8-23.4) of uncircumcised males had a UTI. For the 4 studies that reported UTI prevalence by race, UTI rates were higher among white infants 8.0% (CI: 5.1-11.0) than among black infants 4.7% (CI: 2.1-7.3). Among older children (<19 years) with urinary symptoms, the pooled prevalence of UTI (both febrile and afebrile) was 7.8% (CI: 6.6-8.9). CONCLUSIONS: Prevalence rates of UTI varied by age, gender, race, and circumcision status. Uncircumcised male infants less than 3 months of age and females less than 12 months of age had the highest baseline prevalence of UTI. Prevalence estimates can help clinicians make informed decisions regarding diagnostic testing in children presenting with signs and symptoms of urinary tract infection.     

Can circumcision prevent recurrent urinary tract infections in hospitalized infants?

Urinary tract infection (UTI) is an uncommon but concerning condition for hospitalized premature infants. A retrospective chart review of all male infants admitted to the neonatal intensive care unit (NICU) from June 1996 through March 1999 was conducted at the Medical College of Georgia--a large academic medical center with a tertiary Level III NICU--to investigate the frequency and potential prevention of recurrent UTI in hospitalized infants. The effect of circumcision on recurrence of UTI was also investigated. There were 38 infants with 53 UTIs among 744 male infants admitted during the study period (5.1%). Infants were divided into two groups: A1 <37 weeks with a single UTI and A2 <37 weeks with more than one UTI. In groups A1 and A2, 57% of the first UTIs were due to Candida or E. coli, the remaining were due to other gram-negative organisms and Staphylococcus species. Mean gestational age (GA) in groups A1 and A2 were similar (29 +/- 2 weeks, and 29 +/- 4 weeks); however, mean GA of infants with Candida UTI was 27 +/- 2 weeks, and for bacterial UTI, 30 +/- 3 weeks (p<0.01). None of the premature infants in the study had a recurrent UTI once a circumcision was performed. Premature uncircumcised males had an increased risk for UTI (Odds Ratio=11.1, 95% CI, 3.3-28.9, p<0.001). Circumcision appears beneficial in reducing the risk for recurrent UTI in these infants.     

C-reactive protein as a marker of serious bacterial infections in hospitalized febrile infants

Objective:  To determine the potential predictive power of C-reactive protein (CRP) as a marker of serious bacterial infection (SBI) in hospitalized febrile infants aged ≤3 months.
Patients and Methods:  Data on blood CRP levels were collected prospectively on admission for all infants aged ≤3 months who were hospitalized for fever from 2005 to 2008. The patients were divided into two groups by the presence or absence of findings of SBI.
Results:  A total of 892 infants met the inclusion criteria, of whom 102 had a SBI. Mean CRP level was significantly higher in the infants who had a bacterial infection than in those who did not (5.3 ± 6.3 mg/dL vs. 1.3 ± 2.2 mg/dL, p < 0.001). The area under the ROC curve (AUC) was 0.74 (95% CI: 0.67–0.80) for CRP compared to 0.70 (95% CI: 0.64–0.76) for white blood cell (WBC) count. When analyses were limited to predicting bacteremia or meningitis only, the AUCs for CRP and WBC were 0.81 (95% CI: 0.66–0.96) and 0.63 (95% CI: 0.42–0.83), respectively.
Conclusion:  C-reactive protein is a valuable laboratory test in the assessment of febrile infants aged ≤3 months old and may serve as a better diagnostic marker of SBI than total WBC count.     

Urinalysis in urinary tract infection

In 376 children, between 6 months and 5 years of age, with suspected urinary tract infection, 4 parameters of a routine urine examination were correlated with culture reports. In diagnosing urinary infection, the sensitivity and specificity of proteinuria was 79 and 80% respectively, that of bacteriuria 78 and 96% and that of pyuria >10 wbc/hpf 80 and 82% respectively. 61% among the culture positive groups had all these three parameter present, as against only 0.5% in the culture negative group (P<0.001). All these 3 parameters were absent in 70% in the culture negative group, as against 8% in the culture positive group (P<0.001). Bacteriuria in association with either proteinuria or Pyuria >10 Wbc/hpf had 98% specialty is diagnosis. In diagnosis UTI, Pyuria >10 wbc/hpf was significantly more specific (82∶66.6) than the conventional >5 wbc/hpf. Isolated proteinuria, isolated pyuria, isolated bacteriuria and microscopic haematuria were not features of urinary tract infection in children. Urine culture can be more selectively done if the routine urinalysis is well interpreted. In the absence of dependable culture facilities, a routine urine examination can be reliably used in the diagnosis of UTI in children.     

Aseptic meningitis in infants younger than six months of age hospitalized with urinary tract infections

BACKGROUND: Aseptic meningitis associated with urinary tract infection (UTI) in young infants has not been described in detail in the literature. We performed a retrospective study to determine the incidence and clinical features of aseptic meningitis accompanying UTI. METHODS: We retrospectively reviewed the medical records of all infants younger than 6 months of age hospitalized with a UTI at Miller Children's Hospital from March 1995 through March 2000. UTI was defined as a urine culture growing > or =10,000 colony-forming units/ml of a single organism from a catheterized specimen or > or =100,000 colony-forming units/ml of a single organism from a bagged urine specimen. Meningitis was defined as a positive cerebrospinal fluid culture or cerebrospinal fluid with >35 white blood cells/mm3 in infants < or =30 days of age or with >10 white blood cells/mm3 in infants >30 days of age. RESULTS: Of 386 infants with UTI, a lumbar puncture was performed in 260, and 31 (11.9%) had aseptic meningitis. One infant had bacterial meningitis. None of the 26 infants with UTI and bacteremia had aseptic meningitis. Two infants with meningitis had confirmed enteroviral infections, but aseptic meningitis did not occur more frequently in any particular month or during times of peak enteroviral activity. CONCLUSIONS: A cerebrospinal fluid pleocytosis is relatively common in hospitalized infants <6 months of age who have a UTI and usually does not reflect bacterial meningitis. Knowledge of this may prevent unnecessary courses of antibiotics for presumed bacterial meningitis and lead to evaluation for other possible causes of aseptic meningitis including viral or congenital infections.     

Should complete blood count be part of the evaluation of febrile infants aged ≤2 months?

Objective: To determine the utility and importance of total white blood cell count (WBC) and absolute neutrophil count (ANC) as markers of serious bacterial infection (SBI) in hospitalized febrile infants aged ≤2 months. Patients and methods: Data on WBC and ANC were collected prospectively for all infants aged ≤2 months who were hospitalized for fever at our centre. The patients were divided into two groups by the presence or absence of SBI. Results: A total of 1257 infants met the inclusion criteria, of whom 134 (10.7%) had a SBI. The area under the ROC curve was 0.73 (95% CI: 0.67–0.78) for ANC, 0.70 (95% CI: 0.65–0.76) for %ANC and 0.69 (95% CI: 0.61–0.73) for WBC. The independent contribution of these three tests in reducing the number of missed cases of SBI was significant. Conclusion: Complete blood cell count should remain as part of the routine laboratory assessment in this age group as it is reducing the number of missing infants with SBI. Of the three parameters, ANC and %ANC serve as better diagnostic markers of SBI than total WBC. However, more accurate tests such as C‐reactive protein and procalcitonin should also be part of the evaluation of febrile infants in these age group as they perform better than WBC or ANC for predicting SBI.     

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection.

BACKGROUND: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. AIMS: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. METHODS: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. RESULTS: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. CONCLUSION: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.     

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

Background: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. Aims: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. Methods: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. Results: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. Conclusion: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.     

Plasma IP-10 as a predictor of serious bacterial infection in infants less than 4 months of age

Background: Early diagnosis of serious bacterial infection (SBI) in young infants is a difficult problem by clinical symptoms and signs. The goal of this study is to evaluate the predictive value of plasma IP-10 levels for early diagnosis of SBI in young infants <4 months of age. Methods: We enrolled pediatric patients who were <4 months of age with a clinical suspicion to have SBI admitted in neonatal intensive care unit or complete nursing unit of Pediatric Department of Kaohsiung Medical University Hospital. Blood was drawn for measurement of complete blood counts, C-reactive protein (CRP) and plasma IP-10 levels and microbiological cultures were obtained at the time of admission. Results: There were 60 patients enrolled in this study. The SBI group (n = 21) have higher plasma IP-10 levels than those infants without SBI (n = 39) [median 104.8 (range 0-1457.1) versus 0 (range 0-129.3) pg ml(-1), P = 0.0161 after adjusting age]. A plasma IP-10 level >48.2 pg ml(-1) had the best diagnostic accuracy for indicating SBI {sensitivity 81.0% [95% confidence interval (CI) 71.1-90.1%]; specificity 94.9% [95% CI 65.4-87.0%]; positive likelihood ratio 15.9, negative likelihood ratio 0.2}. Conclusion: In infants who were <4 months of age with suspicion of SBI, IP-10 assay might be a good predictor. Key words: chemokine, IP-10, serious bacterial infection, young infant, C-reactive protein.