Cerebrospinal fluid values in the term neonate

Meta-analysis of Cerebrospinal Fluid Cell Count and Biochemistry to Diagnose Meningitis in Infants Aged < 90 Days

OBJECTIVE

Cerebrospinal fluid (CSF) white blood cell (WBC) count, protein, and glucose (cytochemistry) are performed to aid in the diagnosis of meningitis in young infants. However, studies have reported varying diagnostic accuracies. We assessed the diagnostic accuracy of CSF cytochemistry in infants below 90 days and determined the certainty of evidence.

STUDY DESIGN

We searched PubMed, Embase, Cochrane Library, Ovid, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Scopus databases in August 2021. We included studies that evaluated the diagnostic accuracy of CSF cytochemistry compared with CSF culture, Gram stain, or polymerase chain reaction in neonates and young infants <90 days with suspected meningitis. We pooled data using the hierarchical summary receiver operator characteristic (ROC) model.

RESULTS

Of the 10,720 unique records, 16 studies were eligible for meta-analysis, with a cumulative sample size of 31,695 (15 studies) for WBC, 12,936 (11 studies) for protein, and 1,120 (4 studies) for glucose. The median (Q1, Q3) specificities of WBC, protein, and glucose were 87 (82, 91), 89 (81, 94), and 91% (76, 99), respectively. The pooled sensitivities (95% confidence interval [CI]) at median specificity of WBC count, protein, and glucose were 90 (88, 92), 92 (89, 94), and 71% (54, 85), respectively. The area (95% CI) under ROC curves were 0.89 (0.87, 0.90), 0.87 (0.85, 0.88), and 0.81 (0.74, 0.88) for WBC, protein, and glucose, respectively. There was an unclear/high risk of bias and applicability concern in most studies. Overall certainty of the evidence was moderate. A bivariate model-based analysis to estimate the diagnostic accuracy at specific thresholds could not be conducted due to a paucity of data.

CONCLUSION

CSF WBC and protein have good diagnostic accuracy for the diagnosis of meningitis in infants below 90 days of age. CSF glucose has good specificity but poor sensitivity. However, we could not identify enough studies to define an optimal threshold for the positivity of these tests.

KEY POINTS

· Median specificity of CSF leucocyte count, protein and glucose are similar in young infants.. · At median specificity, CSF leukocyte count and protein are more sensitive than glucose.. · Owing to inadequate data, bivariate modelling to suggest optimal diagnostic thresholds is not possible..

Diagnostic Utility of Cerebrospinal Fluid White Blood Cell Components for the Identification of Bacterial Meningitis in Infants

BACKGROUND

To evaluate the diagnostic and predictive utility of cerebrospinal fluid (CSF) white blood cell (WBC) components in the diagnosis of bacterial meningitis in infants discharged from the neonatal intensive care unit (NICU).

METHODS

We identified a cohort of infants discharged from a Pediatrix NICU between 1997 and 2020 who did not have an immunodeficiency, had at least 1 CSF culture collected within the first 120 days of life, and at least 1 CSF laboratory specimen obtained on the day of culture collection. We only included an infant's first CSF culture and excluded cultures from CSF reservoirs and those growing contaminants or nonbacterial organisms. We examined the utility of CSF WBC components to diagnose or predict bacterial meningitis by calculating sensitivity, specificity, positive and negative predictive values, likelihood ratios, and area under the receiver operating curve (AUC) at different cutoff values for each parameter. We performed subgroup analysis excluding infants treated with antibiotics the day before CSF culture collection.

RESULTS

Of the 20 756 infants that met the study inclusion criteria, 320 (2%) were diagnosed with bacterial meningitis. We found (AUC [95% CI]) CSF WBC count (0.76 [0.73-0.79]), CSF neutrophil count (0.74 [0.70-0.78]), and CSF neutrophil percent (0.71 [0.67-0.75]) had the highest predictive values for bacterial meningitis, even when excluding infants with early antibiotic administration.

CONCLUSIONS

No single clinical prediction rule had the optimal discriminatory power for predicting culture-proven bacterial meningitis, and clinicians should be cautious when interpreting CSF WBC parameters in infants with suspected meningitis.

Reference range for cerebrospinal fluid values in neonates: 5-year retrospective study

BACKGROUND

Cerebro spinal fluid (CSF) parameters (white blood cell count, protein, glucose) in the diagnosis of neonatal bacterial meningitis.

OBJECTIVES

To report the reference range of CSF parameters (white blood cell count, protein, glucose) in both term and preterm infants.

METHODS

This was a single center retrospective study over a period of 5 years (2015-2020). We included infants aged 0-3 months admitted to the neonatal unit and infants ≤28 days attending pediatric acute care and who underwent Lumbar Puncture. We excluded infants with evidence of CSF bacteremia, viral infection and traumatic lumbar puncture defined as CSF Red Blood Cell >500 cells/µL. Clinical, demographic, and microbiological data were collected from the hospital database. The study was approved by ethics committee.

RESULTS

We identified a total of 518 CSF samples, with 232 CSF samples available for final analysis. 54% of excluded samples were traumatic. Median birth gestation and birth weight of the study cohort were 38 (IQR 35-40) weeks and 3030 (IQR 1965-3565) grams respectively. Median RBC, WBC count, protein and glucose were 15 (IQR 3-85)/µL, 3(IQR 0-8.5)/µL, 0.72 (0.53-1.06) g/L and 2.8 (2.4-3.3) mmol/L respectively. There was no difference in CSF WBC cell count between preterm and term infants. Higher CSF protein content was noted in preterm infants and infants in the first 7 days of life. Use of antibiotics prior to LP was associated with higher CSF protein. Presence of any CSF RBC (including <500 cells/µL) influenced the CSF WBC count and protein content.

CONCLUSION

We have provided a reference range of CSF parameters in neonates without meningitis. CSF WBC count between preterm and term infants were similar with higher CSF protein content in preterm infants and for infants in the first seven days of life. Presence of any CSF RBC influenced CSF parameters.

Determining Normative Values for Cerebrospinal Fluid Profiles in Infants

BACKGROUND

Previous studies of reference values for cerebrospinal fluid (CSF) profiles have been limited by small sample size and few exclusion criteria.

OBJECTIVE

To determine age-specific normative CSF white blood cell count (WBC), glucose, and protein values in infants ≤90 days old.

METHODS

Performed a retrospective cross-sectional study of infants ≤90 days old who had a diagnostic lumbar puncture between 2008 and 2016. Infants with bacterial meningitis, bacteremia, UTI, positive CSF herpes simplex virus polymerase chain reaction (PCR) result, traumatic lumbar puncture, ventriculoperitoneal shunt, prematurity, recent seizure, previous antibiotic use, and history of a complex chronic condition were excluded for calculations to determine normative values. Data on demographics and CSF values (WBC with differential, protein, glucose, enterovirus PCR) were collected. CSF values were compared by age and by enterovirus PCR results using Kruskal-Wallis and Wilcoxon rank tests.

RESULTS

A total of 1029 out of 2000 patients were included and divided into 3 age groups: 0 to 28 days, 29 to 60 days, 61 to 90 days. CSF WBC values were significantly greater for 0- to 28-day old infants (median: 3, 95th percentile: 14) than for 29- to 60-day and 61- to 90-day old infants (median: 2 and 2; 95th percentile: 7 and 11, respectively) (P < .001). With each month of life, the median CSF protein significantly decreased and glucose significantly increased. In the CSF WBC differential, monocytes were found to be prevalent.

CONCLUSION

We determined age-specific normative components for CSF profile values for infants 0 to 90 days.

Normal Values for Cerebrospinal Fluid in Neonates: A Systematic Review

BACKGROUND

The diagnosis of neonatal meningitis often rests on microscopic and biochemical findings in the cerebrospinal fluid (CSF). There is ongoing uncertainty about age-related normal values for CSF findings in neonates, and many previous studies have included infants in whom antibiotics were administered before lumbar puncture or in whom viral meningitis was not excluded.

METHODS

A systematic search was done using MEDLINE and EMBASE to identify original studies which investigated CSF normal values in either healthy neonates or febrile neonates in whom bacterial and viral meningitis were reliably excluded.

RESULTS

We identified seven studies investigating 270 term and 96 preterm neonates. There were minimal differences between preterm and term neonates in the CSF white blood cell (WBC) count and glucose concentration. In contrast, the CSF neutrophil count and protein concentration were influenced by gestational and chronological age. In the four studies that reported individual patient data, in 95% of cases the CSF WBC count was <12 cells/μL in preterm and <10 cells/μL in term neonates, the neutrophil count was <16 and 8 cells/μL, and the protein concentration was <210 and 110 mg/dL, respectively.

CONCLUSION

The normal range for CSF parameters in neonates is different to that in older infants, and some parameters are influenced by gestational and chronological age. CSF parameters alone are not sufficiently reliable to exclude meningitis.

Management of Acute Bacterial Meningitis in Children

Acute community-acquired bacterial meningitis (ABM) in children continues to have high rates of neurological morbidity and mortality despite the overall declining rates of infection attributed to the use of vaccines and intrapartum Group B Streptococcus prophylaxis. Prompt diagnosis and early antibiotic therapy are crucial and should not be delayed to obtain cranial imaging. Differentiating bacterial from viral meningitis continues to be a clinical dilemma especially in patients with previous antibiotic exposure. Clinical models and inflammatory biomarkers can aid clinicians in their diagnostic approach. Multiplex polymerase chain reaction and metagenomic next-generation sequencing are promising tools that can help in early and accurate diagnosis. This review will present the epidemiology of ABM in children, indications of cranial imaging, role of different models and serum biomarkers in diagnosing ABM, and management including the use of adjunctive therapies and methods of prevention.

C-reactive protein as a predictor of meningitis in early onset neonatal sepsis: a single unit experience

Objectives To determine whether there is a cut off value of serum C-reactive protein (CRP) associated with a higher risk of meningitis in suspected early onset sepsis (EOS) (onset birth to 7 days of life). Methods A retrospective cohort study on neonates admitted in neonatal intensive care unit at McMaster Children's Hospital from January 2010 to 2017 and had lumbar puncture (LP) and CRP for workup of EOS. Included subjects had either (a) non-traumatic LP or (b) traumatic LP with cerebral spinal fluid (CSF) polymerase chain reaction or gram stain or culture-positive or had received antimicrobials for 21 days. Excluded were CSF done for metabolic errors, before cytomegalovirus (CMV) treatment; from ventriculo-peritoneal (VP) shunts; missing data and contamination. Neonates were classified into definite and probable meningitis and on the range of CRP. We calculated sensitivity, specificity, and likelihood ratios for CRP values; and area under the receiver operating characteristic (AUROC) curve. Results Out of 609 CSF samples, 184 were eligible (28 cases of definite or probable meningitis and 156 controls). Sensitivity, specificity, predictive values, likelihood ratios, and AUROC were too low to be of clinical significance to predict meningitis in EOS. Conclusions Serum CRP values have poor discriminatory power to distinguish between subjects with and without meningitis, in symptomatic EOS.

Early-Onset Neonatal Sepsis

Despite the great progress made in neonatal and perinatal medicine over the last couple of decades, sepsis remains one of the main causes of morbidity and mortality. Sepsis in pediatric population was defined at the Pediatric Sepsis Consensus Conference in 2005. There is still no consensus on the definition of neonatal sepsis. Neonatal sepsis is a sepsis that occurs in the neonatal period. According to the time of occurrence, neonatal sepsis can be of early onset, when it occurs within the first 72 hours of birth and results from vertical transmission, and of late onset, in which the source of infection is found most often in the environment and occurs after the third day of life. The most common causes of early-onset sepsis are Group B Streptococcus (GBS) and E. coli. Risk factors can be mother-related and newborn-related. Clinical symptoms and signs of sepsis are quite unspecific. The dysfunction of different organs may imitate sepsis. On the other hand, infectious and non-infectious factors may exist simultaneously. The start of the antimicrobial therapy in any newborn with suspected sepsis should not be delayed. Pentoxifylline may have potential benefits in preterm newborns with sepsis. The only proven intervention that has been shown to reduce the risk of early-onset neonatal sepsis is intrapartum intravenous antibiotic administration to prevent GBS infection. It is still a great challenge to discontinue antibiotic treatment in non-infected newborns as soon as possible, because any extended antibiotic use may later be associated with other pathological conditions.

Age-specific reference values for cerebrospinal fluid protein concentrations in children in southern China

Cerebrospinal fluid (CSF) protein values decline over the first few months of life as the infant's blood-CSF barrier matures. However, published studies have not reported CSF protein reference values of Chinese infants and differ in the reported rate, timing, and magnitude of this decline. The objective of this study was to determine reference intervals for CSF protein using available data of children in southern China. This retrospective study included infants who had a lumbar puncture (LP) performed in the Department of Pediatrics of Southern Medical University Affiliated Maternal and Child Health Hospital of Foshan of an urban tertiary care children's hospital between January 1, 2008 and May 31, 2018. Infants with conditions suspected or known to cause elevated CSF protein concentrations were excluded. Of 3712 infants undergoing LP, 1043 (28.1%) met inclusion criteria. Results showed that there is an age-related decline in CSF protein concentration. The median CSF protein value was 62 mg/dL [interquartile range (IQR): 47-81 mg/dL] in infants aged 0 to 56 days (group 1). The 95th percentile values were 116 mg/dL for infants 0 to 28 days and 80 mg/dL for infants 29 to 56 days. The 95th percentile values by age category were as follows: ages 0 to 14 days, 117 mg/dL; ages 15 to 28 days, 107 mg/dL; ages 29 to 42 days, 96 mg/dL; and ages 43 to 56 days, 74 mg/dL. The median CSF protein value was 21 mg/dL (IQR: 16-31 mg/dL) in infants aged 2 months to <3 years (group 2). The 95th percentile values were 57 mg/dL for infants 2 to <6 months and 34 mg/dL for infants 6 to ≤24 months. The 95th percentile values by age category were as follows: ages 2 to <3 months, 66 mg/dL; ages 3 to <4 months, 52 mg/dL; ages 4 to <5 months, 53 mg/dL; and ages 5 to <6 months, 42 mg/dL. We quantify the age-related decline in CSF protein concentrations among infants 2 years of age and younger and provide age-specific reference values. The values reported here can be used to interpret the results of LP in infants ≤2 years of age.

Dilemma in Diagnosis of Pyogenic Meningitis in Cerebrospinal Fluid Contaminated with Blood: Does Leucocyte Esterase Test Help?

Context:

Pyogenic meningitis is often a devastating condition which is diagnosed by analysis of cerebrospinal fluid (CSF) obtained by lumbar puncture (LP). CSF thus obtained can get contaminated with peripheral blood leucocytes during LP which renders it unusable for cytological analysis. Leucocyte esterase strips are available for identifying leucocyte esterase activity in urine and other body fluids which suggest inflammation. We conducted this experiment to see whether the leucocyte esterase strip can differentiate between neutrophils invited at the inflammatory site and circulating neutrophils in CSF.

Aim:

To compare the diagnostic ability of the leucocyte esterase test between pyogenic meningitis and CSF contaminated with circulating neutrophils.

Setting and Design:

Prospective analytical study conducted in a tertiary care hospital.

Materials and Methods:

The CSF samples of pyogenic meningitis patients were analyzed for leucocyte esterase activity. The other group was normal CSF which was deliberately contaminated with buffy coat preparation, and leukocyte esterase activity was determined.

Statistical Analysis:

Diagnostic ability of a test in terms of sensitivity and specificity.

Results:

Overall sensitivity of the dipsticks in diagnosing pyogenic meningitis is 81% and specificity is 99%. When compared with experimentally contaminated CSF sample, a reading of 2+ on the strip had a sensitivity of 70% and specificity of 100% for pyogenic meningitis.

Conclusion:

Leucocyte esterase strip is specific for pyogenic meningitis (activated neutrophils), and hence can differentiate from CSF contaminated with blood.

Comparing Single vs. Combined Cerebrospinal Fluid Parameters for Diagnosing Full-Term Neonatal Bacterial Meningitis

Objectives: To identify and compare the cerebrospinal fluid (CSF) parameters that predict the presence of neonatal bacterial meningitis using optimal cutoff values, and to derive and compare predictive profiles based on a combination of individual parameters for the same purpose.

Study Design: The retrospective component of the Shanghai Neonate Meningitis Cohort included all term neonates who underwent lumbar puncture between 2000 and 2017. Those with severe neurological diseases, histories of ventricular drainage, or traumatic lumbar punctures were excluded. Reference ranges were determined for non-bacterial meningitis neonates based on the 5th, 25th, 50th, 75th, and 95th CSF parameter quantiles, and their relationships with age were calculated using generalized additive models that tested for linear relationships. The optimal cutoff value for each measured CSF parameter was calculated using receiver operating characteristic analysis and by deriving the Youden's index. Parameters with good diagnostic efficacies were combined to produce predictive profiles using logistic regression. The diagnostic efficacies of the single parameters and profiles were compared in neonates with confirmed bacterial meningitis.

Results: White blood cells (WBCs) in CSF showed a higher diagnostic ability for neonatal bacterial meningitis than CSF protein, glucose, lactate dehydrogenase, or chloride. The sensitivity and specificity of the diagnostic cutoff value for WBCs (20 × 10⁶/L) were 95.1 and 98.7%, respectively. Profiles based on CSF parameter combinations improved the specificities slightly to 99.0–99.7%. However, employing predictive profiles did not improve sensitivities, which remained at 95.1–96.0%.

Conclusions: Profiles for predicting neonatal bacterial meningitis improve the sensitivity and specificity of diagnosis slightly, although not appreciably, compared to the single parameter of CSF WBC alone.

Neonate and infant brain development from birth to 2 years assessed using MRI-based quantitative susceptibility mapping

The human brain rapidly develops during the first two years following birth. Quantitative susceptibility mapping (QSM) provides information of iron and myelin variations. It is considered to be a valuable tool for studying brain development in early life. In the present work, QSM is performed on neonates, 1-year and 2-year old infants, as well as a group of adults for the purpose of reference. Age-specific templates representing common brain structures are built for each age group. The neonate and infant QSM templates have shown some unique findings compared to conventional T1w and T2w imaging techniques. The contrast between the gray and white matters on the QSM images did not change through brain development from neonate to adult. A linear correlation was found between brain myelination determined in this study and the microscopic myelin degree determined by a previous autopsy study. Also, the magnetic susceptibility values of the cerebral spinal fluid (CSF) exhibit a gradually decreasing trend from birth to 2 years old and to adulthood. The findings suggest that the macromolecular content, myelin, and iron may play the most important contributing factors for the magnetic susceptibility of neonate and infant brain. QSM can be a powerful means to study early brain development and related pathologies that involve alterations in macromolecular content, iron, or brain myelination.

Cerebrospinal Fluid Reference Values for Young Infants Undergoing Lumbar Puncture

OBJECTIVES

To determine age-specific reference values and quantify age-related changes for cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein and glucose concentrations in infants ≤60 days of age.

METHODS

This multicenter, cross-sectional study included infants ≤60 days old with CSF cultures and complete CSF profiles obtained within 24 hours of presentation. Those with conditions suspected or known to cause abnormal CSF parameters (eg, meningitis) and those with a hospital length of stay of >72 hours were excluded. Reference standards were determined for infants ≤28 days of age and 29 to 60 days of age by using the third quartile +1.5 interquartile range for WBC and protein and the first quartile -1.5 interquartile range for glucose. CSF parameter centile curves based on age were calculated by using the LMST method.

RESULTS

A total of 7766 patients were included. CSF WBC counts were higher in infants ≤28 days of age (upper bound: 15 cells/mm³) than in infants 29 to 60 days of age (upper bound: 9 cells/mm³; P < .001). CSF protein concentrations were higher in infants ≤28 days of age (upper bound: 127 mg/dL) than in infants 29 to 60 days of age (upper bound: 99 mg/dL; P < .001). CSF glucose concentrations were lower in infants ≤28 days of age (lower bound: 25 mg/dL) than in infants 29 to 60 days of age (lower bound: 27 mg/dL; P < .001).

CONCLUSIONS

The age-specific CSF WBC count, protein concentration, and glucose concentration reference values identified in this large, multicenter cohort of infants can be used to interpret the results of lumbar puncture in infants ≤60 days of age.

Immune responses in perinatal brain injury

The perinatal period has often been described as immune deficient. However, it has become clear that immune responses in the neonate following exposure to microbes or as a result of tissue injury may be substantial and play a role in perinatal brain injury. In this article we will review the immune cell composition under normal physiological conditions in the perinatal period, both in the human and rodent. We will summarize evidence of the inflammatory responses to stimuli and discuss how neonatal immune activation, both in the central nervous system and in the periphery, may contribute to perinatal hypoxic-ischemic brain injury.

Clinical relevance and contemporary methods for counting blood cells in body fluids suspected of inflammatory disease

In many inflammatory diseases, the cellular components in body fluids [cerebrospinal fluid (CSF), serous fluids] are increased, rendering essential diagnostic information. The diagnostic value of the total white blood cell count (WBC) and differential count has been evaluated extensively over the years, and a remarkable amount of knowledge has been gained; yet, there is a great deal of clinical uncertainty whether the diagnosis should be based solely on these variables. In some diseases, such as peritonitis, the total WBC and differential count has high sensitivity; whereas, in differentiating pleural effusions, it lacks the sensitivity required to be clinically useful. Nevertheless, many guidelines consider these tests as cornerstone parameters, and in combination with clinical variables, they can successfully guide clinical decision making in initiating or postponing a treatment course for infection and/or inflammatory diseases while awaiting culture results. Although other methods are available for detecting and differentiating WBCs in body fluids, manual microscopy is still considered the gold standard despite its many limitations. During the last decade, automated analyzers have become a popular method for first line screening. Continued progress in their design has led to major improvements including their speed, improved accuracy and lower variability compared with microscopy. Disadvantages of this method include high imprecision in low ranges (depending on the method) and interfering factors. In a time where automation is at the front line in clinical laboratories, it is essential the results obtained are precise, accurate and reproducible. This review provides an overview of the relevance for cell counting in a variety of diagnostic body fluids, and highlights the current technologies used.

The rights and wrongs of blood-brain barrier permeability studies: a walk through 100 years of history

Careful examination of relevant literature shows that many of the most cherished concepts of the blood-brain barrier are incorrect. These include an almost mythological belief in its immaturity that is unfortunately often equated with absence or at least leakiness in the embryo and fetus. The original concept of a blood-brain barrier is often attributed to Ehrlich; however, he did not accept that permeability of cerebral vessels was different from other organs. Goldmann is often credited with the first experiments showing dye (trypan blue) exclusion from the brain when injected systemically, but not when injected directly into it. Rarely cited are earlier experiments of Bouffard and of Franke who showed methylene blue and trypan red stained all tissues except the brain. The term “blood-brain barrier” “Blut-Hirnschranke” is often attributed to Lewandowsky, but it does not appear in his papers. The first person to use this term seems to be Stern in the early 1920s. Studies in embryos by Stern and colleagues, Weed and Wislocki showed results similar to those in adult animals. These were well-conducted experiments made a century ago, thus the persistence of a belief in barrier immaturity is puzzling. As discussed in this review, evidence for this belief, is of poor experimental quality, often misinterpreted and often not properly cited. The functional state of blood-brain barrier mechanisms in the fetus is an important biological phenomenon with implications for normal brain development. It is also important for clinicians to have proper evidence on which to advise pregnant women who may need to take medications for serious medical conditions. Beliefs in immaturity of the blood-brain barrier have held the field back for decades. Their history illustrates the importance of taking account of all the evidence and assessing its quality, rather than selecting papers that supports a preconceived notion or intuitive belief. This review attempts to right the wrongs. Based on careful translation of original papers, some published a century ago, as well as providing discussion of studies claiming to show barrier immaturity, we hope that readers will have evidence on which to base their own conclusions.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Role of dexamethasone in neonatal meningitis: a randomized controlled trial

OBJECTIVES

To evaluate the role of dexamethasone therapy in neonatal meningitis in a randomized placebo controlled trial.

METHODS

The participants were eighty neonates with meningitis randomized to receive dexamethasone or saline placebo. Dexamethasone was started prior to the first dose of antibiotics in the dose of 0.15 mg/kg intravenous 6 hourly for 2 d. Primary outcome measure was mortality. Secondary outcome measures included progression of systemic inflammatory response syndrome (SIRS) up to 48 h, differences in cerebrospinal fluid (CSF) cytokines between baseline levels and 24 h after enrolment and brain stem auditory evoked response (BAER) after 4 to 6 wk of discharge.

RESULTS

Baseline variables were comparable in both the groups. Mortality was significantly decreased in dexamethasone group (p = 0.005) and the absolute risk difference was 27.5 % (95 % CI 9.5-45.8 %). There was a significant reduction in cells per mm(3) (62.5 vs. 100) and proteins (162 vs. 217.5 mg/dl) after 24 h of treatment in the dexamethasone group. IL-1β was significantly reduced after 24 h in dexamethasone group (290 vs 665 pg/ml). TNF- α was significantly lower (157.5 vs 427.5 pg/ml) and sugar significantly higher (50 vs 38 mg/dl) in the dexamethasone group after 24 h. Significant difference was noted between dexamethasone and saline groups in the progression of SIRS.

CONCLUSIONS

Dexamethasone significantly reduced fatality, progression of SIRS and CSF inflammatory indices.

Lumbar puncture in the neonate: challenges in decision making and interpretation

Multiple studies have provided normative ranges for cerebrospinal fluid (CSF) parameters in term and preterm infants and described changes with advancing postnatal age, as well as in special circumstances, such as traumatic lumbar puncture (LP), previous antibiotic administration, seizures, and concomitant infections at other sites. Although guidelines exist for the interpretation of CSF parameters in neonates, there appears to be no single combination of parameters that conclusively excludes meningitis. It remains important for clinicians to perform LPs early in the course of illness, ideally before the administration of antibiotic therapy. This review presents currently available literature on the indications for LP as well as guidelines for the interpretation of CSF parameters in neonates.

Evaluation of cerebrospinal fluid parameters in preterm infants with intraventricular reservoirs

OBJECTIVE

Intraventricular reservoirs (IVRs) are used to drain cerebrospinal fluid (CSF) in neonates with post-hemorrhagic ventricular dilatation (PHVD). The objectives of this case-control study were to evaluate changes in CSF parameters in serial IVR taps and to compare CSF parameters in culture-positive and -negative specimens.

STUDY DESIGN

Clinical and laboratory data from serial (up to 7) reservoir taps at 5- to 8-day intervals were collected on preterm neonates with PHVD and IVR insertion.

RESULT

The median (range) gestational age and birth weight of our cohort (n=52) was 26 (23 to 33) weeks and 796 (450 to 1620) grams. Significant decreases in percentage of CSF neutrophils and protein were noted in later taps, compared with the first tap at insertion of IVR. Five (9.6%) infants had positive CSF cultures on 10 occasions. Compared with negative specimens (n=266), the mean (s.d.) proportion of neutrophils in CSF (55% (33) vs 26% (23)) was significantly higher and ratio of CSF to serum glucose significantly lower (0.19 (0.08) vs 0.29 (0.13)) in culture-positive specimens (n=10). The area under the curve was 0.82 (95% confidence interval (CI) 0.72 to 0.93) for CSF white blood cell (WBC) count, 0.79 (95% CI 0.68 to 0.90) for CSF protein and 0.75 (95% CI 0.56 to 0.95) for percentage of neutrophils. The sensitivities and specificities for diagnosis of infection was 90 and 63% for CSF WBC count > 42 mm(-3), 89 and 58% for CSF protein at > 250 mg dl(-1) and 80 and 67% for CSF neutrophil proportion >31.5%.

CONCLUSION

CSF parameters from IVR taps, specifically proportion of neutrophils and proteins are higher at insertion and progressively normalize over time. Although they vary widely, CSF WBC, protein and neutrophil proportion using higher cut-off values have good sensitivity in the diagnosis of infection.

Cerebrospinal fluid reference ranges in term and preterm infants in the neonatal intensive care unit

OBJECTIVE

To determine reference ranges of cerebrospinal fluid (CSF) laboratory findings in term and preterm infants in the neonatal intensive care unit.

STUDY DESIGN

Data were collected prospectively as part of a multisite study of infants aged <6 months undergoing lumbar puncture for evaluation of suspected sepsis. Infants with a red blood cell count >500 cells/μL or a known cause of CSF pleocytosis were excluded from the analysis.

RESULTS

A total of 318 infants met the inclusion criteria. Of these, 148 infants (47%) were preterm, and 229 (72%) received antibiotics before undergoing lumbar puncture. The upper reference limit of the CSF white blood cell (WBC) count was 12 cells/μL in preterm infants and 14 cells/μL in term infants. CSF protein levels were significantly higher in preterm infants (upper reference limit, 209 mg/dL vs 159 mg/dL in term infants; P < .001), and declined with advancing postnatal age in both groups (preterm, P = .008; term, P < .001). CSF glucose levels did not differ in term and preterm infants. Antibiotic exposure did not significantly affect CSF WBC, protein, or glucose values.

CONCLUSIONS

CSF WBC counts are not significantly different in preterm and term infants. CSF protein levels are higher and decline more slowly with postnatal age in preterm infants compared with term infants. This study provides CSF reference ranges for hospitalized preterm and term infants, particularly in the first month of life.

Cerebrospinal fluid glucose and lactate: age-specific reference values and implications for clinical practice

Cerebrospinal fluid (CSF) analysis is an important tool in the diagnostic work-up of many neurological disorders, but reference ranges for CSF glucose, CSF/plasma glucose ratio and CSF lactate based on studies with large numbers of CSF samples are not available. Our aim was to define age-specific reference values. In 1993 The Nijmegen Observational CSF Study was started. Results of all CSF samples that were analyzed between 1993 and 2008 at our laboratory were systematically collected and stored in our computerized database. After exclusion of CSF samples with an unknown or elevated erythrocyte count, an elevated leucocyte count, elevated concentrations of bilirubin, free hemoglobin, or total protein 9,036 CSF samples were further studied for CSF glucose (n = 8,871), CSF/plasma glucose ratio (n = 4,516) and CSF lactate values (n = 7,614). CSF glucose, CSF/plasma glucose ratio and CSF lactate were age-, but not sex dependent. Age-specific reference ranges were defined as 5–95^th percentile ranges. CSF glucose 5^th percentile values ranged from 1.8 to 2.9 mmol/L and 95^th percentile values from 3.8 to 5.6 mmol/L. CSF/plasma glucose ratio 5^th percentile values ranged from 0.41 to 0.53 and 95^th percentile values from 0.82 to 1.19. CSF lactate 5^th percentile values ranged from 0.88 to 1.41 mmol/L and 95^th percentile values from 2.00 to 2.71 mmol/L. Reference ranges for all three parameters were widest in neonates and narrowest in toddlers, with lower and upper limits increasing with age. These reference values allow a reliable interpretation of CSF results in everyday clinical practice. Furthermore, hypoglycemia was associated with an increased CSF/plasma glucose ratio, whereas hyperglycemia did not affect the CSF/plasma glucose ratio.

Management of neonates with suspected or proven early-onset bacterial sepsis

With improved obstetrical management and evidence-based use of intrapartum antimicrobial therapy, early-onset neonatal sepsis is becoming less frequent. However, early-onset sepsis remains one of the most common causes of neonatal morbidity and mortality in the preterm population. The identification of neonates at risk for early-onset sepsis is frequently based on a constellation of perinatal risk factors that are neither sensitive nor specific. Furthermore, diagnostic tests for neonatal sepsis have a poor positive predictive accuracy. As a result, clinicians often treat well-appearing infants for extended periods of time, even when bacterial cultures are negative. The optimal treatment of infants with suspected early-onset sepsis is broad-spectrum antimicrobial agents (ampicillin and an aminoglycoside). Once a pathogen is identified, antimicrobial therapy should be narrowed (unless synergism is needed). Recent data suggest an association between prolonged empirical treatment of preterm infants (≥5 days) with broad-spectrum antibiotics and higher risks of late onset sepsis, necrotizing enterocolitis, and mortality. To reduce these risks, antimicrobial therapy should be discontinued at 48 hours in clinical situations in which the probability of sepsis is low. The purpose of this clinical report is to provide a practical and, when possible, evidence-based approach to the management of infants with suspected or proven early-onset sepsis.

Progression of cerebrospinal fluid cell count and differential over a treatment course of shunt infection

OBJECT

The physiological reaction of CSF white blood cells (WBCs) over the course of treating a shunt infection is undefined. The authors speculated that the CSF WBC count varies with different infecting organisms in peak level and differential percentage of polymorphonuclear (PMN) leukocytes, lymphocytes, monocytes, and eosinophils. The authors hope to identify clinically useful trends in the progression of CSF WBCs by analyzing a large group of patients with successfully treated shunt infections.

METHODS

The authors reviewed 105 successfully treated cases of shunt infections at Riley Hospital for Children. The study dates ranged from 2000 to 2004; this represented a period prior to the routine use of antibiotic-impregnated shunt catheters. They analyzed the following organisms: coagulase-negative staphylococci, Staphylococcus aureus, Propionibacterium acnes, Streptococcal species, and gram-negative organisms. The initial CSF sample at diagnosis was analyzed, as were levels over 14 days of treatment. Model fitting was performed to generate curves for the expected progression of the WBC counts and the differential PMN leukocytes, lymphocyte, monocyte, and eosinophil percentages.

RESULTS

Gram-negative organisms resulted in a higher initial (p = 0.03) and peak WBC count with a greater differential of PMN leukocytes compared with other organisms. Propionibacterium acnes infections were associated with a significantly lower WBC count and PMN leukocytes percentage (p = 0.02) and higher eosinophil percentage (p = 0.002) than other organisms. The pattern progression of the CSF WBC count and differential percentages was consistent for all infections. There was an initial predominance of PMN leukocytes, followed by a delayed peak of lymphocytes, monocytes, and eosinophils over a 14-day course. All values trended toward zero over the treatment course.

CONCLUSIONS

The initial and peak levels of CSF WBCs vary with the infecting organisms. The CSF cell counts showed a predictable pattern during the treatment of shunt infection. These trends may be useful to the physician in clinical decision making, although there is a wide range of variability.

Cerebrospinal fluid findings in infants with pertussis or parapertussis(1))

BACKGROUND

Pertussis has been increasing in frequency and can cause protean manifestation in infants, often resulting in extensive laboratory evaluation.

METHODS

We examined the prevalence of cerebrospinal fluid (CSF) anomalies in infants with pertussis and parapertussis over a 5-year period.

RESULTS

In total, 239 of 1489 children (16.1%) had a positive PCR for pertussis or parapertussis. Eighty-three percent were infants; the mean age of the 39 years who received a lumbar puncture (LP) was 43 days. Reasons for performing LP included apnea (62%), toxic appearance (38%), fever (26%), and altered mentation (10%); several had >1 indication for LP. Twenty-four (62%) children had elevated CSF protein. No child had hypoglycorrhachia, bacterial meningitis, bacteremia, or intracranial hemorrhage; one child had a urinary tract infection and five had pneumonia. Seven children had brain imaging performed; one had a subarachnoid hemorrhage and six had normal studies. Elevated age-normalized CSF protein was a common finding in infants with pertussis, potentially due to transfer across a damaged or immature blood-brain barrier. This finding was seen in the absence of concomitant bacterial infections or detectable intracranial anomalies.

CONCLUSIONS

While the diagnostic evaluation and clinical management of a toxic-appearing infant should not be limited by a positive pertussis or parapertussis PCR, it is useful for physicians to be cognizant that elevated CSF protein can be seen in association with these infections.

Cerebrospinal fluid characteristics of infants who present to the emergency department with fever: establishing normal values by week of age

BACKGROUND This study describes differences in the values of cerebrospinal fluid (CSF) white blood cell (WBC), glucose, and protein counts in infants less than 60 days of age with fever who were not proven to have viral or bacterial meningitis.

METHODS

Three independent retrospective medical record reviews were conducted using a population of infants less than 60 days of age who presented to the Emergency Department with fever. Full-term infants were included if a lumbar puncture was performed within 24 hours of admittance and bacterial or viral meningitis was not identified as the cause of fever.

RESULTS

A total of 1091 infants were included and grouped by week of age. Significant trends were found for CSF WBC and CSF protein with the highest values observed during the first week of life. Mean for CSF WBC was 8.63 cells/mm for infants aged 0 to 1 week and decreased for each age group ending with infants 8 weeks of age having a mean of 2.22 cell/mm. For CSF protein, a similar trend was observed. No significant differences were found for CSF glucose.

CONCLUSIONS

Significant differences exist for infants by week of age for CSF WBC and CSF protein. These values can be used to assist in interpreting laboratory findings and making management decisions for infants less than 60 days of age.

Age-specific reference values for cerebrospinal fluid protein concentration in neonates and young infants

BACKGROUND

Cerebrospinal fluid (CSF) protein values decline over the first few months of life as the infant's blood-CSF barrier matures. However, published studies differ in the reported rate, timing, and magnitude of this decline.

OBJECTIVE

To quantify the age-related changes in CSF protein concentration and to determine accurate, age-specific reference values for neonates and young infants.

DESIGN, SETTING AND PATIENTS

This cross-sectional study included infants age 56 days or younger who had a lumbar puncture performed in the emergency department of an urban tertiary care children's hospital between January 1, 2005 and June 30, 2007. Infants with conditions associated with elevated CSF protein concentrations, including traumatic lumbar puncture and bacterial or viral meningitis, were excluded.

RESULTS

Of 1064 infants undergoing lumbar puncture, 375 (35%) met inclusion criteria. The median CSF protein value was 58 mg/dL (interquartile range: 48-72 mg/dL). In linear regression, the CSF protein concentration decreased 6.8% (95% confidence interval [CI], 5.4%-8.1%; P < 0.001) with each 1 week increase in age. The 95th percentile values were 115 mg/dL for infants ≤28 days and 89 mg/dL for infants 29-56 days. The 95th percentile values by age category were as follows: ages 0-14 days, 132 mg/dL; ages 15-28 days, 100 mg/dL; ages 29-42 days, 89 mg/dL; and ages 43-56 days, 83 mg/dL.

CONCLUSIONS

We quantify the age-related decline in CSF protein concentration among infants 56 days of age and younger and provide age-specific reference values. The values reported here represent the largest series to-date for this age group.

Normative cerebrospinal fluid profiles in febrile infants

OBJECTIVE

To describe the cerebrospinal fluid (CSF) profiles of febrile infants aged 1 to 90 days with negative bacterial culture test results and negative results for enteroviruses with polymerase chain reaction.

STUDY DESIGN

Statistical analysis of a retrospective cohort.

RESULTS

CSF profiles from 823 infants with negative test results for infection were analyzed. For 677 infants with atraumatic lumbar punctures (red blood cell [RBC] count < 1000/mm(3)), the mean and median CSF white blood cell (WBC) counts were 4.3/mm(3) and 3.0/mm(3), respectively, with a range from 0 to 12/mm(3). Mean CSF WBC counts (6.1/mm(3) versus 3.1/mm(3) and 3.0/mm(3)) and protein levels (75.4 mg/dL versus 58.9 mg/dL and 39.2 mg/dL) were higher in the first month compared with months 2 and 3, respectively (P < .001 for all). CSF glucose levels were lower in the first month compared with month 3 (45.3 mg/dL versus 48.0 mg/dL and 57.7 mg/dL; P < .001). Increasing RBC counts were statistically associated with increasing WBC counts (P < .001). However, the contribution of RBC < 10,000/mm(3) was small, and the reference range for WBC in uninfected infants with traumatic lumbar punctures was 0 to 16/mm(3).

CONCLUSION

CSF WBC counts in febrile infants without evidence of bacterial or enteroviral infection, even in those with traumatic lumbar puncture, are lower than reported in pediatric references.

Defining cerebrospinal fluid white blood cell count reference values in neonates and young infants

OBJECTIVE

Cerebrospinal fluid (CSF) white blood cell (WBC) counts for neonates and young infants are usually interpreted on the basis of values reported in reference texts or handbooks; however, current reference texts either present normal CSF parameters without citation or cite studies with significant limitations. The objective of this study was to determine accurate, age-specific reference values for CSF WBC counts in a large population of neonates and young infants.

METHODS

This cross-sectional study included patients who were aged < or =56 days and had a lumbar puncture performed in the emergency department from January 1, 2005, to June 30, 2007. Patients were excluded from analysis for conditions that are suspected to cause CSF pleocytosis, including traumatic lumbar puncture, serious bacterial infection, congenital infection, seizure, and presence of a ventricular shunt. Children who tested positive for enterovirus (EV) in the CSF by polymerase chain reaction were also excluded. Two-sample Wilcoxon rank-sum tests were used to compare median CSF WBC values of those who had negative EV testing with those who did not have EV testing.

RESULTS

A total of 380 (36%) of 1064 patients met inclusion criteria; 54% were male, 15% were preterm, and 39% presented during EV season. The median CSF WBC count was significantly higher in infants who were aged < or =28 days (3/microL, 95th percentile: 19/microL) than in infants who were aged 29 to 56 days (2/microL, 95th percentile: 9/microL; P < .001). In both age groups, infants with a negative EV PCR had a higher upper bound of the 95% confidence interval of the mean values compared with infants who did not have EV testing performed.

CONCLUSIONS

We determined age-specific CSF WBC reference values in a large cohort of neonates and young infants that can be used to interpret accurately the results of lumbar punctures in this population.

Meningitis in a newborn infant with urosepsis, negative blood cultures and initially normal cerebrospinal fluid findings

This case presentation supports the observation that initial cerebrospinal fluid findings can be normal in newborn infants with sepsis syndrome who then develop evidence for meningeal involvement. Therefore, if initial lumbar puncture results are negative, a repeat lumbar puncture is recommended to look for meningitis in newborns that are critically ill with sepsis syndrome.

Analysis of cerebrospinal fluid in the neonate

NEONATES PRESENTING WITH apnea, seizures, signs and symptoms of infection or neurologic disorders often require evaluation of cerebrospinal fluid (CSF) as part of their diagnostic workup. Multiple studies can be done on CSF, including, but not limited to, evaluation of color, bacterial culture and Gram’s stain, viral culture, cell count and differential, polymerase chain reaction (PCR), and quantitative determination of a number of laboratory values. Proper evaluation of CSF depends on knowing which tests to order, normal ranges for the patient’s age, and the limitations of the test.1 Reference ranges for CSF studies have been well established in the adult, but are not as well defined in the neonatal population.2,3 This situation is further complicated by the vast differences between preterm and term infants. This column covers the interpretation of the most common tests done on CSF in the neonate. Many of the references cited are more than ten years old, but little new data support changes in the interpretation of neonatal CSF studies.

Traumatic lumbar punctures in neonates: test performance of the cerebrospinal fluid white blood cell count

BACKGROUND

Cerebrospinal fluid (CSF) findings are often used to diagnose meningitis in neonates given antibiotics before the lumbar puncture is performed. Traumatic lumbar punctures are common and complicate interpretation of CSF white blood cell counts. The purpose of this study is to evaluate the diagnostic utility of adjusting CSF white blood cell counts based on CSF and peripheral red blood cell counts.

METHODS

Cohort study of lumbar punctures performed between 1997 and 2004 at 150 neonatal intensive care units managed by the Pediatrix Medical group. Traumatic lumbar punctures were defined as CSF specimens with > or =500 red blood cells/mm. CSF white blood cell counts were adjusted downward for traumatic lumbar punctures using several commonly used methods. We calculated sensitivity, specificity, likelihood ratios, and area under the receiver operating characteristic curve of unadjusted and adjusted CSF white blood cell counts for predicting meningitis in neonates with traumatic lumbar punctures.

RESULTS

Of 6374 lumbar punctures, 2519 (39.5%) were traumatic. 114/6374 (1.8%) were positive for meningitis; 50 neonates with traumatic lumbar punctures had meningitis. The areas under the receiver operating characteristic curve for white blood cell count unadjusted and adjusted by all methods were similar.

CONCLUSIONS

Adjustment of CSF white blood cell counts to account for increased red cells does not improve diagnostic utility. Adjustment can result in loss of sensitivity with marginal gain in specificity. Adjustment of WBC counts in the setting of a traumatic lumbar puncture does not aid in the diagnosis of bacterial and fungal meningitis in neonates.

Sterile cerebrospinal fluid pleocytosis in young infants with urinary tract infections

In a multicenter prospective study, 91 of 1025 febrile infants <or=60 days of age had urinary tract infections. Among patients with urinary tract infections and without traumatic lumbar punctures, sterile cerebrospinal fluid pleocytosis was uncommon (0%-8%, depending on the definition) in contrast to earlier studies reporting this association.

Predictive value of cerebrospinal fluid parameters in neonates with intraventricular drainage devices

OBJECT

Infection is a common and potentially devastating complication following placement of ventriculoperitoneal (VP) shunts and cerebrospinal fluid (CSF) reservoirs in neonates. The goal of this study was to determine the normal ranges for cell count parameters in neonates with VP shunts and CSF reservoirs, as well as to determine the predictive value of CSF parameters as markers of infection.

METHODS

The authors evaluated neonates from 150 different neonatal intensive care units of the Pediatrix Medical Group who had undergone a lumbar puncture, VP shunt insertion, or CSF reservoir placement between 1997 and 2004. Data were collected from 9704 neonates with a mean birthweight of 2573 g and a mean gestational age of 35 weeks. Of these neonates, 181 had VP shunt insertions or CSF reservoir placements.

RESULTS

In neonates with negative CSF cultures, significant differences were found between those with and without VP shunts or CSF reservoirs when comparing red blood cell (RBC) count (620/mm' compared with 155/mm3, p < 0.05), absolute eosinophil count (4/mm3 compared with 2/mm3, p < 0.001), protein levels (179 mg/dl compared with 115 mg/dl, p < 0.001), and glucose levels (27.5 mg/dl compared with 49 mg/dl, p < 0.001). No significant difference was found between white blood cell (WBC) counts in neonates with or without VP shunts who had negative CSF cultures. The sensitivity and specificity of a cutoff value of 20 WBCs/mm3 for diagnosing meningitis in neonates with positive cultures and intraventricular drainage devices were 67% and 62%, respectively.

CONCLUSIONS

Although differences exist between CSF parameters found in neonates with or without VP shunts or CSF reservoirs, only the difference in RBC count is large enough to be clinically significant. The authors found that the utility of CSF parameters in neonates with VP shunts or CSF reservoirs was limited due to poor diagnostic sensitivity and specificity.

Cerebrospinal fluid leucocyte counts in healthy neonates

OBJECTIVES

To determine the cerebrospinal fluid (CSF) white blood cell (WBC) count of normal term neonates, and compare the CSF WBC profile of normal and symptomatic infants without infection of the central nervous system (CNS).

METHOD

Neonates were included if (a) they were at risk of congenital Toxoplasma infection and had undergone a lumbar puncture to assess CNS involvement, and (b) serial specific serum IgG and IgM determinations had ruled out congenital infection. According to neonatal chart reviews, 30 consecutive patients without CNS infection were classified as normal (absolutely asymptomatic) or symptomatic (any kind of symptoms).

RESULTS

CSF WBC count was higher in 11 symptomatic (7/mm(3), 0-30/mm(3)) than in 19 normal (1/mm(3), 0-5/mm(3)) neonates (p<0.01).

CONCLUSION

Normal neonatal CSF contains up to 5 WBCs/mm(3). Mild pleocytosis can be found in symptomatic infants without CNS infection.

Paediatric Investigators Collaborative Network on Infections in Canada (PICNIC) study of aseptic meningitis

Background

The seasonality, clinical and radiographic features and outcome of aseptic meningitis have been described for regional outbreaks but data from a wider geographic area is necessary to delineate the epidemiology of this condition.

Methods

A retrospective chart review was completed of children presenting with aseptic meningitis to eight Canadian pediatric hospitals over a two-year period.

Results

There were 233 cases of proven enteroviral (EV) meningitis, 495 cases of clinical aseptic meningitis and 74 cases of possible aseptic meningitis with most cases occurring July to October. Headache, vomiting, meningismus and photophobia were more common in children ≥ 5 years of age, while rash, diarrhea and cough were more common in children < 5 years of age. Pleocytosis was absent in 22.3% of children < 30 days of age with proven EV meningitis. Enterovirus was isolated in cerebrospinal fluid (CSF) from 154 of 389 patients (39.6%) who had viral culture performed, and a nucleic acid amplification test for enterovirus was positive in CSF from 81 of 149 patients (54.3%). Imaging of the head by computerized tomography or magnetic resonance imaging was completed in 96 cases (19.7%) and 24 had abnormal findings that were possibly related to meningitis while none had changes that were definitely related to meningitis. There was minimal morbidity and there were no deaths.

Conclusion

The clinical presentation of aseptic meningitis varies with the age of the child. Absence of CSF pleocytosis is common in infants < 30 days of age. Enterovirus is the predominant isolate, but no etiologic agent is identified in the majority of cases of aseptic meningitis in Canadian children.

Neonatal meningitis: what is the correlation among cerebrospinal fluid cultures, blood cultures, and cerebrospinal fluid parameters?

BACKGROUND

Meningitis is a substantial cause of morbidity and mortality in neonates. Clinicians frequently use the presence of positive blood cultures to determine whether neonates should undergo lumbar puncture. Abnormal cerebrospinal fluid (CSF) parameters are often used to predict neonatal meningitis and determine length and type of antibiotic therapy in neonates with a positive blood culture and negative CSF culture.

METHODS

We evaluated the first lumbar puncture of 9111 neonates at > or =34 weeks' estimated gestational age from 150 NICUs, managed by the Pediatrix Medical Group, Inc. CSF culture results were compared with results of blood cultures and CSF parameters (white blood cells [WBCs], glucose, and protein) to establish the concordance of these values in culture-proven meningitis. CSF cultures positive for coagulase-negative staphylococci and other probable contaminants, as well as fungal and viral pathogens, were excluded from analyses.

RESULTS

Meningitis was confirmed by culture in 95 (1.0%) neonates. Of the 95 patients with meningitis, 92 had a documented blood culture. Only 57 (62%) of 92 patients had a concomitant-positive blood culture; 35 (38%) of 92 had a negative blood culture. In neonates with both positive blood and CSF cultures, the organisms isolated were discordant in 2 (3.5%) of 57 cases. In each case, the CSF pathogen required different antimicrobial therapy than the blood pathogen. For culture-proven meningitis, CSF WBC counts of >0 cells per mm3 had sensitivity at 97% and specificity at 11%. CSF WBC counts of >21 cells per mm3 had sensitivity at 79% and specificity at 81%. Culture-proven meningitis was not diagnosed accurately by CSF glucose or by protein.

CONCLUSIONS

Neonatal meningitis frequently occurs in the absence of bacteremia and in the presence of normal CSF parameters. No single CSF value can reliably exclude the presence of meningitis in neonates. The CSF culture is critical to establishing the diagnosis of neonatal meningitis.

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.

Double blind placebo-controlled trial of pleconaril in infants with enterovirus meningitis

BACKGROUND

Enterovirus (EV) meningitis is common in infants and may have neurologic complications. Treatment of older children and adults with pleconaril has been associated with reduced severity and duration of symptoms. This study evaluated the pharmacokinetics, safety and efficacy of pleconaril in infants with EV meningitis.

METHODS

Infants < or =12 months old with suspected EV meningitis were randomized 2:1 to receive pleconaril, 5 mg/kg/dose orally three times a day or placebo for 7 days. Evaluations included pharmacokinetic determinations, safety laboratory testing, serial culture and PCR assays and clinical evaluations.

RESULTS

Of 21 evaluable subjects 20 were confirmed with EV infection (12 pleconaril, 8 placebo). Among pleconaril-treated subjects 26 of 29 peak and trough pleconaril levels exceeded the 90% inhibitory concentration for EVs. A median 3.5-fold drug accumulation occurred between Days 2 and 7. Pleconaril was well-tolerated, although twice as many adverse events occurred per subject in the pleconaril group. Serial cultures from the oropharynx, rectum and serum had low yield (< or =50%) and positivity generally persisted for <4 days in both groups. Serial PCR assays of culture-negative oropharyngeal and rectal specimens had high positivity rates (generally > or =50%) persisting through Day 14. No significant differences in duration of positivity by culture or PCR, hospitalization or symptoms were detected between groups.

CONCLUSIONS

The dose of pleconaril studied provided sufficient plasma levels and was well-tolerated; however, drug accumulation was evident. The low yields of serial viral cultures, relatively short and benign clinical courses and the small number of subjects enrolled precluded demonstration of efficacy. If this medication is to be prescribed in infants, surveillance for toxicity related to drug accumulation will be necessary.

Central nervous system infection in congenital syphilis

BACKGROUND

Identification of infants with Treponema pallidum infection of the central nervous system remains challenging.

METHODS

We used rabbit-infectivity testing of the cerebrospinal fluid to detect T. pallidum infection of the central nervous system in infants born to mothers with syphilis. The results were compared with those of clinical, radiographic, and conventional laboratory evaluations; IgM immunoblotting of serum and cerebrospinal fluid; polymerase-chain-reaction (PCR) assay testing of serum or blood and cerebrospinal fluid; and rabbit-infectivity testing of serum or blood.

RESULTS

Spirochetes were detected in the cerebrospinal fluid of 19 of 148 infants by rabbit-infectivity testing. Exposure of the infant to antibiotics before cerebrospinal fluid was obtained for rabbit-infectivity testing was associated with a negative test result (P=0.001). Spirochetes were detected in the cerebrospinal fluid in 17 of 76 infants (22 percent) who had no prior antibiotic exposure. These 17 infants included 41 percent (16 of 39) of those with some abnormality on clinical, laboratory, or radiographic evaluation; 60 percent (15 of 25) of those with abnormal findings on physical examination that were consistent with congenital syphilis; and 41 percent (17 of 41) of those with a positive result on IgM immunoblotting or PCR testing of serum, blood, or cerebrospinal fluid, or a positive result on rabbit-infectivity testing of serum or blood. Only one infant who had normal findings on clinical evaluation had a positive cerebrospinal fluid rabbit-infectivity test. Overall, central nervous system infection was best predicted by IgM immunoblotting of serum or PCR assay of serum or blood.

CONCLUSIONS

Most infants with T. pallidum infection of the central nervous system can be identified by physical examination, conventional laboratory tests, and radiographic studies. However, the identification of all such infants requires the use of additional tests, including IgM immunoblotting and PCR assay.

Neonatal bacterial meningitis

Despite major improvements in infant intensive care, neonatal meningitis remains a devastating disease. Survivors of bacterial meningitis are at high-risk for life-long neurological handicaps, and despite a reduction in mortality, the morbidity of neonatal meningitis has not changed substantially over the last thirty years. A substantial improvement in outcome is unlikely to result from further refinements in ICU technology or new antibiotics. However, recent advancements in our understanding of the pathogenesis of meningitis and the pathophysiology of brain injury in meningitis may provide the opportunity to interrupt the mechanisms that allow bacteria to enter the central nervous system and initiate the inflammatory response. Strategies aimed at modulating the inflammatory response must be chosen carefully, so as not to disrupt normal host responses needed for the infant to recover from the infectious episode.