Meningitis in premature infants with respiratory distress: role of admission lumbar puncture

Is Lumbar Puncture Avoidable in Low-Risk Neonates with Suspected Sepsis?

OBJECTIVE

Performing lumbar punctures (LP) in all clinically suspected neonatal sepsis, as per current recommendations, results in many "negative" LPs. LPs are not without their own risks. With the intention of minimizing unnecessary LPs among neonates, we aimed to identify a subgroup at extremely low risk of developing possible meningitis so that an LP could be safely avoided in it.

STUDY DESIGN

This was a prospective, observational, and cross-sectional study in a level III neonatal unit. We included 300 episodes, in which LP was performed for suspected sepsis. We recorded a comprehensive set of clinico-demographic variables, laboratory parameters, sickness score, organ dysfunction score, and organ localization and studied association of these factors with "definite (culture positive) or possible meningitis." "Possible" meningitis was defined with liberal criteria, intending not to miss any meningitis. A subgroup without a single factor associated with "definite or possible meningitis" was analyzed for incidence of meningitis.

RESULTS

There were 121 episodes of "definite or possible meningitis" among 300 episodes of sepsis. On unadjusted analysis, apnea, irritability, high-pitched cry, seizures, neutrophilia, high C-reactive protein (CRP), score for acute neonatal physiology and perinatal extension II (SNAPPE-II), urine output, and leukomalacia were associated with "definite or possible" meningitis (p < 0.05). On multivariate analysis, no apneas, no neutrophilia, and normal CRP were independently associated with "no definite or possible meningitis." Nevertheless, the subgroup that had a combination of no apneas, no neutrophilia, and normal CRP (n = 118) had a 29% probability of "definite or possible meningitis."

CONCLUSION

The lowest risk subgroup had a 29% chance of having "definite or possible" meningitis. There is no subgroup that we could identify among neonates with suspected sepsis, in which it is safe to avoid an LP.

KEY POINTS

· LP are performed in all cases of late onset neonatal sepsis.. · Previous authors unsuccessfully tried to identify high-risk groups for performing LP.. · We were unable to identify an extremely low-risk group in which LP could be safely avoided..

When to Include a Lumbar Puncture in the Evaluation for Neonatal Sepsis

Meningitis is a devastating infection in infants and is linked to adverse long-term outcomes. The prevalence of meningitis is variable and depends on gestational age, postnatal age, and clinical setting. Early diagnosis and treatment with appropriate antibiotics are crucial to decrease the risk of morbidity and mortality. Lumbar punctures are essential for the diagnosis of meningitis, but clinicians may defer lumbar puncture if the risk for meningitis is low or if there are substantial concerns regarding the risk associated with the procedure. Awareness of the epidemiology and microbiology of meningitis in infants, as well as valid contraindications to performing a lumbar puncture, is necessary to avoid missed diagnoses and procedure-related adverse effects.

Pitfalls in the diagnosis of meningitis in neonates and young infants: the role of lumbar puncture

Meningitis occurs frequently in neonates and can lead to a number of acute, severe complications and long-term disabilities. An early diagnosis of neonatal meningitis is essential to reduce mortality and to improve outcomes. Initial clinical signs of meningitis are often subtle and frequently overlap with those of sepsis, and current haematologic tests do not distinguish sepsis from meningitis. Thus, lumbar puncture (LP) remains the gold standard for the diagnosis of meningitis in infants, and this procedure is recommended in clinical guidelines. Nevertheless, in clinical practice, LP is frequently deferred or omitted due to concerns regarding hypothetical adverse events or limited experience of the performer. Future studies should assess whether a combination of clinical findings and select haematologic tests at disease onset can identify those neonates with the highest risk of meningitis who should undergo LP. Furthermore, clinicians should be convinced that the actual benefits of an early diagnosis of meningitis far outweigh the hypothetical risks associated with LP.

La prise en charge des nouveau-nés à terme à risque de sepsis bactérien d’apparition précoce

Le sepsis bactérien néonatal d’apparition précoce (SAP) se manifeste avant l’âge de sept jours. Le présent document de principes contient des recommandations à jour sur les soins aux nouveau-nés à terme (d’au moins 37 semaines d’âge gestationnel) à risque de SAP, dans les 24 heures suivant la naissance. La colonisation de la mère par le streptocoque du groupe B (SGB) pendant la grossesse en cours, la bactériurie à SGB, une maladie à SGB invasive chez un nourrisson précédent, une rupture prolongée des membranes (d’au moins 18 heures) et la fièvre de la mère (température d’au moins 38 °C) sont les facteurs de risque les plus associés au SAP. Puisque ces facteurs s’accumulent, la probabilité de SAP augmente en fonction de leur nombre. Il n’existe actuellement aucun test de laboratoire assez sensible, y compris les indices leucocytaires, pour permettre aux cliniciens d’écarter le SAP en toute sécurité. Tous les nouveau-nés malades dont les signes cliniques laissent supposer un sepsis doivent recevoir une antibiothérapie empirique après le prélèvement de cultures. La prise en charge des nouveau-nés à terme qui semblent en bonne santé, mais qui sont à risque, dépend du nombre de facteurs de risque (y compris la colonisation de la mère par le SGB) et de l’utilisation d’une antibioprophylaxie contre le SGB par la mère pendant la période intrapartum. Dans certains cas, il faut personnaliser la prise en charge. Il est essentiel d’évaluer et d’observer attentivement ces nouveau-nés à risque pour prodiguer des soins appropriés.

Management of term infants at increased risk for early-onset bacterial sepsis

Early-onset neonatal bacterial sepsis (EOS) is sepsis occurring within the first 7 days of life. This statement provides updated recommendations for the care of term (≥37 weeks' gestational age) newborns at risk of EOS, during the first 24 hours of life. Maternal Group B streptococcus (GBS) colonization in the current pregnancy, GBS bacteriuria, a previous infant with invasive GBS disease, prolonged rupture of membranes (≥18 hours) and maternal fever (temperature ≥38°C) are the factors most commonly associated with EOS. These risk factors are additive; the presence of more than one factor increases the likelihood of EOS. At present, there is no laboratory test, including white blood cell indices, that has sufficient sensitivity to allow clinicians to safely rule out EOS. All unwell infants with clinical signs suggesting sepsis must be treated empirically with antibiotics, once cultures have been taken. The management of well-appearing, at-risk term infants depends on the number of risk factors (including maternal GBS colonization) and whether maternal intrapartum antibiotic prophylaxis for GBS was used. In some cases, management should be individualized. Careful assessment and observation of these at-risk infants are a fundamental component of appropriate care.

Optimizing the Use of Antibacterial Agents in the Neonatal Period

Antibiotics are invaluable in the management of neonatal infections. However, overuse or misuse of antibiotics in neonates has been associated with adverse outcomes, including increased risk for future infection, necrotizing enterocolitis, and mortality. Strategies to optimize the use of antibiotics in the neonatal intensive care unit include practicing effective infection prevention, improving the diagnostic evaluation and empiric therapy for suspected infections, timely adjustment of therapy as additional information becomes available, and treating proven infections with an effective, narrow-spectrum agent for the minimum effective duration. Antibiotic stewardship programs provide support for these strategies but require the participation and input of neonatologists as stakeholders to be most effective.

Variation in lumbar punctures for early onset neonatal sepsis: a nationally representative serial cross-sectional analysis, 2003-2009

BACKGROUND

Whether lumbar punctures (LPs) should be performed routinely for term newborns suspected of having early onset neonatal sepsis (EONS) is subject to debate. It is unclear whether variations in performance of LPs for EONS may be associated with patient, hospital, insurance or regional factors. Our objective was to identify characteristics associated with the practice of performing LPs for suspected EONS in a nationally representative sample.

METHODS

Utilizing data from the 2003, 2006 and 2009 Kids' Inpatient Database (KID) compiled by the Agency for Healthcare Research and Quality, we examined the frequency and characteristics of term, normal-birth weight newborns receiving an LP for EONS. Survey-weighting was applied for national estimates and used in chi squared and multivariable regression analysis.

RESULTS

In 2009, there were 13,694 discharges for term newborns that underwent LPs for apparent EONS. Newborns having LPs performed were more likely to be covered by Medicaid vs. private insurance (51.9 vs. 45.1 percent; p < 0.001), be born in urban vs. rural hospitals (94.8 vs. 87.3 percent; p < 0.001), teaching vs. non-teaching (60.8 vs. 43.1 percent; p < 0.001) and children's hospitals vs. non-children's (23.0 vs. 11.2 percent; p < 0.001). Lastly, newborns having LPs performed were disproportionately born in the Northeast census region (p = 0.03). In multi-year adjusted analysis, infants with Medicaid coverage, and those born in urban or teaching hospitals, consistently had higher odds of having an LP performed.

CONCLUSIONS

We found pronounced variation in LPs performed for EONS, even when adjusting for clinical conditions that would prompt LPs. These findings indicate practice variations in newborn care that merit further examination and explanation.

Meningitis in preterm neonates: importance of cerebrospinal fluid parameters

Cerebrospinal fluid parameters are of great importance in diagnosing meningitis, but normal values for preterm neonates are based on small, single-center studies. We sought to determine current values for preterm neonate cerebrospinal fluid parameters and assess the association of cerebrospinal fluid parameters with culture proven meningitis. We performed a cohort study of the first lumbar puncture from 4632 neonates < 34 weeks' gestation performed in the years 1997 to 2004 at 150 neonatal intensive care units managed by the Pediatrix Medical Group. We identified 95 cases of meningitis from the 4632 lumbar punctures. The area under the receiver operating characteristic curves for white blood cell count, glucose, and protein were 0.80, 0.63, and 0.72, respectively, for prediction of culture-proven meningitis. Cerebrospinal fluid parameters used to diagnose meningitis in the absence of dependable cerebrospinal fluid cultures are unreliable. Caution should be employed when interpreting cerebrospinal fluid parameters in the premature neonate.

Infection in late preterm infants

Late preterm neonates have unique susceptibilities to infection. The closed setting of the neonatal ICU (NICU) and the immunologic immaturity of premature infants set the state for the development of nosocomial infections. This article discusses infections that might be seen in this population and gives options for diagnosis and treatment.

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.

Diagnosis and management of bacterial infections in the neonate

Perinatally acquired bacterial neonatal sepsis is a low-incidence,high-risk disease. Although incidence of the most common etiology,group B Streptococcus, has been reduced by prophylactic strategies,neonatal sepsis has not been eradicated, and vigilance must remain high. Accurate diagnosis is difficult: signs and symptoms are hard to distinguish from other causes of neonatal distress, and definitive diagnostic tests are not available. The clinician must make a judgment call, considering the perinatal history, the constellation of signs and symptoms, and the results of existing diagnostic tests,before neonatal sepsis can diagnosed or excluded. With diagnosis,knowledge of the specific disease states and clinical algorithms for management aid in formulating a plan of treatment with antimicrobial agents and supportive care.

Controversies in neonatal infection

Antibiotics are an important part of neonatal care, but we must be careful that a short-sighted approach to their use does not magnify the problems they are designed to prevent. Prevention of infections by good infection control practices and minimizing risk factors for sepsis is just as important as appropriate antibiotic use. Attempts to eradicate colonizing organisms of low virulence may result in their replacement by more problematic organisms, so over-vigorous use of antibiotics to try to prevent infections is not always wise.

Clinical microbiology of bacterial and fungal sepsis in very-low-birth-weight infants

Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.

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.

Early-onset neonatal group B streptococcal infection: implications for practice

Group B streptococcus (GBS) is the leading bacterial infection associated with morbidity and mortality of newborns in the United States. Most neonatal infections can be prevented through the use of intrapartum antimicrobial prophylaxis in women who are at increased risk for transmitting infection to their newborns. However, prevention strategies have not been implemented widely or consistently, and the incidence of neonatal GBS disease has not declined. An understanding of GBS epidemiology, clinical presentation, and prevention strategies enhances the PNP's decision-making skills in the nursery and strengthens the PNP's ability to evaluate and compare new approaches to GBS prevention.

Bacterial meningitis and the newborn infant

Bacterial meningitis in the neonate differs from meningitis in the older infant and child in a number of ways. Bacterial pathogens primarily are associated with the maternal genitourinary tract. Symptoms and physical findings may be nonspecific, and a high index of suspicion is needed. Management may vary depending on the maturity of the infant and the bacterial pathogen that is isolated.

Bacterial meningitis in the newborn: a prospective study of mortality and morbidity

Neonatal bacterial meningitis is a serious disease around the world, with the incidence changing little in the past 30 years. Group B streptococci, Escherichia coli, and Klebsiella pneumoniae are common causative organisms and lumbar puncture remains the definitive method of diagnosis. The mortality rate has declined in industrialized countries over the years, from almost 50% in the 1970s to less than 10% in 1997. However, neurological sequelae are still frequently observed despite major changes in treatment. Preliminary analysis of our own data from a prospective study of cases in the United Kingdom suggests that treatment with third generation cephalosporins is related to a decrease in mortality but not morbidity.

Early onset neonatal bacterial infections

The evaluation of a neonate with suspected sepsis is one of the most common, most demanding, and most important tasks of the pediatrician or neonatologist. This review summarizes the difficulties in the prompt diagnosis of neonatal sepsis and the appropriate utilization of screening laboratory tests of blood, urine, and cerebrospinal fluid in this setting. The appropriate utilization of these laboratory tests requires careful consideration of the inherent limitations and appreciation of the sensitivity and specificity of these tests for the diagnosis of early onset bacteremia and sepsis.

Term newborns who are at risk for sepsis: are lumbar punctures necessary?

OBJECTIVES

To determine: (1) whether a lumbar puncture (LP) is indicated in asymptomatic full-term newborns delivered by mothers at risk of intrapartum sepsis; and (2) whether gentamicin improves bacterial coverage for such newborns when used with ampicillin.

DESIGN

A retrospective chart review from 1987 through 1993 of all newborns with positive blood and/or cerebrospinal fluid cultures in the first 7 days of life.

METHODS

Pregnant women were screened in the second trimester for group B streptococci and given ampicillin during labor if two or more risk factors were present: group B streptococci colonization, maternal fever or leukocytosis, rupture of membranes at more than 18 hours, foul-smelling amniotic fluid, and fetal tachycardia. After sepsis evaluation (LP, blood culture, white blood cell count, and differential), asymptomatic infants received ampicillin and gentamicin for 48 to 72 hours unless cultures grew pathogens.

RESULTS

Of approximately 24 452 full-term births in 7 years, 7% (1712) had evaluations for symptoms of sepsis, and 14% (3423) were asymptomatic but had evaluations for maternal risk factors. There were 11 cases of meningitis, all involving symptomatic newborns; 10 of these 11 had positive blood cultures for the same organism. In asymptomatic infants, none of the 3423 had meningitis (95% confidence interval, 0 to 0.0008), although 35 grew contaminants. Of 73 pathogens isolated from blood or cerebrospinal fluid, 7 (9.5%) were resistant to ampicillin. Addition of gentamicin provided coverage for only 2 of these 7 pathogens. Of 5135 infants who received ampicillin and gentamicin, only 2 required gentamicin for improved coverage.

CONCLUSIONS

(1) LP is unnecessary in asymptomatic full-term newborns. (2) Empiric coverage for asymptomatic newborns with maternal risk factors need not include gentamicin at all hospitals, because it only improved the coverage of ampicillin alone from 90% to 93% of pathogens, but it exposed more than 5000 infants to the side effects of gentamicin. (3) The presence of leukopenia (<5000 white blood cells/mm) is highly predictive of bacteremia.

[Retrospective analysis of 1331 samples of cerebrospinal fluid in newborn infants with suspected infection]

BACKGROUND

Definitive diagnosis of a neonatal infection usually requires recovery of an etiologic agent from body fluids or tissues such as spinal fluid, blood and urine. Routine lumbar puncture (LP) may raise some problems in interpreting results.

POPULATION AND METHODS

A retrospective analysis of 1331 samples of CSF was made. LP had been performed on 1041 neonates including 569 prematures (54.6%) as a part of the evaluation for suspected bacterial infection.

RESULTS

In 50.7% of the cases, the CSF was haemorrhagic. The frequency of traumatic taps increased with the degree of prematurity, low birth weight, precocity of LP, association with respiratory distress and disorders of coagulating factors. In addition, haemorragic taps modified biochemical and cytologic characteristics of CSF. One hundred and six (8%) CSF samples contained organisms but the diagnosis of meningitis was certain in only 23 cases (2.2%). In the other 83 cases, CSF was thought to be contaminated, mostly by coagulase-negative staphylococci. Since both blood and CSF cultures were positive for the same bacterial organism in 18 cases, it was concluded that the LP had been useful in identifying the pathogens in only five cases. The high frequency of contaminated CSF led to overestimation of the incidence of true bacterial meningitis (0.57% in our study).

CONCLUSIONS

The low incidence of meningitis in neonates, the risk of having an haemorragic tap associated with the possibility of clinical aggravation during LP and the fact that the same pathogen is frequently (78.2% of cases) identified in blood cultures suggest that the immediate and routine LP is of less value than expected in infants suspected to be infected. LP could be postponed when the neonate presents with a respiratory distress syndrome and/or a precarious haemodynamic state.

Role of routine lumbar puncture in neonatal sepsis

OBJECTIVE

To evaluate the utility of lumbar puncture done routinely as part of complete workup in neonatal sepsis.

METHODOLOGY

Two hundred and nine consecutive lumbar punctures performed in 169 neonates were prospectively evaluated for the diagnosis of meningitis over a 6 month period in a tertiary care referral neonatal unit.

RESULTS

Among babies with 'suspected clinical sepsis', five (3.3%) were diagnosed to have meningitis. None of the clinically normal babies with high risk obstetric factors alone had meningitis. The lumbar puncture was traumatic in 22.9%, and in 26.3% the fluid obtained was inadequate for complete analysis. The results were inconclusive in 37% of the cases.

CONCLUSION

Based on this study, routine lumbar puncture may not be required in clinically normal newborns with adverse obstetric factors. In babies with clinical sepsis, though the yield is not very high; there are no reliable clinical or laboratory markers to predict which babies will have meningitis and hence these babies would warrant a lumbar puncture.

Lumbar puncture in suspected neonatal sepsis

OBJECTIVE

The importance of lumbar puncture (LP) as part of the evaluation of suspected neonatal sepsis is assessed, as it may be the only positive diagnostic test in about 10% of septic babies with meningitis but negative blood cultures. However, LP may compromise respiratory function, and the interpretation of cerebrospinal fluid (CSF) may not be straightforward.

CONCLUSION

The clinical setting and the probability of meningitis are important determinants of the likely value of LP. For asymptomatic neonates with obstetric risk factors for sepsis, and for babies with early-onset respiratory distress alone, LP may be delayed and only performed later if blood cultures are positive. This is because hundreds of LP will be needed to diagnose a single case. However, infants with suspected late-onset sepsis should have an immediate LP because finding Gram-negative bacilli or fungi in the CSF will affect treatment choices.