In defense of empiric acyclovir therapy in certain neonates

Parenteral aciclovir for suspected herpes simplex virus infection in children: 0-18 years

BACKGROUND

Variations in neonatal aciclovir prescribing for suspected herpes simplex virus (HSV) disease are well-known, but there are limited data describing aciclovir prescribing in older children.

METHODS

Medical records of neonates (≤28 days) and children (29 days to 18 years) prescribed intravenous aciclovir for suspected HSV disease (1 January 2019-12 December 2019) in eight Australian and New Zealand hospitals were reviewed. Prescribing indication, HSV testing, aciclovir prescription details, adverse events and discharge diagnosis were recorded.

RESULTS

1426 received empirical aciclovir. For neonates (n = 425), the median duration was 1 day (IQR 1-3), 411/425 underwent HSV investigations and 13/425 had HSV disease (two with disseminated encephalitis, four with encephalitis and seven with skin, eye, mouth disease). Of the 1001 children, 906 were immunocompetent. 136/906 suspected of mucocutaneous disease received aciclovir for a median of 2 days (1-2), 121/136 underwent HSV testing, and 69/136 had proven disease. 770/906 received aciclovir for suspected disseminated disease or encephalitis for a median of 1 day (1-2), 556/770 underwent HSV testing, and 5/770 had disseminated disease or encephalitis. Among 95 immunocompromised children, 53/58 with suspected mucocutaneous disease had HSV testing and this was confirmed in 22. Disseminated disease or encephalitis was suspected in 37/95, HSV testing conducted in 23/37 and detected in one. The median aciclovir duration was 3 (2-7) days for immunocompromised children. Nephrotoxicity occurred in 7/1426 and 24/1426 had an extravasation injury.

CONCLUSION

Frequent and often unnecessary intravenous aciclovir prescribing for suspected HSV encephalitis or disseminated disease occurred in children, as evidenced by incomplete HSV investigations and only 5/770 older children having the diagnosis confirmed.

Mucosal Site Detection of Herpes Simplex Virus in Neonates

From 2001 to 2023, 17 (14%) of 120 neonates with confirmed herpes simplex virus infection tested positive for herpes simplex virus by polymerase chain reaction (PCR) from only mucosal sites without a clinical mucosal lesion. Whether mucosal PCR positivity reflects early infection that may lead to recognizable disease, transient colonization, or a false-positive PCR result remains a clinical conundrum and warrants further study.

Universal versus targeted treatment of neonatal herpes simplex virus among neonates presenting for sepsis evaluations

PURPOSE OF REVIEW

The American Academy of Pediatrics recently published guidance for the evaluation and management of febrile infants. However, guidance on testing and empiric treatment for neonatal herpes simplex virus (HSV) remains less standardized and subject to clinical practice variation.

RECENT FINDINGS

Recent reports reveal that high numbers of infants presenting for sepsis evaluations need to be treated empirically with acyclovir to capture one case of neonatal HSV. Clinical and laboratory risk factors for neonatal HSV identified in the literature can be used for a targeted approach to testing and treating infants for HSV to optimize resource utilization.

SUMMARY

The literature supports a targeted approach to evaluation and empiric acyclovir treatment for neonatal HSV, but additional studies are needed to validate this approach given the rarity of disease.

Herpes simplex virus infection among neonates suspected of invasive bacterial infection: a population-based cohort study

OBJECTIVE

To estimate the incidence of neonatal herpes simplex virus (HSV) infection and the number of neonates with suspected invasive bacterial infection (IBI) needed to treat (NNT) with acyclovir to ensure prompt treatment of invasive HSV infections.

DESIGN

A nationwide population-based cohort study.

SETTING

All neonatal and paediatric emergency departments in Denmark from 1 January 2010 to 31 December 2019.

PATIENTS

Neonates aged 0-28 days with HSV infection.

MAIN OUTCOME MEASURES

The main outcome measures were incidence and NNT. The NNT was calculated based on neonates with invasive HSV infection whose onset symptoms resembled IBI and the estimated number of Danish neonates who received antibiotics for suspected IBI.

RESULTS

Fifty-four neonates with HSV infection were identified, that is, an incidence of 9 per 100 000 live births. Twenty presented with symptoms resembling IBI, all within the first 14 days of life. Of 18 (78%) neonates, 14 had elevated C reactive protein, 14 of 19 (74%) had elevated alanine aminotransferase and 11 of 17 (65%) had thrombocytopaenia. The estimated NNTs with empiric acyclovir at postnatal ages 0-3, 4-7 and 8-14 days were 1139 (95% CI 523 to 3103), 168 (95% CI 101 to 726) and 117 (95% CI 48 to 198), respectively.

CONCLUSIONS

The incidence of neonatal HSV infection was higher than in previous decades; however, the estimated NNT with empiric acyclovir was high. Therefore, we propose not to treat all neonates suspected of IBI with empiric acyclovir, as current European guidelines suggest. However, HSV should be considered in neonates with signs of infection, especially after the third postnatal day and in neonates with high alanine aminotransferases and thrombocytopaenia.

Variation in Diagnostic Testing and Empiric Acyclovir Use for HSV Infection in Febrile Infants

BACKGROUND AND OBJECTIVES

Clinicians evaluating for herpes simplex virus (HSV) in febrile infants must balance detection with overtesting, and there is no universally accepted approach to risk stratification. We aimed to describe variation in diagnostic evaluation and empirical acyclovir treatment of infants aged 0 to 60 days presenting with fever and determine the association between testing and length of stay (LOS).

METHODS

In this retrospective 44-hospital observational study, we used the Pediatric Health Information System database to identify infants aged ≤60 days evaluated for fever in emergency departments from January 2016 through December 2017. We described hospital-level variation in laboratory testing, including HSV, imaging and other diagnostic evaluations, acyclovir use, and LOS. We assessed the relationship between HSV testing and LOS using generalized linear mixed effects models adjusted for age and illness severity.

RESULTS

In 24 535 encounters for fever, the median HSV testing frequency across hospitals was 35.6% (interquartile range [IQR]: 28.5%-53.5%) for infants aged 0 to 21 days and 12% (IQR: 8.6%-15.7%) for infants aged 22 to 60 days. Among HSV-tested patients, median acyclovir use across hospitals was 79.2% (IQR: 68.1%-89.7%) for those aged 0 to 21 days and 63.6% (IQR: 44.1%-73%) for those aged 22 to 60 days. The prevalence of additional testing varied substantially by hospital and age group. Risk-adjusted LOS for HSV-tested infants was significantly longer than risk-adjusted LOS for those not tested (2.6 vs 1.9 days, P < .001).

CONCLUSIONS

Substantial variation exists in diagnostic evaluation and acyclovir use, and infants who received HSV testing had a longer LOS than infants who did not. This variability supports the need for further studies to help clinicians better risk-stratify febrile infants and to guide HSV testing and treatment decisions.

Evaluation for Neonatal HSV in Infants Undergoing Workup for Serious Bacterial Infection: A 5-Year Retrospective Review

OBJECTIVES

To describe the characteristics of infants evaluated for serious bacterial infection, focusing on empirical testing and treatment of herpes simplex virus (HSV) and describe the characteristics of HSV-positive patients.

METHODS

We included infants aged 0 to 60 days undergoing evaluation for serious bacterial infection in the emergency department. This descriptive study was conducted between July 2010 and June 2014 at a tertiary-care children's hospital. Eligible patients were identified on the basis of age at presentation to the hospital and laboratory specimens. Infant characteristics, symptoms on presentation, and laboratory workup were compared between HSV-positive and HSV-negative patients by using the 2-sample t test or the Wilcoxon rank test.

RESULTS

A total of 1633 infants were eligible for inclusion, and 934 (57.2%) were 0 to 28 days of age. HSV was diagnosed in 19 infants, 11 of whom had disseminated disease. Compared with those without HSV, HSV-positive infants were younger, less likely to be febrile and to present with nonspecific symptoms, and more likely to have a mother with HSV symptoms (P < .05). Testing from all recommended locations was only performed in 22% of infants. Infants tested or empirically treated with acyclovir had a longer median length of stay compared with children who were not tested or treated (P < .01).

CONCLUSIONS

The absence of fever should not preclude a workup for HSV in neonates, and when a workup is initiated, emphasis should be placed on obtaining samples from serum, cerebrospinal fluid, and surface specimens. Physicians may benefit from a guideline for evaluation of HSV with specific guidance on high-risk features of presentation and recommended testing.

Factors Associated With HSV PCR CSF Testing and Empiric Acyclovir Therapy in Young Febrile Infants

Herpes simplex virus (HSV) infection in infants is a devastating disease with an often subtle presentation. We examined cerebrospinal fluid (CSF) HSV PCR (polymerase chain reaction) testing and empiric acyclovir therapy in young febrile infants. Chart review identified hospitalized infants aged ≤60 days with fever ≥38°C who had undergone lumbar puncture. Previously published criteria were used to define patients at high risk for HSV. Primary outcomes were CSF HSV PCR testing and empiric acyclovir therapy. Of 536 febrile infants, 23% had HSV testing; empiric acyclovir was started in 15%. HSV testing and therapy were associated with younger age, seizure, maternal vaginal lesions, postnatal HSV contact, vesicles, poor tone, CSF pleocytosis, and enteroviral testing. Sixty-two percent of high-risk infants did not undergo HSV testing, and 75% did not receive acyclovir. High-risk infants were untested and untreated at relatively high rates. Evidence-based criteria to guide HSV testing and treatment are needed.

Association of Herpes Simplex Virus Testing with Hospital Length of Stay for Infants ≤60 Days of Age Undergoing Evaluation for Meningitis

Although neonatal herpes simplex virus (HSV) causes significant morbidity, utilization of the cerebrospinal fluid (CSF) HSV polymerase chain reaction (PCR) test remains variable. Our objective was to examine the association of CSF HSV PCR testing with length of stay (LOS) in a 20-center retrospective cohort of hospitalized infants aged ≤60 days undergoing evaluation for meningitis after adjustment for patient-level factors and clustering by center. Of 20,496 eligible infants, 7,399 (36.1%) had a CSF HSV PCR test performed, and 46 (0.6% of those tested) had a positive test. Infants who had a CSF HSV PCR test performed had a 23% longer hospital LOS (incident rate ratio 1.23; 95% CI: 1.14-1.33). Targeted CSF HSV PCR testing may mitigate the impact on LOS for low-risk infants.

Impact of an Institutional Guideline on the Care of Neonates at Risk for Herpes Simplex Virus in the Emergency Department

BACKGROUND AND OBJECTIVES

Herpes simplex virus (HSV) is rare in neonates but carries significant morbidity and mortality in that group. Emergency department (ED) clinicians have little guidance to decide when to test for HSV and give acyclovir. We created an institutional guideline to provide guidance in patients younger than 6 weeks. Our objective was to evaluate whether guideline implementation affected the ED's decision to test for HSV, and ED use of HSV polymerase chain reactions (PCRs) and acyclovir.

METHODS

We reviewed charts for patients 1 year before implementation and 1 year after implementation of our guideline. Inclusion criteria were younger than 60 days, admitted through the ED, symptom onset younger than 6 weeks, and any one of the following criteria: (1) ED blood culture obtained, (2) ED or inpatient HSV PCR obtained, and (3) ED or inpatient acyclovir treatment. Premature patients and transfer patients were excluded. We compared whether the decision to initiate HSV testing, ED use of HSV PCRs, serum alanine aminotransferase, and acyclovir use changed post-guideline implementation.

RESULTS

We reviewed 173 charts pre-implementation and 129 post-implementation. We found a significant decrease in ED testing for HSV among patients who did not meet guideline criteria (P < 0.01). We saw an improvement in the use of alanine aminotransferase among patients who met criteria for testing (P = 0.02), but no change in the use of HSV PCRs or acyclovir use among tested patients.

CONCLUSIONS

Guideline implementation reduced HSV evaluations in low-risk patients, but did not improve test utilization or acyclovir administration among those tested. Additional work is needed to improve guideline utilization.

Persistent Gaps in Appropriate Use of Empiric Acyclovir in Neonates

The use of empiric acyclovir for suspected neonatal herpes simplex virus (HSV) infection has been debated for years. To identify the gap in the decision to initiate empiric acyclovir, we performed a retrospective chart review and administered a survey to pediatricians to assess current practices regarding evaluation for possible HSV infection. Seventy infants received empiric acyclovir over a 1-year period; of these, 3 infants (4.3%) had positive HSV testing. Fourteen infants were identified as "high-risk" for HSV infection; of these, 13 infants had incomplete testing. Survey results revealed uncertainty in the decision to initiate acyclovir and in the composition of complete diagnostic testing. This study confirmed the clinical uncertainty in the decision to initiate empiric acyclovir. Using this chart review and survey as a baseline, future efforts will focus on a quality improvement project to reduce empiric acyclovir use in low-risk infants and to ensure complete diagnostic evaluation in high-risk infants.

A 34-Day-Old With Fever, Cerebrospinal Fluid Pleocytosis, and Staphylococcus aureus Bacteremia

A 34-day-old previously healthy boy born full term presented to the emergency department with fever at home (38.1°C), fussiness, and decreased oral intake for 1 day. He was difficult to console at home. He had decreased oral intake without emesis, diarrhea, or a change in urine output. He did not have rhinorrhea, cough, or increased work of breathing noted by parents. He lived at home with his parents and 13-year-old brother, did not attend day care, and had no sick contacts. On examination, he was fussy but consolable. He was febrile to 39.3°C, tachycardic (180 beats per minute), and tachypneic (64 breaths per minute), with mottling and a capillary refill of 3 seconds. The remainder of his examination was normal, without an infectious focus for his fever. A complete blood cell count with differential revealed leukocytosis. A basic metabolic panel was normal. A catheter urinalysis was normal. Cerebrospinal fluid examination yielded pleocytosis, low glucose, and elevated protein. Blood cultures were persistently positive with methicillin-sensitive Staphylococcus aureus, but cerebrospinal fluid cultures remained negative. We present his case, management, and ultimate diagnosis.

Pharmacokinetic considerations in the use of antivirals in neonates

INTRODUCTION

Neonatal patients, because of the inability of their immune system to properly respond to microbial challenge, are highly susceptible to viral infections. Immunoglobulins, monoclonal antibody and antiviral drugs are used for prophylaxis and treatment of viral diseases in neonates. Neonates and, especially, preterm infants differ in drug absorption, distribution, metabolism and excretion from adults and older children.

AREAS COVERED

This review will evaluate deficiencies of neonatal immune responses to microbial challenge that predispose newborns to viral infections, clinical manifestations and the treatment of viral diseases in neonates. We focus on published studies describing antiviral drug pharmacokinetics in neonates and make recommendations on the dosing of these drugs, allowing achievement of maximal clinical benefits in neonates.

EXPERT OPINION

While some efforts were undertaken to study pharmacokinetics and pharmacodynamics of antiviral drugs, much more needs to be done. Current data indicate that the pharmacokinetics of antiviral drugs may vary significantly depending on gestational age, maturation processes of drug-metabolizing enzymes and renal clearance. Specifics of pharmacokinetics of antiviral drugs need to be taken into consideration when they are prescribed to neonates and infants.

Clinical and laboratory characteristics of disseminated herpes simplex virus infection in neonates

BACKGROUND AND OBJECTIVES

Disseminated herpes simplex virus (HSV) infection is the most fulminant type of neonatal HSV infection and has the highest mortality. Early diagnosis and treatment are essential for patient survival. We describe the clinical presentation, laboratory characteristics, and outcomes of neonates with disseminated HSV infection at our institution.

METHODS

A retrospective review of electronic medical records from 2006 to 2013 was performed. Only neonates with disseminated HSV infection, confirmed by using polymerase chain reaction or viral culture results, were included.

RESULTS

Twenty-two cases were identified; the age range was 1 to 14 days. The majority of patients did not have a maternal history of HSV or a history of maternal fever at delivery. Eleven of the patients were delivered by cesarean delivery, and 3 of these patients did not have prolonged rupture of membranes. Neonatal fever, the most common historical characteristic, was present in only one-half of the patients. Pneumonia and respiratory distress were present in one-half of the patients. Serum aspartate aminotransferase and alanine aminotransferase levels were elevated in most, but not all, patients. The blood HSV polymerase chain reaction was positive in all patients tested. Of the 22 study patients, 16 survived and 6 died. The majority of the patients who died had respiratory disease and a delay in the initiation of acyclovir therapy.

CONCLUSIONS

Disseminated HSV infection in neonates can be challenging to diagnose and is associated with high mortality. Clinicians must strongly consider this diagnosis, test the blood for HSV polymerase chain reaction, and initiate early treatment in the appropriate clinical scenarios.

Neonatal herpes simplex virus infections

Neonatal herpes simplex virus infections are uncommon, but because of the morbidity and mortality associated with the infection they are often considered in the differential diagnosis of ill neonates. The use of polymerase chain reaction for diagnosis of central nervous system infections and the development of safe and effective antiviral therapy has revolutionized the diagnosis and management of these infants. Initiation of long-term antiviral suppressive therapy in these infants has led to significant improvement in morbidity. This article summarizes the epidemiology of neonatal herpes simplex virus infections and discusses clinical presentation, diagnosis, management, and follow up of infants with neonatal herpes disease.

Herpes simplex testing in neonates in the emergency department

OBJECTIVES

To determine the prevalence of central nervous system (CNS) herpes simplex virus (HSV) infection in neonates evaluated in the emergency department and to identify factors associated with cerebrospinal fluid (CSF) HSV polymerase chain reaction (PCR) testing. An existing testing paradigm was then applied to determine its potential impact on testing frequency.

METHODS

This nested case-control study included infants aged 0 to 28 days who had lumbar puncture in the emergency department. Multivariate logistic regression was used to identify factors associated with CSF HSV PCR testing.

RESULTS

The CSF HSV PCR testing was performed in 266 (47%) of 570 neonates. The prevalence of CNS HSV infection was 0.5% compared with 1.6% for bacterial meningitis. Performance of CSF HSV PCR testing was not associated with known HSV risk factors. Application of a known HSV testing paradigm would have reduced the proportion of infants tested by 21% without missing any of the cases of CNS HSV infection.

CONCLUSIONS

The HSV testing remains common despite the low prevalence of HSV infection. The CSF HSV PCR testing is not well aligned with known risk factors. Future testing strategies should incorporate community HSV prevalence, known neonatal risk factors, and clinical judgment.

Neonatal herpes disease following maternal antenatal antiviral suppressive therapy: a multicenter case series

OBJECTIVE

The goal was to describe herpes simplex virus (HSV) disease in neonates whose mothers received suppressive acyclovir therapy for HSV infection.

STUDY DESIGN

A multicenter case series of 8 infants who developed neonatal HSV disease following maternal antiviral suppressive therapy during pregnancy.

RESULTS

Eight infants were identified from New Jersey (5), Maine (1), New York (1), and Texas (1) between 2005 and 2009. All 6 mothers of infants infected with HSV who were screened prenatally for group B Streptococcus were positive; 1 mother was not tested and the other had bacterial vaginosis and genital human papillomavirus infection. Six mothers had a first clinical episode of genital HSV infection during this pregnancy; mothers with a prior history of genital HSV had no clinically recognized outbreak during the pregnancy. Perinatal transmission of HSV occurred in 7 infants (despite suppressive therapy until the day of delivery in 5 instances). Seven of 8 patients were born at term; 6 infants were male. In 7 of 8 cases, HSV was diagnosed by 8 days of age. Five infants had skin, eye, and mucous membrane disease, 2 had central nervous system disease (without and with disseminated disease), and one had intrauterine/disseminated disease.

CONCLUSIONS

Although maternal antiviral suppressive therapy is an increasingly wide practice, physicians caring for neonates should be aware that suppressive therapy does not prevent neonatal HSV disease, which can have an atypical clinical presentation and drug resistance.

Delayed acyclovir therapy and death among neonates with herpes simplex virus infection

OBJECTIVE

To determine the association of delayed acyclovir therapy with death among neonates with herpes simplex virus (HSV) infection.

METHODS

A multicenter, retrospective, cohort study was conducted between January 1, 2003, and December 31, 2009, with 1086 neonates (age: ≤28 days) with HSV infection from 41 tertiary care children's hospitals. Early acyclovir therapy was defined as initiation of intravenous acyclovir treatment within 1 day after hospital admission, and delayed acyclovir therapy was defined as initiation of treatment >1 and ≤7 days after hospital admission. Multivariate logistic regression models determined the association between delayed acyclovir therapy and death, with the use of propensity scores for each neonate's likelihood of receiving delayed acyclovir treatment to control for differences in illness severity between groups.

RESULTS

The median age was 10 days. Delayed acyclovir therapy was administered to 262 neonates (24.1%). In most cases (86.2%) of delayed receipt, acyclovir administration occurred on the second or third day of hospitalization. The overall mortality rate was 7.3% (95% confidence interval: 5.8%-9.0%); 9.5% of those who received delayed acyclovir treatment and 6.6% of those who received early acyclovir treatment died. In a multivariate analysis, delayed acyclovir therapy was associated with significantly greater odds of death (adjusted odds ratio: 2.63 [95% confidence interval: 1.36-5.08]) compared with early acyclovir therapy.

CONCLUSIONS

In this multicenter observational study of neonates with HSV infection, delayed initiation of acyclovir therapy was associated with in-hospital death. Our data support the use of empiric acyclovir therapy for neonates undergoing testing for HSV infection.

Empiric acyclovir for neonatal herpes simplex virus infection

BACKGROUND

Because neonatal herpes simplex virus (NHSV) infection is difficult to diagnose, there has been a move towards using more empiric acyclovir (ACV).

OBJECTIVE

The purpose of this study was to review the use of ACV to optimize future management of NHSV.

METHODS

Charts were reviewed for infants started on intravenous ACV up to day 43 of life--January 2001 through February 2007--at five hospitals in Edmonton and Calgary.

RESULTS

ACV was started for possible (N = 115) or proven (N = 3) herpes simplex virus (HSV) infection. Six of the infants with possible HSV infection later had proven HSV infection. Seizures (34%), hemodynamic instability (29%) and skin lesions (24%) were the most common indications for ACV. Among the 118 infants, 106 (90%) had cerebrospinal fluid obtained and 82 (69%) had at least one surface swab for HSV but 4 (3%) had no specimens submitted for HSV detection. ACV was continued for 3.9 ± 3.5 days in the infants with no proven HSV disease. Possible nephrotoxicity from ACV was recorded in 3 of these 109 infants and in none of the infants with proven HSV disease.

CONCLUSIONS

Clinicians in Alberta primarily consider the diagnosis of NHSV infection when confronted with a neonate with seizures, hemodynamic instability or suspicious skin lesions, but need to consider the diagnosis more often if all cases are to be treated at first presentation. They often perform incomplete investigations to rule out NHSV infection. Adverse events from ACV appear to be uncommon when the drug is used for suspected NHSV disease.

Herpes simplex virus infection in young infants during 2 decades of empiric acyclovir therapy

OBJECTIVE

To describe the clinical presentation of HSV-infected young infants and to seek distinctive features that could permit a targeted approach to empiric use of acyclovir.

METHODS

Case study of neonatal HSV during a 22-year period of an institutional strategy of consistent use of acyclovir empirically in all infants with onset of an illness at ≤ 21 days of age for which antibiotics were given empirically. Multiple sources were used to optimize HSV case data, and to estimate the rate of HSV infection in empirically treated infants.

RESULTS

A total of 32 infants with perinatally acquired HSV infection were identified. All received acyclovir empirically at admission. At presentation, 50% of infants had only nonspecific complaints, which was fever in 75%. After testing, 75% of infants with HSV had central nervous system (CNS) infection, including 40% who presented with mucocutaneous lesions, 83% with seizures, and 94% with nonspecific complaints. Cerebrospinal fluid (CSF) polymerase chain reaction confirmed CNS infection in 16 of 22 (73%) patients tested. Cultures of mucocutaneous lesion yielded HSV in 8 of 10 cases, but culture of CSF was negative in all 26 cases tested, and screening cultures of unaffected mucosal sites were the only HSV-confirmatory test in a single patient. Laboratory and CSF findings were not distinctive in patients with HSV. Age of ≤ 21 days at onset of symptoms captured 90% of all infants with HSV and 94% of those with nonspecific complaints. An estimated 1.3% of empirically treated patients had HSV infection.

CONCLUSIONS

Early manifestations of perinatally acquired HSV are frequently nonspecific, yet CNS infection is common. Empiric acyclovir strategy narrowly restricted to infants with onset of illness at ≤ 21 days of age, who would receive antibiotics empirically, captured 90% of HSV cases and anticipated a rate of HSV CNS infection similar to that of bacterial meningitis.