Predictors of Invasive Herpes Simplex Virus Infection in Young Infants

OBJECTIVES

To identify independent predictors of and derive a risk score for invasive herpes simplex virus (HSV) infection.

METHODS

In this 23-center nested case-control study, we matched 149 infants with HSV to 1340 controls; all were ≤60 days old and had cerebrospinal fluid obtained within 24 hours of presentation or had HSV detected. The primary and secondary outcomes were invasive (disseminated or central nervous system) or any HSV infection, respectively.

RESULTS

Of all infants included, 90 (60.4%) had invasive and 59 (39.6%) had skin, eyes, and mouth disease. Predictors independently associated with invasive HSV included younger age (adjusted odds ratio [aOR]: 9.1 [95% confidence interval (CI): 3.4-24.5] <14 and 6.4 [95% CI: 2.3 to 17.8] 14-28 days, respectively, compared with >28 days), prematurity (aOR: 2.3, 95% CI: 1.1 to 5.1), seizure at home (aOR: 6.1, 95% CI: 2.3 to 16.4), ill appearance (aOR: 4.2, 95% CI: 2.0 to 8.4), abnormal triage temperature (aOR: 2.9, 95% CI: 1.6 to 5.3), vesicular rash (aOR: 54.8, (95% CI: 16.6 to 180.9), thrombocytopenia (aOR: 4.4, 95% CI: 1.6 to 12.4), and cerebrospinal fluid pleocytosis (aOR: 3.5, 95% CI: 1.2 to 10.0). These variables were transformed to derive the HSV risk score (point range 0-17). Infants with invasive HSV had a higher median score (6, interquartile range: 4-8) than those without invasive HSV (3, interquartile range: 1.5-4), with an area under the curve for invasive HSV disease of 0.85 (95% CI: 0.80-0.91). When using a cut-point of ≥3, the HSV risk score had a sensitivity of 95.6% (95% CI: 84.9% to 99.5%), specificity of 40.1% (95% CI: 36.8% to 43.6%), and positive likelihood ratio 1.60 (95% CI: 1.5 to 1.7) and negative likelihood ratio 0.11 (95% CI: 0.03 to 0.43).

CONCLUSIONS

A novel HSV risk score identified infants at extremely low risk for invasive HSV who may not require routine testing or empirical treatment.

The Champagne Tap: Time to Pop the Cork?

BACKGROUND

A "champagne tap" is a lumbar puncture with no cerebrospinal fluid (CSF) red blood cells (RBCs). Clinicians disagree whether the absence of CSF white blood cells (WBCs) is also required.

AIMS

As supervising providers frequently reward trainees after a champagne tap, we investigated how varying the definition impacted the frequency of trainee accolades.

MATERIALS & METHODS

We performed a secondary analysis of a retrospective cross-sectional study of infants ≤60 days of age who had a CSF culture performed in the emergency department (ED) at one of 20 centers participating in a Pediatric Emergency Medicine Collaborative Research Committee (PEM CRC) endorsed study. Our primary outcomes were a champagne tap defined by either a CSF RBC count of 0 cells/mm³ regardless of CSF WBC count or both CSF RBC and WBC counts of 0 cells/mm³ .

RESULTS

Of the 23,618 eligible encounters, 20,358 (86.2%) had both a CSF RBC and WBC count obtained. Overall, 3,147 (13.3%) had a CSF RBC count of 0 cells/mm³ and 377 (1.6%) had both CSF WBC and RBC counts of 0 cells/mm³ (relative rate 8.35, 95% confidence interval 7.51 to 9.27).

CONCLUSIONS

In infants, a lumbar puncture with a CSF RBC count of 0 cells/mm³ regardless of the CSF WBC count occurred eight-times more frequently than one with both CSF WBC and RBC counts of 0 cells/mm³ . A broader champagne tap definition would allow more frequent recognition of procedural success, with the potential to foster a supportive community during medical training, potentially protecting against burnout.

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.

Herpes Simplex Virus Infection in Infants Undergoing Meningitis Evaluation

BACKGROUND

Although neonatal herpes simplex virus (HSV) is a potentially devastating infection requiring prompt evaluation and treatment, large-scale assessments of the frequency in potentially infected infants have not been performed.

METHODS

We performed a retrospective cross-sectional study of infants ≤60 days old who had cerebrospinal fluid culture testing performed in 1 of 23 participating North American emergency departments. HSV infection was defined by a positive HSV polymerase chain reaction or viral culture. The primary outcome was the proportion of encounters in which HSV infection was identified. Secondary outcomes included frequency of central nervous system (CNS) and disseminated HSV, and HSV testing and treatment patterns.

RESULTS

Of 26 533 eligible encounters, 112 infants had HSV identified (0.42%, 95% confidence interval [CI]: 0.35%-0.51%). Of these, 90 (80.4%) occurred in weeks 1 to 4, 10 (8.9%) in weeks 5 to 6, and 12 (10.7%) in weeks 7 to 9. The median age of HSV-infected infants was 14 days (interquartile range: 9-24 days). HSV infection was more common in 0 to 28-day-old infants compared with 29- to 60-day-old infants (odds ratio 3.9; 95% CI: 2.4-6.2). Sixty-eight (0.26%, 95% CI: 0.21%-0.33%) had CNS or disseminated HSV. The proportion of infants tested for HSV (35%; range 14%-72%) and to whom acyclovir was administered (23%; range 4%-53%) varied widely across sites.

CONCLUSIONS

An HSV infection was uncommon in young infants evaluated for CNS infection, particularly in the second month of life. Evidence-based approaches to the evaluation for HSV in young infants are needed.

Spatial and temporal operation of the Scotia Sea ecosystem: a review of large-scale links in a krill centred food web

The Scotia Sea ecosystem is a major component of the circumpolar Southern Ocean system, where productivity and predator demand for prey are high. The eastward-flowing Antarctic Circumpolar Current (ACC) and waters from the Weddell-Scotia Confluence dominate the physics of the Scotia Sea, leading to a strong advective flow, intense eddy activity and mixing. There is also strong seasonality, manifest by the changing irradiance and sea ice cover, which leads to shorter summers in the south. Summer phytoplankton blooms, which at times can cover an area of more than 0.5 million km2, probably result from the mixing of micronutrients into surface waters through the flow of the ACC over the Scotia Arc. This production is consumed by a range of species including Antarctic krill, which are the major prey item of large seabird and marine mammal populations. The flow of the ACC is steered north by the Scotia Arc, pushing polar water to lower latitudes, carrying with it krill during spring and summer, which subsidize food webs around South Georgia and the northern Scotia Arc. There is also marked interannual variability in winter sea ice distribution and sea surface temperatures that is linked to southern hemisphere-scale climate processes such as the El Niño-Southern Oscillation. This variation affects regional primary and secondary production and influences biogeochemical cycles. It also affects krill population dynamics and dispersal, which in turn impacts higher trophic level predator foraging, breeding performance and population dynamics. The ecosystem has also been highly perturbed as a result of harvesting over the last two centuries and significant ecological changes have also occurred in response to rapid regional warming during the second half of the twentieth century. This combination of historical perturbation and rapid regional change highlights that the Scotia Sea ecosystem is likely to show significant change over the next two to three decades, which may result in major ecological shifts.

Implanted medical devices in workers exposed to radio-frequency radiation

This paper discusses the management of radio-frequency radiation workers who have implanted medical devices which may be adversely affected by such radiation fields. The implants include orthopedic devices, cardiac pacemakers, and cochlear implants, but exclude dental work. The effect of radio-frequency radiation on the devices may be to increase heat load and/or produce signal interference. The mechanics of interaction are outlined and protocols for managing cases are described. The implications for safety standards are discussed.

Pseudohypertrophic Muscular Dystrophy in a Girl

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