Predictors of Invasive Herpes Simplex Virus Infection in Young Infants

Predicting Serious Bacterial Infections Among Hypothermic Infants in the Emergency Department

BACKGROUND

There is insufficient evidence to guide the initial evaluation of hypothermic infants. We aimed to evaluate risk factors for serious bacterial infections (SBI) among hypothermic infants presenting to the emergency department (ED).

METHODS

We conducted a multicenter case-control study among hypothermic (rectal temperature <36.5°C) infants ≤90 days presenting to the ED who had a blood culture collected. Our outcome was SBI (bacteremia, bacterial meningitis, and/or urinary tract infection). We performed 1:2 matching. Historical, physical examination and laboratory covariables were determined based on the literature review from febrile and hypothermic infants and used logistic regression to identify candidate risk factors.

RESULTS

Among 934 included infants, 57 (6.1%) had an SBI. In univariable analyses, the following were associated with SBI: age > 21 days, fever at home or in the ED, leukocytosis, elevated absolute neutrophil count, thrombocytosis, and abnormal urinalysis. Prematurity, respiratory distress, and hypothermia at home were negatively associated with SBI. The full multivariable model exhibited a c-index of 0.91 (95% confidence interval: 0.88-0.94). One variable (abnormal urinalysis) was selected for a reduced model, which had a c-index of 0.82 (95% confidence interval: 0.75-0.89). In a sensitivity analysis among hypothermic infants without fever (n = 22 with SBI among 116 infants), leukocytosis, absolute neutrophil count, and abnormal urinalysis were associated with SBI.

CONCLUSIONS

Historical, examination, and laboratory data show potential as variables for risk stratification of hypothermic infants with concern for SBI. Larger studies are needed to definitively risk stratify this cohort, particularly for invasive bacterial infections.

La prise en charge des nourrissons de 90 jours ou moins, fiévreux mais dans un bon état général

On constate des pratiques très variées en matière d'évaluation et de prise en charge des jeunes nourrissons fiévreux. Bien que la plupart des jeunes nourrissons fiévreux mais dans un bon état général soient atteints d'une maladie virale, il est essentiel de détecter ceux qui sont à risque de présenter des infections bactériennes invasives, notamment une bactériémie et une méningite bactérienne. Le présent document de principes porte sur les nourrissons de 90 jours ou moins dont la température rectale est de 38,0 °C ou plus, mais qui semblent être dans un bon état général. Il est conseillé d'appliquer les récents critères de stratification du risque pour orienter la prise en charge, ainsi que d'intégrer la procalcitonine à l'évaluation diagnostique. Les décisions sur la prise en charge des nourrissons qui satisfont aux critères de faible risque devraient refléter la probabilité d'une maladie, tenir compte de l'équilibre entre les risques et les préjudices potentiels et faire participer les parents ou les proches aux décisions lorsque diverses options sont possibles. La prise en charge optimale peut également dépendre de considérations pragmatiques, telles que l'accès à des examens diagnostiques, à des unités d'observation, à des soins tertiaires et à un suivi. Des éléments particuliers, tels que la mesure de la température, le risque d'infection invasive à Herpes simplex et la fièvre postvaccinale, sont également abordés.

Management of well-appearing febrile young infants aged ≤90 days

The evaluation and management of young infants presenting with fever remains an area of significant practice variation. While most well-appearing febrile young infants have a viral illness, identifying those at risk for invasive bacterial infections, specifically bacteremia and bacterial meningitis, is critical. This statement considers infants aged ≤90 days who present with a rectal temperature ≥38.0°C but appear well otherwise. Applying recent risk-stratification criteria to guide management and incorporating diagnostic testing with procalcitonin are advised. Management decisions for infants meeting low-risk criteria should reflect the probability of disease, consider the balance of risks and potential harm, and include parents/caregivers in shared decision-making when options exist. Optimal management may also be influenced by pragmatic considerations, such as access to diagnostic investigations, observation units, tertiary care, and follow-up. Special considerations such as temperature measurement, risk for invasive herpes simplex infection, and post-immunization fever are also discussed.

Congenital herpes simplex with ophthalmic and multisystem features: a case report

BACKGROUND

Neonatal herpes simplex virus (HSV) infection is rare and has significant morbimortality rates. Approximately 85% of newborns are infected intrapartum, and risk factors for mother-to-child transmission include vaginal delivery, primary maternal infection, and prolonged rupture of membranes. Neonatal HSV can manifest with isolated mucocutaneous lesions, neurological involvement, or disseminated disease. In general, herpetic infection can cause blepharoconjunctivitis or keratitis. We report a rare case of congenital herpes with ophthalmologic manifestations and multisystemic involvement.

CASE PRESENTATION

A preterm infant, born at 32 weeks and 2 days, with presumed neonatal infection developed intestinal and respiratory complications, as well as hyperemic lesions on the left nostril and oral mucosa. An ophthalmological assessment was requested and brought up the suspicion of HSV infection, indicating empirical treatment with endovenous acyclovir. Later, a new ocular examination was suggestive of panuveitis. Afterward, serum IgM antibodies to HSV-1 and HSV-2 were positive. Proper antiviral therapy led to an improvement in the condition.

DISCUSSION

Neonatal herpes is associated with a high risk of persistent skin lesions, long-term neurological disability and other lasting sequelae. It is essential to consider HSV infection in cases of neonatal conjunctivitis, especially in patients with an epithelial defect and no improvement after initial treatment with topical or systemic antibiotics.

CONCLUSIONS

In the management of neonatal HSV, early diagnosis is essential for the timely initiation of antiviral therapy. Our report highlights that ocular assessment can be crucial in the correct diagnostic investigation of this condition.

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.

Prevalence of Invasive Bacterial Infection in Hypothermic Young Infants: A Multisite Study

OBJECTIVE

To determine the prevalence of bacteremia and meningitis (invasive bacterial infection [IBI]) in hypothermic young infants, and also to determine the prevalence of serious bacterial infections (SBI) and neonatal herpes simplex virus and to identify characteristics associated with IBI.

STUDY DESIGN

We conducted a retrospective cohort study of infants ≤90 days of age who presented to 1 of 9 hospitals with historical or documented hypothermia (temperature ≤36.0°C) from September 1, 2017, to May 5, 2021. Infants were identified by billing codes or electronic medical record search of hypothermic temperatures. All charts were manually reviewed. Infants with hypothermia during birth hospitalization, and febrile infants were excluded. IBI was defined as positive blood culture and/or cerebrospinal fluid culture treated as a pathogenic organism, whereas SBI also included urinary tract infection. We used multivariable mixed-effects logistic regression to identify associations between exposure variables and IBI.

RESULTS

Overall, 1098 young infants met the inclusion criteria. IBI prevalence was 2.1% (95% CI, 1.3-2.9) (bacteremia 1.8%; bacterial meningitis 0.5%). SBI prevalence was 4.4% (95% CI, 3.2-5.6), and neonatal herpes simplex virus prevalence was 1.3% (95% CI, 0.6-1.9). Significant associations were found between IBI and repeated temperature instability (OR, 4.9; 95% CI, 1.3-18.1), white blood cell count abnormalities (OR, 4.8; 95% CI, 1.8-13.1), and thrombocytopenia (OR, 5.0; 95% CI, 1.4-17.0).

CONCLUSIONS

IBI prevalence in hypothermic young infants is 2.1%. Further understanding of characteristics associated with IBI can guide the development decision tools for management of hypothermic young infants.

Serious infections are rare in well-appearing neonates with hypothermia identified incidentally at routine visits

OBJECTIVES

It is not established whether diagnostic testing and antimicrobial treatment are warranted in well-appearing neonates without other signs or symptoms who have hypothermia identified incidentally at a routine visit with their primary care provider.

METHODS

This was a retrospective observational study of well-appearing neonates who were noted at a routine visit to be hypothermic (<97.7°F or <36.5°C) and referred to a pediatric emergency department over an 8.5-year period. Excluded were those transferred from an outside hospital and those with signs of illness, including apnea, bradycardia, fever, hypoglycemia, ill appearance, lethargy, poor feeding, respiratory distress, tachycardia, or vomiting. Patient characteristics, laboratory results, antimicrobial treatment, and clinical outcomes were recorded.

RESULTS

Among a final cohort of 212 neonates with incidental hypothermia, no urine (n = 195) or blood (n = 198) culture grew a bacterial pathogen. No CSF culture (n = 168) grew a bacterial pathogen and no CSF PCR test (n = 142) was positive for herpes simplex virus. Contaminants were isolated in 3 urine and 3 blood cultures.

CONCLUSION

Well-appearing neonates with incidentally noted hypothermia at a routine visit are at low risk for serious infection and may not warrant a full sepsis evaluation.