Absence of pleocytosis alone is insufficient to exclude encephalitis caused by herpes simplex virus in children

Herpes simplex encephalitis initially presenting without fever or cerebrospinal fluid pleocytosis and with typical neuroimaging findings: a case report

Herpes simplex encephalitis (HSE) is a common viral encephalitis that can be fatal if not adequately treated. Fever, cerebrospinal fluid (CSF) pleocytosis, and typical neuroimaging findings are commonly observed in HSE cases. We encountered a patient with HSE who did not exhibit these classic clinical features. A 63-year-old male presented with his first-ever seizure. Fever did not develop until the fourth day of admission, and neither neuroimaging nor CSF analysis revealed abnormalities. Under suspicion of autoimmune encephalitis, methylprednisolone was administered. Subsequently, when the patient developed fever, a follow-up neuroimaging study was performed and revealed abnormalities consistent with HSE. The patient was promptly treated with acyclovir, which led to a full recovery. Diagnosing HSE in patients who present without fever or CSF pleocytosis and with typical neuroimaging findings poses a challenge. Therefore, prior to initiating immunosuppressive treatment, it is crucial to closely observe patients and to conduct follow-up tests, including neuroimaging and CSF analysis.

Diagnosis and Management of Neonatal Herpes Simplex Infection in the Emergency Department

Neonatal herpes simplex virus infection (HSV) is rare in neonates, with an estimated global incidence of 10 per 100,000 live births. Neonatal HSV is challenging to diagnose due to often vague signs and symptoms. Untreated, the mortality of some HSV subtypes exceeds 80%. Overtesting and overtreatment can result in prolonged hospitalizations and expose neonates to medication toxicity. In contrast, prompt evaluation and use of empiric antiviral therapy before the results of definitive testing can improve outcomes for infants with HSV. A wide degree of practice variation exists with respect to testing and treatment for neonatal HSV, and more research is required to safely risk-stratify this population. This review presents the epidemiology, risk factors, presenting features, and emergency department management of neonatal HSV infection.

Economic Evaluation: Onsite HSV PCR Capabilities for Pediatric Care

Objective:

Herpes simplex virus (HSV) encephalitis has an overall mortality rate of 11%–29% with treatment. Although rare, HSV encephalitis is frequently tested for and empirically treated, especially in the neonatal population. HSV infection can be diagnosed with polymerase chain reaction (PCR) testing, although this frequently requires sending samples to reference laboratories. The inherent delay in results may lead to prolonging empiric treatment and hospital stay, resulting in increased costs. This study investigates whether onsite HSV PCR testing decreases hospitalization duration, acyclovir treatment duration, and financial cost on an institution.

Project design:

This single-center project utilized the IHI model for improvement to evaluate third-party HSV PCR processing versus an implemented onsite PCR-based meningitis–encephalitis panel for HSV central nervous system evaluation. The primary outcome was hospital cost differential with secondary outcomes, including duration of acyclovir administration and time to result.

Results:

We identified 96 children age 0–18 from 2010 to 2016, 74 patients utilizing offsite third-party testing, and 22 patients utilizing onsite. We observed a per-patient cost savings of $428 ($618.43–$190.43, P = 0.029) upon the implementation of onsite testing. The mean duration of acyclovir therapy decreased from 3.7 to 0.26 days per patient (P < 0.001). Time to result decreased from 4.6 to 0.13 days (P < 0.001).

Conclusions:

Acquisition of real-time local HSV PCR capabilities significantly decreased time to result and empiric medication use while significantly reducing hospital costs in a military treatment facility.

Criteria to Screen Molecular Tests for the Diagnosis of Herpes Simplex Virus in the Central Nervous System have no Propensity to Harm

Objectives:

Investigators have ruled out herpes simplex virus (HSV) infection without the detection of herpes simplex deoxyribonucleic acid in cerebrospinal fluid (CSF) (i.e., HSV polymerase chain reaction [PCR]) by laboratory (normal CSF white blood cell count and protein) and clinical criteria (age ≥2 years, no history of human immunodeficiency virus or solid-organ transplant). Compared to HSV PCR of all samples, the algorithm saves money in test costs and may decrease exposure to acyclovir by illustrating the low probability that the patient has HSV. Concern exists that algorithm use may cause harm through alteration of empiric acyclovir treatment in patients with true HSV central nervous system infection.

Methods:

All Department of Veterans Affair's patients with a positive HSV PCR of the CSF between 2000 and 2013 were identified and their medical records reviewed to determine the extent and possible impact of omitted HSV PCR testing by the algorithm.

Results:

Of 6357 total results, 101 patients had a positive CSF HSV PCR in the study period. Among the positive CSF HSV PCR results, the algorithm excluded 7 (7%) from PCR testing. Record review indicated these seven patients not tested by the algorithm with a positive CSF HSV PCR were considered by their attending physician not to have active HSV.

Conclusion:

The algorithm to screen HSV tests had no propensity to harm.