Herpes Simplex Virus Encephalitis: Patterns of Epidemiology and Outcomes of Patients Admitted to the Intensive Care Unit in Texas, 2008 - 2016

Neuroimaging of the Most Common Meningitis and Encephalitis of Adults: A Narrative Review

Meningitis is the infection of the meninges, which are connective tissue membranes covering the brain, and it most commonly affects the leptomeninges. Clinically, meningitis may present with fever, neck stiffness, altered mental status, headache, vomiting, and neurological deficits. Encephalitis is an infection of the brain, which usually presents with fever, altered mental status, neurological deficits, and seizure. Meningitis and encephalitis are serious conditions which could also coexist, with high morbidity and mortality, thus requiring prompt diagnosis and treatment. Imaging plays an important role in the clinical management of these conditions, especially Magnetic Resonance Imaging. It is indicated to exclude mimics and evaluate the presence of complications. The aim of this review is to depict imaging findings of the most common meningitis and encephalitis.

Herpes simplex encephalitis in France: incidence, 6-month rehospitalizations and mortality

BACKGROUND

Herpes simplex encephalitis (HSE) is a disease with unfavorable vital and functional prognoses. There are no recent epidemiological data on HSE at a national level using real-life databases, especially in France. This study aimed to report the incidence, the clinical characteristics and outcomes of the patients with HSE.

METHODS

We conducted a comprehensive retrospective cohort study on all patients hospitalized for HSE in France between 2015 and 2022 using national hospital discharge databases. Incidence, socio-demographic and clinical characteristics (including comorbidities, seizure, stays' features, intensive care supports) were described. The short- (first stay) and long-term (6-month) outcomes were reported, in terms of mortality and rehospitalizations.

RESULTS

1425 HSE patients were included (median age 67 [54-77] years old, M/F sex ratio 1.07), giving a mean yearly hospital incidence of 2.3 [2.1-2.5] per 1,000,000 inhabitants. 51.2% of the patients were admitted in ICU (n = 730), of whom 59.0% were mechanically ventilated. The overall mortality during the first stay was 14.3% (n = 204), up to 17.9% for ICU patients. Within 6 months, among the survivors, 10.1% had at least one rehospitalization related to HSE. At 6 months, 16.5% of all patients had died (n = 235), 20.8% for ICU patients.

CONCLUSION

In France, the incidence of hospitalizations for HSE was 2.3 per 1,000,000 inhabitants with more than half of the patients admitted in ICU and a 6-month in-hospital mortality about 16.5%. This real-life update on the characteristics and severe outcomes of the disease raises awareness among care practitioners, of the serious nature of the disease, and thus can lead to higher vigilance.

Can we forecast poor outcome in herpes simplex and varicella zoster encephalitis? A narrative review

Herpes simplex virus (HSV) and varicella zoster virus (VZV) are among the most commonly diagnosed infectious causes of sporadic encephalitis worldwide. Despite treatment, mortality and morbidity rates remain high, especially for HSV encephalitis. This review is intended to provide an overview of the existing scientific literature on this topic from the perspective of a clinician who is confronted with serious decisions about continuation or withdrawal of therapeutic interventions. We performed a literature review searching two databases and included 55 studies in the review. These studies documented or investigated specifically outcome and predictive parameters of outcome of HSV and/or VZV encephalitis. Two reviewers independently screened and reviewed full-text articles meeting the inclusion criteria. Key data were extracted and presented as a narrative summary. Both, HSV and VZV encephalitis have mortality rates between 5 and 20% and complete recovery rates range from 14 to 43% for HSV and 33 to 49% for VZV encephalitis. Prognostic factors for both VZV and HSV encephalitis are older age and comorbidity, as well as severity of disease and extent of magnetic resonance imaging (MRI) lesions on admission, and delay in treatment initiation for HSV encephalitis. Although numerous studies are available, the main limiting factors are the inconsistent patient selection and case definitions as well as the non-standardised outcome measures, which hampers the comparability of the studies. Therefore, larger and standardised observational studies applying validated case definitions and outcome measures including quality of life assessment are required to provide solid evidence to answer the research question.

Herpes Simplex Virus Encephalitis With Initial Negative Polymerase Chain Reaction in the Cerebrospinal Fluid

OBJECTIVES

To describe the prevalence, associated factors, and clinical impact of an initial negative herpes simplex virus (HSV) polymerase chain reaction (PCR) in critically ill patients with PCR-proven HSV encephalitis.

DESIGN

Retrospective multicenter study from 2007 to 2017.

SETTING

Forty-seven French ICUs.

PATIENTS

Critically ill patients admitted to the ICU with possible/probable acute encephalitis and a positive cerebrospinal fluid (CSF) PCR for HSV.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 273 patients with a median Glasgow Coma Scale score of 9 (6-12) at ICU admission. CSF HSV PCR was negative in 11 cases (4%), exclusively in lumbar punctures (LPs) performed less than 4 days after symptoms onset. Patients with an initial negative PCR presented with more frequent focal neurologic signs (4/11 [36.4%] vs 35/256 [13.7%]; p = 0.04) and lower CSF leukocytosis (4 cells/mm3 [3-25 cells/mm3] vs 52 cells/mm3 [12-160 cells/mm3]; p < 0.01). An initial negative PCR was associated with an increased delay between LP and acyclovir treatment (3 d [2-7 ] vs 0 d [0-0 d]; p < 0.01) and was independently associated with a poor neurologic outcome at hospital discharge (modified Rankin Scale score ≥ 4) (adjusted odds ratio, 9.89; 95% CI, 1.18-82.78).

CONCLUSIONS

In severe herpes simplex encephalitis, initial negative CSF HSV PCR occurred in 4% of cases and was independently associated with worse neurologic outcome at hospital discharge. In these patients, a systematic multimodal diagnostic approach including early brain MRI and EEG will help clinicians avoid delayed acyclovir initiation or early inappropriate discontinuation.

US Hospitalizations and 60-Day Readmission Rates Associated with Herpes simplex virus Encephalitis: Analysis of All Cause Readmissions and Encephalopathy Associated Readmissions

BACKGROUND

Herpes simplex encephalitis (HSE) is the most common cause of encephalitis hospitalizations. We sought to describe and analyze features associated with all cause readmissions and encephalopathy associated readmissions amongst HSE cases.

METHODS

HSE hospitalizations and 60-day rehospitalizations were assessed in a retrospective cohort using linked hospitalizations from the Healthcare Utilization Project (HCUP) National Readmission Database (NRD) from 2010 through 2017. Risk factors for all-cause readmissions and encephalopathy associated readmissions were assessed with a weighted logistic regression model.

RESULTS

There were 10,272 HSE cases in the US between 2010 and 2017, resulting in a national rate of 4.95 per 100,000 hospitalizations. A total of 23.7% were readmitted at least once within 60-days. Patients that were readmitted were older (mean age 62.4 vs. 57.9, p<0.001), had a greater number of procedures at the index hospitalization (aOR 1.03, p<0.001) and have a higher Charlson comorbidity score (aOR 1.11, p<0.001). Amongst those readmitted, 465 (16.5%) had an encephalopathy related diagnosis. Over eight years, the rate of encephalopathy associated readmissions increased from 0.12 to 0.20. Encephalopathy specific readmissions were found to be associated with greater age (mean age 65.9 vs. 61.7, p = 0.004) and findings of cerebral edema at index hospitalization (aOR 2.16, p <0.001).

CONCLUSIONS

HSE readmissions are relatively common, particularly among older and sicker individuals. However, early signs and symptoms of neurological disease at index were correlated with encephalopathic specific readmissions.