Functional outcomes in adult patients with herpes simplex encephalitis admitted to the ICU: a multicenter cohort study

Characteristics, management and outcome of Herpes Simplex and Varicella-Zoster virus encephalitis: a multicentre prospective cohort study

OBJECTIVE

To characterize differences between Herpes Simplex virus encephalitis and Varicella-Zoster virus encephalitis (HSVE and VZVE) and other aetiologies of infectious encephalitis (IE), and to investigate the impact of time-to-aciclovir (ACV) start, ACV dose and duration on outcome.

METHODS

We compared 132 HSVE, 65 VZVE and 297 other IE enrolled in a prospective cohort (ENCEIF). We estimated associations between time-to-ACV start, dose or duration and outcome through adjusted odds ratio (aOR) using logistic regression analysis.

RESULTS

Prevalence of immunodepression differed among aetiologies: 15/65 (23%) for VZVE, 13/132 (10%) for HSVE and 30/297 (10%) for other IE (p <0.05), as was presence of seizure at admission: 27/132 (20%) for HSVE, 4/65 (6%) for VZVE and 43/297 (14%) for other IE (p <0.05). Poor outcome at hospital discharge (Glasgow outcome scale ≤3) differed among the three groups: 40/127 (31%) for HSVE, 12/65 (18%) for VZVE and 38/290 (13%) for other IE (p <0.05). Time-to-ACV start was associated with outcome in HSVE (aOR 3.61 [1.25-10.40]), but not in VZVE (aOR 0.84 [0.18-3.85]). Increased ACV dose was not associated with outcome among HSVE (aOR 1.25 [0.44-3.64]) nor VZVE (aOR 1.16 [0.24-5.73]).

DISCUSSION

HSVE and VZVE are distinct in clinical presentation, outcome and prognostic factors. The impact of early ACV initiation was more apparent for HSVE than for VZVE; however, this could be because of VZVE's smaller sample size and lower outcome rate leading to low statistical power or because of potential distinct IE pathophysiology.

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.

Predictors of mortality and poor outcome for patients with severe infectious encephalitis in the intensive care unit: a cross-sectional study

BACKGROUND

There are few thorough studies assessing predictors of severe encephalitis, despite the poor prognosis and high mortality associated with severe encephalitis. The study aims to evaluate the clinical predictors of mortality and poor outcomes at hospital discharge in patients with severe infectious encephalitis in intensive care units.

METHOD

In two Chinese hospitals, a retrospective cohort study comprising 209 patients in intensive care units suffering from severe infectious encephalitis was carried out. Univariate and multivariate logistic regression analyses were used to identify the factors predicting mortality in all patients and poor outcomes in all survivors with severe infectious encephalitis.

RESULTS

In our cohort of 209 patients with severe encephalitis, 22 patients died, yielding a mortality rate of 10.5%. Cerebrospinal fluid pressure ≥ 400mmH2O (OR = 7.43), abnormal imaging (OR = 3.51), abnormal electroencephalogram (OR = 7.14), and number of rescues (OR = 1.12) were significantly associated with an increased risk of mortality in severe infectious encephalitis patients. Among the 187 survivors, 122 (65.2%) had favorable outcomes, defined as the modified Rankine Scale (mRS) score (0 ~ 3), and 65(34.8%) had poor outcomes (mRS scores 4 ~ 5). Age (OR = 1.02), number of rescues (OR = 1.43), and tubercular infection (OR = 10.77) were independent factors associated with poor outcomes at discharge in all survivors with severe infectious encephalitis.

CONCLUSIONS

Multiple clinical, radiologic, and electrophysiological variables are independent predictive indicators for mortality and poor outcomes in patients with severe encephalitis in intensive care units. Identifying these outcome predictors early in patients with severe encephalitis may enable the implementation of appropriate medical treatment and help reduce mortality rates.

The immunobiology of herpes simplex virus encephalitis and post-viral autoimmunity

Herpes simplex virus encephalitis (HSE) is the leading cause of non-epidemic encephalitis in the developed world and, despite antiviral therapy, mortality and morbidity is high. The emergence of post-HSE autoimmune encephalitis reveals a new immunological paradigm in autoantibody-mediated disease. A reductionist evaluation of the immunobiological mechanisms in HSE is crucial to dissect the origins of post-viral autoimmunity and supply rational approaches to the selection of immunotherapeutics. Herein, we review the latest evidence behind the phenotypic progression and underlying immunobiology of HSE including the cytokine/chemokine environment, the role of pathogen-recognition receptors, T- and B-cell immunity and relevant inborn errors of immunity. Second, we provide a contemporary review of published patients with post-HSE autoimmune encephalitis from a combined cohort of 110 patients. Third, we integrate novel mechanisms of autoimmunization in deep cervical lymph nodes to explore hypotheses around post-HSE autoimmune encephalitis and challenge these against mechanisms of molecular mimicry and others. Finally, we explore translational concepts where neuroglial surface autoantibodies have been observed with other neuroinfectious diseases and those that generate brain damage including traumatic brain injury, ischaemic stroke and neurodegenerative disease. Overall, the clinical and immunological landscape of HSE is an important and evolving field, from which precision immunotherapeutics could soon emerge.

Clinical description and outcome of overall varicella-zoster virus-related organ dysfunctions admitted in intensive care units: the VAZOREA cohort study

BACKGROUND

Due to aging population and increasing part of immunocompromised patients, a raise in life-threatening organ damage related to VZV can be expected. Two retrospective studies were already conducted on VZV in ICU but focused on specific organ injury. Patients with high-risk of VZV disease still must be identified. The objective of this study was to report the clinical features and outcome of all life-threatening VZV manifestations requiring intensive care unit (ICU) admission. This retrospective cohort study was conducted in 26 French ICUs and included all adult patients with any life-threatening VZV-related event requiring ICU admission or occurring in ICU between 2010 and 2019.

RESULTS

One-hundred nineteen patients were included with a median SOFA score of 6. One hundred eight patients (90.8%) were admitted in ICU for VZV disease, leaving 11 (9.2%) with VZV disease occurring in ICU. Sixty-one patients (51.3%) were immunocompromised. Encephalitis was the most prominent organ involvement (55.5%), followed by pneumonia (44.5%) and hepatitis (9.2%). Fifty-four patients (45.4%) received norepinephrine, 72 (60.5% of the total cohort) needed invasive mechanical ventilation, and 31 (26.3%) received renal-replacement therapy. In-hospital mortality was 36.1% and was significantly associated with three independent risk factors by multivariable logistic regression: immunosuppression, VZV disease occurring in ICU and alcohol abuse. Hierarchical clustering on principal components revealed five phenotypically distinct clusters of patients: VZV-related pneumonia, mild encephalitis, severe encephalitis in solid organ transplant recipients, encephalitis in other immunocompromised hosts and VZV disease occurring in ICU. In-hospital mortality was highly different across phenotypes, ranging from zero to 75% (p < 0.001).

CONCLUSION

Overall, severe VZV manifestations are associated with high mortality in the ICU, which appears to be driven by immunosuppression status rather than any specific organ involvement. Deciphering the clinical phenotypes may help clinicians identify high-risk patients and assess prognosis.

Severe meningoencephalitis: epidemiology and outcomes

PURPOSE OF REVIEW

This article aims to provide an updated review on the epidemiology and outcomes of severe meningoencephalitis.

RECENT FINDINGS

Meningoencephalitis is a critical medical condition characterized by inflammation in both the meninges and brain parenchyma. Bacterial, viral, or fungal infections are common causes, although noninfectious factors, such as autoimmune causes, can also contribute. In patients requiring intensive care, meningoencephalitis is associated with a severe prognosis, including mortality rates ranging from 11 to 25% and functional disability in 15-25% of survivors. Recent multicenter studies have identified several parameters linked to poor outcomes, including older age, immunocompromised status, focal neurologic signs, abnormal brain imaging, and delayed administration of antimicrobials. The use of new multiplex PCR techniques for diagnosis has generated debate based on recent data. Investigation is still needed to determine the effectiveness of adjunctive therapies, including seizure prophylaxis, and adjunctive steroids for nonbacterial causes.

SUMMARY

Recent multicenter studies have enhanced our understanding of the current epidemiology and outcomes of severe meningoencephalitis in adult patients.

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.

Analysis of Metagenomic Next-Generation Sequencing (mNGS) in the Diagnosis of Herpes Simplex Virus (HSV) Encephalitis with Normal Cerebrospinal Fluid (CSF)

Background

Metagenomic next-generation sequencing (mNGS) is becoming increasingly extensive in diagnosing herpes simplex encephalitis (HSE). However, many HSE patients with normal cerebrospinal fluid (CSF) diagnosed by mNGS have been found during the clinical application. This study aimed to summarize and analyze the clinical characteristics, supplementary examinations, and prognosis of patients with HSE whose cerebrospinal fluid was confirmed to be normal by mNGS.

Methods

This retrospective study evaluated the clinical characteristics, auxiliary examinations, and patient prognosis of patients with HSE that were diagnosed by mNGS but had normal CSF. Clinical data collected included baseline information, signs and symptoms upon admission, and risk factors for infection. Auxiliary examinations included indirect immunofluorescence assay (IIF), cell-based assay (CBA), and CSF testing. Prognosis was evaluated based on hospital stay and patient survival.

Results

Seven of the nine patients (77.8%) experienced headaches, and four (44.4%) had a fever of 38°C or higher. The average leukocyte count in the CSF was 2.6 ± 2.3/L. According to the mNGS, the median sequence count of HSV was 2 (1, 16). Magnetic resonance imaging (MRI) revealed one bilateral temporal lobe lesion (11.1%), two isolated bilateral frontal lobe lesions (22.2%), and one bilateral cingulate gyrus lesion (11.1%). One patient (11.1%) was admitted to the intensive care unit and passed away in the hospital. The remaining patients (88.9%) had a positive prognosis upon discharge.

Conclusion

Patients with HSE who had normal CSF were typically middle-aged women with normal immune function. They showed typical HSE clinical features, such as fever, headache and epilepsy, that did not differ from those of other HSE patients. A normal CSF result is generally associated with a low viral load and the body's ability to mount an effective immune response. Most of these patients have a favorable prognosis.

Characteristics, management, and outcomes of patients with infectious encephalitis requiring intensive care: A prospective multicentre observational study

PURPOSE

Infectious encephalitis (IE) is a severe disease which requires intensive care unit (ICU) admission in up to 50% of cases. We aimed to describe characteristics, management and outcomes of IE patients who required ICU admission.

MATERIALS AND METHODS

Ancillary study focusing on patients with ICU admission within the ENCEIF cohort, a French prospective observational multicentre study. The primary criteria for outcome was the functional status at hospital discharge, categorized using the Glasgow outcome scale (GOS). Logistic regression model was used to identify risk factors for poor outcome, defined as a GOS ≤ 3.

RESULTS

We enrolled 198 ICU patients with IE. HSV was the primary cause (n = 72, 36% of all IE, 53% of IE with microbiological documentation). Fifty-two patients (26%) had poor outcome at hospital discharge, including 22 deaths (11%). Immunodeficiency, supratentorial focal signs on admission, lower cerebrospinal fluid (CSF) white cells count (<75/mm3), abnormal brain imaging, and time from symptoms onset to acyclovir start >2 days were independent predictors of poor outcome.

CONCLUSION

HSV is the primary cause of IE requiring ICU admission. IE patients admitted in ICU have a poor prognosis with 11% of in-hospital mortality and 15% of severe disabilities in survivors at discharge.

Clinical features, etiologies, and outcomes in adult patients with meningoencephalitis requiring intensive care (EURECA): an international prospective multicenter cohort study

PURPOSE

We aimed to characterize the outcomes of patients with severe meningoencephalitis requiring intensive care.

METHODS

We conducted a prospective multicenter international cohort study (2017-2020) in 68 centers across 7 countries. Eligible patients were adults admitted to the intensive care unit (ICU) with meningoencephalitis, defined by an acute onset of encephalopathy (Glasgow coma scale (GCS) score [Formula: see text] 13), a cerebrospinal fluid pleocytosis [Formula: see text] 5 cells/mm3, and at least two of the following criteria: fever, seizures, focal neurological deficit, abnormal neuroimaging, and/or electroencephalogram. The primary endpoint was poor functional outcome at 3 months, defined by a score of three to six on the modified Rankin scale. Multivariable analyses stratified on centers investigated ICU admission variables associated with the primary endpoint.

RESULTS

Among 599 patients enrolled, 589 (98.3%) completed the 3-month follow-up and were included. Overall, 591 etiologies were identified in those patients which were categorized into five groups: acute bacterial meningitis (n = 247, 41.9%); infectious encephalitis of viral, subacute bacterial, or fungal/parasitic origin (n = 140, 23.7%); autoimmune encephalitis (n = 38, 6.4%); neoplastic/toxic encephalitis (n = 11, 1.9%); and encephalitis of unknown origin (n = 155, 26.2%). Overall, 298 patients (50.5%, 95% CI 46.6-54.6%) had a poor functional outcome, including 152 deaths (25.8%). Variables independently associated with a poor functional outcome were age > 60 years (OR 1.75, 95% CI 1.22-2.51), immunodepression (OR 1.98, 95% CI 1.27-3.08), time between hospital and ICU admission > 1 day (OR 2.02, 95% CI 1.44-2.99), a motor component on the GCS [Formula: see text] 3 (OR 2.23, 95% CI 1.49-3.45), hemiparesis/hemiplegia (OR 2.48, 95% CI 1.47-4.18), respiratory failure (OR 1.76, 95% CI 1.05-2.94), and cardiovascular failure (OR 1.72, 95% CI 1.07-2.75). In contrast, administration of a third-generation cephalosporin (OR 0.54, 95% CI 0.37-0.78) and acyclovir (OR 0.55, 95% CI 0.38-0.80) on ICU admission were protective.

CONCLUSION

Meningoencephalitis is a severe neurologic syndrome associated with high mortality and disability rates at 3 months. Actionable factors for which improvement could be made include time from hospital to ICU admission, early antimicrobial therapy, and detection of respiratory and cardiovascular complications at admission.

Electroencephalography for prognostication of outcome in adults with severe herpes simplex encephalitis

BACKGROUND

Electroencephalography (EEG) is recommended for the practical approach to the diagnosis and prognosis of encephalitis. We aimed to investigate the prognostic value of standard EEG (_stdEEG) in adult patients with severe herpes simplex encephalitis.

METHODS

We performed a retrospective analysis of consecutive ICU patients with severe herpes simplex encephalitis in 38 French centers between 2006 and 2016. Patients with at least one _stdEEG study performed at ICU admission were included. _stdEEG findings were reviewed independently by two investigators. The association between _stdEEG findings (i.e., background activity, lateralized periodic discharges, seizures/status epilepticus, and reactivity to painful/auditory stimuli) and poor functional outcome, defined by a score on the modified Rankin Scale (mRS) of 3 to 6 (moderate to severe disability or death) at 90 days, were investigated.

RESULTS

We included 214 patients with at least one available _stdEEG study. The first _stdEEG was performed after a median time of one (interquartile range (IQR) 0 to 2) day from ICU admission. At the time of recording, 138 (64.5%) patients were under invasive mechanical ventilation. Lateralized periodic discharges were recorded in 91 (42.5%) patients, seizures in 21 (9.8%) and status epilepticus in 16 (7.5%). In the whole population, reactivity to auditory/noxious stimuli was tested in 140/214 (65.4%) patients and was absent in 71/140 (33.2%) cases. In mechanically ventilated patients, _stdEEG reactivity was tested in 91/138 (65.9%) subjects, and was absent in 53/91 (58.2%) cases. Absence of reactivity was the only independent _stdEEG finding associated with poor functional outcome in the whole population (OR 2.80, 95% CI 1.19 to 6.58) and in the subgroup of mechanically ventilated patients (OR 4.99, 95% CI 1.6 to 15.59). Adjusted analyses for common clinical predictors of outcome and sedation at time of _stdEEG revealed similar findings in the whole population (OR 2.03, 95% CI 1.18 to 3.49) and in mechanically ventilated patients (OR 2.62, 95% CI 1.25 to 5.50).

CONCLUSIONS

Absence of EEG reactivity to auditory/noxious stimuli is an independent marker of poor functional outcome in severe herpes simplex encephalitis.

Neurologic outcome of VZV encephalitis one year after ICU admission: a multicenter cohort study

BACKGROUND

Varicella-zoster virus (VZV) is one of the main viruses responsible of acute encephalitis. However, data on the prognosis and neurologic outcome of critically ill patients with VZV encephalitis are limited. We aimed to describe the clinical features of VZV encephalitis in the ICU and to identify factors associated with a favorable neurologic outcome. We performed a multicenter cohort study of patients with VZV encephalitis admitted in 18 ICUs in France between 2000 and 2017. Factors associated with a favorable neurologic outcome, defined by a modified Rankin Score (mRS) of 0-2 1 year after ICU admission, were identified by multivariable regression analysis.

RESULTS

Fifty-five patients (29 (53%) men, median age 53 (interquartile range 36-66)) were included, of whom 43 (78%) were immunocompromised. ICU admission occurred 1 (0-3) day after the onset of neurological symptoms. Median Glasgow Coma Score at ICU admission was 12 (7-14). Cerebrospinal fluid examination displayed a median leukocyte count of 68 (13-129)/mm³, and a median protein level of 1.37 (0.77-3.67) g/L. CT scan and MRI revealed brain lesions in 30% and 66% of the cases, respectively. Invasive mechanical ventilation was implemented in 46 (84%) patients for a median duration of 13 (3-30) days. Fourteen (25%) patients died in the ICU. One year after ICU admission, 20 (36%) patients had a favorable neurologic outcome (mRS 0-2), 12 (22%) had significant disability (mRS 3-5), and 18 (33%) were deceased (lost to follow-up n = 5, 9%). On multivariable analysis, age (OR 0.92 per year, (0.88-0.97), p = 0.01), and invasive mechanical ventilation (OR 0.09 CI 95% (0.01-0.84), p = 0.03) reduced the likelihood of favorable neurologic outcome.

CONCLUSION

One in every three critically ill patients with VZV encephalitis had a favorable neurologic outcome 1 year after ICU admission. Older age and invasive mechanical ventilation were associated with a higher risk of disability and death.

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.

Cognitive decline following acute viral infections: literature review and projections for post-COVID-19

Recently, much attention has been drawn to the importance of the impact of infectious disease on human cognition. Several theories have been proposed, to explain the cognitive decline following an infection as well as to understand better the pathogenesis of human dementia, especially Alzheimer's disease. This article aims to review the state of the art regarding the knowledge about the impact of acute viral infections on human cognition, laying a foundation to explore the possible cognitive decline followed coronavirus disease 2019 (COVID-19). To reach this goal, we conducted a narrative review systematizing six acute viral infections as well as the current knowledge about COVID-19 and its impact on human cognition. Recent findings suggest probable short- and long-term COVID-19 impacts in cognition, even in asymptomatic individuals, which could be accounted for by direct and indirect pathways to brain dysfunction. Understanding this scenario might help clinicians and health leaders to deal better with a wave of neuropsychiatric issues that may arise following COVID-19 pandemic as well as with other acute viral infections, to alleviate the cognitive sequelae of these infections around the world.

Intensive care management of patients with viral encephalitis

Viral encephalitis is a severe syndrome that can lead to encephalopathy, seizures, focal deficits, and neurological sequelae and death. It is mainly caused by neurotropic herpes viruses (i.e., HSV and VZV), although other pathogens may be observed in specific geographic regions or conditions. Recent advances in neuroimaging and molecular biology (PCR, metagenomics) allow for faster and more accurate etiological diagnoses, although their benefits need to be confirmed to provide guidelines for their use and interpretation. Despite intravenous acyclovir therapy and supportive care, outcomes remain poor in about two-thirds of herpes encephalitis patients requiring ICU admission. Randomized clinical trials focusing on symptomatic measures (i.e. early ICU admission, fever control, and treatment of seizures/status epilepticus) or adjunctive immunomodulatory therapies (i.e. steroids, intravenous immunoglobulins) to improve neurologic outcomes have not been conducted in the ICU setting. Large prospective multicenter studies combining clinical, electrophysiological, and neuroimaging data are needed to improve current knowledge on care pathways, long-term outcomes, and prognostication.

Assessment of Magnetic Resonance Imaging Changes and Functional Outcomes Among Adults With Severe Herpes Simplex Encephalitis

Importance

Current guidelines recommend brain magnetic resonance imaging (MRI) for clinical management of patients with severe herpes simplex encephalitis (HSE). However, the prognostic value of brain imaging has not been demonstrated in this setting.

Objective

To investigate the association between early brain MRI data and functional outcomes of patients with HSE at 90 days after intensive care unit (ICU) admission.

Design, Setting, and Participants

This multicenter cohort study was conducted in 34 ICUs in France from 2007 to 2019 and recruited all patients who received a clinical diagnosis of encephalitis and exhibited cerebrospinal fluid positivity for herpes simplex virus DNA in the polymerase chain reaction analysis. Data analysis was performed from January to April 2020.

Exposures

All patients underwent a standard brain MRI during the first 30 days after ICU admission.

Main Outcomes and Measures

MRI acquisitions were analyzed by radiologists blinded to patients' outcomes, using a predefined score. Multivariable logistic regression and supervised hierarchical classifiers methods were used to identify factors associated with poor outcome at 90 days, defined by a score of 3 to 6 (indicating moderate-to-severe disability or death) on the Modified Rankin Scale.

Results

Overall, 138 patients (median [interquartile range {IQR}] age, 62.6 [54.0-72.0] years; 75 men [54.3%]) with an admission median (IQR) Glasgow Coma Scale score of 9 (6-12) were studied. The median (IQR) delay between ICU admission and MRI was 1 (1-7) days. At 90 days, 95 patients (68.8%) had a poor outcome, including 16 deaths (11.6%). The presence of fluid-attenuated inversion recovery MRI signal abnormalities in more than 3 brain lobes (odds ratio [OR], 25.71; 95% CI, 1.21-554.42), age older than 60 years (OR, 7.62; 95% CI, 2.02-28.91), and the presence of diffusion-weighted MRI signal abnormalities in the left thalamus (OR, 6.90; 95% CI, 1.12-43.00) were independently associated with poor outcome. Machine learning models identified bilateral diffusion abnormalities as an additional factor associated with poor outcome (34 of 39 patients [87.2%] with bilateral abnormalities had poor outcomes) and confirmed the functional burden of left thalamic lesions, particularly in older patients (all 11 patients aged >60 years had left thalamic lesions).

Conclusions and Relevance

These findings suggest that in adult patients with HSE requiring ICU admission, extensive MRI changes in the brain are independently associated with poor functional outcome at 90 days. Thalamic diffusion signal changes were frequently observed and were associated with poor prognosis, mainly in older patients.

[An autopsy case of elderly-onset herpes simplex encephalitis with acute respiratory failure caused by brainstem lesions]

An 89-year-old man was admitted because of persistent fever and impaired consciousness. On admission, his consciousness level was E3V3M4 according to the Glasgow Coma Scale. MRI of the brain showed high intensity lesions in the bilateral cingulate gyri. In the cerebrospinal fluid, both cell counts and glucose level were in the normal ranges. He had received antibiotics and intravenous isotonic saline. On the fifth day of hospitalization, blood examination revealed elevation of anti-herpes simplex virus (HSV) immunoglobulin M antibody, and herpes simplex encephalitis (HSE) was diagnosed. Despite treatment with acyclovir, his respiratory function and consciousness level deteriorated rapidly. On the eighth day, he died of respiratory failure. At autopsy, the brain showed multiple softenings of the gray and white matter in the hippocampus, amygdala, and temporal, insular, and cingulate cortices. Some of these lesions were hemorrhagic. Microscopic examination revealed that the lesions were necrotic and associated with perivascular inflammatory cell infiltration in the limbic system, hypothalamus, brainstem tegmentum area, and medulla. Eosinophilic intranuclear inclusions were rarely found in the astrocytes in the medulla. Immunohistochemistry revealed anti-HSV-1 antibody positive neurons in the brainstem tegmentum including reticular formation and the raphe nuclei. HSV-DNA was also detected in the postmortem cerebrospinal fluid. This was a rare case of HSE in which inflammation in the brainstem proved to be the cause of lethal respiratory failure.

Predicting Inpatient Mortality Among Encephalitis Patients: A Novel Admission Risk Score

Background

Identifying underlying commonalities among all-cause encephalitis cases can be extraordinarily useful in predicting meaningful risk factors associated with inpatient mortality.

Methods

A retrospective cohort of patients with encephalitis was derived from a clinical chart review of adult patients (age ≥18 years) across 16 different hospitals in Houston, Texas, between January 2005 and July 2015. Clinical features at admission were assessed for their correlation with inpatient mortality and used to derive a final risk score prediction tool.

Results

The study included a total of 273 adult patients with all-cause encephalitis, 27 (9.9%) of whom died during hospitalization. A limited number of clinical features were substantially different between patients who survived and those who died (Charlson score, Glasgow coma scale [GCS], immunosuppression, fever on admission, multiple serologic studies, and abnormal imaging). A final multivariable logistic model was derived with the following risk factors, which were transformed into a scoring system: 1 point was assigned to the presence of a Charlson score >2, thrombocytopenia, or cerebral edema, and 2 points for a GCS value <8. Patients were then classified into different risk groups for inpatient mortality: 0 points (0%), 1 point (7%), 2 points (10.9%), 3 points (36.8%), and ≥4 points (81.8%).

Conclusions

The risk score developed from this study shows a high predictive value. This can be highly beneficial in alerting care providers to key clinical risk factors associated with in-hospital mortality in adults with encephalitis.

Validation of the NEOS score in Chinese patients with anti-NMDAR encephalitis

Objective

The performance of anti-NMDAR Encephalitis One-Year Functional Status (NEOS) in predicting the 1-year functional status in Chinese patients with anti-NMDAR encephalitis is unknown.

Methods

We recruited patients with anti-NMDAR encephalitis from the Multicenter and Prospective Clinical Registry Study of Anti-NMDAR Encephalitis in Beijing Area. Patients were followed up for 1 year. We defined the poor functional status as a modified Rankin Scale score of more than 2 and good functional status as a modified Rankin Scale score of no more than 2. We performed a receiver-operator characteristic analysis to assess the discriminatory power of the NEOS score in predicting the 1-year functional status by using the area under the curve (AUC). Calibration was assessed by Pearson correlation coefficient and Hosmer-Lemeshow tests.

Results

Among the 111 patients with anti-NMDAR encephalitis recruited from 364 potentially eligible participants, 87 (78.4%) had good functional status at 1 year, whereas the remaining 24 (21.6%) had poor functional status. The AUC of the NEOS score for 1-year poor functional status was 0.86 (95% CI 0.78–0.93, p < 0.001). The increased NEOS was associated with higher risk of 1-year poor functional status in patients with anti-NMDAR encephalitis.

Conclusions

The NEOS score is considered a reliable predictor of the risk of 1-year poor functional status in Chinese patients with anti-NMDAR encephalitis. This score could help to estimate the velocity of clinical improvement in advance.

Clinicaltrial.gov identifier

NCT02443350.

Classification of evidence

This study provides Class III evidence that in patients with anti-NMDAR encephalitis, the NEOS score predicts 1-year functional status.

Herpes simplex encephalitis: A new type of "ICU-acquired infection"?

Purpose

Although it is a well-known disease, the occurrence of Herpes simplex encephalitis (HSE) during a hospital stay may render the diagnosis particularly challenging. The objective of this report is to alert clinicians about the diagnostic pitfalls arising from hospital-developed HSE.

Materials and methods

Clinical observation of one patient.

Case report

An 87-year-old male was admitted to the Intensive Care Unit (ICU) because of respiratory failure due to an exacerbation of myasthenia gravis. After corticoids and azathioprine treatment, his clinical condition improved, allowing weaning from mechanical ventilation. One month after admission, while still hospitalized in the ICU, the patient developed fever and confusion. In the context of confounding factors, HSE was not suspected before a convulsive status epilepticus occurred, resulting in a significant delay in treatment. Diagnosis was confirmed by PCR-analysis in the cerebrospinal fluid. Serological status confirmed reactivation of prior herpes simplex infection. The patient died one week after the onset of confusion.

Conclusions

Hospital-“acquired” HSE must be suspected in case of new neurologic symptoms associated with fever, even in ICU-hospitalized patients. The diagnosis is made even more difficult by nonspecific symptoms due to previous diseases, leading to an even more severe prognosis in those vulnerable patients.

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

Background

Patients with herpes simplex virus encephalitis (HSVE) often require admission to the intensive care unit (ICU) and have considerably worse outcomes than those not critically ill. The short-term outcomes of critically ill patients in the general population have markedly improved over the past decades. However, the population-level patterns of demand for critical care services among patients with HSVE have not been examined, and it is unknown whether there were corresponding outcome gains among those admitted to the ICU.

Methods

The Texas Inpatient Public Use Data File was used to identify hospitalizations with HSVE aged ≥ 18 years during 2008 - 2016. ICU admissions were identified using unit-specific revenue codes. The patterns of ICU utilization and those of short-term outcomes (with short-term mortality defined as in-hospital death or discharge to hospice) were examined across demographic strata and over time.

Results

Among 1,964 hospitalizations with HSVE, 1,176 (59.9%) were admitted to ICU (45.8% aged ≥ 65 years; 53.1% female, among ICU admissions). ICU utilization increased with age (from 47.9% (age 18 - 44 years) through 61.2% (older adults (age ≥ 65 years)); P = 0.0003 for trend), and increased over time only among older adults (odds ratio: 1.06/year (95% confidence interval (CI): 1.01 - 1.12)). Among ICU admissions, routine home discharge, transfer to a post-acute care facility, and short-term mortality occurred in 26.8%, 39.5%, and 18.7%, respectively; the corresponding outcomes for older adults were 10.6%, 51.4%, and 26.2%, respectively. The outcomes for the whole cohort of ICU admissions remained unchanged over time.

Conclusions

Adults with HSVE had high demand for critical care services, and those admitted to ICU had high short-term mortality and substantial residual morbidity among survivors, which remained unchanged over time. These findings can inform clinicians’ decision-making and discussions about goals of care with affected patients and their surrogates.