Acute central nervous system infections in adults--a retrospective cohort study in the NHS North West region

Diagnostic accuracy of inflammatory markers in adults with suspected central nervous system infections

OBJECTIVES

We aimed to determine diagnostic accuracy of inflammatory markers in plasma and cerebrospinal fluid (CSF) for the diagnosis of central nervous system (CNS) infections and specifically bacterial meningitis.

METHODS

We analyzed 12 cytokines, chemokines, and acute phase reactants in CSF and plasma of 738 patients with suspected neurological infection included in a multicenter prospective cohort. We determined diagnostic accuracy for predicting any CNS infection and bacterial meningitis.

RESULTS

We included 738 episodes between 2017 and 2022, split into a derivation (n = 450) and validation cohort (n = 288). Of these patients, 224 (30%) were diagnosed with CNS infection, of which 81 (11%) with bacterial meningitis, 107 (14%) with viral meningitis or encephalitis, and 35 patients (5%) with another CNS infection. Diagnostic accuracy of CRP, IL-6, and Il-1β in CSF was high, especially for diagnosing bacterial meningitis. Combining these biomarkers in a multivariable model increased accuracy and provided excellent discrimination between bacterial meningitis and all other disorders (AUC = 0.99), outperforming all individual biomarkers as well as CSF leukocytes (AUC = 0.97). When applied to the population of patients with a CSF leukocyte count of 5-1000 cells/mm3, accuracy of the model also provided a high diagnostic accuracy (AUC model = 0.97 vs. AUC CSF leukocytes = 0.80) with 100% sensitivity and 92% specificity. These results remained robust in a temporal validation cohort.

CONCLUSIONS

Inflammatory biomarkers in CSF are able to differentiate CNS infections and especially bacterial meningitis from other disorders. When these biomarkers are combined, their diagnostic accuracy exceeds that of CSF leukocytes alone and as such these markers have added value to current clinical practice.

Clinical features and prognostic factors in adults with viral meningitis

Clinical features applicable to the entire spectrum of viral meningitis are limited, and prognostic factors for adverse outcomes are undetermined. This nationwide population-based prospective cohort study included all adults with presumed and microbiologically confirmed viral meningitis in Denmark from 2015 until 2020. Prognostic factors for an unfavourable outcome (Glasgow Outcome Scale score of 1-4) 30 days after discharge were examined by modified Poisson regression. In total, 1066 episodes of viral meningitis were included, yielding a mean annual incidence of 4.7 episodes per 100 000 persons. Pathogens were enteroviruses in 419/1066 (39%), herpes simplex virus type 2 in 171/1066 (16%), varicella-zoster virus in 162/1066 (15%), miscellaneous viruses in 31/1066 (3%) and remained unidentified in 283/1066 (27%). The median age was 33 years (IQR 27-44), and 576/1066 (54%) were females. In herpes simplex virus type 2 meningitis, 131/171 (77%) were females. Immunosuppression [32/162 (20%)] and shingles [90/149 (60%)] were frequent in varicella-zoster virus meningitis. The triad of headache, neck stiffness and hyperacusis or photophobia was present in 264/960 (28%). The median time until lumbar puncture was 3.0 h (IQR 1.3-7.1), and the median CSF leucocyte count was 160 cells/µl (IQR 60-358). The outcome was unfavourable in 216/1055 (20%) 30 days after discharge. Using unidentified pathogen as the reference, the adjusted relative risk of an unfavourable outcome was 1.34 (95% CI 0.95-1.88) for enteroviruses, 1.55 (95% CI 1.00-2.41) for herpes simplex virus type 2, 1.51 (95% CI 0.98-2.33) for varicella-zoster virus and 1.37 (95% CI 0.61-3.05) for miscellaneous viruses. The adjusted relative risk of an unfavourable outcome was 1.34 (95% CI 1.03-1.75) for females. Timing of acyclovir or valacyclovir was not associated with the outcome in meningitis caused by herpes simplex virus type 2 or varicella-zoster virus. In summary, the outcome of viral meningitis was similar among patients with different aetiologies, including those with presumed viral meningitis but without an identified pathogen. Females had an increased risk of an unfavourable outcome. Early antiviral treatment was not associated with an improved outcome in meningitis caused by herpes simplex virus type 2 or varicella-zoster virus.

Clinical predictors of encephalitis in UK adults-A multi-centre prospective observational cohort study

OBJECTIVES

Encephalitis, brain inflammation and swelling, most often caused by an infection or the body's immune defences, can have devastating consequences, especially if diagnosed late. We looked for clinical predictors of different types of encephalitis to help clinicians consider earlier treatment.

METHODS

We conducted a multicentre prospective observational cohort study (ENCEPH-UK) of adults (> 16 years) with suspected encephalitis at 31 UK hospitals. We evaluated clinical features and investigated for infectious and autoimmune causes.

RESULTS

341 patients were enrolled between December 2012 and December 2015 and followed up for 12 months. 233 had encephalitis, of whom 65 (28%) had HSV, 38 (16%) had confirmed or probable autoimmune encephalitis, and 87 (37%) had no cause found. The median time from admission to 1st dose of aciclovir for those with HSV was 14 hours (IQR 5-50); time to 1st dose of immunosuppressant for the autoimmune group was 125 hours (IQR 45-250). Compared to non-HSV encephalitis, patients with HSV more often had fever, lower serum sodium and lacked a rash. Those with probable or confirmed autoimmune encephalitis were more likely to be female, have abnormal movements, normal serum sodium levels and a cerebrospinal fluid white cell count < 20 cells x106/L, but they were less likely to have a febrile illness.

CONCLUSIONS

Initiation of treatment for autoimmune encephalitis is delayed considerably compared with HSV encephalitis. Clinical features can help identify patients with autoimmune disease and could be used to initiate earlier presumptive therapy.

Encephalitis: diagnosis, management and recent advances in the field of encephalitides

Encephalitis describes inflammation of the brain parenchyma, typically caused by either an infectious agent or through an autoimmune process which may be postinfectious, paraneoplastic or idiopathic. Patients can present with a combination of fever, alterations in behaviour, personality, cognition and consciousness. They may also exhibit focal neurological deficits, seizures, movement disorders and/or autonomic instability. However, it can sometimes present non-specifically, and this combined with its many causes make it a difficult to manage neurological syndrome. Despite improved treatments in some forms of encephalitides, encephalitis remains a global concern due to its high mortality and morbidity. Prompt diagnosis and administration of specific and supportive management options can lead to better outcomes. Over the last decade, research in encephalitis has led to marked developments in the understanding, diagnosis and management of encephalitis. In parallel, the number of autoimmune encephalitis syndromes has rapidly expanded and clinically characteristic syndromes in association with pathogenic autoantibodies have been defined. By focusing on findings presented at the Encephalitis Society's conference in December 2021, this article reviews the causes, clinical manifestations and management of encephalitis and integrate recent advances and challenges of research into encephalitis.

Neurological manifestations of scrub typhus infection: A systematic review and meta-analysis of clinical features and case fatality

BACKGROUND

Scrub typhus has become a leading cause of central nervous system (CNS) infection in endemic regions. As a treatable condition, prompt recognition is vital. However, few studies have focused on describing the symptomology and outcomes of neurological scrub typhus infection. We conducted a systematic review and meta-analysis to report the clinical features and case fatality ratio (CFR) in patients with CNS scrub typhus infection.

METHODS

A search and analysis plan was published in PROSPERO [ID 328732]. A systematic search of PubMed and Scopus was performed and studies describing patients with CNS manifestations of proven scrub typhus infection were included. The outcomes studied were weighted pooled prevalence (WPP) of clinical features during illness and weighted CFR.

RESULTS

Nineteen studies with 1,221 (656 adults and 565 paediatric) patients were included. The most common clinical features in CNS scrub typhus were those consistent with non-specific acute encephalitis syndromes (AES), such as fever (WPP 100.0% [99.5%-100.0%, I2 = 47.8%]), altered sensorium (67.4% [54.9-78.8%, I2 = 93.3%]), headache (65.0% [51.5-77.6%, I2 = 95.1%]) and neck stiffness 56.6% (29.4-80.4%, I2 = 96.3%). Classical features of scrub typhus were infrequently identified; an eschar was found in only 20.8% (9.8%-34.3%, I2 = 95.4%) and lymphadenopathy in 24.1% (95% CI 11.8% - 38.9%, I2 = 87.8%). The pooled CFR (95% CI) was 3.6% (1.5%- 6.4%, I2 = 67.3%). Paediatric cohorts had a CFR of 6.1% (1.9-12.1%, I2 = 77%) whilst adult cohorts reported 2.6% (0.7-5.3%, I2 = 43%).

CONCLUSION

Our meta-analyses illustrate that 3.6% of patients with CNS manifestations of scrub typhus die. Clinicians should have a high index of suspicion for scrub typhus in patients presenting with AES in endemic regions and consider starting empiric treatment whilst awaiting results of investigations, even in the absence of classical signs such as an eschar or lymphadenopathy.

The epidemiology and clinical spectrum of infections of the central nervous system in adults in north India

Infections of the central nervous system (CNS) are a leading cause of mortality in low- and middle-income countries. We studied the spectrum, aetiology and outcome of CNS infections in 401 consecutive patients aged ≥12 years admitted at the medical emergency centre of PGIMER, Chandigarh, India. An aetiological diagnosis was made in 365 (91.0%) patients, with 149 (40.8%) microbiologically confirmed cases. CNS tuberculosis was the most prevalent cause (51.5%), followed by viral meningoencephalitis (13.9%), community-acquired bacterial meningitis (9.7%), cryptococcal meningitis (6.2%), scrub typhus meningoencephalitis (1.7%), neurocysticercosis (1.7%) and fungal brain abscess (1.7%). Human immunodeficiency virus (11.0%) and diabetes mellitus (6.2%) remained the usual predisposing conditions. We found a mortality rate of 27.9%, highest in cases without an aetiology (64.5%). Tuberculosis remained the most common cause; however, an increasing number of scrub typhus, dengue, fungal infections and non-classical bacterial pathogens may indicate a change in the epidemiology of community-acquired CNS infections in India.

Enhanced Detection of DNA Viruses in the Cerebrospinal Fluid of Encephalitis Patients Using Metagenomic Next-Generation Sequencing

The long and expanding list of viral pathogens associated with causing encephalitis confounds current diagnostic procedures, and in up to 50% of cases, the etiology remains undetermined. Sequence-agnostic metagenomic next-generation sequencing (mNGS) obviates the need to specify targets in advance and thus has great potential in encephalitis diagnostics. However, the low relative abundance of viral nucleic acids in clinical specimens poses a significant challenge. Our protocol employs two novel techniques to selectively remove human material at two stages, significantly increasing the representation of viral material. Our bioinformatic workflow using open source protein- and nucleotide sequence-matching software balances sensitivity and specificity in diagnosing and characterizing any DNA viruses present. A panel of 12 cerebrospinal fluid (CSFs) from encephalitis cases was retrospectively interrogated by mNGS, with concordant results in seven of nine samples with a definitive DNA virus diagnosis, and a different herpesvirus was identified in the other two. In two samples with an inconclusive diagnosis, DNA viruses were detected and in a virus-negative sample, no viruses were detected. This assay has the potential to detect DNA virus infections in cases of encephalitis of unknown etiology and to improve the current screening tests by identifying new and emerging agents.

A 9-month retrospective evaluation of the aetiology and management of patients presenting with encephalitis/meningoencephalitis at a South London hospital

Encephalitis causes high morbidity and mortality. An incidence of 4.3 cases of encephalitis/100 000 population has been reported in the UK. We performed a retrospective evaluation of the diagnosis and management of adults admitted to hospital with a clinical diagnosis of encephalitis/meningoencephalitis. Clinical, laboratory and radiological data were collated from electronic records. Thirty-six patients, median age 55 years and 24 (67%) male were included. The aetiology was confirmed over nine months in 25 (69%) of whom 16 were infections (six viral, seven bacterial, two parasitic and one viral and parasitic co-infection); 7 autoimmune; 1 metabolic and 1 neoplastic. Of 24 patients with fever, 15 (63%) had an infection. The median time to computed topography, magnetic resonance imaging and electroencephalography (EEG) was 1, 8 and 3 days respectively. Neuroimaging was abnormal in 25 (69%) and 17 (89%) had abnormal EEGs. Only 19 (53%) received aciclovir treatment. Six (17%) made good recoveries, 16 (44%) had moderate disability, 8 (22%) severe disability and 6 (17%) died. Outcomes were worse for those with an infectious cause. In summary, a diagnosis was made in 69.4% of patients admitted with encephalitis/meningoencephalitis. Autoimmune causes are important to consider at an early stage due to a successful response to treatment. Only 53% of patients received aciclovir on admission. Neuroimaging and EEG studies were delayed. The results of this work resulted in further developing the clinical algorithm for managing these patients.

Clinical features and surgical treatment of epilepsy after viral encephalitis

Encephalitis is an acute inflammatory process of the brain parenchyma, which is often caused by viral infection. It is an vital cause of acute symptomatic seizures and subsequent epilepsy. The incidence of unprovoked and recurrent seizures after previous infections of the central nervous system is high and accounts for 1%~5% of the cases of epilepsy. Viral encephalitis (VE) is directly caused by viral infection. The occurrence of seizures after VE is associated with poor prognosis. In survivors of VE, among other neurological sequelae, the risk of developing epilepsy is increased 10-fold. The risk of severe neurological sequelae after VE is particularly high in very young children. Studies on seizure occurrence, possible underlying mechanisms, clinical characteristics, and clinical treatment (especially surgical treatment) of VE have yielded only limited detailed data. We reviewed the most recent literature on the clinical features and surgical treatment of post-VE epilepsy.

A Cross-Sectional Study of Hyponatremia Associated with Acute Central Nervous System Infections

Hyponatremia can occur with central nervous system (CNS) infections, but the frequency and severity may depend on the organism and nature of CNS involvement. In this cross-sectional study at a large Australian hospital network from 2015 to 2018, we aimed to determine the prevalence and severity of hyponatremia associated with CNS infection clinical syndromes, and the association with specific organisms. We examined the results of cerebrospinal fluid analysis from lumbar punctures performed in 184 adult patients with a serum sodium below 135 mmol/L who had abnormal cerebrospinal fluid analysis and a clinical syndrome consistent with an acute CNS infection (meningitis or encephalitis). Hyponatremia affected 39% of patients and was more severe and frequent in patients with encephalitis compared to meningitis (odds ratio = 3.03, 95% CI: 1.43–6.39, after adjusting for age). Hyponatremia was present on admission in 85% of cases. Herpes simplex virus infection was associated with the highest odds of hyponatremia (odds ratio = 3.25, 95% CI: 1.13–7.87) while enterovirus infection was associated with the lowest (odds ratio = 0.36, 95% CI: 0.14–0.92), compared to cases without an isolated organism. We concluded that the risk of hyponatremia may vary by the organism isolated but the clinical syndrome was a useful surrogate for predicting the probability of developing hyponatremia.

Predictive Role of Electroencephalography in Regard to Neurological and Cognitive Sequelae After Acute Central Nervous System Infection

Introduction:

Electroencephalography can also be used to monitor long-term recovery of the patient after acute phase of the disease. Impaired neurocognitive function after infection, similar to brain injury, may present a transient but also prolonged problem for the functioning of an individual. Some studies have shown that importance of EEG may not be significant in sequel monitoring, because the extensive changes in EEG seen with severe forms of CNS infection do not necessarily imply a longer-term poor outcome.

Aim:

To examine the predictive potential of electroencephalography (EEG) in regard to the emergence of neurological and cognitive sequelae of acute central nervous system (CNS) infection.

Methods:

The study included 62 patients treated at the Clinic for Infectious Diseases, Clinical Center of Sarajevo University, who were diagnosed with acute CNS infection. The EEG record was characterized as: normal, non-specific changes of mild, moderate and severe degree and specific changes. The sequelae (headache, cognitive dysfunction, neurological and neurophysiological disorders, audiological and behavioral disorders) was evaluated by combining neurological, psychiatric, pediatric, otolaryngological, ophthalmic and infectological examination in the Neuroinfective Counseling Department for up to 6 months after discharge.

Results:

After a treatment of an acute CNS infection 25 (40.3%) patients had no sequelae and 37 (59.7%) were with sequelae. The EEG in the initial stage of the disease (Wald’s coefficient = 12.8), followed by the age of the patients (Wald = 6.4), had the greatest influence on the prediction of sequela (p=0.0001). For each additional degree of verified pathological changes in the EEG, the risk of sequelae was increased by 5 degrees (OR = 5.3), respectively. There was no statistically significant association between changes in cerebrospinal fluid (CSF) findings, meningeal symptoms, and signs with sequelae development.

Conclusion:

Younger age, as well as severe clinical status of a patient, which implies a disorder of consciousness and seizures on admission, are associated with irreversible consequences on a previously mentally healthy individual. Pathological changes (Delta and Theta waves, spike slow complex wave) on the EEG finding significantly predicted presence of sequelae. .

A pragmatic cluster randomised controlled trial of a tailored intervention to improve the initial management of suspected encephalitis

OBJECTIVE

To determine whether a tailored multifaceted implementation strategy improves the initial management of patients with suspected encephalitis.

DESIGN

Pragmatic two arm cluster randomised controlled trial.

SETTING

Hospitals within the United Kingdom.

PARTICIPANTS

Twenty-four hospitals nested within 12 postgraduate deaneries. Patients were identified retrospectively by searching discharge, microbiology, radiology and pharmacy records and included if they met clinical criteria or had a recorded suspicion of encephalitis.

INTERVENTION

An implementation strategy designed to overcome barriers to change, comprising local action planning, education and training, feedback on performance, a lumbar puncture pack and a range of optional components.

OUTCOMES

The primary outcome was the proportion of patients with suspected encephalitis undergoing diagnostic lumbar puncture within 12 hours of admission and starting aciclovir treatment within six hours. Secondary outcomes included the proportions of adults and children who had a lumbar puncture, who had appropriate cerebrospinal fluid investigations, and who had appropriate radiological imaging within 24 hours of admission. Data were collected from patient records for 12 months before and 12 months during the intervention period, and analysed blind to allocation.

RESULTS

13 hospitals were randomised to intervention and 11 to control (no intervention), with 266 and 223 patients with suspected encephalitis identified respectively. There was no significant difference in primary outcome between intervention and control hospitals (13.5% and 14.8% respectively, p = 0.619; treatment effect -0.188, 95% confidence interval -0.927 to 0.552), but both had improved compared to pre-intervention (8.5%).

CONCLUSION

The improvement in both intervention and control arms may reflect overall progress in management of encephalitis through wider awareness and education.

TRIAL REGISTRATION

Controlled Trials: ISRCTN06886935.

Transient Generalized Chorea in Influenza A Encephalopathy

Background

Influenza A infections are a rare cause of movement disorders. Previously described patients have suffered from acute-onset myoclonus and/or dystonia or post-viral parkinsonism.

Case Report

We present the case of a 74-year-old female patient with transient generalized chorea due to influenza A-mediated encephalopathy.

Discussion

We discuss whether the clinical presentation and the magnetic resonance imaging changes may be attributable to cytokine-mediated encephalopathy or to direct cytotoxic effects of the virus. Additionally, we would like to make clinicians aware of this clinical sign in the context of viral encephalopathy.

Epidemiology and clinical outcomes of viral central nervous system infections

BACKGROUND

Central nervous system (CNS) viral infections are an important cause of morbidity and mortality. No data are available regarding their epidemiology in Qatar.

DESIGN

We retrospectively evaluated all cerebrospinal fluid findings from January 2011-March 2015 at Hamad Medical Corporation. Those with abnormal CSF finding were included in our study. We excluded those with missing medical records, no clinical evidence of viral CNS infection, or proven bacterial, fungal or tuberculosis CNS infection. CNS clinical findings were classified as meningitis, encephalitis or myelitis.

RESULTS

Among 7690 patients with available CSF results, 550 cases met the inclusion criteria (meningitis 74.7%; encephalitis 25%; myelitis 0.4%). Two-thirds (65%) were male and 50% were between 16-60 years old. Viral etiology was confirmed in 38% (enterovirus, 44.3%; Epstein-Barr virus, 31%; varicella zoster virus, 12.4%). The estimated incidence was 6.4 per 100,000 population. Two persons died and the rest were discharged to home. Among those with confirmed viral etiology, 83.8% received ceftriaxone (mean duration 7.3±5.2 days), 38% received vancomycin (mean duration 2.7±5.4 days) and 38% received at least one other antibiotic. Intravenous acyclovir was continued for more than 48h in patients with confirmed negative viral etiology (mean duration 5±5.6 days).

CONCLUSION

Viral etiology is not uncommon among those evaluated for CNS infection in Qatar. Clinical outcomes are excellent in this group of patients. Antibiotics and acyclovir are overly used even when a viral etiology is confirmed. There is a need for clinician education regarding etiology and treatment of viral CNS infections.

Infectious meningitis and encephalitis in adults in Denmark: a prospective nationwide observational cohort study (DASGIB)

OBJECTIVES

To monitor epidemiological trends of infectious meningitis (bacterial and viral) and encephalitis in Denmark.

METHODS

Nationwide prospective observational study of all cases of proven community-acquired infectious meningitis and encephalitis in adults treated in all infectious diseases departments in Denmark from 1 January 2015 to 30 June 2016. We included data on symptoms, aetiology, treatment and outcome assessed by the Glasgow Outcome Scale (GOS) 30 days after discharge. GOS 1-4 was categorized as unfavourable outcome.

RESULTS

During 18 months of observation, we identified 252 cases of viral meningitis (3.6/100 000/year), 214 cases of bacterial meningitis (3.1/100 000/year) and 96 cases of infectious encephalitis (1.4/100 000/year). In bacterial meningitis, Streptococcus pneumoniae was the most frequent infectious agent (n = 101) followed by Staphylococcus aureus (n = 24) and β-haemolytic streptococci (n = 14). Meningococcal meningitis was rare (n = 11). In encephalitis, herpes simplex virus type 1 was most common (n = 37) followed by varicella zoster virus (n = 20), whereas varicella zoster virus (n = 61) was most common in viral meningitis followed by enterovirus (n = 50) and herpes simplex virus type 2 (n = 46). Case fatality and unfavourable outcome occurred in 31/214 (15%) and 96/214 (45%) with bacterial meningitis and in 5/96 (5%) and 55/89 (62%) with encephalitis. For viral meningitis, unfavourable outcome occurred in 41/252 (17%).

CONCLUSIONS

The epidemiology and clinical presentation of the examined central nervous system infections differed considerably and bacterial meningitis was more frequent than previously estimated. Overall prognosis remains poor for bacterial meningitis and encephalitis. Prospective nationwide clinical databases of central nervous system infections may be superior to epidemiological monitoring based on notifications or laboratory systems.

Viral meningitis: current issues in diagnosis and treatment

PURPOSE OF REVIEW

The purpose of this review is to give an overview of viral meningitis and then focus in on some of the areas of uncertainty in diagnostics, treatment and outcome.

RECENT FINDINGS

Bacterial meningitis has been declining in incidence over recent years. Over a similar time period molecular diagnostics have increasingly been used. Because of both of these developments viral meningitis is becoming relatively more important. However, there are still many unanswered questions. Despite improvements in diagnostics many laboratories do not use molecular methods and even when they are used many cases still remain without a proven viral aetiology identified. There are also no established treatments for viral meningitis and the one potential treatment, aciclovir, which is effective in vitro for herpes simplex virus, has never been subjected to a clinical trial.

SUMMARY

Viruses are in increasingly important cause of meningitis in the era of declining bacterial disease. The exact viral aetiology varies according to age and country. Molecular diagnostics can not only improve the rate of pathogen detection but also reduce unnecessary antibiotics use and length of hospitalization. Further research is required into treatments for viral meningitis and the impact in terms of longer term sequelae.

Cerebrospinal fluid pleocytosis level as a diagnostic predictor? A cross-sectional study

BACKGROUND

Lumbar puncture with quantification of leukocytes and differential count of cellular subsets in the cerebrospinal fluid is a standard procedure in cases of suspected neuroinfectious conditions. However, a number of non-infectious causes may result in a low leukocyte number (0-1000 cells/ml). We wanted to assess the diagnostic diversity of unselected adult patients with pleocytosis in the cerebrospinal fluid.

METHODS

The study is based on data from cerebrospinal fluid (CSF) analyses of all adult patients (15 years or older) admitted to a large university hospital in Denmark during a two-year period (2008-2009). Data from the local patient administrative system supplied with data from patient charts were combined with laboratory data.

RESULTS

A total of 5390 cerebrospinal fluid samples from 3290 patients were included. Pleocytosis >5 leucocytes/μl was found in samples from 262 patients of which 106 (40.5%) were caused by infection of the central nervous system (CNS), 20 (7.6%) by infection outside CNS, 79 (30.2%) due to non-infectious neurological diseases, 23 (8.8%) by malignancy, and 34 (13.0%) caused by other conditions. Significantly higher mean CSF leukocytes was found in patients suffering from CNS infection (mean 1135 cells/μl, p-value <0.0001).

CONCLUSIONS

CNS infection, non-infectious neurological disease, malignancy, and infection outside CNS can cause pleocytosis of the cerebrospinal fluid. Leukocyte counts above 100/μl is mainly caused by CNS infection, whereas the number of differential diagnoses is higher if the CSF leukocyte counts is below 50/μl. These conditions are most commonly caused by non-infectious neurological diseases including seizures.

The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults

Bacterial meningitis and meningococcal sepsis are rare conditions with high case fatality rates. Early recognition and prompt treatment saves lives. In 1999 the British Infection Society produced a consensus statement for the management of immunocompetent adults with meningitis and meningococcal sepsis. Since 1999 there have been many changes. We therefore set out to produce revised guidelines which provide a standardised evidence-based approach to the management of acute community acquired meningitis and meningococcal sepsis in adults. A working party consisting of infectious diseases physicians, neurologists, acute physicians, intensivists, microbiologists, public health experts and patient group representatives was formed. Key questions were identified and the literature reviewed. All recommendations were graded and agreed upon by the working party. The guidelines, which for the first time include viral meningitis, are written in accordance with the AGREE 2 tool and recommendations graded according to the GRADE system. Main changes from the original statement include the indications for pre-hospital antibiotics, timing of the lumbar puncture and the indications for neuroimaging. The list of investigations has been updated and more emphasis is placed on molecular diagnosis. Approaches to both antibiotic and steroid therapy have been revised. Several recommendations have been given regarding the follow-up of patients.

Performing lumbar punctures for suspected CNS infections: experience and practice of trainee doctors

Lumbar punctures are essential in the management of suspected CNS infections. However, despite clear guidelines their use can be haphazard. This survey investigated the training, knowledge and experience of UK doctors in training in relation to lumbar punctures.

Elevated levels of cerebrospinal fluid S100B are associated with brain injury and unfavorable outcomes in children with central nervous system infections

PURPOSE

This work aimed to assess whether elevated levels of cerebrospinal fluid (CSF) S100B are associated with brain injury and unfavorable outcomes at discharge in children with central nervous system (CNS) infections.

METHODS

CSF S100B and associated clinical parameters were retrospectively analyzed in 83 children with CNS infections and 88 children without neurological pathology served as controls. Children with CNS infections were divided into an infectious encephalitis group and an infectious meningitis group based on whether cerebral parenchyma was involved, and CSF S100B levels in different age subgroups between the two groups were compared. The predictive value of CSF S100B in children with infectious encephalitis was evaluated by multivariate logistic regression analysis, and the discriminative power was investigated by receiver operating characteristic (ROC) analysis.

RESULTS

CSF S100B levels in the infectious encephalitis group were significantly higher than the infectious meningitis and the control group at each age range. CSF S100B ≥ 0.96 μg/L had 62.9% sensitivity and 76.2% specificity for diagnosing cerebral parenchyma injury in children with CNS infections. Increased CSF S100B levels were proven to be an independent predictor of unfavorable outcomes in children with infectious encephalitis and the optimal cut-off value (1.77 μg/L of CSF S100B) for predicting unfavorable outcomes in children with infectious encephalitis showed 61.1% sensitivity and 96.2% specificity.

CONCLUSIONS

This study has demonstrated that elevated levels of CSF S100B are associated with brain injury and could be used as an independent predictor of clinically unfavorable outcomes at discharge in children with CNS infections.

An integrated model of care for neurological infections: the first six years of referrals to a specialist service at a university teaching hospital in Northwest England

Background

A specialist neurological infectious disease service has been run jointly by the departments of infectious disease and neurology at the Royal Liverpool University Hospital since 2005. We sought to describe the referral case mix and outcomes of the first six years of referrals to the service.

Methods

Retrospective service review.

Results

Of 242 adults referred to the service, 231 (95 %) were inpatients. Neurological infections were confirmed in 155 (64 %), indicating a high degree of selection before referral. Viral meningitis (35 cases), bacterial meningitis (33) and encephalitis (22) accounted for 38 % of referrals and 61 % of confirmed neurological infections. Although an infrequent diagnosis (n = 19), neurological TB caused the longest admission (median 23, range 5 – 119 days). A proven or probable microbiological diagnosis was found in 100/155 cases (64.5 %). For the whole cohort, altered sensorium, older age and longer hospital stay were associated with poor outcome (death or neurological disability); viral meningitis was associated with good outcome. In multivariate analysis altered sensorium remained significantly associated with poor outcome, adjusted odds ratio 3.04 (95 % confidence interval 1.28 – 7.22, p = 0.01).

Conclusions

A service of this type provides important specialist care and a focus for training and clinical research on complex neurological infections.

Managing acute central nervous system infections in the UK adult intensive care unit in the wake of UK encephalitis guidelines

The acute central nervous system infections meningitis and encephalitis commonly require management on intensive care units. The clinical features often overlap and in the acute phase-altered consciousness and seizures may also need to be managed. In April 2012, the first UK national guideline for the management of suspected viral encephalitis was published by the British Infection Association and Association of British Neurologists, and other key stakeholders, and included a simple management algorithm. The new guideline results from evidence demonstrating a number of common oversights in the standard management of suspected viral encephalitis in many settings. In combination with British Infection Association meningitis guidelines, evidence-based approaches now exist to facilitate the non-expert managing patients with suspected central nervous system infections. Here we bring together these guidelines and the supporting evidence applicable for intensivists into a single resource.

Herpes simplex virus encephalitis in pregnancy - a case report and review of reported patients in the literature

Background

Herpes simplex virus (HSV) encephalitis is the most common sporadic cause of encephalitis with significant morbidity and mortality that is drastically reduced by early antiviral treatment.

Case presentation

We report a 37 year old woman, 33 weeks pregnant, who presented with seizures due to proven HSV-1 encephalitis, and who had had a previous episode of probable viral encephalitis aged 14 years. She was successfully treated with aciclovir on both occasions and, in the latter, went on to deliver a healthy infant. This case is compared with 17 cases of HSV encephalitis in pregnancy in the literature identifying a predominance in the late 2nd and 3rd trimesters, perhaps in part due to immunological changes in pregnancy. The clinical presentation is also compared with non-pregnant patients with HSV encephalitis in the largest prospective UK and European studies. We also present practical advice on management from recent national guidelines.

Conclusion

When pregnant women present with new seizures, headache, impaired consciousness or altered behaviour urgent investigation is required to identify common diagnoses, such as eclampsia, venous sinus thrombosis and metabolic disturbances. Nevertheless, viral encephalitis is a very treatable cause of this presentation with potentially serious complications if missed, and may be more common in latter stages of pregnancy. Encephalitis should not be discounted if the patient is afebrile, has a normal Glasgow coma score, or the cerebrospinal fluid white cell count is only slightly elevated, as these features are well recognised in viral encephalitis.

Herpes simplex encephalitis in glioma patients: a challenging diagnosis

OBJECTIVES

In recent years, herpes simplex encephalitis (HSE) has been reported with increasing frequency in settings of immunosuppression, such as acquired immunodeficiency, transplantation and cancer. As observed, in immunocompromised individuals HSE presents peculiar clinical and paraclinical features, and poorer prognosis.

METHODS

Here we describe a retrospective series of seven cases of HSE in patients with high-grade glioma (HGG), collected among three institutions in a 5-year period (during this time, a total of 1750 patients with HGG were treated).

RESULTS

Diagnosis of the condition was particularly challenging due to the confounding clinical presentation and the atypical biological findings. As a result, antiviral treatment was started with a sharp delay compared with immunocompetent hosts. Prognosis was poor, with high short-term mortality and severe residual disability in survivors.

CONCLUSIONS

The substantial incidence of HSE observed in our centres together with the difficulty in diagnosing the condition suggest that the incidence of this complication may be highly underestimated. The aim of our report is to strengthen the observation of HSE in patients with HGG and outline the key elements that may allow its diagnosis.

The development of an intervention to promote adherence to national guidelines for suspected viral encephalitis

Background

Central nervous system infections can have devastating clinical outcomes if not diagnosed and treated promptly. There is a documented gap between recommended and actual practice and a limited understanding of its causes. We identified and explored the reasons for this gap, focusing on points in the patient pathway most amenable to change and the development of a tailored intervention strategy to improve diagnosis and treatment.

Methods

Using theoretically-informed semi-structured interviews, we explored barriers and enablers to diagnosing and managing patients with suspected encephalitis, specifically performing lumbar punctures and initiating antiviral therapy within 6 h. We purposively sampled hospitals and hospital staff in the UK. We audio recorded and transcribed all interviews prior to a framework analysis. We mapped identified barriers and enablers to the patient pathway. We matched behaviour change techniques targeting clinicians to the most salient barriers and enablers and embedded them within an intervention package.

Results

We interviewed 43 staff in six hospitals. Clinical staff expressed uncertainty when and how to perform lumbar punctures and highlighted practical difficulties in undertaking them within busy clinical settings. Once treatment need was triggered, clinicians generally felt able to take appropriate therapeutic action, albeit within organisational and resource constraints. Matched behaviour change techniques largely targeted antecedents of treatment. These included decision support to prompt recognition, highlighting the consequences of missed diagnoses for clinicians and patients, and practical support for lumbar punctures. We subsequently devised an evidence-informed package comprising ‘core’ interventions and, to allow for local flexibility, ‘optional’ interventions.

Conclusions

We identified several points in the patient pathway where practice could improve, the most critical being around clinical suspicion and initial investigation. Interventions targeting professional beliefs and behaviours whilst optimising their clinical environment were amongst the most promising approaches to improve the care of suspected encephalitis.

Trial registration

Randomised trial registered with Controlled Trials ISRCTN06886935.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-015-0224-2) contains supplementary material, which is available to authorized users.

Results of a multinational study suggest the need for rapid diagnosis and early antiviral treatment at the onset of herpetic meningoencephalitis

Data in the literature regarding the factors that predict unfavorable outcomes in adult herpetic meningoencephalitis (HME) cases are scarce. We conducted a multicenter study in order to provide insights into the predictors of HME outcomes, with special emphasis on the use and timing of antiviral treatment. Samples from 501 patients with molecular confirmation from cerebrospinal fluid were included from 35 referral centers in 10 countries. Four hundred thirty-eight patients were found to be eligible for the analysis. Overall, 232 (52.9%) patients experienced unfavorable outcomes, 44 died, and 188 survived, with sequelae. Age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02 to 1.05), Glasgow Coma Scale score (OR, 0.84; 95% CI, 0.77 to 0.93), and symptomatic periods of 2 to 7 days (OR, 1.80; 95% CI, 1.16 to 2.79) and >7 days (OR, 3.75; 95% CI, 1.72 to 8.15) until the commencement of treatment predicted unfavorable outcomes. The outcome in HME patients is related to a combination of therapeutic and host factors. This study suggests that rapid diagnosis and early administration of antiviral treatment in HME patients are keys to a favorable outcome.

The evaluation of a tailored intervention to improve the management of suspected viral encephalitis: protocol for a cluster randomised controlled trial

Background

Viral encephalitis is a devastating condition for which delayed treatment is associated with increased morbidity and mortality. Clinical audits indicate substantial scope for improved detection and treatment. Improvement strategies should ideally be tailored according to identified needs and barriers to change. The aim of the study is to evaluate the effectiveness and cost-effectiveness of a tailored intervention to improve the secondary care management of suspected encephalitis.

Methods/Design

The study is a two-arm cluster randomised controlled trial with allocation by postgraduate deanery. Participants were identified from 24 hospitals nested within 12 postgraduate deaneries in the United Kingdom (UK). We developed a multifaceted intervention package including core and flexible components with embedded behaviour change techniques selected on the basis of identified needs and barriers to change. The primary outcome will be a composite of the proportion of patients with suspected encephalitis receiving timely and appropriate diagnostic lumbar puncture within 12 h of hospital admission and aciclovir treatment within 6 h. We will gather outcome data pre-intervention and up to 12 months post-intervention from patient records. Statistical analysis at the cluster level will be blind to allocation. An economic evaluation will estimate intervention cost-effectiveness from the health service perspective.

Trial registration

Controlled Trials: ISRCTN06886935.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-014-0201-1) contains supplementary material, which is available to authorized users.

Neurological manifestations of influenza infection in children and adults: results of a National British Surveillance Study

BACKGROUND

The emergence of influenza A(H1N1) 2009 was met with increased reports of associated neurological manifestations. We aimed to describe neurological manifestations of influenza in adults and children in the United Kingdom that presented at this time.

METHODS

A 2-year surveillance study was undertaken through the British adult and pediatric neurological surveillance units from February 2011. Patients were included if they met clinical case definitions within 1 month of proven influenza infection.

RESULTS

Twenty-five cases were identified: 21 (84%) in children and 4 (16%) in adults. Six (29%) children had preexisting neurological disorders. Polymerase chain reaction of respiratory secretions identified influenza A in 21 (81%; 20 of which [95%] were H1N1) and influenza B in 4 (15%). Twelve children had encephalopathy (1 with movement disorder), 8 had encephalitis, and 1 had meningoencephalitis. Two adults had encephalopathy with movement disorder, 1 had encephalitis, and 1 had Guillain-Barré syndrome. Seven individuals (6 children) had specific acute encephalopathy syndromes (4 acute necrotizing encephalopathy, 1 acute infantile encephalopathy predominantly affecting the frontal lobes, 1 hemorrhagic shock and encephalopathy, 1 acute hemorrhagic leukoencephalopathy). Twenty (80%) required intensive care, 17 (68%) had poor outcome, and 4 (16%) died.

CONCLUSIONS

This surveillance study described a cohort of adults and children with neurological manifestations of influenza. The majority were due to H1N1. More children than adults were identified; many children had specific encephalopathy syndromes with poor outcomes. None had been vaccinated, although 8 (32%) had indications for this. A modified classification system is proposed based on our data and the increasing spectrum of recognized acute encephalopathy syndromes.

Development of ClickClinica: a novel smartphone application to generate real-time global disease surveillance and clinical practice data

Background

Identification and tracking of important communicable diseases is pivotal to our understanding of the geographical distribution of disease, the emergence and spread of novel and resistant infections, and are of particular importance for public health policy planning. Moreover, understanding of current clinical practice norms is essential to audit clinical care, identify areas of concern, and develop interventions to improve care quality.

However, there are several barriers to obtaining these research data. For example current disease surveillance mechanisms make it difficult for the busy doctor to know which diseases to notify, to whom and how, and are also time consuming. Consequently, many cases go un-notified. In addition assessments of current clinical practice are typically limited to small retrospective audits in individual hospitals.

Therefore, we developed a free smartphone application to try to increase the identification of major infectious diseases and other acute medical presentations and improve our understanding of clinical practice.

Description

Within the first month there were over 1000 downloads and over 600 specific disease notifications, coming from a broad range of specialities, grades and from all across the globe, including some resource poor settings.

Notifications have already provided important information, such as new cases of TB meningitis, resistant HIV and rabies, and important clinical information, such as where patient with myocardial infarctions are and are not receiving potentially life-saving therapy.

The database generated can also answer new, dynamic and targeted questions. When a new guideline is released, for example for a new pandemic infection, we can track, in real-time, the global usage of the guideline and whether the recommendations are being followed. In addition this allows identification of where cases with key markers of severe disease are occurring. This is a potential resource for guideline-producing bodies, clinical governance and public health institutions and also for patient recruitment into ongoing studies.

Conclusions

Further parallel studies are needed to assess the clinical and epidemiological utility of novel disease surveillance applications, such as this, with direct comparisons made to data collected through routine surveillance routes.

Nevertheless, current disease surveillance mechanisms do not always comprehensively and accurately reflect disease distribution for many conditions. Smartphone applications, such as ClickClinica, are a novel approach with the potential to generate real-time disease surveillance data that may augment current methods.

Management of suspected viral encephalitis in adults--Association of British Neurologists and British Infection Association National Guidelines

In the 1980s the outcome of patients with herpes simplex encephalitis was shown to be dramatically improved with aciclovir treatment. Delays in starting treatment, particularly beyond 48 h after hospital admission, are associated with a worse prognosis. Several comprehensive reviews of the investigation and management of encephalitis have been published. However, their impact on day-to day clinical practice appears to be limited. The emergency management of meningitis in children and adults was revolutionised by the introduction of a simple algorithm as part of management guidelines. In February 2008 a group of clinicians met in Liverpool to begin the development process for clinical care guidelines based around a similar simple algorithm, supported by an evidence base, whose implementation is hoped would improve the management of patients with suspected encephalitis.

Management of suspected viral encephalitis in children - Association of British Neurologists and British Paediatric Allergy, Immunology and Infection Group national guidelines

In the 1980s the outcome of patients with herpes simplex encephalitis was shown to be dramatically improved with aciclovir treatment. Delays in starting treatment, particularly beyond 48 h after hospital admission, are associated with a worse prognosis. Several comprehensive reviews of the investigation and management of encephalitis have been published. However, their impact on day-to-day clinical practice appears to be limited. The emergency management of meningitis in children and adults was revolutionised by the introduction of a simple algorithm as part of management guidelines. In February 2008 a group of clinicians met in Liverpool to begin the development process for clinical care guidelines based around a similar simple algorithm, supported by an evidence base, whose implementation is hoped would improve the management of patients with suspected encephalitis.

Autoimmune encephalitis: a case series and comprehensive review of the literature

Encephalitic syndromes are a common medical emergency. The importance of early diagnosis and appropriate treatment is paramount. If initial investigations for infectious agents prove negative, other diagnoses must be considered promptly. Autoimmune encephalitides are being increasingly recognized as important (and potentially reversible) non-infectious causes of an encephalitic syndrome. We describe four patients with autoimmune encephalitis--3 auto-antibody positive, 1 auto-antibody negative--treated during the last 18 months. A comprehensive review of the literature in this expanding area will be of interest to the infectious diseases, general medical and neurology community.

T cell-, interleukin-12-, and gamma interferon-driven viral clearance in measles virus-infected brain tissue

Genetic studies with immunocompetent mice show the importance of both T cells and gamma interferon (IFN-γ) for survival of a measles virus (MV) challenge; however, the direct role of T cells and IFN-γ within the MV-infected brain has not been addressed. Organotypic brain explants represent a successful ex vivo system to define central nervous system (CNS)-specific mechanisms of leukocyte migration, activation, and MV clearance. Within the heterogeneous, brain-derived, primed leukocyte population which reduced MV RNA levels in brain explants by 60%, CD3 T cells are the active antiviral cells, as purified CD3-positive cells are highly antiviral and CD3-negative leukocytes are unable to reduce the viral load. Neutralization of CCL5 and CXCL10 decreases leukocyte migration to areas of infection by 70%. However, despite chemokines directing the migration of T cells to infected neurons, chemokine neutralization revealed that migration is not required for viral clearance, suggesting a cytokine-mediated antiviral mechanism. In accordance with our hypothesis, the ability of leukocytes to clear the virus is abrogated when explants are treated with anti-IFN-γ neutralizing antibodies. IFN-γ applied to infected slices in the absence of primed leukocytes reduces the viral load by more than 80%; therefore, in brain tissue, IFN-γ is both necessary and sufficient to clear MV. Secretion of IFN-γ is stimulated by interleukin-12 (IL-12) in the brain, as neutralization of IL-12 results in loss of antiviral activity and stimulation of leukocytes with IL-12/IL-18 enhances their immune effector function of viral clearance. MV-primed leukocytes can reduce both West Nile and mouse hepatitis viral RNAs, indicating that cytokine-mediated viral clearance occurs in an antigen-independent manner. The IFN-γ signal is transduced within the brain explant by the Jak/STAT signaling pathway, as inhibition of Jak kinases results in a loss of antiviral activity driven by either brain-derived leukocytes or recombinant IFN-γ. These results reveal that primed T cells directly act to clear MV infection of the brain by using a noncytolytic IL-12- and IFN-γ-dependent mechanism in the CNS and that this mechanism relies upon Jak/STAT signaling.