Herpes simplex encephalitis with two false-negative cerebrospinal fluid PCR tests and review of negative PCR results in the clinical setting

Clinical characteristics and outcomes of patients with Herpes Simplex Encephalitis in Vietnam: a retrospective study

BACKGROUND

Herpes simplex encephalitis (HSE) is an important central nervous infection with severe neurological sequelae. The aim of this study was to describe clinical characteristic and outcomes of patients with HSE in Vietnam.

METHODS

This was a retrospective study of 66 patients with herpes simplex encephalitis who admitted to the National Hospital for Tropical Diseases, Hanoi, Vietnam from 2018 to 2021. The detection of herpes simplex virus (HSV) in cerebrospinal fluid was made by the real-time PCR assay. We reported the clinical manifestation on admission and evaluated clinical outcomes at the hospital discharge by modified Rankin Scale (mRS). Multivariate logistic regression analysis was used to analyze the independent risk factors of severe outcomes.

RESULTS

Of the 66 patients with laboratory confirmed HSE, the median age was 53 years (IQR 38-60) and 44 patients (69.7%) were male. The most common manifestations included fever (100%), followed by the consciousness disorder (95.5%). Other neurological manifestation were seizures (36.4%), memory disorders (31.8%), language disorders (19.7%) and behavioral disorders (13.6%). Conventional magnetic resonance imaging (MRI) showed 93.8% patients with temporal lobe lesions, followed by abnormalities in insula (50%), frontal lobe (34.4%) and 48.4% of patients had bilateral lesions. At discharge, 19 patients (28.8%) completely recovered, 15 patients (22.7%) had mild sequelae, 28 patients (42.4%) had moderate to severe sequelae. Severe neurological sequelae were memory disorders (55.8%), movement disorders (53.5%), language disorders (30.2%). Multivariate logistic regression analysis showed that Glasgow score decrement at admission, seizures, and time duration from onset of symptoms to the start of Acyclovir treatment > 4 days were independent factors associated with severe outcomes in HSE patients.

CONCLUSION

Glasgow score decrement, seizures and delay treatment with Acyclovir were associated with the poor outcome of patients with HSE.

Worth the risk? Contemporary indications, yield and complications of lumbar punctures in a metropolitan Australian health service

BACKGROUND

Performing lumbar punctures carries a risk of harm to the patient, but the information cerebrospinal fluid provides often makes this procedure necessary. Clinicians in the Australian setting would benefit from having more information on these procedures, in order to help them in a risk versus benefit analysis.

AIMS

To describe the contemporary indications, cerebrospinal fluid findings and complications of lumbar punctures in a metropolitan Australian health service.

METHODS

Retrospective electronic medical records audit of lumbar punctures performed on 525 adults within three acute hospitals between 1 July 2018 and 30 June 2019. Main outcome measures include frequency of indication for lumbar puncture by category, normal versus abnormal cerebrospinal fluid for each category, and frequency, severity and type of complications of lumbar punctures.

RESULTS

Of 525 adult lumbar punctures that were assessed in this study, 466 were performed for a diagnostic indication. The most common diagnostic indications were acute severe headache (156 procedures; 33.5%) and encephalopathy (128 procedures; 27.5%). The yield of abnormal results varied by indication category, with the above indications yielding abnormal results in 85 (54.5%) and 72 (56.3%) cases respectively. A complication was recorded in 54 (10.3% of total) procedures. The majority (45; 8.6%) of complications were minor in severity and most frequently consisted of post-dural puncture headache (PDPH).

CONCLUSIONS

In the era of an increased reliance on high quality neuroimaging, lumbar puncture has a high diagnostic yield with a low rate of major complications. The most common complication is PDPH, which is mild and self-limiting in most cases.

Rapid-Onset Temporal Encephalitis With Negative Cerebrospinal Fluid Polymerase Chain Reaction Testing

Herpes simplex encephalitis is a rare disease presentation that is usually characterized by its temporal involvement and positive cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for the herpes simplex virus (HSV). HSV PCR has a sensitivity of 96% and specificity of 99%. Even when the test is negative, if clinical suspicion is high, acyclovir therapy should be continued with a repeated PCR within a week. In this case, we report a 75-year-old female patient who presented with signs of hypertensive emergency with rapid deterioration to seizure-like activity on electroencephalogram (EEG) and signs of temporal encephalitis on magnetic resonance imaging (MRI). The patient did not respond to the initial regimen of antibiotics but did show significant clinical response to acyclovir though she had a negative CSF PCR for HSV ten days after the start of her neurological symptoms. In this case, we argue that alternative methods of diagnosis should be considered in cases of acute encephalitis. Our patient had negative PCR but her computerized tomography (CT), EEG, and MRI results pointed to temporal encephalitis caused by HSV.

An Enigmatic Case of a Febrile Infant With Seizures

Herpes simplex virus (HSV) encephalitis is one of the most common viral infections in infants associated with high morbidity and mortality rates despite available antiviral therapy. For symptomatic infants, starting empiric therapy with acyclovir can prevent serious neurological sequelae while awaiting results from diagnostic studies. The gold standard of diagnosis remains to be the detection of HSV DNA via polymerase chain reaction (PCR) from cerebrospinal fluid (CSF). However, due to the low viral load in the initial stages of infection, even the gold standard test may not detect active infection. We present a case of an eight-month-old child who presented with fever and seizures and had negative HSV DNA PCR from initial CSF studies. Ongoing fever and recurrent seizures prompted an MRI which was suggestive of meningoencephalitis, HSV DNA PCR from repeat CSF sample resulted positive. This case emphasizes the importance of keen clinical judgment and the caution required when deciding to stop empiric therapy when the clinical suspicion for HSV encephalitis remains high.

Contribution of diffusion-weighted imaging to distinguish herpetic encephalitis from auto-immune encephalitis at an early stage

OBJECTIVES

To determine whether diffusion-weighted imaging (DWI) can help to distinguish early stage autoimmune (AI) and herpes simplex virus (HSV) encephalitides.

METHODS

This case-control study included patients from a multi-center cohort of AI encephalitides whose initial MRI including DWI was performed within ten days after symptoms onset. They were compared with patients with HSV encephalitis enrolled prospectively in a single-center from June, 2020 to December, 2020. The final diagnosis of AI encephalitis required a positive autoantibody assay, and that of HSV encephalitis required a positive HSV polymerase chain reaction based on cerebrospinal fluid. Brain MRI were evaluated for restricted diffusion, fluid-inversion recovery (FLAIR) abnormalities, lesion topography, hemorrhagic changes, and contrast enhancement.

RESULTS

Forty-nine patients were included of which, 19 (38.8%) had AI encephalitis. Twenty-seven patients (55.1%) were males and the median age was 46.0 years (interquartile range (IQR):[22.0; 65.0]). Brain MRI were performed after a median of 4 days (IQR:[2.0; 7.0]) of symptom onset and time between symptom onset and MRI was not significantly different (p=0.60). Twenty-six patients had restricted diffusion lesions in the medial temporal lobe, including 25/30 in the HSV encephalitis group (p<0.001). FLAIR abnormalities were observed in 36 patients, including 29/30 in the HSV encephalitis group (p<0.001). Lesion topography, hemorrhagic changes, and contrast enhancement did not differ significantly between the two groups.

CONCLUSION

Our results suggest that restricted diffusion lesions in the medial temporal lobe are a hallmark of HSV encephalitis and may help distinguish it from early-stage AI encephalitis.

Relapse of Herpes Simplex Encephalitis by Epilepsy Surgery 35 Years after the First Infection: A Case Report and Literature Review

Late relapse of herpes simplex encephalitis (HSE) is defined as the recurrence of HSE more than 3 months after the initial exposure. The postoperative diagnosis of HSE following neurosurgery is complicated because the clinical presentation can mimic other common complications of neurosurgery. Cerebrospinal fluid polymerase chain reactions (CSF-PCR) is the gold standard for the diagnosis of HSE. We describe a case of late HSE relapse after epilepsy surgery in a patient who required a brain biopsy due to repeated negative CSF-PCR results. A 38-year-old woman had a history of HSE from the age of 3 years. She had intractable epilepsy from the age of 20 years and underwent right posterior quadrant disconnection (PQD) at the age of 38 years. Postoperatively, she had a right hemispheric intracerebral hemorrhage (ICH) and her consciousness was gradually worsening. Her consciousness improved after removal of the ICH. However, her consciousness gradually deteriorated again. Fluid-attenuated inversion recovery (FLAIR) revealed bilateral hyperintensity in the frontal lobes, including the white matter. CSF-PCR for herpes simplex virus (HSV) was performed twice, but yielded negative results. We performed a brain biopsy to target FLAIR hyperintensity in the right frontal lobe. PCR of the brain specimen was positive for HSV. Her consciousness improved with acyclovir, methylprednisolone, and cyclophosphamide. To our knowledge, this is a case of HSE induced by epilepsy surgery which had the longest duration until relapse after the initial HSE episode. A brain biopsy can be used to confirm the diagnosis of suspected HSE when CSF-PCR results are negative.

Polymerase Chain Reaction (PCR)-Negative Herpes Simplex Virus (HSV) Encephalitis in a 62-Year-Old Woman With p-ANCA Vasculitis

We present the case of a 62-year-old woman with a past medical history significant for p-ANCA vasculitis (on immunosuppression) who was found to have polymerase chain reaction (PCR)-negative herpes simplex virus (HSV) encephalitis. We also present a review of all identifiable reports of PCR-negative HSV encephalitis in the past 20 years. To our knowledge, this is the first case of PCR-negative HSV encephalitis in a patient with p-ANCA vasculitis and the thirteenth overall in this timeframe. The patient presented with new-onset fever, encephalopathy, and a first-in-lifetime focal motor seizure progressing to status epilepticus. Cerebrospinal fluid (CSF) PCR was negative for HSV on three separate instances between the first and thirteenth days since symptom onset, and the CSF profile was not typical for HSV encephalitis. The patient underwent a brain biopsy, which confirmed the presence of HSV. She continued to worsen despite aggressive seizure control and six days of empiric acyclovir. Unfortunately, she expired despite the reinitiation of acyclovir. When faced with the classical features of encephalitis in the immunocompromised, the suspicion of HSV should remain high despite negative PCR results. The completion of a full course of acyclovir in the absence of clinical improvement should be considered.

Multiple Sclerosis Clinic Utilization is Associated with Fewer Emergency Department Visits

OBJECTIVE

Alberta is a Canadian province with a high prevalence of multiple sclerosis (MS). In this ecological study, we examined group differences in health care utilization among persons with MS (pwMS) living within different regions of the province.

METHODS

pwMS were identified from provincial administrative databases spanning 2002-2011. Utilization of health care services was determined for a 2-year period (April 2010-March 2012). Residential postal codes placed patients into their provincial health care zones. As data were provided to the investigators in an aggregated form, tests of statistical significance and confounding were not performed.

RESULTS

In total, 11,721 pwMS were identified. During the 2-year observation period, 96.2% of pwMS accessed a family physician and 57.1% accessed a neurologist. Nearly all (99.0%) pwMS who received neurologist care in Calgary visited an MS clinic, in contrast to Edmonton where a larger proportion (34.8%) received solely community neurologist care. More pwMS living in Edmonton accessed the ED (41.1%) compared to Calgary (35.7%), and the rate of visits per pwMS was higher in Edmonton (1.07/pwMS) than in Calgary (0.81/pwMS). The frequency of inpatient admissions was similar.

CONCLUSIONS

Over 2 years, most pwMS accessed primary care and over half saw a neurologist. Despite a similar frequency of inpatient admissions, the frequency of ED visits by pwMS was higher in Edmonton compared to Calgary, where more patients received MS clinic care. Although this exploratory study is subject to several limitations, our findings suggest that specialized MS clinics may reduce costly ED visits.

Twice Negative PCR in a Patient With Herpes Simplex Virus Type 1 (HSV-1) Encephalitis

Untreated herpes simplex virus type 1 (HSV-1) encephalitis is associated with high mortality. Missed cases can have devastating consequences. Detection of HSV-1 in cerebrospinal fluid (CSF) with polymerase chain reaction (PCR) is reported to have high sensitivity and specificity and is considered the diagnostic gold standard for HSV-1 encephalitis. In this article, we report a case of autopsy-confirmed HSV-1 encephalitis where CSF PCR returned negative on 2 occasions. A 64-year-old man presented with fever, left-sided weakness, and altered level of consciousness. Magnetic resonance imaging demonstrated right mesial temporal lobe diffusion restriction and electroencephalography showed right lateralized periodic discharges. Lumbar puncture was performed on day 1 for which CSF PCR returned negative for HSV-1. Empiric antiviral and antibiotic treatments were continued due to high clinical suspicion of HSV-1 encephalitis. Repeat lumbar puncture on day 5 was unchanged and empiric treatments were discontinued. On day 13, he developed status epilepticus requiring intensive care unit admission. A third CSF sample returned positive for HSV-1. Acyclovir was restarted but he continued to clinically worsen and supportive care was withdrawn. Autopsy confirmed widespread HSV-1 meningoencephalitis. Negative CSF PCR should be interpreted with caution in cases where there is high clinical suspicion of HSV-1 encephalitis. Current guidelines suggest repeating CSF HSV-1 PCR within 3 to 7 days in suspicious cases while continuing empiric therapy. However, missed cases can occur even with repeated testing. Empiric treatment with acyclovir should be considered in cases with high clinical suspicion of HSV-1 encephalitis, while investigations for alternate treatable diagnoses are continued.

Cerebrospinal fluid challenges for the diagnosis of herpes simplex infection in the central nervous system

Abstract Herpes simplex virus (HSV) is a cause of a severe disease of the central nervous system (CNS) in humans. The demonstration of specific antibodies in the cerebrospinal fluid (CSF) may contribute to the retrospective neurological diagnosis. However, the commercial immunological tests for HSV infection are for use in serum samples. Objective: The aim of the present study was to adapt a commercial kit anti-HSV IgG used for serum samples to be performed with a CSF sample. Methods: Forty CSF specimens from 38 patients with suspected CNS HSV infection were serially diluted for detecting anti-HSV IgG by enzyme immunoassay (EIA). The same samples were also analyzed with the polymerase chain reaction (PCR). Results: The sensitivity of EIA test for HSV was 5% (dilution 1:40) and 65% (dilution 1:2) in CSF, and HSV DNA PCR was 15%. The combined analysis of EIA (dilution 1:2) and PCR increased the sensitivity up to 72.5%. The inflammatory CSF was associated with positive HSV PCR. Conclusions: We demonstrated the importance to adapt serological anti-HSV IgG EIA test for CSF assays to increase the accuracy of the analysis, considering the low concentration of specific antibodies in CSF.

HSV-Encephalitis Reactivation after Cervical Spine Surgery

Background

Herpes simplex virus encephalitis (HSVE) is a viral neurological disorder that occurs when the herpes simplex virus (HSV) enters the brain. The disorder is characterized by the inflammation of the brain and a significant decline in mental status. HSVE reactivation after neurosurgery, although rare, can cause severe neurological deterioration. The high morbidity rate among untreated patients necessitates prompt diagnosis and management.

Case Description

We report a case of a 78-year-old woman with no known prior history of HSVE and declining mental status eleven days after a posterior C3-T1 decompression and instrumented fusion following resection of an intradural extramedullary tumor, confirmed to be meningioma on final pathology. Reactivation of HSV-1 encephalitis was suspected to be the underlying cause of her symptoms, though MRI scans of the brain for HSVE were negative. The patient reacted positively to a 21-day treatment of acyclovir and was discharged with a neurological status comparable to her preoperative baseline. This case contributes to the literature in that it is the first reported instance of HSVE reactivation after intradural cervical spinal surgery with negative MRI findings.

Conclusion

We recommend utilizing multiple tests, including PCR, EEG, and MRI, for postoperative neurosurgery patients that have decreased mental status in order to quickly and correctly diagnose/treat patients who are HSVE positive. Clinicians should consider the possibility of receiving false-negative results from PCR, CSF, EEG, or MRI tests before terminating treatment for HSVE reactivation.

A Fatal Case of Herpes Simplex Encephalitis with Two False-Negative Polymerase Chain Reactions

An 88-year-old man presented with a 1-month history of altered mental status and seizures. His electrographic and imaging findings were suggestive of herpes simplex encephalitis (HSE), for which he was empirically treated with acyclovir. He underwent two lumbar punctures 3 days apart; both cerebrospinal fluid analyses tested negative for herpes simplex virus (HSV) by polymerase chain reaction (PCR). These negative results and his continued deterioration after 9 days of acyclovir therapy prompted treatment with steroids for possible autoimmune encephalitis. Shortly after the change in management, the patient died from cardiac arrest. At autopsy, his brain showed both gross and microscopic evidence of encephalitis and was positive for HSV by immunohistochemistry. This fatal case of HSE emphasizes the limitations of HSV PCR and the importance of clinical suspicion in the diagnosis and management of this disease.

Coexisting infectious diseases on admission as a risk factor for mechanical ventilation in patients with Guillain-Barré syndrome

Background

The aim of this study was to investigate patient characteristics on admission to hospital that increase the risk of subsequent mechanical ventilation (MV) use for patients with Guillain–Barré syndrome (GBS).

Methods

We extracted data from the Japanese Diagnosis Procedure Combination (DPC) database for 4132 GBS patients admitted to hospital. Clinical characteristics of GBS patients with and without MV were compared. Multivariate logistic regression analyses were performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of requirement for MV with coexisting infectious diseases, after adjustment for potential confounding variables, age, sex, hospital type, and ambulance transportation.

Results

In total, 281 patients required MV, and 493 patients had coexisting respiratory diseases on admission. After adjustment for covariates and stratification by coexisting respiratory diseases, multivariate logistic regression analysis revealed that coexisting cytomegaloviral (CMV) disease (OR 8.81; 95% CI, 2.34–33.1) and herpes simplex viral (HSV) infections (OR 4.83; 95% CI, 1.16–20.1) were significantly associated with the requirement for MV in the group without coexisting respiratory diseases.

Conclusion

Our findings suggest that coexisting CMV and HSV infections on admission might be significantly associated with increased risk of respiratory failure in GBS patients.

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Subjects of this study were 4132 inpatients with Guillain–Barré syndrome.

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Data were derived from the Japanese Diagnosis Procedure Combination (DPC) database.

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Association between comorbidities and mechanical ventilation use was evaluated.

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Cytomegaloviral and herpes simplex viral infections were associated with ventilation.

Herpes Simplex Encephalitis: an Update

PURPOSE OF REVIEW

The goal of this review is to provide an update on current thinking regarding herpes simplex encephalitis (HSE), emphasizing new information about pathogenesis, diagnosis, and immune responses. Specific questions to be addressed are the following: (1) Is there a genetic predisposition to HSE? (2) What clinical approaches have the greatest impact on improving the long-term outcomes in patients with HSE? And (3) are there immune-mediated mechanisms that may account for relapsing HSE?

RECENT FINDINGS

Toll-like receptor 3 (TLR 3) plays an important role in innate immune responses, including generation of interferons. Multiple single-gene errors in TLR 3 interferon pathways have recently been described in children that result in increased susceptibility to HSE. Conversely, studies in both animal models and humans indicate that both cytolytic viral replication and immune-mediated responses (including cytotoxic T lymphocytes and immune mechanisms mediated by TLR 2) contribute to the pathology of HSV, suggesting possible new therapeutic approaches. In terms of treatment, data clearly indicate that a longer duration between onset of symptoms and initiation of effective antiviral therapy correlates directly with less favorable clinical outcome. Recurrent or relapsing HSE may occasionally occur, but recent observations indicate that many instances of "relapsing HSE", especially in children, are more often anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis triggered by the antecedent HSV infection. Innate immune responses are critical for defense against HSV; genetic defects in this system may predispose patients to HSE. During acute HSE, exuberant immune responses may contribute to the CNS pathology, suggesting that selective immunosuppressive therapy, coupled with potent antiviral drugs, may eventually play a role in the therapeutic management of HSV. While overall clinical outcomes of HSE remain suboptimal, the initiation of high-dose acyclovir therapy as early as possible in the course of the illness provides the best chance for a patient to survive with minimal neurologic damage. Distinguishing relapsing HSE from autoimmune anti-NMDAR antibody encephalitis is critically important because therapeutic approaches will be very different.

CSF in acute and chronic infectious diseases

Infections of the nervous system are an important and challenging aspect of clinical neurology. Immediate correct diagnosis enables to introduce effective therapy, in conditions that without diagnosis may leave the patient with severe neurological incapacitation and sometimes even death. The cerebrospinal fluid (CSF) is a mirror that reflects nervous system pathology and can promote early diagnosis and therapy. The present chapter focuses on the CSF findings in neuro-infections, mainly viral and bacterial. Opening pressure, protein and glucose levels, presence of cells and type of the cellular reaction should be monitored. Other tests can also shed light on the causative agent: serology, culture, staining, molecular techniques such as polymerase chain reaction. Specific examination such as panbacterial and panfungal examinations should be examined when relevant. Our chapter is a guide-text that combines clinical presentation and course with CSF findings as a usuaful tool in diagnosis of neuroinfections.

Imaging of Herpesvirus Infections of the CNS

OBJECTIVE

Herpesviridae are a family of DNA viruses remarkable for their ability to both promote acute infection and enter a latent phase with potential of reactivation. Herpes infections are ubiquitous throughout the human life span, regardless of the degree of immunocompetence.

CONCLUSION

We review the virology and clinical manifestations of each herpesvirus, with emphasis on recent advances in knowledge and characteristic neuroimaging findings important for diagnosis and appropriate clinical management.

Post-malaria neurological syndrome or viral encephalitis?

We present a case of a 60-year-old Caucasian man recently returned from Angola, where he had been successfully treated for a severe (non-cerebral) falciparum malaria infection. He was presented to the emergency room, with a subacute onset encephalopathy, ataxia and a generalised tonic-clonic seizure. Cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis (123 cells/µL) and hyperproteinorrhachia (188 mg/dL). Brain MRI and EEG were unremarkable. CSF PCR testing for neurotropic viruses was negative as were CSF and blood cultures. The patient was treated with ceftriaxone and acyclovir, with full recovery on the second day of treatment. We believe post-malaria neurological syndrome, a rare self-limited encephalopathy, should be considered in the differential diagnosis. Nevertheless, the presentation, lack of changes on brain MRI and EEG, along with possible false-negative CSF viral PCR, could still represent a viral encephalitis, which brings to question the treatment approach to adopt (conservative vs wide spectrum antiviral plus antibiotics).

Reversible Posterior Leukoencephalopathy Syndrome Associated with Treatment for Acute Exacerbation of Ulcerative Colitis

Reversible posterior leukoencephalopathy syndrome (RPLS) is a clinical syndrome of varying etiologies with similar neuroimaging findings. This is a case report of a 25-year-old woman who developed typical, neurological symptoms and magnetic resonance imaging abnormalities after treatment for the acute exacerbation of ulcerative colitis (UC), which included blood transfusion, the systemic administration of prednisolone, and the administration of metronidazole. It has been reported that these treatments may contribute to the development of RPLS. RPLS should therefore be considered in the differential diagnosis of UC patients who exhibit impaired consciousness, seizures or visual deficits during treatment. We report a rare case of RPLS in a patient with UC.

An unusual presentation of herpes simplex encephalitis with negative PCR

A 74-year-old man presented with acute right-sided hemiparesis and epilepsia partialis continua in association with fever and confusion. Initial workup revealed possible cerebritis in the left medial frontal lobe without involvement of the temporal lobes. Cerebrospinal fluid (CSF) analysis revealed minimal lymphocytic pleocytosis but negative real-time herpes simplex virus (HSV) PCR. Acyclovir was discontinued on day 5 due to a negative infectious workup and clinical improvement. On day 9 his condition deteriorated and he was transferred to a higher level of acuity for advanced supportive care. Worsening encephalopathy and refractory status epilepticus ensued despite medical care. Repeat CSF analysis showed mild lymphocytic pleocytosis with negative real-time HSV PCR. Brain MRI revealed progression of cortical enhancement. Immunosuppressive therapy and plasma exchange were attempted without clinical response. On day 24, another lumbar puncture showed only mild lymphocytic pleocytosis. Brain MRI showed involvement of the right medial temporal lobe. Subsequently, acyclovir was resumed. The HSV-1 PCR result was positive on day 30. Unfortunately, the patient expired.

Concurrent meningococcal and herpes simplex infection in a non-immunocompromised child

A previously well 11-month-old infant presented with lethargy, a blanching rash, vomiting and diarrhoea. She was diagnosed with suspected gastroenteritis and discharged. The patient deteriorated and re-presented 24 h later with lumbar puncture (LP) confirming Neisseria meningitidis. Following an initial good response to ceftriaxone, the patient then developed a blistering facial rash on day 3 for which topical aciclovir was started with no improvement. She subsequently developed fever and redeveloped a rising C reactive protein (CRP). A CT of the head on day 6 was normal, however a repeat LP on day 7 showed persistently raised cerebrospinal fluid (CSF), white cell count (WCC), high proteins and low CSF glucose. A CSF viral PCR confirmed concurrent herpes simplex virus (HSV) type 1 for which parenteral aciclovir was started. The patient responded well to bacterial and viral anti-infective treatments and was subsequently discharged on day 16 with no neurological sequelae.

Pitfalls associated with the diagnosis of herpes simplex encephalitis

Herpes simplex encephalitis (HSE) still remains a serious illness with high morbidity and mortality. The characteristic presentation of HSE usually consists of fever, headache, and altered mental function. We present three patients with atypical features of HSE. First, a 48-year-old man with symptomatic posttraumatic epilepsy, who developed a gastrointestinal infection, seizures, and fever. After significant clinical improvement, the patient had fever again and developed a status epilepticus, which led to the diagnosis of HSE. Second, an 84-year-old woman with hyperactive delirium after levofloxacin intake. Cranial computed tomography (CCT) revealed hypodense temporal changes, prompting lumbar puncture and diagnosis of HSE. Third, a 51-year-old diabetic woman presented with fever and acute confusion. As CCT and cell count of cerebrospinal fluid (CSF) were normal, infection and hyperglycemia as initial diagnoses were postulated. Due to aphasic symptoms, the differential diagnosis of a stroke was taken into account. Thus a second lumbar puncture led to the correct diagnosis of HSE. These atypical presentations need a high grade of suspicion and a high willingness to reconsider the initial working diagnosis, in order to prevent a diagnostic delay.

Viral encephalitis and atherothrombotic stroke

The clinical hallmark of viral encephalitis is an acute febrile illness, but stroke-like presentations have been rarely described. We report a patient who arrived at A&E with an acute right middle cerebral artery syndrome, without fever. Following thrombolytic treatment, clinical deficit almost disappeared and a critical ipsilateral carotid stenosis was identified. Stenting was implemented and 7 days later the patient started with high fever and reappearance of the initial deficit. Hyperperfusion syndrome and pneumonia were initially considered as the diagnosis but herpetic encephalitis (HE) was the final diagnosis. A very good response to antiviral treatment was achieved. We discuss whether the patient suffered from an unusual sudden stroke-like onset HE without encephalitic features or whether a stroke led to delayed HE.