Atypical herpes type 2 encephalitis associated with normal MRI imaging

Herpes simplex virus type 2 encephalitis in a child with chronic progressive white matter lesions: A case report

RATIONALE

This case is a rare manifestation of central nervous system infection of Herpes simplex virus (HSV)-2. Due to few studies in China, it provides a pathological basis for further diagnosis and treatment of HSV-2.

PATIENT CONCERNS

We describe a patient with HSV-2 virus infection who was diagnosed with HSV-2 encephalitis in a Chinese patient.

DIAGNOSIS

Based on brain biopsy and pathological findings, the patient was diagnosed with HSV-2 encephalitis.

INTERVENTIONS

Hormone and antiviral therapy were given.

OUTCOME

The patient eventually died.

LESSONS

The diagnosis and differential diagnosis of the disease is very difficult. Its differential diagnosis include cerebrovascular disease, bacteria or fungi and other viral infection of the brain.

Atypical imaging presentation of herpes simplex virus encephalitis in paediatric immunocompromised oncology patients

INTRODUCTION

We aim to assess the imaging manifestations of brain involvement in paediatric immunocompromised patients with haematological malignancies on chemotherapy presenting with encephalitis and positive HSV CSF PCR. We also aim to determine whether our findings are similar or different to those described in literature for paediatric patients in general.

METHODS

A retrospective study was performed in paediatric ALL/lymphoma patients on chemotherapy, and cases with positive CSF HSV-PCR with at least one head MRI scan were included. On imaging, location(typical/atypical), post-contrast enhancement and haemorrhage/diffusivity/gliosis were evaluated.

RESULT

A total of 28 scans were included in study from 16 patients fulfilling inclusion criteria, 12 (75%) HSV-1 and 4 (25%) HSV-2. Of the 16 initial scans (CT n = 10, MRI n = 6), 11 were normal (CT = 7, MRI = 4). Fourteen patients had follow-up MRI, of which two had normal scans. On the abnormal initial scan (5/16), only 20% had typical medial temporal/inferomedial frontal/cingulate involvement. Most had frontal (80%), parietal (60%) and non-medial temporal (40%) lesions. Abnormal diffusivity/haemorrhage was absent in all, and postcontrast enhancement was seen in 20%. On follow-up, more patients (33%) had typical medial temporal/inferomedial frontal/cingulate involvement. Widespread atypical site involvement of frontoparietal (75%), thalamus (58%), non-medial temporal (50%), occipital/basal ganglia (33%) and cerebellum (8%) was noted. Most lesions were cortical (91%)/subcortical (75%) with few periventricular lesions (58%). Few showed abnormal diffusivity (16%), post-contrast parenchymal enhancement/haemorrhage (8%), post-contrast meningeal enhancement (25%) and gliosis (16%).

CONCLUSION

Immunocompromised paediatric patients with haematological malignancies have widespread atypical brain involvement in herpes simplex encephalitis with lack of diffusion restriction and post-contrast enhancement, likely due to haematogenous spread of HSV across the blood-brain barrier, lack of cellular immunity and limited inflammatory cytokine response.

HSV-2 meningoencephalitis in an immunocompetent young man: what is the pathogenesis and what is the treatment?

Herpes simplex encephalitis is rarely caused by herpes simplex virus type 2 (HSV-2) after the neonatal period. The pathogenesis of HSV-2 encephalitis is not known and its treatment has not been discussed. We report a case of mild meningoencephalitis secondary to HSV-2 primary infection after sexual risk behaviour in a healthy young man. The diagnosis was established upon clinical, biological and electroencephalographic criteria. Aciclovir treatment led to rapid clinical improvement. This case highlights HSV-2 as a rare cause of meningoencephalitis, and questions the management of this rare manifestation of HSV-2 infection.

Chronic herpes simplex virus type 2 encephalitis associated with posterior uveitis

We report on a patient with chronic herpes simplex virus-2 encephalitis who was characteristic for concomitantly having chronic or recurrent posterior uveitis. A 66-year-old immunocompetent man suffering from a 6-month refractory posterior uveitis developed a 1-month history of impaired short-term memory and orientation. Brain MRI demonstrated hyperintense lesions in the right parietal lobe in diffusion and fluid attenuated inversion recovery (FLAIR) sequences. Cerebrospinal fluid (CSF) examination showed mild pleocytosis and increased protein concentration. Quantitative PCR for HSV-2 DNA was positive in CSF. Treated with acyclovir, his cognitive functions gradually improved and the posterior uveitis was cured. Clinicians must be aware that HSV-2 should be considered in the aetiological investigation of chronic encephalitis in an immunocompetent patient. HSV-2 is well known for its ability to cause unilateral chronic or recurrent posterior uveitis. Therefore, posterior uveitis should be considered as an associated feature of HSV-2 encephalitis.

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

INTRODUCTION

Herpes simplex virus encephalitis (HSE) is an acute infection accompanied by significant morbidity and mortality with the diagnosis often made by cerebrospinal fluid (CSF) polymerase chain reaction (PCR) testing.

CASE PRESENTATION

We report a case of a healthy 35-year-old woman presenting with altered mental status. Due to suspicion of herpes encephalitis, a CSF PCR for herpes virus was sent for examination and acyclovir was started. The patient had an immediate response to acyclovir; however, when the PCR returned negative she was discharged without therapy. The altered mental status returned and she was started on acyclovir therapy and a second CSF PCR sample was sent and was again negative. MRI performed at initial hospitalization was negative, but a repeat MRI demonstrated bilateral temporal lobe involvement suggestive of herpes encephalitis. The patient was successfully treated for 21 days with acyclovir.

CONCLUSION

CSF PCR for herpes virus is highly sensitive and specific and remains the standard for diagnosing herpes encephalitis. Clinicians should be aware of the pitfalls of CSF PCR testing, specifically false-negative results. Although rare, these false negatives can result in premature termination of treatment.

Encephalitis with herpes simplex-2 in the cerebrospinal fluid and anti-RI (ANNA-2) antibodies: an infectious or a paraneoplastic syndrome?

We report on a 70-year-old woman with partial complex status epilepticus who was initially diagnosed with herpes simplex-2 (HSV-2) encephalitis, based on brain magnetic resonance imaging (MRI) findings, cerebrospinal fluid (CSF) lymphocytic pleocytosis and HSV-2 DNA detection by polymerase chain reaction (PCR) in the CSF, but without improvement on intravenous acyclovir. Anti-Ri antibodies were positive and computed tomography (CT) investigations revealed a small cell carcinoma at biopsy suggesting paraneoplastic encephalitis. The outcome was unfavourable and the autopsy showed typical features of paraneoplastic encephalitis but no evidence of viral inclusions. This case report is interesting because: (1) it is the first report of an autopsy proven paraneoplastic widespread encephalitis with anti-Ri antibodies; (2) despite a positive HSV-2 PCR in the CSF, there was no sign of herpetic infections of the nervous system; and (3) it illustrates the fact that if paraneoplastic antibodies are usually good markers of the underlying tumour, they are not always predictive of neurological deficits.

Herpes simplex virus type 2 encephalitis in an elderly immunocompetent male

An 85-year-old immunocompetent man was hospitalized following the development of increasing confusion and intermittent disorientation over a 48-hour period. Within 48 hours of hospitalization, he was oriented to person only and was unable to follow commands. There were no focal neurologic deficits. Magnetic resonance imaging of the brain showed extensive perivascular demyelination. Lumbar puncture was performed and showed normal opening pressure. Cerebrospinal fluid analysis showed 8 leukocytes (7 lymphocytes), as well as normal glucose and protein levels. Polymerase chain reaction evaluation of cerebrospinal fluid was positive for herpes simplex virus type 2. He was diagnosed with herpes simplex type 2 encephalitis and is to the authors' knowledge the first elderly immunocompetent patient to be reported with this disorder.

Neuropsychological sequelae of acute-onset sporadic viral encephalitis

Acute encephalitis is an inflammation of the brain parenchyma. In the USA, by estimation, 20,000 cases occur every year. A variety of cognitive deficits may persist after the acute stage, and they are often the sole cause of disability. Recent literature demonstrates the heterogeneity of both amnestic disorders and the outcome following encephalitis. Herpes simplex virus is the most commonly recognised single aetiology of sporadic encephalitis and it may be the cause of the most severe symptoms. Antiviral medication, however, seems to have improved the cognitive outcome when compared to the historical, untreated cases. The cognitive sequelae following herpes simplex virus encephalitis (HSVE) are best known and most commonly described, e.g., in textbooks, but they do not represent the typical symptomatology of encephalitis in general. Much less is unfortunately known about other types of encephalitis, those that account perhaps up to 80% of all cases, where both mild and severe defects have been observed. This article summarises the current knowledge.

Herpes simplex virus type 2 infections of the central nervous system: A retrospective study of 49 patients

Herpes simplex virus type 2 (HSV-2) infections of the central nervous system (CNS) are rare with meningitis as the most common clinical presentation. We have investigated the clinical spectrum of CNS infections in 49 adult consecutive patients with HSV-2 genome in the cerebrospinal fluid (CSF). HSV-2 in the CSF was determined by polymerase chain reaction (PCR), and patients were diagnosed as encephalitis or meningitis according to predefined clinical criteria by retrospective data information from consecutive clinical journals. The annual crude incidence rate of HSV-2 CNS disease was 0.26 per 100,000. 43 (88%) had meningitis of whom 8 (19%) had recurring lymphocytic meningitis. Six patients (12%) had encephalitis. 11 of 49 patients (22%) had sequelae recorded during follow-up. None died as a result of HSV-2 CNS disease. Thus, the clinical presentation of HSV-2 infection of the CNS is mainly meningitis but encephalitis does occur and neurological sequelae are common. Recurring lymphocytic meningitis is associated with reactivation of HSV-2 and the condition might be underdiagnosed.

Relative preservation of 'animate' knowledge in an atypical presentation of herpes simplex virus encephalitis

A comprehensive battery of neuropsychological tests designed to assess primary cognitive functions, including language and semantic memory, was given to MG, a patient with confirmed herpes simplex virus encephalitis. MG's initial jargon aphasia resolved over time to leave her with a mild phonological impairment. She had a very mild amnesia that was worse for verbal material and a category-specific impairment of semantic memory. This latter impairment resulted in a significant anomia that was worse for manmade/artefact items than for animate kinds. Her naming difficulties were associated with a mild impairment in comprehension that was not specific to category or feature type. MRI revealed a strongly asymmetric and atypical distribution of pathology in MG with the disease affecting the left medial temporal lobe, temporal pole, left frontotemporal and temporoparietal regions.

Herpes simplex type-2 encephalitis masked by diabetic ketoacidosis

Diabetic ketoacidosis is a life-threatening acute complication of type-1 diabetes mellitus. Infection is the most common precipitating factor for diabetic ketoacidosis and is responsible for more than 50% of the cases. Here, we present a case study of a young man with herpes simplex virus type-2 encephalitis masked by diabetic ketoacidosis. We aim to orient clinicians towards being vigilant against such clinical scenarios.

Herpes simplex encephalitis: an audit of the use of laboratory diagnostic tests

BACKGROUND

The combination of both PCR and intrathecal antibody studies is recommended to confirm or refute the diagnosis of herpes simplex encephalitis (HSE).

AIM

To investigate the pattern of use of laboratory tests in the diagnosis of suspected cases of HSE, and to determine the final diagnosis in cases proven not to be HSE.

DESIGN

Structured audit.

METHODS

We reviewed the case-notes of all patients who, over a five-year time period, presented with suspected encephalitis; and/or were prescribed aciclovir. Clinical and laboratory criteria were used to categorize the likelihood of HSE.

RESULTS

We identified 222 patients: 10 (5%) had definite HSE, 24 (10%) possible HSE, and 144 (65%) a definite alternative diagnosis. In 44 (20%), no final diagnosis was made, but the diagnosis of HSE was excluded. PCR was performed in 68 (31%), intrathecal antibody studies in 24 (11%), and brain biopsy in 17 (8%). A wide range of diseases mimicked HSE, but most common were inflammatory diseases and other infections of the central nervous system.

DISCUSSION

Laboratory tests, particularly intrathecal antibody assays, are under-used in the diagnosis of HSE. Although early empirical treatment of suspected HSE is essential, confirmation or exclusion of the diagnosis is equally important to avoid overlooking alternative diagnoses. Identification of the aetiology of encephalitis is of particular importance, given the current concerns of emerging infections and bioterrorism.

Sexually transmitted herpes simplex viruses

Herpes simplex virus type 2 (HSV-2) is the dominant primary causative agent in genital ulcerative infections. Since infections with HSV-2 usually are acquired through sexual contacts, antibodies are rarely found before the age of onset of sexual activity. Although most genital infections are caused by HSV-2, a rising proportion has become attributable to primary type 1 herpes simplex virus (HSV-1) infection. Genital HSV-1 infections are usually both less severe clinically and less prone to recur. HSV-1 infection might render a certain protection against an HSV-2 infection and seems to mitigate the HSV-2 illness. It is not yet clear whether the advent of HSV-1 genitally will reduce the general occurrence of HSV-2. Increased efforts to protect against sexual transmission of the herpes viruses should have an effect on the transmission of other chronic diseases, such as the human immunodeficiency virus (HIV). In conclusion, it seems that increased sexual promiscuity and more advanced sexual techniques contribute to an unnecessary rise in prevalence of genital HSV infections, thus also affecting transmission of other genitally manifested diseases in targeted populations.