The varicella zoster virus vasculopathies: clinical, CSF, imaging, and virologic features

Acute viral infections of the central nervous system in immunocompetent adults: diagnosis and management

Patients with viral infections of the central nervous system (CNS) may present with a variety of neurological symptoms, most commonly dominated by either encephalitis or meningitis. The aetiological panorama varies in different parts of the world as well as over time. Thus, virological first-line diagnostics must be adapted to the current epidemiological situation and to the individual patient history, including recent travels. This review focuses on the diagnostics and treatment of viral CNS infections in the immunocompetent host from a Northern European perspective. Effective vaccines are available for viruses such as poliovirus and tick-borne encephalitis virus (TBEV) and for the childhood diseases morbilli (measles), rubella (German measles), parotitis (mumps) and varicella (chickenpox). However, cases do appear due to suboptimal immunization rates. In viral CNS infections, epidemiological surveillance is essential for establishing preventive strategies and for detecting emerging viruses. Knowledge of the possibilities and limitations of diagnostic methods for specific viral CNS infections is vital. A positive cerebral spinal fluid (CSF) polymerase chain reaction (PCR) finding is usually reliable for aetiological diagnosis. The demonstration of intrathecal antibody synthesis is useful for confirming the aetiology in a later stage of disease, hitherto sufficiently evaluated in herpes simplex encephalitis (HSE) and tick-borne encephalitis (TBE). Despite improved virological and differential diagnostic methods, aetiology remains unknown in about half of the cases with suspected viral encephalitis. Antiviral treatment is available chiefly for infections caused by herpesviruses, and acyclovir (aciclovir) is the drug of choice for empirical therapy in suspected viral encephalitis. However, randomized, controlled antiviral trials have only been conducted for HSE, while such studies are lacking in other viral CNS infections. Viral cytolysis and immune-mediated mechanisms may contribute to varying extents to neurological damage. Although the brain damage is believed to depend, to a varying degree, on the intrathecal host immune response, the use of corticosteroids in viral CNS infections is scarcely studied, as is specific treatment for neuroinflammation. Improved antiviral and immunomodulating treatment is desirable. Since neurological sequelae are still abundant, follow-up after severe viral CNS disease must include a neuropsychological assessment and an individually adapted rehabilitation plan.

Thrombophilia and varicella zoster in children

From 2005 to 2011, 25 children of both sexes (13 boys and 12 girls, mean age 7.8 ± 2.5 years, 5-12.4 years) with acute varicella zoster virus (VZV) infection were selected. Five patients showed venous thromboembolism characterized by deep venous thrombosis (DVT). Comparison of activated partial thromboplastin time, antithrombin III, D-dimer, lupus anticoagulant, free S protein (PS), C protein, and antiphospholipid and PS antibodies was performed on children with acute VZV and DVT (group I), acute uncomplicated VZV (group II), and 30 healthy controls of both sexes (15 boys and 15 girls, mean age 7.5 ± 2.6 years, group III). Genetic thrombophilic mutations (Factor V Leiden, MTHFR C677T, and Prothrombin G20210A) were evaluated. Coagulation disorders and PS antibody were found in children with acute VZV (groups I and II). Significant differences were shown among the three groups (P < 0.05). Acute VZV infection could be associated with coagulation disorders and production of inhibitory PS antibodies in many uncomplicated cases.

HIV infection and stroke: current perspectives and future directions

HIV infection can result in stroke via several mechanisms, including opportunistic infection, vasculopathy, cardioembolism, and coagulopathy. However, the occurrence of stroke and HIV infection might often be coincidental. HIV-associated vasculopathy describes various cerebrovascular changes, including stenosis and aneurysm formation, vasculitis, and accelerated atherosclerosis, and might be caused directly or indirectly by HIV infection, although the mechanisms are controversial. HIV and associated infections contribute to chronic inflammation. Combination antiretroviral therapies (cART) are clearly beneficial, but can be atherogenic and could increase stroke risk. cART can prolong life, increasing the size of the ageing population at risk of stroke. Stroke management and prevention should include identification and treatment of the specific cause of stroke and stroke risk factors, and judicious adjustment of the cART regimen. Epidemiological, clinical, biological, and autopsy studies of risk, the pathogenesis of HIV-associated vasculopathy (particularly of arterial endothelial damage), the long-term effects of cART, and ideal stroke treatment in patients with HIV are needed, as are antiretrovirals that are without vascular risk.

Extensive extracranial and intracranial Varicella zoster vasculopathy

Varicella zoster virus (VZV)-induced vasculopathy is an uncommon cause of stroke in a young immunocompetent host. Owing to scarcity of data of VZV-induced vasculopathy and lack of awareness about this condition and its diagnostic test, these cases may be easily missed. In this case, we report an immunocompetent host presenting right-side hemiplegia with motor aphasia and complete loss of vision in the left eye due to complete occlusion of the left common carotid artery without any history of skin rash preceding stroke. Cerebrospinal fluid analysis for varicella antibody revealed very high titres and CT aortogram demonstrated aortoarteritis with occlusion of left common carotid artery. To our knowledge, varicella zoster vasculopathy-associated aortoarteritis has not been described in the literature.

Varicella zoster central nervous system vasculitis after allogeneic hematopoietic stem cell transplant successfully treated with cyclophosphamide

We report the first case of varicella zoster central nervous system vasculitis, to our knowledge, which responded to intravenous pulses of cyclophosphamide in an immunocompromised child with severe and progressive disease, without sequelae.

Zoster sine herpete, vertebral artery stenosis, and ischemic stroke

Although a previous or recent history of varicella-zoster virus (VZV) infection is known to increase the risk of stroke in both children and adults, the influence of zoster sine herpetic remains unclear. We report an immunocompetent man with common cold symptoms and conjunctivitis, followed by an acute onset of bulbar weakness and hemihypesthesia without preceding skin rash. Acute medullary infarction and left vertebral artery stenosis were detected. VZV infection was finally identified. Zoster sine herpetic interferes with accurate diagnosis of infectious stroke, and vertebral artery involvement is unusual in ischemic stroke in this situation. An unexplained course of ischemic stroke event should be suspected in patients with VZV cerebrovasculopathy, especially in those without conventional stroke risk factors and those exhibiting concomitant infectious complications.

Varicella zoster virus vasculopathy: a treatable form of rapidly progressive multi-infarct dementia after 2 years' duration

We describe an extraordinarily protracted case of varicella zoster virus (VZV) multifocal vasculopathy in a man who presented initially with ischemic optic neuropathy and then suffered 4 episodes of stroke manifesting as multi-infarct dementia over a 2-year period. Brain magnetic resonance imaging (MRI) and angiography (MRA) revealed cortical and subcortical infarctions as well as vasculitic occlusion and stenosis. The patient was treated with corticosteroids and later with cyclophosphamide. More than 2 years after the onset of neurological disease, two cerebrospinal fluid (CSF) examinations revealed the presence of anti-VZV IgG antibody with reduced serum-to-CSF ratios of anti-VZV IgG compared with ratios for total IgG and albumin, indicative of intrathecal synthesis of anti-VZV IgG. After definitive diagnosis, immunosuppressive drugs were discontinued and he was treated with intravenous acyclovir; both mental status and gait improved and no further episodes of neurological dysfunction ensued. The favorable outcome in this patient indicates that VZV vasculopathy can be treated successfully even after 26 months. VZV must be considered as a possible cause of neurological disease in any patient with idiopathic multifocal vasculopathy.

Adult primary central nervous system vasculitis

Primary CNS vasculitis is an uncommon disorder of unknown cause that is restricted to brain and spinal cord. The median age of onset is 50 years. The neurological manifestations are diverse, but generally consist of headache, altered cognition, focal weakness, or stroke. Serological markers of inflammation are usually normal. Cerebrospinal fluid is abnormal in about 80-90% of patients. Diagnosis is unlikely in the presence of a normal MRI of the brain. Biopsy of CNS tissue showing vasculitis is the only definitive test; however, angiography has often been used for diagnosis even though it has only moderate sensitivity and specificity. The size of the affected vessels varies and determines outcome and response to treatment. Early recognition is important because treatment with corticosteroids with or without cytotoxic drugs can often prevent serious outcomes. The differential diagnosis includes reversible cerebral vasoconstriction syndromes and secondary cerebral vasculitis.

Clinical recognition of varicella zoster virus vasculopathy

INTRODUCTION

It is important to recognize acutely evolving ischemic stroke attributable to reactivation of varicella zoster virus vasculopathy since antiviral agents are effective.

METHODS

Three cases seen by the author over a 2-year period are highlighted.

RESULTS

All patients presented with an evolving arterial or venous ischemia in the background of postherpetic neuralgia proceeding for weeks to months.

CONCLUSION

Chronic neuralgic pain in a dermatomal distribution of an evolving central nervous system vasculopathy is an important clue to its recognition.

Cerebrovascular disease in HIV-infected individuals in the era of highly active antiretroviral therapy

The widespread use of highly active antiretroviral therapy (HAART) in HIV-infected individuals mostly in developed countries has dramatically improved their prognosis. In such advantaged regions of the world, therefore, many patients are now transitioning from middle into older age, with altered patterns of disease. While previously a rare complication of HIV infection, cerebrovascular disease (particularly that associated with atherosclerosis) is becoming relatively more important in this treated group of individuals. This review summarises the evidence regarding the shifting epidemiology of cerebrovascular diseases affecting HIV-infected individuals. While outlining the association between HIV infection and AIDS and cerebrovascular disease, as well as opportunistic diseases and HIV-associated vasculopathies, the current evidence supporting an increase in atherosclerotic disease in treated HIV-infected individuals is emphasised and a management approach to ischaemic stroke in HIV-infected individuals is presented. Evidence supporting the important role of HAART and HIV infection itself in the pathogenesis of atherosclerotic disease is discussed, together with preventative approaches to this increasingly important disease process as the population ages. Finally, a discussion regarding the significant association between cerebrovascular disease and HIV-associated neurocognitive disorder is presented, together with possible mechanisms behind this relationship.

Varicella zoster virus meningoencephalitis after allogeneic hematopoietic stem cell transplantation

Although the reactivation of varicella zoster virus (VZV) is a common complication after allogeneic hematopoietic stem cell transplantation (HSCT), VZV meningoencephalitis is a rare life-threatening infectious disease after HSCT. We describe here a patient who developed VZV meningoencephalitis 2 years after human leukocyte antigen-matched unrelated HSCT for acute myeloblastic leukemia. She developed chronic graft-versus-host disease, and cyclosporine (CSA) was continued until 17 months after HSCT. Low-dose acyclovir (ACV) at 200 mg/day was administered to prevent the reactivation of VZV from day -7 to the termination of CSA. At 22 months, she suddenly developed fever, loss of consciousness, and seizure, with generalized skin rash. A high level of VZV DNA was detected in her cerebrospinal fluid (CSF). She was diagnosed to have VZV meningoencephalitis. Intravenous ACV at 30 mg/kg/day was given for 2 months. Although loss of consciousness was quickly resolved, some neurologic symptoms persisted. She did not have any known risk factors for VZV reactivation. Therefore, we should keep in mind that any HSCT recipient may develop VZV meningoencephalitis, and examination of CSF for VZV infection with an empiric administration of ACV may be recommended for HSCT recipients with central nervous system symptoms, even in the absence of skin manifestations.

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.

CD4 T cell immunity is critical for the control of simian varicella virus infection in a nonhuman primate model of VZV infection

Primary infection with varicella zoster virus (VZV) results in varicella (more commonly known as chickenpox) after which VZV establishes latency in sensory ganglia. VZV can reactivate to cause herpes zoster (shingles), a debilitating disease that affects one million individuals in the US alone annually. Current vaccines against varicella (Varivax) and herpes zoster (Zostavax) are not 100% efficacious. Specifically, studies have shown that 1 dose of varivax can lead to breakthrough varicella, albeit rarely, in children and a 2-dose regimen is now recommended. Similarly, although Zostavax results in a 50% reduction in HZ cases, a significant number of recipients remain at risk. To design more efficacious vaccines, we need a better understanding of the immune response to VZV. Clinical observations suggest that T cell immunity plays a more critical role in the protection against VZV primary infection and reactivation. However, no studies to date have directly tested this hypothesis due to the scarcity of animal models that recapitulate the immune response to VZV. We have recently shown that SVV infection of rhesus macaques models the hallmarks of primary VZV infection in children. In this study, we used this model to experimentally determine the role of CD4, CD8 and B cell responses in the resolution of primary SVV infection in unvaccinated animals. Data presented in this manuscript show that while CD20 depletion leads to a significant delay and decrease in the antibody response to SVV, loss of B cells does not alter the severity of varicella or the kinetics/magnitude of the T cell response. Loss of CD8 T cells resulted in slightly higher viral loads and prolonged viremia. In contrast, CD4 depletion led to higher viral loads, prolonged viremia and disseminated varicella. CD4 depleted animals also had delayed and reduced antibody and CD8 T cell responses. These results are similar to clinical observations that children with agammaglobulinemia have uncomplicated varicella whereas children with T cell deficiencies are at increased risk of progressive varicella with significant complications. Moreover, our studies indicate that CD4 T cell responses to SVV play a more critical role than antibody or CD8 T cell responses in the control of primary SVV infection and suggest that one potential mechanism for enhancing the efficacy of VZV vaccines is by eliciting robust CD4 T cell responses.

Varicella zoster virus (VZV) causes chickenpox and establishes a life-long latent infection in humans. VZV can reactivate years later to cause shingles, a debilitating and painful disease. Vaccines against both chickenpox and shingles are available but not 100% efficacious. Two doses of the chickenpox vaccine are required to provide adequate protection and the shingles vaccine reduces the incidence of this disease by 51%. To improve these vaccines, we must identify the components of the immune system that are important for the control of VZV replication. However, the contribution of T versus B cell responses is unknown. Infection of rhesus macaques with simian varicella virus is a robust model of VZV infection. Here, we used this unique animal model to show for the first time that the absence of B cells does not alter disease severity and that the loss of CD8 T cells only results in a mild increase in disease severity. In sharp contrast, the lack of CD4 T cells leads to disseminated varicella. These data highlight the importance of CD4 T cells and suggest that novel vaccines that focus on engendering a more robust CD4 T cell response against VZV might provide better protection from chickenpox and shingles.

Neurologic infectious disease emergencies

Nearly 70 years after the discovery of penicillin, neurologic infectious diseases (NIDs) remain an important worldwide source of morbidity and mortality. The clinician faced with a potential NID must urgently consider patient demographics, pace of illness and clinical syndrome, and laboratory data. In keeping with the topics of this issue, initial emergency diagnosis and management are emphasized, with appropriate references to relevant literature for subsequent longer-term interventions.

Review: The neurobiology of varicella zoster virus infection

Varicella zoster virus (VZV) is a neurotropic herpesvirus that infects nearly all humans. Primary infection usually causes chickenpox (varicella), after which virus becomes latent in cranial nerve ganglia, dorsal root ganglia and autonomic ganglia along the entire neuraxis. Although VZV cannot be isolated from human ganglia, nucleic acid hybridization and, later, polymerase chain reaction proved that VZV is latent in ganglia. Declining VZV-specific host immunity decades after primary infection allows virus to reactivate spontaneously, resulting in shingles (zoster) characterized by pain and rash restricted to one to three dermatomes. Multiple other serious neurological and ocular disorders also result from VZV reactivation. This review summarizes the current state of knowledge of the clinical and pathological complications of neurological and ocular disease produced by VZV reactivation, molecular aspects of VZV latency, VZV virology and VZV-specific immunity, the role of apoptosis in VZV-induced cell death and the development of an animal model provided by simian varicella virus infection of monkeys.

HIV/AIDS patients with HIV vasculopathy and VZV vasculitis: a case series

PURPOSE

Stroke is a rising cause of mortality in human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) populations. The etiology of stroke remains at the core of the decision-making process to treat and prevent recurrent events. In this population HIV vasculopathy (HIV-V) and varicella zoster virus (VZV) vasculitis are elusive causes of stroke. This study investigated radiological markers that could help identify possible etiological causes.

METHODS

A series of nine consecutive patients seen at a large metropolitan hospital who presented with AIDS and stroke with the suspicion of either HIV vasculopathy (HIV-V) or VZV vasculitis (VZV-V) were included. A standardized diagnostic approach was used to for HIV-V and VZV-V. Data on frequencies and typical images are reported.

RESULTS

Of the nine patients five had VZV-V and four had HIV-V. Patients with VZV-V were generally younger than those with HIV-V; however, no other significant demographic or cardiovascular differences were found. Of the five patients with VZV-V four had small, deep, subcortical ischemic strokes and only one in this group had a large, cortical, hemispheric stroke but in the HIV-V group three patients had large, cortical hemispheric strokes and only one patient had small, subcortical ischemic strokes.

CONCLUSIONS

In this series VZV-V seemed to present more often with deep-seated ischemic infarcts, while HIV-V appeared to be associated with large, hemispheric stroke. It seems plausible that this difference is related to the type of arteries infected by each virus. These findings are preliminary and should be confirmed with better studies.

Varicella zoster virus vasculopathy: analysis of virus-infected arteries

OBJECTIVE

Varicella zoster virus (VZV) is an under-recognized yet treatable cause of stroke. No animal model exists for stroke caused by VZV infection of cerebral arteries. Thus, we analyzed cerebral and temporal arteries from 3 patients with VZV vasculopathy to identify features that will help in diagnosis and lead to a better understanding of VZV-induced vascular remodeling.

METHODS

Normal and VZV-infected cerebral and temporal arteries were examined histologically and by immunohistochemistry using antibodies directed against VZV, endothelium, and smooth muscle actin and myosin.

RESULTS

All VZV-infected arteries contained 1) a disrupted internal elastic lamina; 2) a hyperplastic intima composed of cells expressing α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain (SM-myosin) but not endothelial cells expressing CD31; and 3) decreased medial smooth muscle cells. The location of VZV antigen, degree of neointimal thickening, and disruption of the media were related to the duration of disease.

CONCLUSIONS

The presence of VZV primarily in the adventitia early in infection and in the media and intima later supports the notion that after reactivation from ganglia, VZV spreads transaxonally to the arterial adventitia followed by transmural spread of virus. Disruption of the internal elastic lamina, progressive intimal thickening with cells expressing α-SMA and SM-MHC, and decreased smooth muscle cells in the media are characteristic features of VZV vasculopathy. Stroke in VZV vasculopathy may result from changes in arterial caliber and contractility produced in part by abnormal accumulation of smooth muscle cells and myofibroblasts in thickened neointima and disruption of the media.

Efficacy of live zoster vaccine in preventing zoster and postherpetic neuralgia

Declining cell-mediated immunity to varicella zoster virus (VZV) in elderly individuals results in virus reactivation manifest by zoster (shingles) and postherpetic neuralgia (PHN). To prevent virus reactivation, a new VZV vaccine (Zostavax; Merck) that boosts cell-mediated immunity to VZV was developed. The 3-year Shingles Prevention Study showed that Zostavax significantly reduced burden of disease because of zoster and PHN. Despite its cost-effectiveness for adults aged 65-75 years, as determined in the United States, Canada and UK, <2% of immunocompetent adults over age 60 years in the United States were immunized in 2007. This was because of a combination of lack of patient awareness of the vaccine, physicians' uncertainty about the duration of protection and different cost-sharing plans for immunization. Nevertheless, zoster vaccine is safe, effective and highly recommended for immunization of immunocompetent individuals over age 60 years with no history of recent zoster.

A virulent vasculopathy

Arteriopathy is an uncommon complication of primary varicella zoster virus (VZV) infection in the immunocompetent adult. We report a case of a 39-year-old woman known to be VZV negative prior to the event. She presented to the emergency department having experienced an episode of expressive aphasia and right upper limb paraesthesia lasting 15 min. The symptoms followed a 3-day period of general malaise, arthralgia and a generalised maculopapular itchy rash involving face and limbs. No immunocompromise was detected but an infectious contact was identified in the home. Imaging findings were consistent with a focal cerebritis/vasculopathy and VZV infection was confirmed with cerebrospinal fluid PCR analysis. Resolution of radiological signs occurred following prompt treatment with appropriate antivirals.

Varicella zoster vasculopathy

Varicella-zoster virus can cause neurological disease in primary and reactivated latent forms, with a wide spectrum of disorders throughout a person's lifetime. 35-year-old male with AIDS; histoplasmosis; mild, intermittent asthma; and hypertension presented to hospital with left-sided weakness and slurred speech. Exam showed left hemiparesis with left upper motor neurons facial palsy and dysarthria. Acute right basal ganglia infarct was detected in head CT without contrast. A subsequent MRI showed acute non-hemorrhagic infarct, right basal ganglia; fusiform dilatation, and proximal right middle cerebral artery. A CT angiogram of the bilateral carotid arteries revealed occlusion of the right anterior cerebral artery with conical dilatation at the origin; significant stenosis, and dilatation of the right middle cerebral artery. These findings were consistent with vasculitis. Patient was successfully treated with IV acyclovir. Rapid diagnosis of VZV vasculopathy is important because it is a treatable cause of stroke. Mortality rate is 25% without treatment.

Current proceedings of childhood stroke

Stroke is a sudden onset neurological deficit due to a cerebrovascular event. In children, the recognition of stroke is often delayed due to the low incidence of stroke and the lack of specific assessment measures to this entity. The causes of pediatric stroke are significantly different from that of adult stroke. The lack of safety and efficiency data in the treatment is the challenge while facing children with stroke. Nearly half of survivors of pediatric stroke may have neurologic deficits affecting functional status and quality of life. They may cause a substantial burden on health care resources. Hence, an accurate history, including onset and duration of symptoms, risk factors, and a complete investigation, including hematologic, neuroimaging, and metabolic studies is the key to make a corrective diagnosis. A prompt and optimal treatment without delay may minimize the damage to the brain.

Infectious burden: a new risk factor and treatment target for atherosclerosis

Atherosclerosis is a chronic inflammatory process, and several common bacterial and viral infections have been hypothesized to contribute to the inflammation of the vascular wall that leads to atherosclerosis. More recently, investigators have found preliminary evidence that the aggregate burden of these chronic infections, rather than any single organism, may contribute to atherosclerosis and risk of clinical vascular events, including ischemic stroke. This aggregate burden of infections, which has been variably labeled "infectious burden" or "pathogen burden," may be associated with stroke through mechanisms independent of atherosclerosis, as well, including platelet aggregation and endothelial dysfunction. Host factors, moreover, may interact with infectious burden to modify the risk of disease associated with these infections. Currently there is no commonly accepted group of organisms or method of assessing infectious burden, and not all studies confirm an association of infection and stroke risk. Nonetheless, if infectious burden does play a role in atherosclerosis or stroke, it is plausible that preventive anti-infective treatment, such as vaccination, or antibiotics, would reduce the risk of incident or recurrent stroke. While influenza vaccination has been recommended to prevent recurrence among those with coronary disease, similar recommendations for stroke patients have not yet been made. Large scale randomized clinical trials of macrolide antibiotics for coronary patients, moreover, have been negative. Further studies are needed, however, to determine whether an association between infectious burden and stroke exists, and whether infectious burden may be a target for intervention.

Varicella and Stroke in Children

Varicella zoster virus (VZV) is the only human virus known to replicate in arteries. After the acute infection, the virus persists in a noninfectious latent form in ganglia along the neuraxis, with intermittent periods of reactivation. Both primary and secondary reactivation are associated with stroke in children. These patients, regardless of the chosen treatment, have a high risk of recurrence, particularly those with worsening arterial stenosis. There are no specific therapy protocols for varicella-associated stroke in children, and the use of steroids or antiviral drugs is still controversial. We present a series of 4 children with stroke following varicella infection, with no recurrence and stable vascular stenosis at a mean follow-up of 18 months without steroid treatment. We also analyze possible correlations between anti-protein C, protein S and protein Z autoantibodies, and post-varicella arteriopathy.

Varicella-zoster virus human ganglionic latency: a current summary

Varicella-zoster virus (VZV) is a ubiquitous human herpes virus typically acquired in childhood when it causes varicella (chickenpox), following which the virus establishes a latent infection in trigeminal and dorsal root ganglia that lasts for the life of the individual. VZV subsequently reactivates, spontaneously or after specific triggering factors, to cause herpes zoster (shingles), which may be complicated by postherpetic neuralgia and several other neurological complications including vasculopathy. Our understanding of VZV latency lags behind our knowledge of herpes simplex virus type 1 (HSV-1) latency primarily due to the difficulty in propagating the virus to high titers in a cell-free state, and the lack of a suitable small-animal model for studying virus latency and reactivation. It is now established beyond doubt that latent VZV is predominantly located in human ganglionic neurons. Virus gene transcription during latency is epigenetically regulated, and appears to be restricted to expression of at least six genes, with expression of gene 63 being the hallmark of latency. However, viral gene transcription may be more extensive than previously thought. There is also evidence for several VZV genes being expressed at the protein level, including VZV gene 63-encoded protein, but recent evidence suggests that this may not be a common event. The nature and extent of the chronic inflammatory response in latently infected ganglia is also of current interest. There remain several questions concerning the VZV latency process that still need to be resolved unambiguously and it is likely that this will require the use of newly developed molecular technologies, such as GeXPS multiplex polymerase chain reaction (PCR) for virus transcriptional analysis and ChIP-seq to study the epigenetic of latent virus genome ( Liu et al, 2010 , BMC Biol 8: 56).

Recent advances in childhood arterial ischemic stroke

Although many underlying diseases have been reported in the setting of childhood arterial ischemic stroke, emerging research demonstrates that non-atherosclerotic intracerebral arteriopathies in otherwise healthy children are prevalent. Minor infections may play a role in arteriopathies that have no other apparent underlying cause. Although stroke in childhood differs in many aspects from adult stroke, few systematic studies specific to pediatrics are available to inform stroke management. Treatment trials of pediatric stroke are required to determine the best strategies for acute treatment and secondary stroke prevention. The high cost of pediatric stroke to children, families, and society demands further study of its risk factors, management, and outcomes. This review focuses on the recent findings in childhood arterial ischemic stroke.

Infectious vasculopathy of intracranial large- and medium-sized vessels in neurological intensive care unit: a clinico-radiological study

BACKGROUND

Infections are a well-known cause of cerebral vasculopathy and vasculitis. We aimed to analyze the frequency of intracranial vasculopathy attributable to infection, the spectrum of causative microorganisms, imaging, and cerebrospinal fluid (CSF) characteristics as well as clinical course and outcome.

METHODS

We used our institution's medical record system to identify all patients diagnosed with nonatherosclerotic central nervous system vasculopathy from January 1, 1999 through February 28, 2009. We reviewed their clinical charts, imaging data, and results of CSF studies.

RESULTS

Twenty-five adult patients with nonatherosclerotic cerebral vasculopathy of large- and medium-sized intracranial vessels were identified. Eight patients had vasculopathy attributable to infection (32%). The underlying pathologies were acute bacterial meningitis (n = 4), varicella zoster virus (VZV) infection (n = 2), borreliosis (n = 1), and syphilis (n = 1). In six patients, magnetic resonance angiography was performed and showed vasculopathic changes in all patients examined (100%). In both patients with VZV-associated vasculopathy, the arterial wall enhanced on magnetic resonance imaging. The CSF examination of the patients with infectious vasculopathy showed a significantly higher white blood cell count. The outcome of the infectious cohort was unfavorable with one death, two patients with locked-in syndrome, and five patients discharged from intensive care with severe neurological deficits.

CONCLUSION

In this cohort, one-third of all cases of nonatherosclerotic vasculopathy were due to infectious vasculopathy of large and medium intracranial vessels.

Virus vasculopathy and stroke: an under-recognized cause and treatment target

While arteriosclerotic disease and hypertension, with or without diabetes, are the most common causes of stroke, viruses may also produce transient ischemic attacks and stroke. The three most-well studied viruses in this respect are varicella zoster virus (VZV), cytomegalovirus (CMV) and human immunodeficiency virus (HIV), all of which are potentially treatable with antiviral agents. Productive VZV infection in cerebral arteries after reactivation (zoster) or primary infection (varicella) has been documented as a cause of ischemic and hemorrhagic stroke, aneurysms with subarachnoid and intracerebral hemorrhage, arterial ectasia and as a co-factor in cerebral arterial dissection. CMV has been suggested to play a role in the pathogenesis of arteriosclerotic plaques in cerebral arteries. HIV patients have a small but definite increased incidence of stroke which may be due to either HIV infection or opportunistic VZV infection in these immunocompromised individuals. Importantly, many described cases of vasculopathy in HIV-infected patients were not studied for the presence of anti-VZV IgG antibody in CSF, a sensitive indicator of VZV vasculopathy. Unlike the well-documented role of VZV in vasculopathy, evidence for a causal link between HIV or CMV and stroke remains indirect and awaits further studies demonstrating productive HIV and CMV infection of cerebral arteries in stroke patients. Nonetheless, all three viruses have been implicated in stroke and should be considered in clinical diagnoses.

Recurrent polymorphonuclear pleocytosis with increased red blood cells caused by varicella zoster virus infection of the central nervous system: Case report and review of the literature

We describe an immunocompetent 45-year-old woman who had four episodes of neurological disease (meningoencephalitis, multifocal vasculopathy, myelitis and inflammatory brain stem disease) produced by varicella zoster virus (VZV) over an 11-month period, all in the absence of rash. The cerebrospinal fluid (CSF) contained anti-VZV IgG antibody, but not VZV DNA throughout her illness, reaffirming the superiority of detection of anti-VZV IgG in CSF compared to VZV DNA in diagnosing VZV infection of the nervous system. Moreover, 3 of 7 CSF samples examined during the 11 months showed a VZV-induced pleocytosis consisting predominantly of polymorphonuclear cells (PMNs), and 4 of 7 samples also contained increased numbers of red blood cells (RBCs). Because increased PMNs and RBCs in CSF can also occur in patients with central and peripheral nervous system disease produced by cytomegalovirus (CMV), the differential diagnosis of chronic nervous system infection with increased PMNs and RBCs in CSF should include analyses for both VZV and CMV.

[Vasculitis of the nervous system in infectious diseases]

Vasculitis and vasculopathies of the central and peripheral nervous system can be caused by infectious diseases. Vasculitis can lead to stenosis, occlusion and aneurysm formation of blood vessels which may result in stroke or cerebral haemorrhage. In cases of peripheral nervous system involvement mononeuritis multiplex and symmetric peripheral neuropathy are possible. The diagnosis is based on clinical presentation, serology, cerebrospinal fluid analysis and neuroradiologic examinations. In cases of peripheral neuropathy neurophysiologic examinations and biopsy of the sural nerve can lead to the diagnosis. A fast and efficient antimicrobial therapy is the most important treatment option. In cases of peripheral neuropathies short-term treatment with corticosteroids and plasma exchange may be helpful.

Severe meningoencephalitis due to late reactivation of Varicella-Zoster virus in an immunocompetent child

Recurrent reactivation of latent Varicella-Zoster virus may cause various neurological complications including encephalitis, myelitis, stroke episodes, and meningitis. It occurs mainly in elderly or immunocompromised patients and is very rare in children. We report a 14-year girl who presented with meningoencephalitis due to reactivation of Varicella-Zoster virus 10 years after she had chickenpox and 4 years after she had zoster. Characteristic skin lesions of varicella were absent. Varicella-Zoster virus DNA was detected in cerebrospinal fluid and magnetic resonance imaging (MRI) findings were consistent with small vessel cerebral vasculitis. Treatment with acyclovir and high dose methylprednisolone resulted in near-complete neurological recovery. Although rare, Varicella-Zoster virus may reactivate to cause significant central nervous system disease even in immunocompetent children. Diagnosis depends on a high degree of suspicion because the typical rash may not associate the disease. Characteristic lesions on MRI and the presence of Varicella-Zoster virus DNA in cerebrospinal fluid are key findings for the correct diagnosis.

Neurologic manifestations of varicella zoster virus infections

Varicella zoster virus (VZV) causes acute viral exanthema in childhood, becomes latent, and can reactivate years later to produce neurologic disease. Primary VZV infection is associated with acute cerebellitis and stroke, particularly in childhood. VZV reactivation may result in neuropathy, myelitis, stroke, and encephalitis, the latter two syndromes the result of small and large vessel vasculopathy. Prompt diagnosis and treatment are critical to minimize morbidity in herpes zoster as well as morbidity and death in VZV vasculitis and encephalitis. Detection of anti-VZV antibodies in cerebrospinal fluid is the most sensitive method of diagnosing varicella infection of the nervous system. Despite the advent of the VZV vaccine, varicella remains a significant cause of neurologic morbidity.

HIV-associated Intracranial Aneurysmal Vasculopathy in Adults

Diffuse fusiform intracranial aneurysms have been reported in children with human immunodeficiency virus (HIV) for over 2 decades, but have only recently been reported in adults with HIV. Although these aneurysms have important clinical implications, their etiology and optimal therapy are unknown. We present a systematic review of diffuse intracranial fusiform aneurysmal vasculopathy in patients who are HIV-positive. We conducted a comprehensive literature search for relevant case reports and reviews published before February 2009. Patients were included if they had HIV infection and radiographic imaging consistent with fusiform aneurysmal vasculopathy. We identify 11 published adult cases of intracranial fusiform aneurysmal vasculopathy and describe 1 unpublished case from our own institution. Available data regarding clinical presentation, characteristic imaging findings, and treatment of this complex syndrome are reviewed. Adults with HIV-associated intracranial aneurysmal vasculopathy typically are significantly immunosuppressed and present with gross neurologic dysfunction. Characteristic radiographic findings include diffuse cerebral fusiform aneurysms with hemorrhage or infarct. Treatment of any active infection followed by the initiation of antiretroviral therapy and corticosteroids may be a reasonable approach in this complex syndrome.

Viral infections of the central nervous system: a case-based review

Three patients with viral infections of the central nervous system (CNS) were evaluated on an inpatient infectious diseases consultation service within a two-week period. These cases, caused by herpes simplex virus, varicella zoster virus and enterovirus, highlight the importance of viral pathogens in causing debilitating infections of the CNS and provide examples of the utility of molecular diagnostics in evaluating patients with encephalitis and meningitis. The importance of antiviral therapy is particularly underscored by these cases, as is the variability in response of patients to such agents.

Increased risk of stroke after a herpes zoster attack: a population-based follow-up study

BACKGROUND AND PURPOSE

Varicella zoster virus-induced vasculopathy and postherpes zoster attack stroke syndromes have been reported previously; nevertheless, data regarding the exact prevalence and risk of stroke occurring postherpes zoster attack are still lacking. This study aims to investigate the frequency and risk of stroke after a herpes zoster attack using a nationwide, population-based study of a retrospective cohort design. Method- A total of 7760 patients who had received treatment for herpes zoster between 1997 and 2001 were included and matched with 23 280 randomly selected subjects. A 1-year stroke-free survival rate was then estimated using the Kaplan-Meier method. After adjusting for potential confounders, Cox proportional hazard regressions were carried out to compute the adjusted 1-year survival rate.

RESULTS

Of the sampled patients, 439 patients (1.41%) developed strokes within the 1-year follow-up period, that is, 133 individuals (1.71% of the patients with herpes zoster) from the study cohort and 306 individuals (1.31% of patients in the comparison cohort) from the comparison cohort. The log rank test indicated that patients with herpes zoster had significantly lower 1-year stroke-free survival rates than the control (P<0.001). The adjusted hazard ratios of stroke after herpes zoster and herpes zoster ophthalmicus during the 1-year follow-up period were 1.31 and 4.28, respectively.

CONCLUSIONS

The risk for stroke increased after a zoster attack. Although varicella zoster virus vasculopathy is a well-documented complication that may induce a stroke postherpes zoster attack, it does not fully account for the unexpectedly high risk of stroke in these patients.

Varicella zoster virus vasculopathies: diverse clinical manifestations, laboratory features, pathogenesis, and treatment

Vasculopathies caused by varicella zoster virus (VZV) are indicative of a productive virus infection in cerebral arteries after either reactivation of VZV (shingles) or primary infection (chickenpox). VZV vasculopathy can cause ischaemic infarction of the brain and spinal cord, as well as aneurysm, subarachnoid and cerebral haemorrhage, carotid dissection, and, rarely, peripheral arterial disease. VZV vasculopathy in immunocompetent or immunocompromised individuals can be unifocal or multifocal with deep-seated and superficial infarctions. Lesions at the grey-white matter junction on brain imaging are a clue to diagnosis. Involvement of both large and small arteries is more common than that of either alone. Most patients have a mononuclear cerebrospinal fluid pleocytosis, often with red blood cells. Cerebrospinal fluid pleocytosis and rash are absent in about a third of cases. Anti-VZV IgG antibody in the cerebrospinal fluid is found more frequently than VZV DNA. In recent years, the number of recognised VZV vasculopathies has grown, and accurate diagnosis is important for the effective treatment of these disorders.

Varicella zoster virus meningitis with hypoglycorrhachia in the absence of rash in an immunocompetent woman

We report varicella-zoster virus (VZV) meningitis in a healthy adult woman with no antecedent rash and with hypoglycorrhachia. Cerebrospinal fluid (CSF) examination revealed the presence of VZV DNA, anti-VZV immunoglobulin G (IgG) antibody, and intrathecal production of anti-VZV IgG antibody.