Cerebrovascular disease and varicella in children

Neurological features related to influenza virus in the pediatric population: a 3-year monocentric retrospective study

Influenza virus is generally characterized by fever, myalgia, and respiratory symptoms. Neurological entities have already been described, such as acute necrotizing encephalitis (ANE). We aimed to highlight the non-exceptional nature and explore the clinical spectrum and evolution of neurological features related to influenza virus in children. This monocentric observational study included patients under 18 years old, positive for influenza virus, between January 2017 and April 2019 in a pediatric university hospital. Patients were classified into two groups: those with or without a previous significant neurological or metabolic disorder. Two hundred eighty-nine children were identified with influenza infection. Thirty seven had a neurological manifestation: 14 patients who had previous significant neurological or metabolic disorder and 23 patients with no medical history. We identified several clinical patterns: 22 patients had seizures, 7 behavior disorders, 5 disturbances of consciousness, and 3 motor deficits. Four were diagnosed with a known influenza-associated neurological syndrome: 1 ANE, 1 cytotoxic lesion of the corpus callosum, 1 hemiconvulsion-hemiplegia-epilepsia syndrome, and 1 recurrent encephalitis in the context of a RANBP2 mutation. The neurological outcome was favorable in most cases. None of the patients with previous significant disorder retained sequalae or had a recurrence. Two patients had a fatal outcome, and both had a predisposing disorder.

CONCLUSION

Various neurological manifestations can be associated with influenza virus. Certain entities led to a poor prognosis, but in most cases, symptoms improved within a few days. The severity of the neurological manifestations correlated with previous neurological or metabolic disorders.

WHAT IS KNOWN

• Influenza viruses are well known pathogens with a seasonal epidemic evolution, particularly affecting children. These viruses cause acute fever with respiratory symptoms, associated with myalgia and headaches. Neurological presentation in influenza-virus infection is a well-established possibility as influenza virus is considered to be responsible for 27 to 36% of childhood encephalitis. Some specific and severe entity as acute necrotizing encephalitis, cytotoxic lesion of the corpus callosum, or Hemiconvulsion-hemiplegia-epilepsy syndrome are well described.

WHAT IS NEW

• In a French monocentric cohort of 37 children with influenza-related neurologic manifestations, the majority of these manifestations, including seizure, drowsiness, motor deficiency, hallucination… are self limiting and do not lead to after-effects. In rare cases (4/37), they may reveal severe encephalitis requiring rapid and appropriate treatment. Otherwise, comparison of a group of 14 children with underlying neurological or metabolic disorder with a group of 23 children free of any significant disorder show that the severity of the neurological manifestations was largely related to previous neurological or metabolic disorders highlighting the importance of vaccination in this population.

Common Features Between Stroke Following Varicella in Children and Stroke Following Herpes Zoster in Adults : Varicella-Zoster Virus in Trigeminal Ganglion

The cerebral arteries are innervated by afferent fibers from the trigeminal ganglia. Varicella-zoster virus (VZV) frequently resides in the trigeminal ganglion. Reports of arterial ischemic stroke due to VZV cerebral vasculopathy in adults after herpes zoster have been described for decades. Reports of arterial ischemic stroke due to post-varicella cerebral arteriopathy in children have also been described for decades. One rationale for this review has been post-licensure studies that have shown an apparent protective effect from stroke in both adults who have received live zoster vaccine and children who have received live varicella vaccine. In this review, we define common features between stroke following varicella in children and stroke following herpes zoster in adults. The trigeminal ganglion and to a lesser extent the superior cervical ganglion are central to the stroke pathogenesis pathway because afferent fibers from these two ganglia provide the circuitry by which the virus can travel to the anterior and posterior circulations of the brain. Based on studies in pseudorabies virus (PRV) models, it is likely that VZV is carried to the cerebral arteries on a kinesin motor via gE, gI and the homolog of PRV US9. The gE product is an essential VZV protein.

Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation

Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.

Varicella Zoster Virus: A Common Cause of Stroke in Children and Adults

BACKGROUND

Varicella zoster virus (VZV) is a neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. As cell-mediated immunity to VZV declines with advancing age and immunosuppression, VZV reactivates to produce zoster (shingles). One of the most serious complications of zoster is VZV vasculopathy.

METHODS

We reviewed recent studies of stroke associated with varicella and zoster, how VZV vasculopathy is verified virologically, vaccination to prevent varicella and immunization to prevent zoster, and VZV in giant cell arteritis (GCA).

FINDINGS

We report recent epidemiological studies revealing an increased risk of stroke after zoster; the clinical, laboratory, and imaging features of VZV vasculopathy; that VZV vasculopathy is confirmed by the presence of either VZV DNA or anti-VZV IgG antibody in cerebrospinal fluid; special features of VZV vasculopathy in children; vaccination to prevent varicella and immunization to prevent zoster; and the latest evidence linking VZV to GCA.

CONCLUSION

In children and adults, VZV is a common cause of stroke.

Varicella-Zoster Virus Vasculopathy: A Case Report Demonstrating Vasculitis using Black-Blood MRI

Infections are rare but important causes of stroke. Among these, varicella zoster virus has been known to cause ischemic stroke. During an attack of herpes zoster ophthalmicus, it has been hypothesized that the virus replicates in the trigeminal ganglion and travels via the trigeminal nerve centrally to cause cerebral vasculopathy. Here we present a case of a 69 year-old Caucasian immunocompromised woman who suffered recurrent ischemic infarcts within the same vascular distribution following an episode of zoster ophthalmicus three months prior. An imaging technique termed black-blood magnetic resonance imaging was utilized to aid in the diagnosis of cerebral vasculitis. The case is used to provide a literature review of the pathogenesis, diagnosis, and treatment of cerebral varicella zoster vasculopathy. In situations where an isolated unilateral cerebral vasculopathy is identified, neurologists are urged to consider varicella zoster as a treatable etiologic agent, as untreated vasculopathy can lead to further strokes.

Chickenpox and stroke in children: case studies and literature review

Postvaricella cerebral arteriopathy (PVCA) presents with acute haemiparesis and/or haemidistonia, caused by ischaemic lesions of internal capsule and/or basal ganglia, related to stenosis of proximal middle and/or anterior cerebral arteries. Anti-aggregant drugs are recommended to prevent thrombus expansion and recurrent stroke, but neurologic outcome is usually good regardless of the therapeutic approach.

CONCLUSION

Chickenpox should be considered in differential diagnosis of ischaemic stroke in healthy children who fit the clinical and radiological typical profile of PVCA.

[Current management of post-varicella stroke in children: a literature review]

Among infectious factors, varicella-zoster virus (VZV) is a leading cause of central nervous system vasculopathy and stroke in childhood. Not only have viral markers been detected in the cerebrospinal fluid of affected patients, but also direct evidence of viral particles in the wall of cerebral arteries has been demonstrated in rare pathological specimens. This certainly reflects a localized infectious process likely associated with variable indirect inflammatory responses. Yet the usefulness in this setting of a lumbar puncture as well as of subsequent targeted antiviral and/or anti-inflammatory therapies is uncertain. Indeed, in the majority of cases, the so-called post-varicella angiopathy has a monophasic evolution with spontaneous resolution or stabilization, explaining diverging diagnostic and treatment approaches. In this paper, we have addressed this problematic area by reviewing 26 published cases from the year 2000 and three unpublished cases. Post-varicella stroke is typically associated with angiopathy most often involving the initial portion of the middle cerebral artery, causing a basal ganglia stroke. It tends to occur in young immunocompetent children. Thrombophilia work-up is in general negative. Lumbar puncture was performed in 17 out of 29 cases. Viral markers were examined in 14 cases, but were positive in only eight cases. Antiviral therapy was administrated in 11 children. In this small retrospective study, the treated children's vasculopathy did not progress more favorably nor was there a better outcome compared with untreated subjects.

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.

Potential eligibility for recombinant tissue plasminogen activator therapy in children: a population-based study

Intravenous recombinant tissue plasminogen activator is an established therapy for adults with ischemic stroke. In this Greater Cincinnati/Northern Kentucky population-based study, 8% were eligible. However, no established therapy exists for children with acute ischemic stroke. Accordingly, investigators assessed rates of eligibility for recombinant tissue plasminogen activator therapy among children (<18 years of age) in the same population to aid planning of future clinical trials. The investigators identified 29 pediatric ischemic strokes during 3 separate study periods (1993-1994, 1999, and 2005) and determined potential eligibility for recombinant tissue plasminogen activator therapy based on 2007 American Heart Association guidelines for adults. Depending on how relative contraindications were considered, 1 to 3 cases (3%-10%) met eligibility criteria. On the basis of national pediatric stroke incidence rates extrapolated from our population, it is estimated that up to 178 children might be eligible for intravenous recombinant tissue plasminogen activator therapy annually in the United States. Thus, recruitment for clinical studies is likely to be challenging and requires a concerted multicenter effort.

Pediatric stroke: clinical findings and radiological approach

This paper focuses on radiological approach in pediatric stroke including both ischemic stroke (Arterial Ischemic Stroke and Cerebral Sinovenous Thrombosis) and hemorrhagic stroke. Etiopathology and main clinical findings are examined as well. Magnetic Resonance Imaging could be considered as the first-choice diagnostic exam, offering a complete diagnostic set of information both in the discrimination between ischemic/hemorrhagic stroke and in the identification of underlying causes. In addition, Magnetic Resonance vascular techniques supply further information about cerebral arterial and venous circulation. Computed Tomography, for its limits and radiation exposure, should be used only when Magnetic Resonance is not available and on unstable patients.

Inflammatory mechanisms of stroke

Basic and clinical research provides evidence that inflammatory mechanisms play a central role in the pathogenesis and progression of atherosclerosis, plaque rupture, thrombosis, and stroke. Inflammatory biomarkers such as high-sensitivity C-reactive protein have been identified as predictors of first stroke and prognosis after stroke. The value of high-sensitivity C-reactive protein and other markers may depend on the characteristics of the study population; their utility may be less among populations with high vascular risk. A recent randomized, clinical trial suggests that the use of rosuvastatin therapy in otherwise healthy patients with high-sensitivity C-reactive protein >2 mg/dL can reduce the risk of a first stroke by 50%. The prognostic role of high-sensitivity C-reactive protein among patients after stroke, however, is less clear, and other biomarkers, including lipoprotein-associated phospholipase A(2), may provide complementary information about the risk of stroke recurrence. Infections, moreover, may contribute to inflammation and stroke risk. Although no single infectious organism is likely to be identified as the direct cause of atherosclerosis, summary measures of multiple chronic infectious exposures, or "infectious burden," have been associated with the risk of stroke and atherosclerosis affecting the carotid arteries. Acute infections have also been found to serve as stroke triggers in epidemiologic studies. Recommendations to vaccinate patients with cardiovascular disease against influenza represent the first specific anti-infective strategy to be used in vascular prophylaxis. Further studies are needed to determine the role of treatment of inflammation and infection in stroke prevention.

Stroke After varicella-zoster infection: report of a case and review of the literature

Ischemic stroke is a recognized complication of varicella-zoster virus infections. We report on an immunocompetent 5-year-old girl who presented with acute neurologic deficits attributed to cerebral infarction, 3 months after varicella-zoster virus infection. Magnetic resonance imaging of the brain showed subacute ischemic lesions in the territory of the right middle cerebral artery. A literature review of 70 similar cases is reported.

Diagnosis and management of pediatric arterial ischemic stroke

Pediatric stroke is among the top 10 causes of death in children and an important cause of chronic morbidity, with an incidence of 3.3/100,000 children/year. Risk factors associated with stroke in children include cardiac diseases, hematologic and vascular disorders, and infection. Clinical presentation varies depending on age, underlying cause, and stroke location. Antithrombotics and anticoagulants are used in the treatment of pediatric stroke; however, there are no established guidelines for the use of these agents in children. In this article we review the cause, pathophysiology, clinical presentation, diagnosis, acute management, secondary prevention, and outcome of children with stroke. The approach to patients with sickle cell disease and Moyamoya disease is also discussed. Up to date studies to determine the optimal acute treatment of childhood stroke and secondary prevention and risk factor modification are critically needed.

Thrombolytics for hyperacute stroke in children

Intravenous tissue plasminogen activator (tPA) has changed the landscape of acute stroke care in adults, but remains unstudied in children. Developmental differences in both stroke etiologies and the hematologic system may alter the risk benefit ratio of this drug when applied to stroke in children.

The neurotropic herpes viruses: herpes simplex and varicella-zoster

Herpes simplex viruses types 1 and 2 (HSV1 and HSV2) and varicella-zoster virus (VZV) establish latent infection in dorsal root ganglia for the entire life of the host. From this reservoir they can reactivate to cause human morbidity and mortality. Although the viruses vary in the clinical disorders they cause and in their molecular structure, they share several features that affect the course of infection of the human nervous system. HSV1 is the causative agent of encephalitis, corneal blindness, and several disorders of the peripheral nervous system; HSV2 is responsible for meningoencephalitis in neonates and meningitis in adults. Reactivation of VZV, the pathogen of varicella (chickenpox), is associated with herpes zoster (shingles) and central nervous system complications such as myelitis and focal vasculopathies. We review the biological, medical, and neurological aspects of acute, latent, and reactivated infections with the neurotropic herpes viruses.

Neuroimaging of herpesvirus infections in children

Six members of the herpesvirus family cause well-described neurologic disease in children: herpes simplex virus-1 (HSV-1), herpes simplex virus-2 (HSV-2), varicella-zoster (VZV), Epstein-Barr (EBV), cytomegalovirus (CMV), and human herpes virus-6 (HHV-6). When herpesviruses infect the central nervous system (CNS), the clinical presentation is non-specific and often confounding. The clinical urgency is often underscored by progressive neurologic deficits, seizures, or even death, and prompt diagnosis and treatment rely heavily on neuroimaging. This review focuses on the spectrum of cerebral manifestations caused by these viruses, particularly on non-congenital presentations. Recent advances in our understanding of these viruses are discussed, including new polymerase chain reaction techniques that allow parallel detection, which has improved our recognition that the herpesviruses are neurotropic and involve the CNS more often than previously thought. Evolving knowledge has also better elucidated viral neuropathology, particularly the role of VZV vasculitis in the brain, HHV-6 in febrile seizures, and herpesvirus reactivation in immunosuppressed patients. The virology, clinical course, and CNS manifestations of each virus are reviewed, followed by descriptions of neuroimaging findings when these agents infect the brain. Characteristic but often subtle imaging findings are discussed, as well as technical pearls covering appropriate use of MRI and MRI adjuncts to help differentiate viral infection from mimics.

Antiphospholipid antibodies in response to infection

An association between infections and antiphospholipid antibodies (aPL) has been reported in several epidemiologic and experimental studies. Infection-induced aPL have been traditionally regarded as transient and were generally not associated with clinical features of antiphospholipid syndrome. The distinction between autoimmune and postinfectious aPL on the basis of requirement of binding cofactor is not absolute, and in recent years, several reports demonstrated that some patients can produce pathogenic antibodies in response to infection. Infections most frequently associated with antiphospholipid syndrome include parvovirus B19, cytomegalovirus, varicella-zoster virus, HIV, streptococcal and staphylococcal infections, gram-negative bacteria, and Mycoplasma pneumoniae.

Why now? Moving from stroke risk factors to stroke triggers

PURPOSE OF REVIEW

While chronic risk factors for stroke are reasonably well understood, the acute precipitants, or triggers, of stroke, remain relatively understudied.

RECENT FINDINGS

Several converging lines of evidence indicate that transient perturbations in systemic metabolism may provoke the onset of cardiovascular events, including stroke. Epidemiologic data, including studies utilizing novel designs that consider intraindividual differences across different time periods, have been used to clarify triggers for myocardial ischemia, and these methods are beginning to be employed in stroke research. Acute infections, particularly upper respiratory infections, and other inflammatory stimuli have emerged as important triggers of acute ischemic stroke. The mechanisms involved include immunologically mediated activation of platelets and endothelial dysfunction. There also appears to be a period of time, or 'stroke-prone state', characterized by diffuse activation of the vasculature during which patients may be at increased risk of initial and recurrent ischemic events.

SUMMARY

Confirmation of these findings in further studies may help elucidate the mechanisms behind this short-term increase in stroke risk. Improved methods of assessment of this period of heightened susceptibility could lead to more temporally focused preventive interventions.