Herpes simplex virus infection of the central nervous system in human immunodeficiency virus-type 1-infected patients

Diagnostic Methods and Management Strategies of Herpes Simplex and Herpes Zoster Infections

Herpesviruses are medium-sized double-stranded DNA viruses. Of more than 80 herpesviruses identified, only 9 human herpesviruses have been found to cause infection in humans. These include herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), human cyto-megalovirus (HCMV), Epstein-Barr virus (EBV), and human herpesvirus (HHV-6A, HHV-6B, HHV-7, HHV-8). HSV-1, HSV-2, and VZV can be problematic given their characteristic neurotropism which is the ability to invade via fusion of its plasma membrane and reside within neural tissue. HSV and VZV primarily infect mucocutaneous surfaces and remain latent in the dorsal root ganglia for a host's entire life. Reactivation causes either asymptomatic shedding of virus or clinical manifestation of vesicular lesions. The clinical presentation is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent. Affecting 60% to 95% of adults, herpesvirus-associated infections include gingivostomatitis, orofacial and genital herpes,and primary varicella and herpes zoster. Symptomatology, treatment, and potential complications vary based on primary and recurrent infections as well as the patient's immune status.

Neurologic infections in people with HIV: shifting epidemiological and clinical patterns

OBJECTIVES

The aim of this study was to define the frequency, risk factors, and clinical outcomes of both AIDS-defining and non-AIDS-defining neurologic infections among people with HIV (PWH).

DESIGN

We conducted a retrospective observational cohort study by linking the clinical database at the Southern Alberta HIV Clinic (SAC) with the regional hospital and microbiology databases to identify cases and the associated morbidity and mortality for these neurologic infections from 1995 to 2018.

METHODS

Neurologic infections were categorized into AIDS-defining and non-AIDS defining. Annual incidence rates per 1000 person-years were calculated. Cox proportional hazards models estimated adjusted hazard ratios (aHR) and 95% confidence intervals of risk factors for neurologic infections in PWH and mortality outcomes.

RESULTS

Among 2910 PWH contributing 24 237 years of follow-up, 133 (4.6%) neurologic infections were identified; 107 (80%) were AIDS-defining and 26 (20%) non-AIDS defining. While the incidence of AIDS-defining neurologic infections declined over time, no change was seen in incidence of non-AIDS defining infections. The risk of having any neurologic infection was greater among black PWH (aHR = 2.5 [1.6-4.0]) (vs. white PWH) and those with a CD4 + T-cell nadir of less than 200 cells/μl (aHR = 6.6 [4.0-11.1]) (vs. ≥200 cells/μl). More AIDS-defining neurologic infections occurred in PWH with lower CD4 + T-cell counts and higher HIV viral loads. PWH with any neurologic infections experienced more seizures, strokes, all-cause mortality (aHR = 2.2 [1.5-3.2] and HIV-related mortality (aHR = 6.4 [3.9-10.7] (vs. no neurologic infection).

CONCLUSION

Both AIDS and non-AIDS defining neurologic infections continue to occur in PWH resulting in significant morbidity and mortality. Early diagnosis and initiation of ART remain crucial in preventing neurological infections in PWH.

Central Nervous System Infections

This chapter provides an overview of infectious syndromes, pathogens, and diagnostic testing modalities for central nervous system infections in the immunocompromised host.

Acute encephalitis in the immunocompromised individual

PURPOSE OF REVIEW

This article describes recent advances in the diagnosis and management of encephalitis in immunocompromised individuals.

RECENT FINDINGS

Herpes simplex virus (HSV) and varicella zoster virus (VZV) are common causes of encephalitis in immunocompromised individuals, although clinical manifestations may be atypical, and thus challenging to recognize. Recently, an increased incidence of HSV and VZV central nervous system infections has been reported in association with novel immunosuppressive and immunomodulatory treatments. The free-living ameba Balamuthia mandrillaris causes granulomatous encephalitis predominantly in immunocompromised individuals and is associated with nearly uniform fatality. In the setting of organ transplantation, the recipient's immunocompromised state along with the potential for donor-transmitted infections can result in a unique epidemiology of encephalitis, including infection by human herpes virus-6 and BK virus. Recent studies utilizing next-generation sequencing techniques have identified several pathogens, including Leptospira santarosai and a neurotropic astrovirus, as causes of encephalitis in immunocompromised individuals.

SUMMARY

Diagnosis and management of encephalitis is challenging in immunocompromised individuals, in part because of atypical clinical presentations and the presence of uncommon or novel infectious agents. Unbiased techniques for pathogen discovery are likely to play an increasing role in the diagnosis of central nervous system infections in immunocompromised individuals.

Relationship of herpes simplex encephalitis and transcranial direct current stimulation--a case report

We report a rare case of relapsing herpes simplex encephalitis in a-37-year-old patient which was previously confirmed by positive polymerase chain reaction, herpes simplex virus (HSV) type1 IgG antibodies in cerebrospinal fluid and characterized on MRI. During the first admission, he was treated with continuous acyclovir treatment for one month with clinical improvement except for residual aphasia, for which he received a course of outpatient transcranial direct current stimulation (tDCS). A constant current of 1.2 mA was applied for 20 min twice daily. After the 4th day the patient was found to be irritable and uncooperative by staff and family members. A subsequent MRI showed significant deterioration of the lesion on comparison to the first MRI which led to discontinuation of tDCS.The relatively rapid exacerbation of HSV in only a few days is unusual. Our aim is to discuss if tDCS is related to HSV relapse and in doing so highlight possible mechanisms.

Diagnostic methods and management strategies of herpes simplex and herpes zoster infections

Herpes infections are extremely prevalent in the adult population. Recognizing early signs and symptoms is essential to provide effective treatment. The immunocompromised population presents treatment challenges requiring prolonged antiviral therapy and more frequent recurrences. Viral culture is often considered the gold standard diagnostic technique; however, polymerase chain reaction (PCR) should be done in tandem with culture especially for varicella zoster virus infections. Antivirals can decrease viral shedding, recurrences of herpes simplex, and hasten healing of herpes zoster. Herpes virus can be a challenging entity to treat with significant morbidity (both physically and psychologically).

Herpes simplex virus type 1 encephalitis and unusual retinitis in a patient with systemic lupus erythematosus

In this report we discuss a case of a patient with systemic lupus erythematosus who developed herpes simplex virus type 1(HSV-1) infection presenting with encephalitis as well as necrotic and non-necrotic retinitis. The patient presented with typical clinical symptoms and radiologic abnormalities consistent with HSV-1 encephalitis and HSV-1 retinitis in patients with HIV infection, but lacked cerebrospinal fluid pleocytosis and had bilateral retinitis with poor visual acuity. To the best of our knowledge, this is the first such case reported in the literature.

Herpesvirus infections of the central nervous system in immunocompromised patients

Human herpesviruses may cause infections of the central nervous system during primary infection or following reactivation from a latent state. Especially in immunosuppressed patients the infection can take a life-threatening course, and therefore early diagnosis of herpesvirus-associated neurological diseases should have high priority. Clinical presentation in these patients is usually without typical features, making diagnosis even more challenging. Therefore general broad testing for different herpesviruses in cerebrospinal fluid samples is highly recommended. In addition, determination of the virus DNA level in the cerebrospinal fluid by quantitative assays seems to be of high importance to determine prognosis. Moreover, it might help to differentiate between specific virus-associated disease and unspecific presence of virus in the cerebrospinal fluid, especially in immunocompromised patients. Polymerase chain reaction analysis of cerebrospinal fluid has revolutionized the diagnosis of nervous system viral infections, particularly those caused by human herpesviruses. This review summarizes the role human herpesviruses play in central nervous system infections in immunocompromised patients, with a focus on the clinical manifestation of encephalitis.

Complications of immunosuppressive/immunomodulatory therapy in neurological diseases

OPINION STATEMENT

The first critical step in the appropriate treatment of neurological infectious disease accompanying immunosuppressive states or immunomodulatory medication is to properly identify the offending organism. Broadly immunosuppressive conditions will predispose to both common and uncommon infectious diseases. There are substantial differences between neurological infectious disorders complicating disturbances of the innate immunity (neutrophils, monocytes and macrophages) and those due to abnormal adaptive immunity (humoral and cellular immunity). Similarly, there are differences in the types of infections with impaired humoral immunity compared to disturbed cellular immunity and between T- and B-cell disorders. HIV/AIDS has been a model of acquired immunosuppression and the nature of opportunistic infections with which it has been associated has been well characterized and generally correlates well with the degree of CD4 lymphopenia. Increasingly, immunotherapies target specific components of the immune system, such as an adhesion molecule or its ligand or surface receptors on a special class of cells. These targeted perturbations of the immune system increase the risk of particular infectious diseases. For instance, natalizumab, an α4β1 integrin inhibitor that is highly effective in multiple sclerosis, increases the risk of progressive multifocal leukoencephalopathy for reasons that still remain unclear. It is likely that other therapies that result in a disruption of a specific component of the immune system will be associated with other unique opportunistic infections. The risk of multiple simultaneous neurological infections in the immunosuppressed host must always be considered, particularly with a failure to respond to a therapeutic regimen. With respect to appropriate and effective therapy, diagnostic accuracy assumes primacy, but occasionally broad spectrum therapy is necessitated. For a number of opportunistic infectious disorders, particularly some viral and fungal diseases, antimicrobial therapy remains inadequate.

Herpes simplex virus encephalitis despite normal cell count in the cerebrospinal fluid

OBJECTIVES

To describe herpes simplex virus encephalitis despite normal cell count in the cerebrospinal fluid in patients with malignoma after whole brain irradiation.

INTERVENTIONS

Blood and cerebrospinal fluid analysis and magnetic resonance imaging.

MEASUREMENTS AND MAIN RESULTS

Three male and two female patients with malignoma and a recent history of whole-brain irradiation presented with impaired consciousness with or without epileptic seizure. Although cerebrospinal fluid analysis revealed a normal cell count, herpes simplex virus DNA was detected in all samples by polymerase chain reaction.

CONCLUSIONS

In patients with impaired consciousness, epileptic seizure, or temporal lobe symptoms of new onset and a recent history of brain irradiation with normal cerebrospinal fluid, an atypical anergic course of herpes simplex virus encephalitis should be considered. Herpes simplex virus polymerase chain reaction should be used as method of choice to detect herpes simplex virus genomes as early as possible rather than relying on routine cerebrospinal fluid parameters. Importantly, antiviral therapy should be started without delay in any case of faint suspicion and should be continued until herpes simplex virus encephalitis is clearly ruled out.

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

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

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

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

Herpes simplex virus encephalitis: new infection or reactivation?

PURPOSE OF REVIEW

This review describes the pathogenesis, clinical presentation, course, and therapy of herpes simplex encephalitis (HSE), the most fatal viral encephalitis, in which prognosis is dependent on early diagnosis and effective therapy.

RECENT FINDINGS

Herpes simplex viruses types 1 and 2 (HSV-1 and HSV-2) are human neurotropic viruses that 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. HSE is one of the most devastating disorders caused by these viruses. The biology of their ability to establish latency, maintain it for the entire life of the host, reactivate, and cause primary and recurrent disease is being studied in animal models and in humans. Of special interest is the question whether HSE is the result of primary infection or is it the outcome of reactivation. The present review covers the biological, medical, and neurological aspects of HSE, focusing among others on recent molecular findings of gene expression during latent infection of HSV-1.

SUMMARY

Despite accumulating knowledge, there are still several issues regarding both pathogenesis and therapy of HSV-1 that currently defy understanding.

Subacute herpes simplex virus type 1 encephalitis as an initial presentation of chronic lymphocytic leukemia and multiple sclerosis: a case report

Introduction

Herpes simplex virus type 1 encephalitis presents acutely in patients who are immunocompetent. We report what we believe to be the first published case of a subacute course of herpes simplex virus type 1 encephalitis in a patient with asymptomatic chronic lymphocytic leukemia who subsequently developed multiple sclerosis.

Case presentation

A 49-year-old Caucasian woman with a history of fever blisters presented to the emergency department with a history of left temporal headache for four weeks, and numbness of the left face and leg for two weeks. A complete blood count revealed white blood cell count of 11,820 cells/mL, with an absolute lymphocyte count of 7304 cells/mL. The cerebrospinal fluid contained 6 white blood cells/μL, 63 red blood cells/μL, 54 mg glucose/dL, and 49 mg total protein/dL. Magnetic resonance imaging of the brain revealed meningoencephalitis and bilateral ventriculitis. Cerebrospinal fluid polymerase chain reaction for herpes simplex virus type 1 was positive, and the patient's symptoms resolved after ten days of treatment with parenteral aciclovir. Incidental findings on peripheral blood smear and flow cytometry testing confirmed chronic lymphocytic leukemia. One month later, she developed bilateral numbness of the hands and feet; a repeat cerebrospinal fluid polymerase chain reaction for herpes simplex virus type 1 at this time was negative. A repeat magnetic resonance imaging scan showed an expansion of the peri-ventricular lesions, and the cerebrospinal fluid contained elevated oligoclonal bands and myelin basic protein. A brain biopsy revealed gliosis consistent with multiple sclerosis, and the patient responded to treatment with high-dose parenteral steroids.

Conclusion

Herpes simplex virus type 1 encephalitis is a rare presentation of chronic lymphocytic leukemia. Our patient had an atypical, subacute course, presumably due to immunosuppression from chronic lymphocytic leukemia. This unusual case of herpes simplex virus type 1 encephalitis emphasizes the importance of T cell function in diseases of immune dysregulation and autoimmunity such as chronic lymphocytic leukemia and multiple sclerosis. It raises the question of whether atypical presentations of herpes simplex virus encephalitis warrant deliberations on immunocompetence. The development of multiple sclerosis in our patient so soon after she received treatment for herpes simplex virus type 1 encephalitis raises the possibility that herpes simplex virus type 1 encephalitis in an immunosuppressed patient may trigger multiple sclerosis.

Antiviral activities against herpes simplex virus type 1 by HPH derivatives and their structure-activity relationships

The compound named Histidine-pyridine-histidine (HPH) is an oxygen-activating ligand derived from the structure of bleomycin. We synthesized HPH derivatives, namely HPH-1 to -8, and investigated their antiviral activities against herpes simplex virus type 1. HPH-8 showed potent antiviral activity with an EC50 of 15 microM, and relatively high cytotoxicity with a CC50 of 37 microM. In contrast, HPH-4 indicated a weaker antiviral activity with an EC50 of 79 microM, but exhibited a far more less cytotoxicity (CC50 500 microM). Other HPH derivatives showed no effects against antiviral activities and cytotoxicities.

HIV/AIDS: Management of Herpes Simplex Virus Type 2 Infection in HIV Type 1–Infected Persons

Human immunodeficiency virus type 1 (HIV-1)-infected persons have high rates of herpes simplex virus type 2 (HSV-2) infection, ranging from 50% to 90% in studies of HIV-infected populations from different parts of the world. Genital herpes in persons with HIV type 1 (HIV-1) infection is associated with more-severe and chronic lesions, as well as increased rates of asymptomatic genital shedding of HSV-2. Nucleoside analogues (acyclovir, valacyclovir, and famciclovir) decrease the frequency and severity of HSV-2 recurrences and asymptomatic HSV-2 reactivation and are effective, safe, well-tolerated drugs in patients with HIV-1 infection. These anti-HSV drugs may result in additional clinical and public health benefits for persons with HIV-1 and HSV-2 coinfection by decreasing HIV-1 levels in the blood and genital tract. Given these benefits, HIV-1-infected persons should be routinely tested for HSV-2 infection using type-specific serologic tests. Persons with HSV-2 infection should be offered HSV-2 education and treatment options. Studies to quantify the potential clinical and public health benefits of treating individuals who have HIV-1 and HSV-2 coinfection with anti-HSV therapy are underway.