Acute human herpes virus 7 (HHV-7) encephalitis in an immunocompetent adult patient: a case report and review of literature

Clinic-radiological classification of herpesviral encephalitis in humans (systematic review)

The development of a comprehensive classification for herpesvirus encephalitis remains an urgent task. Distinct clinic-radiological forms of herpesvirus cerebral lesions have been characterized, including findings from histopathological studies. Differences among these forms have been demonstrated concerning key clinical and paraclinical parameters. The presented classification identifies several distinct forms of herpesvirus encephalitis: temporal, brainstem, limbic, diencephalic encephalitis, rhombencephalitis, leukoencephalitis, ventriculoencephalitis, diffuse glial micronodular encephalitis, subcortical and cortical encephalitis, cerebellitis, neonatal encephalitis. Additionally, the concepts of combined, coexisting and multimodal lesions are introduced to describe complex forms of herpesvirus neuroinfections. The use of the term "specific spectrum of herpesvirus cerebral lesions" is supported. Both the phenomena of specificity and universality are considered. Fundamental differences between the forms of herpesvirus encephalitis are highlighted with respect to their prevalence within the population, etiological factors, clinical manifestations, typical complications, recovery completeness, mortality rates, immune status. The distinctive diagnostic and therapeutic approaches required for each form of herpesvirus encephalitis are emphasized. The integration of this classification into clinical practice has the potential to optimize medical care for patients with herpesvirus encephalitis, enabling not only etiologically-oriented but also form-specific approaches to treatment.

Hashimoto's Encephalopathy: Clinical Features, Therapeutic Strategies, and Rehabilitation Approaches

Hashimoto's encephalopathy (HE), also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is an autoimmune disorder with heterogeneous presentation that poses diagnostic challenges. This review synthesizes the current literature to clarify the clinical, laboratory, and radiological features of SREAT/HE, including the diagnostic utility of thyroid peroxidase (TPO) antibodies, cerebrospinal fluid (CSF) abnormalities, and neuroimaging findings. Cognitive impairment and behavioral changes are common in HE, but specific manifestations vary widely, which can lead to misdiagnosis. While elevated TPO antibodies are frequently observed, a direct causal relationship with HE is unlikely, and their presence may indicate a general state of autoimmunity. Corticosteroids remain the cornerstone of treatment, although responses vary, and alternative immunosuppressive agents or intravenous immunoglobulin may be needed in some cases. Evidence regarding rehabilitation for people affected by HE is limited, but neurorehabilitation strategies adapted from other neurological conditions, including cognitive re-education (CR), physical therapy, and psychosocial support, may be beneficial. Further research is needed to elucidate the underlying mechanisms of SREAT, refine the diagnostic criteria, and develop more targeted and effective therapies, including rehabilitation strategies, for this debilitating neurological disorder.

Epidemiological Characteristics of Neuro-Specific Antibodies Following Viral Infections

This study aims to explore the epidemiological characteristics of neuro-specific antibodies (ns-Ab) induced by different viral infections within the central nervous system (CNS). Additionally, it seeks to compare the autoimmune effects following several typical viral infections in CNS. We conduct a retrospective study to compare and analyze the prevalence trends of ns-Ab in patients with different viral infections. Additionally, evaluate the intensity of CNS inflammatory responses postviral infection by correlating clinical characteristics and laboratory findings, and briefly demonstrate the immune effects in CNS following various viral infections. This study retrospectively collected data from 1037 patients hospitalized with suspected CNS infections. A total of 654 patients (63.1%) were included in the final analysis. A higher proportion of patients with pathogens present in their cerebrospinal fluid (CSF) (114 out of 332, 34.3%) tested positive for ns-Ab compared to those without pathogens (70 out of 322, 21.7%) (p = 0.0004). Specifically, the screening rate for ns-Ab in patients with CNS viral infections (83 out of 165, 50.3%) and the prevalence of ns-Ab (27 out of 83, 32.5%) were significantly higher than in those with other pathogen infections (p < 0.0001 and p = 0.016, respectively). Among these, human herpesvirus 7 (HHV7) patients had the highest detection rate of ns-Ab during the disease course (11 out of 26, 42.3%), but exhibited infection characteristics distinctly different from those of herpes simplex virus 1 (HSV1). Viral infections significantly promote the development of autoimmune responses in CNS. The production of ns-Ab and the subsequent autoimmune response vary across different viral infections. There is a strong statistical correlation between HHV7 and the presence of ns-Ab, suggesting that HHV7 may serve as an early indicator of secondary autoimmune response following CNS infections.

Update on human herpesvirus 7 pathogenesis and clinical aspects as a roadmap for future research

Human herpesvirus 7 (HHV-7) is a common virus that is associated with various human diseases including febrile syndromes, dermatological lesions, neurological defects, and transplant complications. Still, HHV-7 remains one of the least studied members of all human betaherpesviruses. In addition, HHV-7-related research is mostly confined to case reports, while in vitro or in vivo studies unraveling basic virology, transmission mechanisms, and viral pathogenesis are sparse. Here, we discuss HHV-7-related literature linking clinical syndromes to the viral life cycle, epidemiology, and viral immunopathogenesis. Based on our review, we propose a hypothetical model of HHV-7 pathogenesis inside its host. Furthermore, we identify important knowledge gaps and recommendations for future research to better understand HHV-7 diseases and improve therapeutic interventions.

Case report: A patient with HHV-6 and HHV-7 combined with Whipple's trophoblast infection and streptococcal pneumonia

Adult respiratory distress syndrome due to viral pneumonia occurs predominantly in immunodeficient populations; adult respiratory distress syndrome secondary to human herpesvirus HHV-6 and HHV-7 pneumonia is extremely rare. Whipple's disease, caused by Tropheryma whipplei, a Gram-positive bacillus and obligate intracellular pathogen, is clinically challenging to diagnose. Whipple's disease is a chronic multisystem infectious disease caused by T. whipplei, most often affecting the gastrointestinal tract and joints, seldom the lungs. Both pathogens are opportunistic. We report a case of mixed infectious pneumonia in a patient with type 2 diabetes mellitus. The patient presented with dyspnea and intermittent fever. Imaging revealed multiple large patchy consolidations in the left lung. Routine anti-infective therapy was ineffective. Metagenomic next generation sequencing of bronchoalveolar lavage fluid indicated HHV-6 and HHV-7 pneumonia concurrent with T. whipplei and Streptococcus co-infections. Meropenem was administered to improve treatment. This case represents a rare mixed lung infection by multiple uncommon pathogens, and is of particular clinical significance.

Characteristics of HHV-7 meningitis: a systematic review

There are limited data on HHV-7 meningitis and this systematic review used electronic search to gather pieces of evidence regarding its characteristics. Nine articles were included which three were case reports and the rest of the articles were retrospective studies. Altogether, 32 cases were described in the literature that 13 were females and 26 were aged less than 16 years old. The HHV-7 meningitis has been reported in any season, especially in winter. It affected both immunocompetent and immunocompromised individuals and mostly presented with fever and headache, however rash and seizure have also been documented. The CSF analysis in general showed an elevated range of cell count with lymphocytic predominance and normal to slightly elevated protein levels. Thirteen patients did not receive treatment for HHV-7 meningitis and full recovery was gained in the majority of cases after about 10 days. This review summarizes characteristics of HHV-7 meningitis in the literature, and yet epidemiological studies are needed to shed more light which eventually could be helpful for the diagnosis and management of this disease.

Human herpesvirus-7 meningitis in an immunocompetent adult patient: a case report

Aim

The underlying pathological mechanisms of CNS human herpesvirus-7 (HHV-7) related infections are still unknown, especially among immunocompetent adults. Although HHV-7 meningitis in immunocompetent adults is usually uncommon, serious consideration for possible HHV-7 involvement should be taken when assessing CNS infection of unknown etiology.

Case presentation

We report a 53-year-old female who presented for fever and progressive headaches. Cerebrospinal fluid (CSF) analysis was compatible with a viral meningitis. CSF cultures were negative and HHV-7 DNA was the only strain detected in the CSF analysis. The patient died 1 month later following complications and cardiac arrest.

Conclusion

HHV-7 CNS infection in immunocompetent patient can be a serious infection. Prompt diagnosis and treatment management are essential for better outcome.

Anterior Uveitis Associated with Human Herpesvirus 7 Infection Diagnosed by Multiplex Polymerase Chain Reaction Assay: A Case Report

BACKGROUND

Herpetic anterior uveitis (AU) is usually caused by the herpes simplex virus, varicella-zoster virus, and cytomegalovirus. Herein, we report a case of herpetic AU associated with human herpesvirus 7 (HHV-7) infection.

STUDY DESIGN

A case report.

CASE PRESENTATION

A 49-year-old female patient presented with complaints of blurred vision and hyperemia in the right eye. Slit-lamp examination revealed bilateral fine and a few small white keratic precipitates (KPs), Descemet membrane folds in the right eye, and severe and mild cellular infiltration in the anterior chamber of the right and left eye, respectively. HHV-7 viral DNA was detected by a polymerase chain reaction assay of an aqueous humor sample. The AU improved significantly with topical steroids.

CONCLUSION

We report a rare case of herpetic AU characterized by fine and small white KPs in which only HHV-7 DNA was detected in the aqueous humor.

Herpesvirus-Associated Encephalitis: an Update

Purpose of Review

Recent Findings

Summary

Autoimmune Encephalitis With Multiple Auto-Antibodies With Concomitant Human Herpesvirus-7 and Ovarian Teratoma: A Case Report

Infectious etiologies and tumors are common triggers of autoimmune encephalitis. We herein reported a rare case of autoimmune encephalitis with multiple autoantibodies in cerebrospinal fluid (CSF) and serum, with concomitant human herpesvirus 7 (HHV-7) infection and ovarian teratoma. A 36-year-old woman presented with mental and behavioral changes and gibberish for 13 days, followed by fever for 1 day. Her brain MRI indicated limbic encephalitis. Metagenomic next-generation sequencing (mNGS) of CSF revealed HHV-7. Antibody testing showed positive anti-N-methyl-D-aspartate receptor (NMDAR) and anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) antibodies in CSF and serum. Ovarian teratoma was considered after pelvic MRI, which was then pathologically confirmed after laparoscopic ovariectomy. Her conditions improved after laparoscopic surgery, intravenous steroids, immunoglobulin, and rituximab therapy. Our findings suggested that the combination of multiple therapies including antiviral, immunotherapy, and resection of tumors were appropriate and improved the prognosis, when HHV-7 infection and ovarian teratoma were concomitant with multiple anti-neuronal antibodies of autoimmune encephalitis.

Encephalitis, a Rare Manifestation of Human Herpesvirus 7 Infection

Human herpesvirus 7 (HHV-7) infection typically occurs in childhood and is frequently asymptomatic. Some clinical manifestations include fever and exanthem subitum. There have been rare reports of invasion of HHV-7 into the central nervous system. Here we report a case of encephalitis associated with HHV-7. A 16-year-old girl presented with headache, vomiting, disorientation, and psychomotor agitation. Glasgow Coma Scale on arrival was 9. Cerebrospinal fluid tested positive for HHV-7. Electroencephalogram showed intermittent slowing and rare sharp waves in the left frontal region. She recovered well after appropriate treatment for encephalitis.

This case added to the few existing reports of encephalitis due to HHV-7. Physicians should be aware of this rare neurological manifestation of HHV-7 for prompt management. Similar cases should be reported to further our knowledge about this virus and its role in neurological disease.

Enhanced Virus Detection and Metagenomic Sequencing in Patients with Meningitis and Encephalitis

Meningitis and encephalitis are leading causes of central nervous system (CNS) disease and often result in severe neurological compromise or death. Traditional diagnostic workflows largely rely on pathogen-specific tests, sometimes over days to weeks, whereas metagenomic next-generation sequencing (mNGS) profiles all nucleic acid in a sample. In this single-center, prospective study, 68 hospitalized patients with known (n = 44) or suspected (n = 24) CNS infections underwent mNGS from RNA and DNA to identify potential pathogens and also targeted sequencing of viruses using hybrid capture. Using a computational metagenomic classification pipeline based on KrakenUniq and BLAST, we detected pathogen nucleic acid in cerebrospinal fluid (CSF) from 22 subjects, 3 of whom had no clinical diagnosis by routine workup. Among subjects diagnosed with infection by serology and/or peripheral samples, we demonstrated the utility of mNGS to detect pathogen nucleic acid in CSF, importantly for the Ixodes scapularis tick-borne pathogens Powassan virus, Borrelia burgdorferi, and Anaplasma phagocytophilum. We also evaluated two methods to enhance the detection of viral nucleic acid, hybrid capture and methylated DNA depletion. Hybrid capture nearly universally increased viral read recovery. Although results for methylated DNA depletion were mixed, it allowed the detection of varicella-zoster virus DNA in two samples that were negative by standard mNGS. Overall, mNGS is a promising approach that can test for multiple pathogens simultaneously, with efficacy similar to that of pathogen-specific tests, and can uncover geographically relevant infectious CNS disease, such as tick-borne infections in New England. With further laboratory and computational enhancements, mNGS may become a mainstay of workup for encephalitis and meningitis. IMPORTANCE Meningitis and encephalitis are leading global causes of central nervous system (CNS) disability and mortality. Current diagnostic workflows remain inefficient, requiring costly pathogen-specific assays and sometimes invasive surgical procedures. Despite intensive diagnostic efforts, 40 to 60% of people with meningitis or encephalitis have no clear cause of CNS disease identified. As diagnostic uncertainty often leads to costly inappropriate therapies, the need for novel pathogen detection methods is paramount. Metagenomic next-generation sequencing (mNGS) offers the unique opportunity to circumvent these challenges using unbiased laboratory and computational methods. Here, we performed comprehensive mNGS from 68 prospectively enrolled patients with known (n = 44) or suspected (n = 24) CNS viral infection from a single center in New England and evaluated enhanced methods to improve the detection of CNS pathogens, including those not traditionally identified in the CNS by nucleic acid detection. Overall, our work helps elucidate how mNGS can become integrated into the diagnostic toolkit for CNS infections.

M, Biasolo A, Manganelli R, Palù G, Parisi SG. Viral Molecular Testing of Cerebrospinal Fluid in Adults with Suspected Central Nervous System Infection in an Italian University Hospital Laboratory: A Retrospective Study on 1462 Consecutive Patients

Background:

Generally, about half of the patients with central nervous system infections cases remain unexplained. Therefore, we aimed to describe which viruses were detected in unselected patients with a suspected central nervous system infection and the first diagnostic workflow in a university hospital laboratory.

Methods:

A comprehensive virus testing in cerebrospinal fluid with an in-house real-time PCR method was employed. Determining how many and which viruses to test was at the full discretion of the treating physician.

Results:

1462 patients were evaluated from 2011 to 2017 and 9 898 viral PCRs were made: 176 subjects (12%) had a positive result. There was great heterogeneity in the frequency of patients tested for each virus, ranging from 97.9% (1431 out of 1462) for herpes simplex virus (HSV) to 1.9% (28 out of 1462) for Parvovirus B19, positive in 1 patient. Enterovirus (EV) was the leading virus detected: the frequency was higher with respect to HSV (5.2% vs 2.4%, p=0.0004), varicella-zoster virus (VZV)(5.2% vs 2.9%, p=0.0052), human herpesvirus-6 (5.2% vs 1.7%, p=0.0014) and human herpesvirus-7 (HHV-7)(5.2% vs 2.5%, p=0.0406). Both VZV (83.5%) and HSV (97.9%) were tested significantly more than EV (68.7%, p<0.0001) and HHV-7 (24.1%, p<0.0001): the latter had a positivity comparable to HSV and it was detected in younger patients (median age 29 years), as for EV (median age 35 years). There was no difference found in the age of positive subjects with respect to negative ones for the other viruses tested.

Conclusion:

EV was the fifth virus frequently included in the diagnostic workflow but the most frequently detected, mostly in subjects aged less 40, as HHV-7 was. Testing these two viruses in all younger patients could reduce the number of unknown etiology.

An adolescent with herpes simplex encephalitis, presenting with mild symptoms and rapid deterioration: A case report

Headaches in children are a common, but unspecific symptom that can have many underlying causes, ranging from unspecific tension headache through migraine and up to encephalitis and intracranial hypertension. We present the case of a 14-year-old boy who presented to our emergency department with headache, nausea as well as vomiting and developed seizures later on. The initial diagnosis was complicated by a magnetic resonance imaging which did not show any signs of inflammation, but was of limited informative value due to orthodontic appliances. Despite the unremarkable imaging, prophylactic antiviral and antibiotic treatment was started after lumbar puncture. Herpes simplex virus as well as human herpes virus 7 were confirmed in the cerebrospinal fluid. Although both viruses are ubiquitous, severe infections are a rare complication. Immunodeficiency syndromes are predisposing factors for serious complications and genetic analysis of UNC93B and TLR-3 might be helpful for decision-making. No genetic or immunologic predisposition was found in our patient. The patient’s condition deteriorated rapidly, so he had to be admitted to the pediatric intensive care unit, where he was intubated and his antiviral treatment with acyclovir was extended by foscarnet. After prolonged mechanical ventilation, he slowly improved. With intensive neurorehabilitation, he could finally return to his daily life activities 3 months after diagnosis. Despite headaches being an unspecific symptom, the possibility of a herpes simplex virus encephalitis should always kept in mind, especially in patients presenting with additional symptoms such as vomiting, altered mental status and/or focal neurological deficits. An initial magnetic resonance imaging might be misleading if orthodontic appliances are in place. Initiation of treatment without delay is crucial for neurologic outcome of herpes simplex virus encephalitis.

Persistent Roseoloviruses Infection in Adult Patients with Epilepsy

Background: Human herpesviruses (HHV)-6A, HHV-6B and HHV-7 are considered to be involved in the pathogenesis of epilepsy, a common neurological disorder. The objective of this study was to determine the association of roseoloviruses infection with epilepsy. Methods: 53 epilepsy patients and 104 ordinary blood donors were analyzed to determine presence of virus-specific antibodies by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA), genomic sequences, viral load and gene expression by polymerase chain reactions (PCRs) and restriction analysis, HHV-6 protein expression by IFA and level of cytokines by ELISA. Results: Roseoloviruses genomic sequences in DNA samples from whole blood were found in 86.8% of patients versus 54.8% of controls and active infection was revealed only in patients with epilepsy (19.6% of roseolovirus-positive patients). Significantly higher viral load and more frequent gene expression was detected in patients compared to the controls. HHV-6-encoded protein expression was demonstrated in 53.3% of patients with previously detected HHV-6 DNA. Changes in level of cytokines were determined in patients with elevated viral load compared to the patients without elevated viral loads and to the controls. Conclusions: Results on frequent active HHV-6 and HHV-7 infection in epilepsy patient’ peripheral blood indicate on possible involvement of these viruses in the disease development.

Extracellular vesicles: novel vehicles in herpesvirus infection

Herpesviruses are remarkable pathogens that have evolved multiple mechanisms to evade host immunity, ensuring their proliferation and egress. Among these mechanisms, herpesviruses utilize elaborate extracellular vesicles, including exosomes, for the intricate interplay between infected host and recipient cells. Herpesviruses incorporate genome expression products and direct cellular products into exosomal cargoes. These components alter the content and function of exosomes released from donor cells, thus affecting the downstream signalings of recipient cells. In this way, herpesviruses hijack exosomal pathways to ensure their survival and persistence, and exosomes are emerging as critical mediators for virus infection-associated intercellular communication and microenvironment alteration. In this review, the function and effects of exosomes in herpesvirus infection will be discussed, so that we will have a better understanding about the pathogenesis of herpesviruses.