Subacute sclerosing panencephalitis

Extracellular vesicles in the pathogenesis of neurotropic viruses

Neurotropic viruses, characterized by their capacity to invade the central nervous system, present a considerable challenge to public health and are responsible for a diverse range of neurological disorders. This group includes a diverse array of viruses, such as herpes simplex virus, varicella zoster virus, poliovirus, enterovirus and Japanese encephalitis virus, among others. Some of these viruses exhibit high neuroinvasiveness and neurovirulence, while others demonstrate weaker neuroinvasive and neurovirulent properties. The clinical manifestations of infections caused by neurotropic viruses can vary significantly, ranging from mild symptoms to severe life-threatening conditions. Extracellular vesicles (EVs) have garnered considerable attention due to their pivotal role in intracellular communication, which modulates the biological activity of target cells via the transport of biomolecules in both health and disease. Investigating EVs in the context of virus infection is crucial for elucidating their potential role contribution to viral pathogenesis. This is because EVs derived from virus-infected cells frequently transfer viral components to uninfected cells. Importantly, EVs released by virus-infected cells have the capacity to traverse the blood-brain barrier (BBB), thereby impacting neuronal activity and inducing neuroinflammation. In this review, we explore the roles of EVs during neurotropic virus infections in either enhancing or inhibiting viral pathogenesis. We will delve into our current comprehension of the molecular mechanisms that underpin these roles, the potential implications for the infected host, and the prospective diagnostic applications that could arise from this understanding.

The Rare Case Presentation of Adult-Onset Fulminant Subacute Sclerosing Panencephalitis in a 24-Year-Old Male

Subacute sclerosing panencephalitis (SSPE) is a late effect of measles in children. Its features include seizures, a gradual loss of physical and cognitive function, and finally death. Despite the absence of a definitive cure for this disorder, a regimen combining intrathecal interferon-α (IFN-α) and daily oral isoprinosine has demonstrated effectiveness. We present the case of a 24-year-old male with spastic seizure epilepsy. He exhibited progressive weakness, frequent postural instability, and recurrent generalized tonic-clonic seizures. Increased measles antibody concentrations in the cerebrospinal fluid (CSF), prominent amplitude spikes on the electroencephalogram (EEG), and heightened fluid-attenuated inversion recovery (FLAIR) signals on brain magnetic resonance imaging (MRI) suggested a diagnosis of SSPE.

The Calm Before the Storm? An Unusual Case of Measles Retinopathy

A 30-year-old male presented with sudden painless loss of vision in the right eye for the last two days. Slit-lamp examination of the right eye revealed a quiet anterior chamber and anterior vitreous. Fundus examination of the right eye revealed a large, focal retinitis lesion centered around the fovea, whereas examination of the left was unremarkable. He gave us a history of Measles at the age of 5 years but denied any history of systemic illness. Optical coherence tomography (OCT) revealed disruption of retinal architecture with ballooning of intact internal limiting membrane. His serology was negative for syphilis, human immunodeficiency virus and toxoplasmosis. Based on clinical suspicion, he was investigated by a neurologist. His electroencephalogram and Magnetic Resonance Imaging of brain were within normal limits, but high titres of anti-measles antibodies were found in serum and cerebrospinal fluid. The diagnosis of measles retinopathy should be considered in cases with focal necrotizing retinitis, even when classical findings of CNS involvement do not exist.

The EEG Features of Four Cases of Subacute Sclerosing Panencephalitis in North China: SSPE EEG Features

Objective. To analyze the EEG features of four subacute sclerosing panencephalitis cases in North China. Methods. We retrospectively analyzed the EEG features in four patients with subacute sclerosing panencephalitis and 12 patients in control group from North China. Results. The periodic long-interval diffuse discharges were found in all of the four cases with subacute sclerosing panencephalitis. The morphology and component of periodic complexes were varied in different patients and different wakefulness states. Some EEG parameter settings help to identify periodic long-interval diffuse discharges including the slowed sweep speed, decreased sensitivity and reduced number of montages. In each patient with subacute sclerosing panencephalitis, the periodic long-interval diffuse discharges associated with two types of brief episodes (1:1) during awake period were found and none of the patients in the control group had this EEG pattern. The score system based on the periodic discharges and brief episodes also shows that all the patients with SSPE reached score 5 while none of the patients in the control group has a score greater than 3, which suggests that this EEG pattern may have diagnostic value. Conclusions. In subacute sclerosing panencephalitis, the morphology and component of periodic long-interval diffuse discharges were varied in different patients and different wakefulness states. Specific EEG parameter settings help to identify periodic long-interval diffuse discharges. Periodic long-interval diffuse discharges associated with two types of brief episodes (1:1) during awake period may strongly suggest the diagnosis of subacute sclerosing panencephalitis.

Optical Coherence Tomography Angiographic Follow-Up in a Case of Subacute Sclerosing Panencephalitis and Unilateral Necrotising Retinitis

We present a 20-year-old woman who was diagnosed with subacute sclerosing panencephalitis (SSPE) 20 months after presenting with unilateral retinitis. At presentation, the patient had two inferotemporal macular lesions in her left eye. Corresponding to these areas, optical coherence tomography (OCT) showed hyporeflective spaces with loss of nearly all of the retinal layers. OCT-angiography (OCTA) demonstrated some flow deficit areas with a reduction in the vessel density. Her serum measles antibody titre was high (IgG >5000.0 mIU/ml). Twenty months later the macular lesions had diminished in size, and there was some focal retinal thinning with interruption of the ellipsoid zone. OCTA showed that the flow deficit areas were diminished in size together with the relatively improved perfusion density. Neurological examination disclosed myoclonic jerks. Neuropsychological assessment demonstrated impaired executive function, attention, and narrowed lexical fluency. Measles IgG antibody was high in the cerebrospinal fluid (>230.0 U/ml). Brain magnetic resonance imaging demonstrated bilateral, non-specific, small foci of T2 hyperintensity in the frontoparietal subcortical white matter and centrum semiovale. The present case is the first where OCTA findings of SSPE-related retinal lesions have been described.

Spectral Domain Optical Coherence Tomography Findings of Subacute Sclerosing Panencephalitis Presenting with Macular Necrotizing Retinitis: A Case Report

PURPOSE

To report the fundus photographs and spectral domain optical coherence tomography (SD-OCT) findings of a patient with subacute sclerosing panencephalitis (SSPE) presenting merely with ocular symptoms.

CASE REPORT

A 20-year-old patient presented with sudden loss of vision in the left eye (LE). Fundus photograph showed a yellow lesion in the macula and SD-OCT showed increased reflectivity of the inner retinal layers. Disorganization of the necrotizing retinal layers in the LE gradually progressed to the atrophic retina. Then, visual complaints began in the right eye (RE) accompanied by neurological symptoms. SD-OCT revealed the inner and outer plexiform layers edema and interruption of the ellipsoid zone in RE. Fundus photographs showed macular atrophy for both eyes on the day patient died.

CONCLUSION

This case report demonstrates the SD-OCT findings of SSPE retinitis with close follow-up from the acute retinitis to the total atrophic macula. These unique findings may be considered as characteristical for the diagnosis.

A 12-YEAR-OLD ASIAN INDIAN BOY WITH BILATERAL RAPIDLY PROGRESSIVE NECROTIZING MACULAR RETINITIS

PURPOSE

To describe clinical and imaging findings in a young boy presenting with bilateral rapidly progressive necrotizing macular retinitis.

METHODS

A 12-year-old Asian Indian boy developed bilateral progressive macular retinitis. He had generalized tonic-clonic seizures for the past 3 months and gave a history of poor scholastic performance with dementia of recent onset. Multimodal imaging comprising and detailed systemic and laboratory work-up was performed.

RESULTS

Both eyes showed rapidly progressive full-thickness retinitis lesions observed as disruption of retinal architecture in both eyes. Left eye optical coherence tomography shows full-thickness retinal involvement with sparing of the internal limiting membrane. Electroencephalogram and magnetic resonance imaging (brain) were suggestive of subacute sclerosing panencephalitis and the diagnosis was confirmed by elevated cerebrospinal fluid and serum IgG measles. The patient did not survive despite treatment with systemic interferon therapy.

CONCLUSION

It is important to look for the measles virus as a probable cause of necrotizing retinitis and neurologic symptoms in immunocompetent unvaccinated young patients. Early referral to a neurologist may assist in the early diagnosis of subacute sclerosing panencephalitis and targeted therapy.

The Reemergence of Measles

OBJECTIVES

Present-day pathologists may be unfamiliar with the histopathologic features of measles, which is a reemerging disease. Awareness of these features may enable early diagnosis of measles in unsuspected cases, including those with an atypical presentation. Using archived tissue samples from historic patients, a unique source of histopathologic information about measles and other reemerging infectious diseases, we performed a comprehensive analysis of the histopathologic features of measles seen in commonly infected tissues during prodrome, active, and late phases of the disease.

METHODS

Subspecialty pathologists analyzed H&E-stained slides of specimens from 89 patients accessioned from 1919 to 1998 and correlated the histopathologic findings with clinical data.

RESULTS

Measles caused acute and chronic histopathologic changes, especially in the respiratory, lymphoid (including appendix and tonsils), and central nervous systems. Bacterial infections in lung and other organs contributed significantly to adverse outcomes, especially in immunocompromised patients.

CONCLUSIONS

Certain histopathologic features, especially Warthin-Finkeldey cells and multinucleated giant cells without inclusions, allow pathologists to diagnose or suggest the diagnosis of measles in unsuspected cases.

Viral-induced neuroinflammation: Different mechanisms converging to similar exacerbated glial responses

There is increasing evidence that viral infections are the source/origin of various types of encephalitis, encephalomyelitis, and other neurological and cognitive disorders. While the involvement of certain viruses, such as the Nipah virus and measles virus, is known, the mechanisms of neural invasion and the factors that trigger intense immune reactions are not fully understood. Based on recent publications, this review discusses the role of the immune response, interactions between viruses and glial cells, and cytokine mediators in the development of inflammatory diseases in the central nervous system. It also highlights the significant gaps in knowledge regarding these mechanisms.

Cortical activation and motor body representations in a patient with subacute sclerosing panencephalitis

The current neuroimaging study investigated the sensorimotor maps during hand, feet and lips movements at one year after diagnosis of of subacute sclerosing panencephalitis (SSPE) in a 17 years-old patient. A lesion prediction algorithm showed that the posterior thalamic radiations, the splenium of the corpus callosum, the posterior and superior corona radiate, and the cingolum, showed a high lesion probability. Comparing the fMRI activations of the left and right hemisphere, we found that the representation of the left hand movement was more inferior/anterior and less represented than the representation of the right one; and the representation of the right foot movement was more superior, less represented than the representation of the left one and poorly activated at the predefined statistical threshold. The fMRI results are in line with the clinical report, describing an asymmetrical distribution of the periodic stereotyped myoclonic jerks, which mainly occurred for the left arm/hand and for the right leg/foot. This is the first fMRI study investigating the representation of the body parts in patients with SSPE. Results show that in SSPE the hyper-stimulation of the motor system (dedicated to the arm/hand and leg/foot more involved by the occurrence of the jerks) is accompanied by an under-activation of the corresponding motor representations in coincidence with voluntary movements.

Subacute Sclerosing Panencephalitis (SSPE): Experience from a Tertiary-Care Pediatric Center

Introduction  Subacute sclerosing panencephalitis (SSPE) is a devastating neurodegenerative disease occurring as a complication of measles infection that is still prevalent in low-resource countries. Clinical and electrographical variability in SSPE can lead to diagnostic delays.

Methods  Children diagnosed with SSPE in a tertiary care pediatric hospital in India in a period of 8 years were included in the study. The diagnosis was established on the basis of Dyken's criteria. The demographic data, clinical presentations, investigations, treatment approaches, and outcomes were reviewed and recorded.

Results  Thirty-four patients were included in the analysis. Average age at symptom onset was 7 years, 5 months. Majority of the children were not vaccinated for measles. Most patients (80%) presented with stage 2 of illness. Nearly 25% presented with atypical clinical features. Myoclonus was the most predominant feature seen after diagnosis. Electroencephalography (EEG) was the most useful investigation for suspecting the diagnosis. All patients showed deterioration in neurological status with time and 20% died during follow-up.

Conclusion  Atypical presentations of SSPE must be recognized in areas with high incidence to institute timely treatment and establish prognosis. EEG findings were found to be the most important indicator for diagnosis. Measles eradication will pave the way for elimination of this dreaded disease.

Measles-Associated CNS Complications: A Review

Measles virus infection is a common infectious disease of childhood, incidence of which is still high in developing countries. Other than the morbidity associated with the acute systemic infection, the measles virus can cause serious fatal neural complications. It can either enter the brain leading to acute encephalitis like primary measles encephalitis and acute post infectious measles encephalomyelitis or it may persist in brain cells (as mutated virus) leading to long-term neurodegenerative diseases like measles inclusion body encephalitis and subacute sclerosing pan encephalitis. The patho-clinical features, treatment, and the outcomes of these complications are different and should be identified in time for early diagnosis and management.

Emerging Role of the Ketogenic Dietary Therapies beyond Epilepsy in Child Neurology

Ketogenic dietary therapies (KDTs) have been in use for refractory paediatric epilepsy for a century now. Over time, KDTs themselves have undergone various modifications to improve tolerability and clinical feasibility, including the Modified Atkins diet (MAD), medium chain triglyceride (MCT) diet and the low glycaemic index treatment (LGIT). Animal and observational studies indicate numerous benefits of KDTs in paediatric neurological conditions apart from their evident benefits in childhood intractable epilepsy, including neurodevelopmental disorders such as autism spectrum disorder, rarer neurogenetic conditions such as Rett syndrome, Fragile X syndrome and Kabuki syndrome, neurodegenerative conditions such as Pelizaeus-Merzbacher disease, and other conditions such as stroke and migraine. A large proportion of the evidence is derived from individual case reports, case series and some small clinical trials, emphasising the vast scope for research in this avenue. The term 'neuroketotherapeutics' has been coined recently to encompass the rapid strides in this field. In the 100^th year of its use for paediatric epilepsy, this review covers the role of the KDTs in non-epilepsy neurological conditions among children.

Electroencephalography Patterns of Subacute Sclerosing Panencephalitis

Introduction and background: This article explores the electroencephalography (EEG) pattern in patients of suspected subacute sclerosing panencephalitis (SSPE) visiting Lady Reading Hospital, Peshawar. Pakistan has a huge deficit of research culture, and limited studies are done on this topic. This study concluded that a typical pattern is the most common EEG pattern, although atypical and normal EEG patterns were also observed. It is worth inclusion into the existing literature and may be used for future literature review of similar studies done elsewhere in Pakistan to give a wider perspective comprised of a larger sample size - integrating all studies.

Objective: To determine the frequency of different patterns of EEG (typical, atypical, and normal) in SSPE patients.

Methodology: Seventy-seven patients of both male and female genders between ages one to 20 years, who were diagnosed with SSPE, were included in the study. Dyken’s criteria were used to diagnose the patients. A prior history of previous measles infection with signs and symptoms suggestive of SSPE and positive anti-measles IgG antibodies in the cerebrospinal fluid (CSF) was found in all the patients included in the study. Besides this, typical EEG patterns and raised CSF globulin levels were also used for confirmation of the diagnosis. All the patients fulfilling the above criteria and presenting to the neurology department of Lady Reading Hospital, Peshawar, from February 1, 2019, to November 30, 2019, were included in the study. All the patients underwent the EEG monitoring in the same EEG laboratory and were reported by the same consultant with careful exclusion of any artifacts during the study.

Result: There were 59 (76.62%) males and 18 (23.37%) females. The mean age was 15 ± 8.6 years, and the mean duration of symptoms was 4.79 ± 1.68 months. EEG was normal in 14 (18.18%) patients, while 63 (81.81%) patients had an abnormal EEG pattern, with a majority of 53 (84.12%) patients showing periodic delta wave complexes. Only 10 (15.87%) patients showed atypical patterns.

Conclusion: Almost all the patients of SSPE showed periodic high-amplitude delta waves complexes, which usually occurs in patients with a disease duration of more than four months. However, further studies with a large sample size are needed for the confirmation of this observation.

A Rare Case of Subacute Sclerosing Panencephalitis Presenting As Generalized Seizure

Subacute sclerosing panencephalitis (SSPE) is a late complication of childhood measles. It is characterized by a progressive decline in cognitive and motor functions, seizures, and eventually death. Although a combination of intrathecal interferon alpha (IFN-α) and daily oral isoprinosine has been reported to have a good outcome, there is no cure for this condition.  We present a case of a 16-year-old male with SSPE who presented with progressive weakness, frequent loss of postural control, multiple episodes of generalized tonic-clonic seizures, and urinary incontinence. On exploration of his history, he had measles at the age of two months. Investigation showed increased serum measles antibody titer, high amplitude spikes in electroencephalogram (EEG), and high fluid-attenuated inversion recovery (FLAIR) signals on MRI of the brain consistent with probable SSPE. He was managed symptomatically until his condition got worse and he eventually passed away.

Subacute sclerosing panencephalitis and brain stem involvement: a rare combination

Subacute sclerosing panencephalitis (SSPE) is a progressive lethal neurological inflammatory disease due to persistent, wild measles virus infection in the central nervous system that is seen most frequently in children and young adolescents. Atypical presentations are seen in up to 10% of cases. Most frequently and severely affected region in the brain is the parieto-occipital region of the brain. Less commonly involved organs are the cerebellum, basal ganglia and corpus callosum. Brainstem involvement is rare and usually occurs when other areas of brain are involved along with it. Here, we describe an unusual male patient of 15 years age, having SSPE with MRI of brain showing extensive involvement of brainstem with no significant involvement of other cortical structures of the brain. It is very rarely described in SSPE, but one should be vigilant about such involvement of brainstem and cerebellum, and SSPE should not be missed when brainstem hyperintensities are seen in MRI brain with or without other region of the brain to avoid misdiagnosis.

Subacute Sclerosing Panencephalitis manifesting as Bell's palsy and bilateral macular necrotizing retinitis: an atypical presenting feature

Background

Subacute sclerosing panencephalitis (SSPE) is a potentially lethal complication of measles infection. Neurological complications take years to manifest after primary viral infection of brain and can lead to blindness in some individuals.

Findings

A 13-year-old female patient with history of Bell’s palsy 2 months prior, presented with rapidly progressing necrotizing retinitis in both eyes. Soon after, she was unable to walk, developed myoclonic jerks, altered sensorium and loss of bowel and bladder control. Her clinical history, CSF IgG measles antibody analysis, MRI brain and EEG findings confirmed the diagnosis of SSPE.

Conclusion

SSPE in our case presented as Bell’s palsy and sudden painless diminution of vision due to ocular involvement, and developed full blown disease within 2 months. SSPE can present as a diagnostic challenge and warrants early identification and referral for timely diagnosis and management.

Advances in Antiviral Therapy for Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a late-onset, intractable, and fatal viral disease caused by persistent infection of the central nervous system by a mutant strain of the measles virus. Ribavirin intracerebroventricular therapy has already been administered to several SSPE patients in Japan based on fundamental and clinical research findings from our group, with positive therapeutic effects reported in some patients. However, the efficacy of this treatment approach has not been unequivocally established. Hence, development of more effective therapeutic methods using new antiviral agents is urgently needed. This review describes the current status of SSPE treatment and research, highlighting promising approaches to the development of more effective therapeutic methods.

The Spectrum of Repetitive Behaviors Associated With Subacute Sclerosing Panencephalitis

BACKGROUND

Repetitive behaviors refer to a broad class of responses ranging from stereotypic body movements to impulsive/compulsive behaviors. They may be associated with neurological disorders.

METHODS

This is a case series of six subacute sclerosing panencephalitis (SSPE) patients who presented with a wide spectrum of repetitive motor behaviors and vocalizations.

RESULTS

Repetitive motor behaviors involved the upper limbs in all patients and lower limbs in 3 patients. The repetitive movements in the upper limbs were clapping, finger-clicking, hand rubbing, flailing, and dystonic posturing. In the lower limbs, the repetitive movements were rubbing with the heel, pelvic thrusting with flexion extension of the leg, and foot tapping. The spectrum of vocalizations included palilalia, whistling, grunting with spitting, and pathological crying. Repetitive behaviors were the presenting features in 2 patients.

CONCLUSIONS

This case series expands the spectrum of repetitive behaviors seen in neurological disorders associated with brain infections. © 2020 International Parkinson and Movement Disorder Society.

Adult-Onset Subacute Sclerosing Panencephalitis With a 30-Year Latent Period

Subacute sclerosing panencephalitis (SSPE) is a rare progressive neuroinfectious disease due to a late complication of the measles virus. The hallmark clinical features of this disease include behavioral changes, myoclonus, dementia, visual disturbances, and pyramidal and extrapyramidal signs. The presence of characteristic high-amplitude periodic complexes on electroencephalography and raised antibody titers against measles in the cerebrospinal fluid help solidify the diagnosis. We present a case of a 40-year-old patient with SSPE who initially developed ophthalmologic manifestations 30 years after the primary measles infection. This case highlights both typical and atypical features of SSPE and provides a diagnostic framework for evaluating cases that fall outside of the standard scope of this disease.

Adult-onset subacute sclerosing panencephalitis presenting with tonic motor seizures

PURPOSE/AIM OF THE STUDY

Subacute sclerosing panencephalitis (SSPE) is a degenerative disease of the brain caused by a persistent measles virus infection occurring mostly in childhood or early adolescence. The spectrum of epileptic phenomena associated with SSPE is wide, varying from partial or generalized tonic-clonic seizures and atypical absences to myoclonic-atonic attacks. Tonic seizures are very rare in SSPE.

MATERIALS AND METHODS

Herein, we discuss a case of 25 years old male that presented with adult-onset SSPE with tonic seizures accompanying myoclonic seizures.

RESULTS

Patient was treated with clonazepam 5 mg/day and an isoprinosine regimen with a dose of 70 mg/kg/day. This is the fourth case of SSPE presenting with myoclonic and tonic seizures and the first case of SSPE with myoclonic and tonic seizures reported in an adult-onset case in the English literature.

CONCLUSIONS

Adult-onset SSPE with tonic seizures is rare and may be confusing, thus, it is important to recognize the presence of this type of tonic motor seizures in SSPE patients.

Atypical Subacute Sclerosing Panencephalitis in a Young Child: Implications for Change in Vaccination Strategy

Subacute sclerosing panencephalitis (SSPE) is a serious neurological complication of measles with no satisfactory treatment options. The prolonged incubation period makes it rare in young children. The occurrence of primary measles infection in infants before age of vaccination can be prevented only by ensuring adequate vaccination of all females in childbearing age. Here, we present a case of an atypical presentation of SSPE in a toddler who contracted measles at 6 months of age.

Henipavirus infection of the central nervous system

Nipah virus (NiV) and Hendra virus are highly pathogenic zoonotic viruses of the genus Henipavirus, family Paramyxoviridae. These viruses were first identified as the causative agents of severe respiratory and encephalitic disease in the 1990s across Australia and Southern Asia with mortality rates reaching up to 75%. While outbreaks of Nipah and Hendra virus infections remain rare and sporadic, there is concern that NiV has pandemic potential. Despite increased attention, little is understood about the neuropathogenesis of henipavirus infection. Neuropathogenesis appears to arise from dual mechanisms of vascular disease and direct parenchymal brain infection, but the relative contributions remain unknown while respiratory disease arises from vasculitis and respiratory epithelial cell infection. This review will address NiV basic clinical disease, pathology and pathogenesis with a particular focus on central nervous system (CNS) infection and address the necessity of a model of relapsed CNS infection. Additionally, the innate immune responses to NiV infection in vitro and in the CNS are reviewed as it is likely linked to any persistent CNS infection.

Elevated quinolinic acid levels in cerebrospinal fluid in subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a rare neurodegenerative disorder caused by a persistent infection with aberrant measles virus. Indoleamine-2, 3-dioxygenase (IDO) initiates the increased production of kynurenine pathway (KP) metabolites quinolinic acid (QUIN), which has an excitotoxic effect for neurons. We measured serum IDO activity and cerebrospinal fluid (CSF) levels of QUIN. The CSF QUIN levels were significantly higher in SSPE patients than in controls, and increased according as neurological disability in a patient studied. Elevation of CSF QUIN and progression of SSPE indicate a pathological role of KP metabolism in the inflammatory neurodestruction.

Marine Morbilliviruses: Diversity and Interaction with Signaling Lymphocyte Activation Molecules

Epidemiological reports of phocine distemper virus (PDV) and cetacean morbillivirus (CeMV) have accumulated since their discovery nearly 30 years ago. In this review, we focus on the interaction between these marine morbilliviruses and their major cellular receptor, the signaling lymphocyte activation molecule (SLAM). The three-dimensional crystal structure and homology models of SLAMs have demonstrated that 35 residues are important for binding to the morbillivirus hemagglutinin (H) protein and contribute to viral tropism. These 35 residues are essentially conserved among pinnipeds and highly conserved among the Caniformia, suggesting that PDV can infect these animals, but are less conserved among cetaceans. Because CeMV can infect various cetacean species, including toothed and baleen whales, the CeMV-H protein is postulated to have broader specificity to accommodate more divergent SLAM interfaces and may enable the virus to infect seals. In silico analysis of viral H protein and SLAM indicates that each residue of the H protein interacts with multiple residues of SLAM and vice versa. The integration of epidemiological, virological, structural, and computational studies should provide deeper insight into host specificity and switching of marine morbilliviruses.

Neuroinflammation During RNA Viral Infections

Neurotropic RNA viruses continue to emerge and are increasingly linked to diseases of the central nervous system (CNS) despite viral clearance. Indeed, the overall mortality of viral encephalitis in immunocompetent individuals is low, suggesting efficient mechanisms of virologic control within the CNS. Both immune and neural cells participate in this process, which requires extensive innate immune signaling between resident and infiltrating cells, including microglia and monocytes, that regulate the effector functions of antiviral T and B cells as they gain access to CNS compartments. While these interactions promote viral clearance via mainly neuroprotective mechanisms, they may also promote neuropathology and, in some cases, induce persistent alterations in CNS physiology and function that manifest as neurologic and psychiatric diseases. This review discusses mechanisms of RNA virus clearance and neurotoxicity during viral encephalitis with a focus on the cytokines essential for immune and neural cell inflammatory responses and interactions. Understanding neuroimmune communications in the setting of viral infections is essential for the development of treatments that augment neuroprotective processes while limiting ongoing immunopathological processes that cause ongoing CNS disease.

IL28B, IL29 and micro-RNA 548 in subacute sclerosing panencephalitis as a rare disease

Subacute sclerosing panencephalitis (SSPE) is a progressive neurodegenerative disease which affects children and young adults, caused by a persistent infection of defective measles virus. IFN-λs (IL-28A, IL-28B and IL-29) are a group of cytokines mediating antiviral responses. It has been shown that IL-29 levels are significantly higher in infected cells with defective measles virus. IL-29 expression is thought to be regulated at post-transcriptional level and miRNA-548 family targets the 3'UTR of the IFNL1 gene. Impaired immune system has an important role as well as viral factors in SSPE. The aim of our study investigates whether IL-28B, IL-29 levels and gene polymorphisms contribute to the damaged immune response leading to the development of SSPE. Also possible association of miR-548 family with IL-29 and SSPE is explored. Frequencies of rs12979860, rs8099917, rs30461, serum levels of IL-28B, IL-29 and expression levels of miR-548b, miR-548c, miR-548i are determined at 64 SSPE patients and 68 healthy controls. Serum IL-29 levels are statistically significant higher in SSPE patients. Allele frequencies of rs8099917 are statistically significant higher in SSPE patients and resulted G allele is found to increase 2.183-fold risk of SSPE. The expression levels of miR-548b-5p, miR-548c-5p and miR-548i are found to be statistically significant higher in SSPE patients. Dramatically increased level of IL-29 seen in patient group indicates that the elevated miR-548 expression is compensatory result of the over-activated immune system response. Further studies referred to IL28, IL29 and related miRNA's will be enlightened the pathogenesis of SSPE.

Genetic characterization of measles virus genotype D6 subacute sclerosing panencephalitis case, Alberta, Canada

Subacute sclerosing panencephalitis (SSPE) is a progressive and eventually fatal neurological disease arising from a persistent infection with measles virus (MV) acquired at a young age. SSPE measles virus strains are defective and unable to produce progeny virions, due to multiple and extensive mutations in a number of key genes. We sequenced the full MV genome from our recently reported SSPE case, which typed as genotype D6, and compared it with other genotype D6 wild type and SSPE sequences. The Alberta D6 strain was significantly different from other reported SSPE D6 sequences. Mutations were observed in all the genes of the Alberta strain, with the greatest sequence divergence noted in the M gene with 17.6% nucleotide and 31% amino acid variation. The L gene showed the least variation with 1.3% nucleotide and 0.7% amino acid differences respectively. The nucleotide variability for 15,672 bases of the complete genome compared to the wild type and other SSPE D6 strains was around 3%.

Retinitis as the presenting feature of subacute sclerosing panencephalitis in an Indian male: A case report

Measles virus is a rare but important cause for acute retinitis as it can eventually lead to the fulminant complication of SSPE. We report a case of a young Indian male with acute viral retinitis who subsequently developed SSPE. It is of paramount importance to consider measles virus and SSPE as a cause in an immunocompetent young adult with necrotizing viral retinitis

In vivo nose-to-brain delivery of the hydrophilic antiviral ribavirin by microparticle agglomerates

Nasal administration has been proposed as a potential approach for the delivery of drugs to the central nervous system. Ribavirin (RBV), an antiviral drug potentially useful to treat viral infections both in humans and animals, has been previously demonstrated to attain several brain compartments after nasal administration. Here, a powder formulation in the form of agglomerates comprising micronized RBV and spray-dried microparticles containing excipients with potential absorption enhancing properties, i.e. mannitol, chitosan, and α-cyclodextrin, was developed for nasal insufflation. The agglomerates were characterized for particle size, agglomeration yield, and ex vivo RBV permeation across rabbit nasal mucosa as well as delivery from an animal dry powder insufflator device. Interestingly, permeation enhancers such as chitosan and mannitol showed a lower amount of RBV permeating across the excised nasal tissue, whereas α-cyclodextrin proved to outperform the other formulations and to match the highly soluble micronized RBV powder taken as a reference. In vivo nasal administration to rats of the agglomerates containing α-cyclodextrin showed an overall higher accumulation of RBV in all the brain compartments analyzed as compared with the micronized RBV administered as such without excipient microparticles. Hence, powder agglomerates are a valuable approach to obtain a nasal formulation potentially attaining nose-to-brain delivery of drugs with minimal processing of the APIs and improvement of the technological and biopharmaceutical properties of micronized API and excipients, as they combine optimal flow properties for handling and dosing, suitable particle size for nasal deposition, high surface area for drug dissolution, and penetration enhancing properties from excipients such as cyclodextrins.

Subacute sclerosing panencephalitis - current perspectives

Subacute sclerosing panencephalitis is a progressive neurodegenerative disease. It usually occurs 7–10 years after measles infection. The clinical course is characterized by progressive cognitive decline and behavior changes followed by focal or generalized seizures as well as myoclonus, ataxia, visual disturbance, and later vegetative state, eventually leading to death. It is diagnosed on the basis of Dyken’s criteria. There is no known cure for subacute sclerosing panencephalitis to date, but it is preventable by ensuring that an effective vaccine program for measles is made compulsory for all children younger than 5 years in endemic countries.

BILATERAL SUBRETINAL FLUID AND RETINAL VASCULOPATHY ASSOCIATED WITH SUBACUTE SCLEROSING PANENCEPHALITIS

PURPOSE

To report a case of bilateral retinopathy associated with subacute sclerosing panencephalitis.

METHODS

History and clinical examination, fluorescein angiography, and optical coherence tomography.

RESULTS

We report a rare case of unilateral, followed by bilateral retinopathy, subretinal fluid, and vasculopathy in a young boy. History of missed measles vaccination, behavioral and neurologic symptoms, and electroencephalogram suggested a diagnosis of subacute sclerosing panencephalitis. Retinal imaging using optical coherence tomography was performed to document changes in the retinal microstructure through the natural course of the disease. Within 8 weeks, the changes progressed to retinal atrophy in both eyes.

CONCLUSION

The progressive course of retinitis associated with subacute sclerosing panencephalitis can be monitored on optical coherence tomography. Retinitis is subacute sclerosing panencephalitis rapidly progressive from the acute stage to the stage of atrophy, involving full thickness of the retina.

Ophthalmic examination as a means to diagnose Subacute Sclerosing Panencephalitis: an optical coherence tomography and ultrawide field imaging evaluation

Background

Subacute sclerosing panencephalitis (SSPE) is a potentially fatal complication of measles. The authors report a case of recurrent myoclonic jerks under investigation, whose ophthalmic examination pointed to the diagnosis.

Case presentation

A 12-year-old boy with recurrent episodes of myoclonic jerks was found to have optic disc pallor and an irregular macular scar with pigmentation in the left eye. The retinal finding proved to be a strong diagnostic clue for SSPE. There was a history of exanthematous fever in childhood. Antibodies against measles were detected in both the cerebrospinal fluid and serum. Retinitis with intraretinal and subretinal hemorrhage in the right eye was noted 6-weeks after the initial presentation.

Conclusion

The authors describe the importance of ophthalmic evaluation in cases of recurrent myoclonic jerks. Optical coherence tomographic features and ultrawide field imaging characteristics of a case of SSPE are described.

A Novel Peptide Derived from the Fusion Protein Heptad Repeat Inhibits Replication of Subacute Sclerosing Panencephalitis Virus In Vitro and In Vivo

Subacute sclerosing panencephalitis (SSPE) is a persistent, progressive, and fatal degenerative disease resulting from persistent measles virus (MV) infection of the central nervous system. Most drugs used to treat SSPE have been reported to have limited effects. Therefore, novel therapeutic strategies are urgently required. The SSPE virus, a variant MV strain, differs virologically from wild-type MV strain. One characteristic of the SSPE virus is its defective production of cell-free virus, which leaves cell-to-cell infection as the major mechanism of viral dissemination. The fusion protein plays an essential role in this cell-to-cell spread. It contains two critical heptad repeat regions that form a six-helix bundle in the trimer similar to most viral fusion proteins. In the case of human immunodeficiency virus type-1 (HIV-1), a synthetic peptide derived from the heptad repeat region of the fusion protein enfuvirtide inhibits viral replication and is clinically approved as an anti-HIV-1 agent. The heptad repeat regions of HIV-1 are structurally and functionally similar to those of the MV fusion protein. We therefore designed novel peptides derived from the fusion protein heptad repeat region of the MV and examined their effects on the measles and SSPE virus replication in vitro and in vivo. Some of these synthetic novel peptides demonstrated high antiviral activity against both the measles (Edmonston strain) and SSPE (Yamagata-1 strain) viruses at nanomolar concentrations with no cytotoxicity in vitro. In particular, intracranial administration of one of the synthetic peptides increased the survival rate from 0% to 67% in an SSPE virus-infected nude mouse model.

A 29-year-old pregnant woman with worsening left hemiparesis, encephalopathy, and hemodynamic instability: a case report of subacute sclerosing panencephalitis

A 29-year-old pregnant woman developed progressively worsening encephalopathy, left hemiparesis, and hemodynamic instability over a 6-week period. Initial brain MRI and work-up for infectious and autoimmune causes were normal, although elevated IgG and oligoclonal bands were seen on analysis of the cerebrospinal fluid (CSF). After uncomplicated spontaneous delivery of a preterm healthy infant, her condition worsened. Repeat brain MRI demonstrated generalized volume loss and evidence of corticospinal tract degeneration. She underwent a brain biopsy, which showed characteristic viral inclusions of the type seen in subacute sclerosing panencephalitis (SSPE). The diagnosis was confirmed by immunohistochemistry and electron microscopy, and additional CSF analysis also showed markedly elevated IgG titer for measles. Sequence analysis of the nucleoprotein gene N-450 demonstrated a close relationship to the sequences of viruses in genotype D7. This case documents an ~ 6-month progression to death of SSPE in a pregnant woman.

Subacute sclerosing panencephalitis presenting as acute cerebellar ataxia and brain stem hyperintensities

BACKGROUND

Subacute sclerosing panencephalitis is a devastating neurodegenerative disease with a characteristic clinical course. Atypical presentations may be seen in 10% of the cases.

AIMS

To describe the atypical clinical and radiological features of SSPE in a child form endemic country.

METHODS

A 5-year-old boy presented with acute-onset cerebellar ataxia without associated encephalopathy, focal motor deficits, seizures or cognitive decline. He had varicella-like illness with vesicular, itchy truncal rash erupting one month prior to the onset of these symptoms. He underwent detailed neurological assessment, relevant laboratory and radiological investigations.

RESULTS

Neuroimaging revealed peculiar brain stem lesions involving the pons and cerebellum suggestive of demyelination. With a presumptive diagnosis of clinically isolated syndrome of demyelination, he was administered pulse methylprednisolone (30 mg/kg/day for 5 days). Four weeks later he developed myoclonic jerks. Electroencephalogram showed characteristic periodic complexes time-locked with myoclonus. CSF and serum anti-measles antibody titres were elevated (1:625).

CONCLUSION

Our report highlights that subacute sclerosing panencephalitis can present atypically as isolated acute cerebellar ataxia and peculiar involvement of longitudinal and sparing of transverse pontine fibres. The predominant brainstem abnormalities in the clinical setting may mimick acute demyelinating syndrome. Hence, it is important to recognize these features of subacute sclerosing panencephalitis in children, especially in the endemic countries.

Cetacean Morbillivirus-Associated Pathology: Knowns and Unknowns

The present minireview deals with the pathology of Cetacean Morbillivirus (CeMV) infection in free-ranging cetaceans. In this respect, while "classical" CeMV-associated lesions were observed in the lung, brain, and lymphoid tissues from striped dolphins (Stenella coeruleoalba) and pilot whales (Globicephala melas) which were victims of the 1990-1992 and 2006-2008 epidemics in the Western Mediterranean, an apparent reduction in CeMV neurovirulence, along with a different viral antigen's tissue and cell distribution, were found during the 2010-2011 and the 2013 outbreaks in the same area. Of remarkable concern are also the documented CeMV ability to induce maternally acquired infections in wild cetaceans, coupled with the progressively expanding geographic and host range of the virus in both Hemispheres, as well as in conjunction with the intriguing forms of "brain-only" morbilliviral infection increasingly reported in Mediterranean-striped dolphins. Future research in this area should address the virus-host interaction dynamics, with particular emphasis on the cell receptors specifying viral tissue tropism in relation to the different cetacean species and to their susceptibility to infection, as well as to the CeMV strains circulating worldwide.

Subacute sclerosing panencephalitis in pregnancy

We present a case of subacute sclerosing panencephalitis that developed in a previously healthy 29-year-old pregnant woman who had returned from a trip to rural India shortly before the onset of symptoms. She was admitted to hospital at 27 weeks' gestation with a history of cognitive decline and difficulty completing simple tasks. She had no clinical signs of infection. The working diagnosis was autoimmune encephalitis, although extensive investigations did not lead to a final classifying diagnosis. The patient became comatose and developed hypertension, and an emergency caesarean section was done at 31 weeks to deliver the child, who seemed healthy. The patient died about 6 weeks after the onset of symptoms. The patient was found to have had subacute sclerosing panencephalitis at autopsy. In this Grand Round, we review the clinical features and treatment of subacute sclerosing panencephalitis, and the epidemiological and public health aspects of the case.

Subacute sclerosing panencephalitis with parkinsonian features in a child: A case report

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) can present with atypical clinical signs which may result in delayed diagnosis and treatment. We present a child with SSPE whose initial manifestation was parkinsonism.

PATIENT

This 12-year-old boy presented with the complaint of difficulty in standing up and walking for 2 months. Neurological examination revealed generalized rigidity, bradykinesia, impaired postural reflexes, and a mask-like facies. The initial diagnosis of Juvenile Parkinson Disease was made. He had no improvement with levodopa, trihexyphenidyl, tetrabenazine and clonazepam. The EEG showed irregular background activity with generalized slow waves which were not suppressed with diazepam injection. SSPE was considered and the diagnosis was confirmed with the identification of measles antibodies in cerebrospinal fluid.

CONCLUSION

SSPE should be considered in children and adolescents with parkinsonian symptoms, particularly in the absence of a history of vaccination against measles.