A recent surge of fulminant and early onset subacute sclerosing panencephalitis (SSPE) in the United Kingdom: An emergence in a time of measles

Subacute Sclerosing Panencephalitis: Impact on Public Health, Current Insights, and Future Perspectives

BACKGROUND

Subacute Sclerosing Panencephalitis (SSPE) is a rare complication of the measles infection. SSPE is a chronic disease of the central nervous system (CNS) that causes encephalitis, leading to the demyelination of neurons in the brain. It affects the brain in 9 months or less and hence subacute, causing encephalitis and lesions in the entire brain, so the term panencephalitis is used.

METHODS

A comprehensive literature search was conducted using the databases PubMed and Google Scholar starting in April 2024, and all relevant articles were extracted for this review.

RESULTS

A recent surge in SSPE cases in developed countries has been reported. This has been attributed to reduced vaccination, aggravated by misinformation and a decline in immunization after the COVID-19 pandemic. SSPE is a progressive and relatively rare neurological complication of measles, which almost always results in a vegetative state followed by death. It typically presents 10 years following exposure to measles. Manifestations of SSPE are divided into four stages that range from general personality changes to coma. Complications include ocular pathology and eventual blindness, as well as psychiatric illnesses. Treatment options for SSPE include symptomatic control with antiepileptic drugs, interferon combined treatment, vitamin A, ribavirin, and a ketogenic diet for disease modification.

CONCLUSION

The only prevention for SPPE is through vaccination. Several collaborative efforts have been made with WHO to improve surveillance and increase vaccination, but still many challenges prevail. Better prevention strategies and improved treatment outcomes can only be achieved by enhancing healthcare access, improving public awareness, analyzing community-based data, and studying the genetic and molecular associations of measles and SSPE.

Neuroimaging Abnormalities in Patients with Subacute Sclerosing Panencephalitis : Prospective Follow-up Study

OBJECTIVE

This study aimed to assess the neuroimaging abnormalities and their progression in patients with Subacute sclerosing panencephalitis (SSPE) and identify clinical predictors of these imaging findings.

METHODS

This prospective observational study evaluated clinical and neuroimaging features in patients with SSPE. Patients were categorized using Dyken's criteria, Jabbour's staging system, and the definition of fulminant SSPE. They underwent comprehensive clinical assessments, cerebrospinal fluid examination, Electroencephalogram (EEG), and Magnetic Resonance Imaging (MRI) scans. Treatment involved intrathecal interferon‑α and antiepileptic medications. Functional disability was assessed using the modified Barthel index. Follow-ups were performed at 6 months, including reassessment of Modified Barthel Index (MBI) and Jabbour's staging and EEG and MRI scans.

RESULTS

The mean age was 13.9 ± 6.7 years, with males comprising 81.5% (44/54) of the cohort. Fulminant SSPE was noted in 33% (18/54) of cases. Disease duration before presentation varied significantly between fulminant and non-fulminant forms (p = 0.001). Neuroimaging abnormalities were more prevalent in JS III stage patients, with diffuse cerebral atrophy being a significant finding (p = 0.011). Basal ganglia involvement correlated with movement disorders. The 6‑month follow-up showed increased cerebral atrophy (p = 0.004). Increasing disease duration was an independent predictor of cerebral atrophy. An Intercomplex interval (ICI) of more than 10 minutes correlated with normal neuroimaging, 10 patients died within the study period, 8 of whom had fulminant SSPE.

CONCLUSION

Parieto-occipital White matter hyperintensity (WMH) is the most prevalent and sensitive neuroimaging finding for the diagnosis of SSPE. Despite interferon treatment, cerebral atrophy progressed in both aggressive and fulminant SSPE. Increasing disease duration is an independent predictor of cerebral atrophy.

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.

Global genetic diversity of measles virus (Paramyxoviridae: Morbillivirus: Morbillivirus hominis): historical aspects and current state

Monitoring the circulation of the measles virus and studying its genetic diversity is an important component of the measles elimination program. A methodological approach to molecular genetic studies and their interpretation in the measles surveillance was developed in the early 2000s. During its development, clear areas of circulation of each genotype of the virus were identified, therefore, the determination of viruses' genotypes was proposed to monitor circulation and identify transmission pathways. However, in the future, due to a significant decrease in the number of active genotypes, an approach based on sub-genotyping was proposed: determining not only the genotype of the virus, but also its genetic lineage/genetic variant. The Global Measles and Rubella Laboratory Network (GMRLN) systematically monitors the circulation of the measles virus at the sub-genotypic level, depositing the results in a specialized database MeaNS2. It is this database that is the most complete and reliable source of information about the genetic characteristic of measles viruses. This review presents both historical information and the latest data on the global genetic diversity of the measles virus.

The collective burden of childhood dementia: a scoping review

Childhood dementia is a devastating and under-recognized group of disorders with a high level of unmet need. Typically monogenic in origin, this collective of individual neurodegenerative conditions are defined by a progressive impairment of neurocognitive function, presenting in childhood and adolescence. This scoping review aims to clarify definitions and conceptual boundaries of childhood dementia and quantify the collective disease burden. A literature review identified conditions that met the case definition. An expert clinical working group reviewed and ratified inclusion. Epidemiological data were extracted from published literature and collective burden modelled. One hundred and seventy genetic childhood dementia disorders were identified. Of these, 25 were analysed separately as treatable conditions. Collectively, currently untreatable childhood dementia was estimated to have an incidence of 34.5 per 100 000 (1 in 2900 births), median life expectancy of 9 years and prevalence of 5.3 per 100 000 persons. The estimated number of premature deaths per year is similar to childhood cancer (0-14 years) and approximately 70% of those deaths will be prior to adulthood. An additional 49.8 per 100 000 births are attributable to treatable conditions that would cause childhood dementia if not diagnosed early and stringently treated. A relational database of the childhood dementia disorders has been created and will be continually updated as new disorders are identified (https://knowledgebase.childhooddementia.org/). We present the first comprehensive overview of monogenic childhood dementia conditions and their collective epidemiology. Unifying these conditions, with consistent language and definitions, reinforces motivation to advance therapeutic development and health service supports for this significantly disadvantaged group of children and their families.

State of the Art: Acute Encephalitis

Encephalitis is a devastating neurologic disease often complicated by prolonged neurologic deficits. Best practices for the management of adult patients include universal testing for a core group of etiologies, including herpes simplex virus (HSV)-1, varicella zoster virus (VZV), enteroviruses, West Nile virus, and anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibody encephalitis. Empiric acyclovir therapy should be started at presentation and in selected cases continued until a second HSV-1 polymerase chain reaction test is negative. Acyclovir dose can be increased for VZV encephalitis. Supportive care is necessary for other viral etiologies. Patients in whom no cause for encephalitis is identified represent a particular challenge. Management includes repeat brain magnetic resonance imaging, imaging for occult malignancy, and empiric immunomodulatory treatment for autoimmune conditions. Next-generation sequencing (NGS) or brain biopsy should be considered. The rapid pace of discovery regarding autoimmune encephalitis and the development of advanced molecular tests such as NGS have improved diagnosis and outcomes. Research priorities include development of novel therapeutics.

Spotting a potential threat: Measles among pediatric solid organ transplantation recipients

BACKGROUND

Low-vaccination rates worldwide have led to the re-emergence of vaccine-preventable infections, including measles. Immunocompromised patients, including pediatric solid organ transplant (SOT) recipients, are at risk for measles because of suboptimal vaccination, reduced or waning vaccine immunity, lifelong immunosuppression, and global re-emergence of measles.

OBJECTIVES

To review published cases of measles in pediatric SOT recipients to heighten awareness of its clinical manifestations, summarize diagnostic and treatment strategies, and identify opportunities to optimize prevention.

METHODS

We conducted a literature review of published natural measles infections in SOT recipients ≤21 years of age, summarizing management and outcomes. We describe measles epidemiology, recommended diagnostics, treatment, and highlight prevention strategies.

RESULTS

There are seven published reports of measles infection in 12 pediatric SOT recipients, the majority of whom were unvaccinated or incompletely vaccinated. Subjects had atypical or severe clinical presentations, including lack of rash and complications, most frequently with encephalitis and pneumonitis, resulting in 33% mortality. Updated recommendations on testing and vaccination are provided. Treatment options beyond supportive care and vitamin A are limited, with no approved antivirals.

CONCLUSION

While measles is infrequently reported in pediatric SOT recipients, morbidity and mortality remain significant. A high index of suspicion is warranted in susceptible SOT recipients with clinically compatible illness or exposure. Providers must recognize this risk, educate families, and be aware of both classic and atypical presentations of measles to rapidly identify, isolate, and diagnose measles in pediatric SOT recipients. Continued efforts to optimize measles vaccination both pre- and post-SOT are warranted.

A Re-emergence of Subacute Sclerosing Panencephalitis in the United Kingdom

New pediatric and adult subacute sclerosing panencephalitis cases between 1996 and 2020 were reported based on an established UK registry with no evidence of under-ascertainment using a separate pediatric surveillance system. After 15 years with no pediatric UK-acquired cases, 3 cases arose from 2017 after increased measles. Modeling suggested this was in line with measles notifications, underreporting of laboratory-confirmed measles or increased subacute sclerosing panencephalitis risk.

Diagnostic reference value of antibody levels measured using enzyme immunoassay for subacute sclerosing panencephalitis

High measles-specific antibody titers in the cerebrospinal fluid (CSF) have important diagnostic significance for subacute sclerosing panencephalitis (SSPE), a progressive neurological disorder caused by measles virus variants. However, the diagnostic reference value of antibody levels and the usefulness of the CSF/serum ratio measured using enzyme immunoassays (EIAs) for SSPE diagnosis remain unclear. To facilitate SSPE diagnosis using EIAs, measles immunoglobulin G (IgG) titers in the CSF and serum of patients with and without SSPE were measured and their CSF/serum antibody ratios evaluated. Serum and CSF antibody levels were compared among three patients with SSPE (59 paired samples), 37 non-SSPE patients, and 2618 patients of unknown backgrounds. Of the 59 paired samples from three patients with SSPE, 56 paired samples (94.9%) showed CSF measles IgG levels ≥0.5 IU/mL and a CSF/serum ratio ≥0.05, whereas non-SSPE cases showed CSF measles IgG levels <0.1 IU/mL and a CSF/serum ratio <0.03. Of the 2618 CSF samples with unknown backgrounds, 951 showed measurable IgG levels with EIA, with a CSF/serum ratio peak of 0.005-0.02, with a 90th percentile of 0.05. Assuming the SSPE criteria as CSF measles IgG ≥0.5 IU/mL and a CSF/serum ratio ≥0.05, only 20 samples (0.8%) with unknown backgrounds were categorized as having SSPE. Conversely, assuming the non-SSPE criteria as CSF measles IgG <0.1 IU/mL and a CSF/serum ratio <0.03, 2403 samples (92%) with unknown backgrounds were categorized as not having SSPE. In conclusion, high CSF/serum ratios (≥0.05) and high measles CSF IgG levels (≥0.5 IU/mL) may be useful for diagnosing SSPE.

Spectrum of Movement Disorders Among Children With Subacute Sclerosing Panencephalitis: A Cross-Sectional Study

Background: Subacute sclerosing panencephalitis is a progressive devastating condition due to persistence of mutant measles virus, affecting children and adolescents, characterised by myoclonus, seizures, and neuropsychiatric issues. Movement disorders apart from myoclonus are reportedly uncommon. We aimed to describe frequency and proportion of movement disorders among children with subacute sclerosing panencephalitis, hypothesizing that these occur more frequently than previously reported. Methods: In this cross-sectional study, we enrolled children with subacute sclerosing panencephalitis between 1 month and 18 years of age who fulfilled the diagnosis of subacute sclerosing panencephalitis as per modified Dyken criteria, and examined them for movement disorders. We also assessed their clinical profile and disease severity via Jabbour staging and modified Rankin Scale score. We compared demographic, clinical, and laboratory features of children with and without movement disorders. Results: We enrolled 50 children (36 males; 72%) (age range 1.5-14 years). Of these, 28 (56%) had movement disorders. Among movement disorders, the most frequent was myoclonus (92%), followed by ataxia (9; 18%), chorea-athetosis (7; 14%), dystonia (6; 12%), tremor (4; 8%), repetitive behavior (4; 8%), and parkinsonism (3; 6%). Movement disorders were the presenting feature of subacute sclerosing panencephalitis among 7 children. There were no significant differences in clinical or laboratory features among children with and without movement disorders. Conclusions: Movement disorders were frequent in subacute sclerosing panencephalitis. Hyperkinetic disorders were dominant. Dystonia and chorea-athetosis occurred more commonly among nonmyoclonus movement disorders. Movement disorders may manifest even in earlier stages of subacute sclerosing panencephalitis and may be the heralding feature. Recognition of these features is important to plan management and reduce morbidity.