Acute disseminated encephalomyelitis: a follow-up study in Taiwan

Rapid Progressive Fatal Acute Hemorrhagic Encephalomyelitis

Acute hemorrhagic encephalomyelitis (AHEM) is the most severe form of acute disseminated encephalomyelitis (ADEM). Patients with AHEM usually have unfavorable outcomes with high mortality rate. We reported a middle-aged male, who was diagnosed with AHEM and died 35 days after admission even under intensive immune therapy. Clinical courses were recorded and serial MR images were demonstrated to illustrate the rapidly changes in brain parenchyma. By highlighting these aspects, we hope to provide valuable insights for future studies and potential advancements in the management of AHEM.

An Adult Case of Adenovirus-Associated Acute Disseminated Encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an autoimmune neurological disease that predominately affects pediatric population. Only a single fatal adult case of adenovirus-associated ADEM has previously been published by Qamar et al. in 2021. Here, we present an adult case of adenovirus-associated ADEM, which was diagnosed early in her clinical course. The patient was treated with the prompt initiation of steroids, intravenous immune globulin (IVIG), and plasmapheresis (PLEX), and the patient recovered fully. This case highlights the importance of early accurate diagnosis for other clinicians to treat adenovirus-associated ADEM in a timely fashion to prevent a potentially fatal outcome.

Levamisole-associated multifocal inflammatory encephalopathy: clinical and MRI characteristics, and diagnostic algorithm

Levamisole-associated multifocal inflammatory encephalopathy (LAMIE) is a devastating adverse effect of levamisole (LEV) treatment. In Russia, people often use LEV without a doctor's prescription for anthelmintic prophylaxis. LAMIE often misdiagnosed as the first episode of MS or acute disseminated encephalomyelitis (ADEM). The aim of our study was to describe clinical, laboratory and morphological characteristics of LAMIE, magnetic resonance imaging (MRI) patterns and create an algorithm for the differential diagnosis. This study was a prospective observational study with retrospective analysis of cases. It was performed at two hospitals with ambulatory service for MS. We included 43 patients with LAMIE with follow-up was from 1 year to 5 years. Age was 19-68 y.o. with female predominance. The most typical manifestations of LAMIE were cerebellar, pyramidal and cognitive symptoms, and majority of patients had biphasic course of the disease. Three main types of MRI patterns were described: ADEM-like, MS-like, atypical demyelination. About 40% of patients had CSF specific oligoclonal bands synthesis, but only 20 % of them converted to MS during the period from 1 month until 2 years. The CSF albumin levels and immunoglobulin G index were elevated in LAMIE patients compared to reference values. We described results of brain biopsy in two cases. Therefore LAMIE should be considered in patients with demyelinating or inflammatory conditions with biphasic onset of the disease and variable MRI presentation.

Clinical Presentation and Outcomes of Acute Disseminated Encephalomyelitis in Adults Worldwide: Systematic Review and Meta-Analysis

Background

Acute disseminated encephalomyelitis (ADEM) is a rare demyelinating disorder that is often misdiagnosed. To improve early diagnosis, we performed a systematic review and meta-analysis of clinical features, outcomes for ADEM in adults.

Methods

The PubMed, Embase, Web of Science and Cochrane Library databases were searched for studies reporting the clinical features of adults with ADEM between January 1990 and May 2021. A random-effects meta-analysis model was used to pool data on clinical features and functional outcomes.

Results

Twelve studies examining 437 adults with ADEM met the inclusion criteria. Overall, the clinical features and diagnostic findings observed in more than two-thirds of the patients were white matter lesions [87.1%, 95% confidence interval (CI)=75-95.6], polyfocal onset (80.5%, 95% CI=50.5-98.9) and pyramidal signs (68.7%, 95% CI =40.0-91.9). The mortality rate was 7.8% (95% CI = 3.3–13.5), and the risk of residual deficits was 47.5% (95% CI = 31.8–63.4).

Conclusions

Adults with ADEM had worse outcomes than children. Clinicians should maintain high clinical suspicion for patients presenting with certain clinical features and diagnostic findings.

Acute disseminated encephalomyelitis following vaccination against SARS-CoV-2: A case report

Acute disseminated encephalomyelitis (ADEM) is an inflammatory emyelinating disease of the central nervous system that is usually considered a monophasic disease Post-vaccination ADEM has been associated with several vaccines, however, there is scarce information related to SARS-CoV-2 vaccines. We present the case of a 26- year-old female who suffered from ADEM four weeks after Gam-COVID-Vac administration.

Acute Disseminated Encephalomyelitis and Acute Hemorrhagic Leukoencephalitis Following COVID-19: Systematic Review and Meta-synthesis

BACKGROUND AND OBJECTIVES

Since the onset of the COVID-19 pandemic, a growing number of reports have described cases of acute disseminated encephalomyelitis (ADEM) and acute hemorrhagic leukoencephalitis (AHLE) following infection with COVID-19. Given their relatively rare occurrence, the primary objective of this systematic review was to synthesize their clinical features, response to treatments, and clinical outcomes to better understand the nature of this neurologic consequence of COVID-19 infection.

METHODS

Patients with a history of COVID-19 infection were included if their reports provided adequate detail to confirm a diagnosis of ADEM or AHLE by virtue of clinical features, radiographic abnormalities, and histopathologic findings. Cases purported to be secondary to vaccination against COVID-19 or occurring in the context of a preexisting relapsing CNS demyelinating disease were excluded. Case reports and series were identified via PubMed on May 17, 2021, and 4 additional cases from the authors' hospital files supplemented the systematic review of the literature. Summary statistics were used to describe variables using a complete case analysis approach.

RESULTS

Forty-six patients (28 men, median age 49.5 years, 1/3 >50 years old) were analyzed, derived from 26 case reports or series originating from 8 countries alongside 4 patient cases from the authors' hospital files. COVID-19 infection was laboratory confirmed in 91% of cases, and infection severity necessitated intensive care in 67%. ADEM occurred in 31 cases, whereas AHLE occurred in 15, with a median presenting nadir modified Rankin Scale score of 5 (bedridden). Anti-MOG seropositivity was rare (1/15 patients tested). Noninflammatory CSF was present in 30%. Hemorrhage on brain MRI was identified in 42%. Seventy percent received immunomodulatory treatments, most commonly steroids, IV immunoglobulins, or plasmapheresis. The final mRS score was ≥4 in 64% of patients with adequate follow-up information, including 32% who died.

DISCUSSION

In contrast to ADEM cases from the prepandemic era, reported post-COVID-19 ADEM and AHLE cases were often advanced in age at onset, experienced severe antecedent infection, displayed an unusually high rate of hemorrhage on neuroimaging, and routinely had poor neurologic outcomes, including a high mortality rate. Findings are limited by nonstandardized reporting of cases, truncated follow-up information, and presumed publication bias.

Acute disseminated encephalomyelitis: A retrospective study of 20 children in a pediatrics department in Tunisia

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disorder of the central nervous system. Little information is available about the clinical and neuroradiological profile or the follow-up of this disease in Tunisian children.

AIM

To determine the clinical, laboratory, and radiological features and the outcome of ADEM in children admitted to the pediatrics department of a university hospital in Tunisia.

METHODS

All children ≤ 18 years old presenting with ADEM and admitted to the tertiary referral center for pediatrics at Sahloul University Hospital from January 2000 to December 2020 were included in the study. The diagnosis of ADEM was confirmed according to the international pediatric multiple sclerosis study group criteria.

RESULTS

A total of 20 patients (13 girls and 7 boys) fulfilled the diagnostic criteria for ADEM. The mean age at diagnosis was 5.6 years. The clinical presentation included polyfocal neurological signs such as cranial hypertension (45%), seizures (35%), and motor weaknesses (55%). Pyramidal tract signs and cranial nerve palsies were noted in 55% of cases. Brain magnetic resonance imaging showed particular features, namely, a relapsing tumor-like form in one case, and optic neuritis and demyelinating lesions of the white matter in the brain and the spinal cord with gadolinium cerebral ring-like enhancement in another case. The treatment consisted of intravenous immunoglobulin in 16 cases (80%) and corticosteroid in 19 cases (95%). Plasmapheresis was used for one patient. Complete recovery was observed in 12 patients (60%); 19 patients (95%) had a monophasic course of the disease while only one patient developed multiphasic ADEM.

CONCLUSIONS

ADEM remains a difficult diagnosis in children. Nevertheless, after prompt diagnosis and adequate treatment, most children with ADEM have a favorable outcome with restitutio ad integrum.

COVID-19-Associated Acute Disseminated Encephalomyelitis: A Systematic Review

Objective:

The objective of this study was to provide an overview of acute disseminating encephalomyelitis, a potential and serious complication of COVID-19.

Methods:

Three primary databases were used, PubMed, LitCovid, and WHO. The final review articles reported acute disseminated encephalomyelitis (ADEM) in COVID-19-positive patients and were full-text, peer-reviewed articles. Articles which did not have patient data such as in vitro studies and articles with unclear inference were excluded.

Results:

Out of 21 cases of ADEM, the diagnosis of severe acute respiratory syndrome-coronavirus 2 was confirmed in 18 and suspected in 3. Among the neurological symptoms, altered consciousness was most common (7/21), followed by anosmia (3), paraplegia (3/21), brain stem involvement (3/21), sphincter involvement (2/21), and quadriplegia (1/21). Raised inflammatory markers were most commonly seen in 9/17. Central nervous system imaging was abnormal in 19 cases and unavailable in 2 cases. Fifteen patients were treated with corticosteroids, 11 patients received intravenous immunoglobulin, while 3 patients received convalescent plasma. Two patients needed surgical intervention. Complications included seizures (1), acute kidney injury and septicemic shock (1), raised intracranial pressure (1), and supraventricular tachycardia secondary to hydroxychloroquine (1). One patient recovered completely and one had good recovery with mild deficits. Thirteen patients had incomplete recovery with residual neurological deficit while three patients died as the consequence of the disease.

Conclusion:

The physicians and neurosurgeons should be diligent while treating the COVID-19 patients with neurological manifestations and include ADEM as a differential diagnosis and stress on early diagnosis and treatment to reduce mortality and achieve satisfactory clinical outcome.

Update on Acute Disseminated Encephalomyelitis in Children and Adolescents

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated, inflammatory demyelinating disease of the central nervous system (CNS) that usually affects children and young adults after an infection or vaccination. The presence of several conditions mimicking ADEM, added to the lack of specific biomarkers, makes diagnosis potentially hard. Prompt diagnosis is necessary to start adequate treatment to improve the clinical course and long-term outcome. Because of its heterogeneity in both clinical presentation and course, challenges remain in establishing the most appropriate therapeutic approach in each patient. The aim of this review is to provide an update on management of this disease with a focus on acute treatment and to give suggestions for future research. We showed that there are currently no guidelines that help clinicians manage ADEM and therapeutic decisions are often made on a case-by-case basis. Further studies are necessary to identify clinical, laboratory, and instrumental criteria that could be correlated with outcomes and guide clinicians in choosing when and what treatment should be given in each case.

Spinal Cord Involvement in MS and Other Demyelinating Diseases

Diagnostic accuracy is poor in demyelinating myelopathies, and therefore a challenge for neurologists in daily practice, mainly because of the multiple underlying pathophysiologic mechanisms involved in each subtype. A systematic diagnostic approach combining data from the clinical setting and presentation with magnetic resonance imaging (MRI) lesion patterns, cerebrospinal fluid (CSF) findings, and autoantibody markers can help to better distinguish between subtypes. In this review, we describe spinal cord involvement, and summarize clinical findings, MRI and diagnostic characteristics, as well as treatment options and prognostic implications in different demyelinating disorders including: multiple sclerosis (MS), neuromyelitis optica spectrum disorder, acute disseminated encephalomyelitis, anti-myelin oligodendrocyte glycoprotein antibody-associated disease, and glial fibrillary acidic protein IgG-associated disease. Thorough understanding of individual case etiology is crucial, not only to provide valuable prognostic information on whether the disorder is likely to relapse, but also to make therapeutic decision-making easier and reduce treatment failures which may lead to new relapses and long-term disability. Identifying patients with monophasic disease who may only require acute management, symptomatic treatment, and subsequent rehabilitation, rather than immunosuppression, is also important.

Imagerie de l'encéphalomyélite aiguë disséminée: étude de 22 cas

L'Encéphalomyélite aiguë disséminée (ADEM) est une cause rare d'encéphalite de l'adulte, caractérisée par des lésions inflammatoires de la substance blanche du système nerveux central (SNC). Le tableau clinique initial peut mimer un tableau sévère d'infection du SNC avec fièvre, encéphalopathie, crises convulsives, ou un tableau de sclérose en plaque. Le but de notre travail est de rapporter les caractéristiques épidémiologiques, cliniques, radiologiques, thérapeutiques et évolutives de l'ADEM, aussi évaluer l'apport des séquences IRM dans le diagnostic, le suivi et le pronostic de la maladie. Il s'agit d'une étude rétrospective des dossiers cliniques et radiologiques d'ADEM sur 11 ans (janvier 2006-janvier 2017) portant sur 22 cas suivis au service de neurologie et explorés au niveau du service d'imagerie médicale de l'Hôpital Militaire d'Instruction Mohammed V de Rabat. L'âge moyen des patients était de 35 ans [12-57ans]. Une notion d'infection récente était retrouvée dans 31%, une vaccination récente dans 4%. La symptomatologie était dominée par un déficit neurologique focal avec un pourcentage de 72%. La TDM était normale dans 78%. L'IRM a montré un hyper signal FLAIR de la SB sus et sous tentoriel dans 70%, sans restriction de la diffusion dans la totalité des cas, avec rehaussement des lésions dans 27%, l'atteinte de la moelle cervicale estimait à 68%. L'évolution clinique et radiologique était favorable dans la totalité des cas.

Epidemiological, Clinical, and Laboratory Characteristics of Acute Disseminated Encephalomyelitis in Children: A Retrospective Study

OBJECTIVES

We aimed to study the precipitating factors, demographic data, clinical and radiological manifestations, electroencephalography and laboratory findings, as well as association with infections, immunization and incidence of relapse of acute disseminated encephalomyelitis (ADEM) in children admitted to Mofid Children Hospital, Tehran, Iran from Mar 2013 to Mar 2016.

MATERIALS & METHODS

A 3-yr retrospective review of 29 children with definite final diagnosis of ADEM in Mofid Hospital in Tehran, Iran was performed. The diagnosis was based on specified criteria, including a presumed acute demyelinating process with no history of unexplained neurological symptoms and at least one demyelinating lesion shown on magnetic resonance imaging without evidence of previous destructive white matter lesions.

RESULTS

Overall, 29 children diagnosed as ADEM were studied in terms of demographic characteristics, clinical manifestations and laboratory findings in two groups according to their recurrence. The mean age of the patients with recurrence was less than those without it were. It was more common in females but the difference was not statistically meaningful. There was no relationship between the season of the first episode of the disease and the recurrence incidence. Moreover, the relationship between viral infections and recurrence was statistically non-meaningful. No relationship between the recurrence of ADEM and clinical manifestations, radiological and laboratory findings was found.

CONCLUSION

The reason for high rate of recurrence in our patients may be related to the younger age of children in our study.

A Simplified Approach to Encephalitis and Its Mimics: Key Clinical Decision Points in the Setting of Specific Imaging Abnormalities

RATIONALE AND OBJECTIVES

Infectious encephalitis is a relatively common cause of morbidity and mortality. Treatment of infectious encephalitis with antiviral medication can be highly effective when administered promptly. Clinical mimics of encephalitis arise from a broad range of pathologic processes, including toxic, metabolic, neoplastic, autoimmune, and cardiovascular etiologies. These mimics need to be rapidly differentiated from infectious encephalitis to appropriately manage the correct etiology; however, the many overlapping signs of these various entities present a challenge to accurate diagnosis. A systematic approach that considers both the clinical manifestations and the imaging findings of infectious encephalitis and its mimics can contribute to more accurate and timely diagnosis.

MATERIALS AND METHODS

Following an institutional review board approval, a health insurance portability and accountability act (HIPAA)-compliant search of our institutional imaging database (teaching files) was conducted to generate a list of adult and pediatric patients who presented between January 1, 1995 and October 10, 2013 for imaging to evaluate possible cases of encephalitis. Pertinent medical records, including clinical notes as well as surgical and pathology reports, were reviewed and correlated with imaging findings. Clinical and imaging findings were combined to generate useful flowcharts designed to assist in distinguishing infectious encephalitis from its mimics. Key imaging features were reviewed and were placed in the context of the provided flowcharts.

RESULTS

Four flowcharts were presented based on the primary anatomic site of imaging abnormality: group 1: temporal lobe; group 2: cerebral cortex; group 3: deep gray matter; and group 4: white matter. An approach that combines features on clinical presentation was then detailed. Imaging examples were used to demonstrate similarities and key differences.

CONCLUSIONS

Early recognition of infectious encephalitis is critical, but can be quite complex due to diverse pathologies and overlapping features. Synthesis of both the clinical and imaging features of infectious encephalitis and its mimics is critical to a timely and accurate diagnosis. The use of the flowcharts presented in this article can further enable both clinicians and radiologists to more confidently differentiate encephalitis from its mimics and improve patient care.

An Acute Disseminated Encephalomyelitis-Like Illness in the Elderly: Neuroimaging and Neuropathology Findings

INTRODUCTION

Acute disseminated encephalomyelitis (ADEM) is a rare demyelinating disease of the central nervous system (CNS) that classically occurs in children and adolescents. It characteristically presents with acute inflammation, resulting in demyelination, often following an infectious disease. ADEM has been described in adult patients, but the incidence in the adult and especially elderly population is low.

CASES

We describe five older adults (age 57 to 85) who presented with acute neurological symptoms. Three patients presented with an infectious illness preceding the event, 4 patients were encephalopathic, and oligoclonal bands (OCBs) were negative in all tested cases. The clinical scenario and imaging studies suggested alternative diagnoses, such as metastasis, primary CNS tumor, or stroke. Two patients had contrast enhancing lesions, two other patients had lesions with restricted diffusion on diffusion-weighted imaging. Neuropathologic diagnostic from biopsy or autopsy was eventually conclusive, showing perivascular zones of myelin loss with relative axonal sparing in all five cases.

CONCLUSION

Each of these patients was found to have pathological findings of acute demyelination on tissue diagnosis, suggesting ADEM or ADEM-like disease. The initial presentation and imaging was pointing toward other diagnoses. Broad differential diagnosis is important, especially for older patients, and pathological proof might be warranted for a conclusive diagnosis.

[Acute disseminated encephalomyelitis in children]

L'encéphalomyélite aiguë disséminée (ADEM) est une maladie inflammatoire, démyélinisante, multifocale intéressant principalement la substance blanche du système nerveux central. Elle est rare mais non exceptionnelle chez l'enfant. Les auteurs rapportent une étude colligeant 9 cas d'ADEM pris en charge au service de Pédiatrie du CHU Hassan II à Fès, sur une période de 4 ans. Il s'agit de cinq garçons et quatre filles; âgés entre 2 ans et 13 ans. Les antécédents (ATCD) d'infection virale sont notés chez quatre patients. La fièvre est constante. Les convulsions sont présentes dans cinq cas et les troubles de conscience dans cinq cas. L'examen neurologique était anormal. L’étude de liquide céphalo-rachidien a révélé une réaction méningée. On ne notait pas de syndrome inflammatoire biologique. L'imagerie par résonance magnétique (IRM) cérébrale a objectivé des lésions en hyper-signal en T2 et T2 FLAIR chez tous les patients. Pour le traitement, des bolus de corticoïdes intraveineux ont été administrés, relayés par une corticothérapie orale et associés à une kinésithérapie motrice et un traitement antiépileptique pour certains patients. L’évolution de nos malades était favorable globalement et on a déploré le décès d'une patiente. L'ADEM est une affection rare du système nerveux central. Les critères diagnostiques sont fondés sur des éléments cliniques et des données d'imagerie. La prise en charge doit être précoce et multidisciplinaire.

Treatment of acute disseminated encephalomyelitis

OPINION STATEMENT

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease, characterized by an acute onset of polyfocal central nervous system (CNS) deficits, including encephalopathy, demonstrating multifocal lesions on MRI. ADEM is typically a monophasic disorder, but recurrent and multiphasic courses have been described. Furthermore, an ADEM presentation has been reported in neuromyelitis optica (NMO) and multiple sclerosis (MS), particularly in younger children. CNS infections, other autoimmune diseases, and neurometabolic disorders may mimic ADEM at manifestation. There is no single test confirming the diagnosis of ADEM, and diagnosis is based upon a combination of clinical and radiologic features and exclusion of diseases that resemble ADEM. Therefore, a broad workup including infectious, immunologic, and metabolic tests, as well as a systematic follow-up including MRI, is indicated to establish an accurate diagnosis as a prerequisite for an optimized treatment approach. There is a lack of evidence-based, prospective clinical trial data for the management of ADEM. Empiric antibacterial and antiviral treatment is standard of care until an infectious disease process is ruled out. Based on the presumed autoimmune etiology of ADEM, the common treatment approach consists of intravenous methylprednisolone at a dosage of 20 to 30 mg/kg per day (maximum 1 g/day) for 3 to 5 days, followed by an oral corticosteroid taper of 4 to 6 weeks. In case of insufficient response or contraindications to corticosteroids, intravenous immunoglobulin G (IVIG) at a dosage of 2 g/kg divided over 2 to 5 days is a therapeutic option. For severe or life-threatening cases of ADEM, plasmapheresis should be considered early in the disease course. Decompressive craniectomy has been reported as a life-saving measure for ADEM patients with intracranial hypertension. There is a lack of specific recommendations for the long-term management of recurrent and multiphasic ADEM. In children with relapsing demyelinating events, the diagnosis of a chronic autoimmune CNS disease like MS or NMO should be considered.

Biologically plausible and evidence-based risk intervals in immunization safety research

In immunization safety research, individuals are considered at risk for the development of certain adverse events following immunization (AEFI) within a specific period of time referred to as the risk interval. These intervals should ideally be determined based on biologic plausibility considering features of the AEFI, presumed or known pathologic mechanism, and the vaccine. Misspecification of the length and timing of these intervals may result in introducing bias in epidemiologic and clinical studies of immunization safety. To date, little work has been done to formally assess and determine biologically plausible and evidence-based risk intervals in immunization safety research. In this report, we present a systematic process to define biologically plausible and evidence-based risk interval estimates for two specific AEFIs, febrile seizures and acute disseminated encephalomyelitis. In addition, we review methodologic issues related to the determination of risk intervals for consideration in future studies of immunization safety.

Acute disseminated encephalomyelitis and its place amongst other acute inflammatory demyelinating CNS disorders

The diagnosis of acute inflammatory demyelinating CNS conditions is complex and this is reflected in variations in how cohorts are defined across studies. For some conditions the diagnosis relies on whether it is monophasic or relapsing, in others the anatomical site of inflammation is used as a means of categorisation. Clinical features such as precipitants, gender and age may affect the probability of certain diagnoses, but are not highly accurate. Exclusive features for the pathology are identifiable for some but not all conditions, and are seldom available during life. Specific markers such as antibodies are informative and new developments in this area are likely in the near future. This review outlines the features and classification of acute disseminated encephalomyelitis and contrasts it with other related conditions before attempting to define a pragmatic organisation of these conditions based upon present evidence.

Acute disseminated encephalomyelitis that meets modified McDonald criteria for dissemination in space is associated with a high probability of conversion to multiple sclerosis in Taiwanese patients

BACKGROUND

Patients with acute disseminated encephalomyelitis (ADEM) may relapse and some may ultimately convert to multiple sclerosis (MS); however, no criteria that can predict MS conversion are available to date. Our aim was to describe the clinical and magnetic resonance imaging (MRI) features of patients with an initial ADEM attack and evaluate which MRI criteria can predict conversion to MS.

METHODS

We retrospectively reviewed the records of 36 patients diagnosed with ADEM. We determined clinical signs/symptoms, examined the cerebrospinal fluid (CSF), and performed brain MRI scans and compared the findings between patients who did and did not convert to MS.

RESULTS

Clinical signs/symptoms, and CSF analysis show no significant difference between the two groups. The rate of conversion to MS from ADEM in Taiwanese patients is low (11%) after a mean follow-up period of 28.36 months. Modified McDonald criteria were fulfilled in 19/36 patients: 21% (4/19) of those patients developed MS according to Poser criteria subsequently. Of the other patients (17/36) who did not fulfill these criteria, none converted to MS. (log rank test; P=0.027).

CONCLUSIONS

It is difficult to predict from initial clinical presentations to address which patients with ADEM will convert to MS. Patients with ADEM whose brain MRI findings met the modified McDonald criteria may have clinically isolated syndrome because they have a significantly higher probability of conversion to MS. In contrast, patients whose brain MRI findings did not meeting these criteria may be considered as having classic ADEM because they have a lower probability of conversion to MS.

Disease course and outcome of acute disseminated encephalomyelitis is more severe in adults than in children

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) affects children more frequently than adults. Current studies investigating ADEM in different age groups are difficult to compare.

OBJECTIVE

To investigate whether the clinical presentation, outcome and disease course of ADEM differ between adults and children.

METHODS

Disease characteristics of 25 adults and 92 children suffering from ADEM between 1988 and 2008 were compared.

RESULTS

The most common presenting symptoms of ADEM in both groups were pyramidal signs and encephalopathy. Ataxia occurred more frequently in children (p  = 0.002). In general, MRI showed ill-defined and large white matter lesions in both groups, whereas periventricular lesions were more prevalent in adults (p = 0.001). In adults, duration of hospitalization was longer (p = 0.002) and intensive care unit (ICU) admission was more frequently required (p = 0.043). Three adults (12%) and one child (1%) died (p = 0.030). Fewer adults had complete motor recovery after their first clinical event (p < 0.001). In 73 patients follow-up time was ≥ 2 years and most of these patients remained monophasic. Although relapses after ADEM can occur, only one adult (5%) and five children (6%) converted to MS.

CONCLUSIONS

The clinical presentations in children and adults share similarities, but the disease course and outcome of ADEM is more severe in adults with respect to hospitalization, ICU admission, recovery and mortality.

Clinical study of childhood acute disseminated encephalomyelitis, multiple sclerosis, and acute transverse myelitis in Fukuoka Prefecture, Japan

Acute disseminated encephalomyelitis (ADEM) has recently been studied in several countries owing to the development and wide spread use of imaging technology, but few epidemiological studies of childhood ADEM have been undertaken in Asian countries. To perform a comprehensive survey of ADEM and related diseases in Japanese children, we conducted a multicenter, population-based study on childhood ADEM, multiple sclerosis, and acute isolated transverse myelitis in Fukuoka Prefecture, Japan. We identified 26 children with ADEM, 8 with multiple sclerosis, and 4 with acute transverse myelitis during 5 years between September 1998 and August 2003. The incidence of childhood ADEM under the age of 15 years was 0.64 per 100,000 person-years, mean age at onset was 5.7 years, and male-female ratio was 2.3:1. The prevalence of childhood multiple sclerosis was 1.3 per 100,000 persons. The mean age at onset of multiple sclerosis, 9.3 years, was significantly higher than that of ADEM. Nineteen (73%) and four (15%) patients with ADEM experienced antecedent infectious illnesses and vaccinations, respectively, within 1 month before the onset. Clinical and radiological findings of ADEM revealed that the frequency of seizures, mean white blood cell counts in cerebrospinal fluid, and the frequency of subcortical lesions in Fukuoka study, seemed to be higher than those in previous non-Asian studies. These findings suggest that there are ethnic or geographical differences in the incidence and clinical features of ADEM, and that there might be potent genetic or environmental risk factors for ADEM distinct from those for multiple sclerosis.

Encefalomielite acuta disseminata

L’encefalomielite acuta disseminata (EMAD) è una malattia infiammatoria autoimmune che coinvolge il cervello e il midollo spinale. Descritta soprattutto nel bambino, generalmente fa seguito a un episodio infettivo o a una vaccinazione, ma può essere idiopatica. La sua presentazione clinica comprende un’encefalopatia acuta associata a segni e a sintomi neurologici multifocali. La sua diagnosi si basa sulla clinica e sulla risonanza magnetica, che rivela lesioni multifocali della sostanza bianca in ipersegnale T2 mal delimitate, della stessa età, che prendono il gadolinio e possono anche riguardare il talamo e i nuclei della base. Il liquor può mostrare un’iperlinfocitosi con iperproteinorrachia e, a volte, la presenza di bande oligoclonali transitorie. La sua prognosi è piuttosto favorevole, passato l’episodio monofasico, con un trattamento specifico. È quindi fondamentale escludere fino dall’inizio le sue molte diagnosi differenziali. Il trattamento dell’EMAD, di prima scelta, consiste in boli di corticosteroidi endovenosi a forti dosi. In caso di insuccesso bisogna ricorrere agli scambi plasmatici o alle immunoglobuline endovenose. Anche se, di solito, è monofasica, possono verificarsi altri episodi che fanno allora pensare a un’EMAD multifasica. Tuttavia, in alcuni casi queste nuove poussées sono una modalità di esordio di un’autentica sclerosi multipla.

Post-infectious encephalitis in adults: diagnosis and management

Many important central nervous system (CNS) syndromes can develop following microbial infections. The most severe forms of post-infectious encephalitis include acute disseminated encephalomyelitis (ADEM), acute hemorrhagic leukoencephalitis and Bickerstaff's brainstem encephalitis. ADEM is an inflammatory demyelinating disorder of the CNS. It typically follows a minor infection with a 2–30 days latency period and is thought to be immune-mediated. It is clinically characterized by the acute onset of focal neurological signs and encephalopathy. Patients can require intensive care unit admission because of coma, seizures or tetraplegia. Cerebrospinal fluid analysis usually shows lymphocytic pleocytosis but, unlike viral or bacterial encephalitis, no evidence of direct CNS infection is found. There are no biologic markers of the disease and cerebral magnetic resonance imaging is essential to diagnosis, detecting diffuse or multifocal asymmetrical lesions throughout the white matter on T2- and FLAIR-weighted sequences. High-dose intravenous steroids are accepted as first-line therapy and beneficial effects of plasma exchanges and intravenous immunoglobulins have also been reported. Outcome of ADEM is usually favorable but recurrent or multiphasic forms have been described.

Predicting the motor outcome of acute disseminated encephalomyelitis by apparent diffusion coefficient imaging: Two case reports

We present two cases of young adults with acute disseminated encephalomyelitis (ADEM) who developed severe conscious and motor disturbances. Despite their similar initial clinical course and MRI findings, their motor function outcomes were quite different. In both cases, fluid attenuated inversion recovery (FLAIR) sequenced MRI showed multiple symmetric hyperintense lesions in the internal capsule and the brainstem at the subacute stage. However, in case 1 the apparent diffusion coefficient (ADC) was pathologically decreased in the internal capsule, whereas the ADC for case 2 was normal. At the end of the examination period, severe motor disability (bedridden state) with brain atrophy apparent on MRI remained in case 1, whereas case 2 made an almost full recovery without brain atrophy. These two cases suggest that altered ADC in the internal capsules at the subacute stage may reflect a different pathogenesis between cytotoxic and vasogenic edema, and may be a valuable indicator for the prognosis of motor disturbance.

[Acute disseminated encephalomyelitis and severe post-infectious encephalitis]

L’encéphalomyélite aiguë disséminée, acute disseminated encephalomyelitis, (ADEM), est une maladie inflammatoire démyélinisante du système nerveux central (SNC). Également appelée encéphalite post-infectieuse, elle est liée à un mécanisme auto-immun et s’installe typiquement dans les suites d’une infection après un intervalle libre de deux à 30 jours. L’ADEM est caractérisée cliniquement par un tableau d’encéphalopathie aiguë avec signes neurologiques multifocaux. Les patients peuvent nécessiter une admission en réanimation du fait de troubles de la conscience, de crises convulsives ou d’une tétraplégie. L’analyse du liquide céphalorachidien peut montrer une méningite lymphocytaire, mais on ne retrouve pas d’infection évolutive du SNC. Il n’existe pas de marqueur spécifique de la maladie et l’imagerie par résonance magnétique cérébrale est essentielle au diagnostic, permettant de mettre en évidence des lésions multifocales de la substance blanche du SNC sur les séquences T2 et FLAIR. Le traitement de l’ADEM est basé sur les corticoïdes fortes doses, éventuellement associés aux immunoglobulines polyvalentes ou aux échanges plasmatiques. Le pronostic est généralement favorable sous traitement, des récurrences peuvent néanmoins survenir dans l’évolution.

Acute disseminated encephalomyelitis: an acute hit against the brain

PURPOSE OF REVIEW

In this review, the possible etiology, clinical characteristics, diagnosis, and treatment of acute disseminated encephalomyelitis (ADEM) are discussed. ADEM is a para- or postinfectious autoimmune demyelinating disease of the central nervous system and has been considered a monophasic disease. The highest incidence of ADEM is observed during childhood.

RECENT FINDINGS

Over the last decade, many cases of multiphasic ADEM have been reported. The occurrence of relapses potentially poses a diagnostic dilemma for the treating physician, as it may be difficult to distinguish multiphasic ADEM from multiple sclerosis (MS). Many retrospective patient studies have thus focused on the clinical and paraclinical features of ADEM and have attempted to define specific diagnostic criteria. Additionally, several experimental models have provided insight with respect to the pathogenic relation of an infectious event and subsequent demyelinating autoimmunity.

SUMMARY

Capitalizing on experience based on a large body of well characterized patient data collected both cross-sectionally and longitudinally, pharmacotherapy has been improved and mortality and comorbidities due to ADEM have been reduced. Unfortunately, the pathogenic events that trigger the initial clinical attack, and possibly pave the way for ongoing relapsing disease, remain unknown. Clinically applicable diagnostic criteria are still lacking.