Long term MRI follow-up of patients with post infectious encephalomyelitis: evidence for a monophasic disease

Monkeypox-Associated Central Nervous System Disease: A Case Series and Review

OBJECTIVE

Monkeypox virus (MPXV) disease has been declared a public health emergency by the World Health Organization, creating an urgent need for neurologists to be able to recognize, diagnosis, and treat MPXV-associated neurologic disease.

METHODS

Three cases of MPXV-associated central nervous system (CNS) disease occurring during the 2022 outbreak, and their associated imaging findings are presented, with 2 cases previously published in a limited capacity in a public health bulletin.

RESULTS

Three previously healthy immunocompetent gay men in their 30s developed a febrile illness followed by progressive neurologic symptoms with presence of a vesiculopustular rash. MPXV nucleic acid was detected by polymerase chain reaction (PCR) from skin lesions of 2 patients, with the third patient having indeterminate testing but an epidemiologic link to a confirmed MPXV disease case. Cerebrospinal fluid demonstrated a lymphocytic pleocytosis, elevated protein, and negative MPXV-specific PCR. In 2 patients, magnetic resonance imaging of the brain and spine demonstrated partially enhancing, longitudinally extensive central spinal cord lesions with multifocal subcortical, basal ganglia, thalamic, cerebellar, and/or brainstem lesions. The third patient had thalamic and basal ganglia lesions. All patients received 14 days of tecovirimat, and 2 patients also received multiple forms of immunotherapy, including intravenous immunoglobulin, pulsed high-dose steroids, plasmapheresis, and/or rituximab. Good neurologic recovery was observed in all cases.

INTERPRETATION

MPXV can be associated with CNS disease. It is unclear whether this is from a parainfectious immune-mediated injury or direct CNS viral invasion. ANN NEUROL 2023.

Assessment and Management of Acute Disseminated Encephalomyelitis (ADEM) in the Pediatric Patient

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system that typically presents in childhood and is associated with encephalopathy and multifocal brain lesions. Although ADEM is thought to be a post-infectious disorder, the etiology is still poorly understood. ADEM is often a monophasic disorder, in contrast to other demyelinating disorders such as multiple sclerosis and neuromyelitis optica spectrum disorder. With increasing awareness, understanding, and testing for myelin oligodendrocyte glycoprotein antibodies, this disease is now known to be a cause of pediatric ADEM and also has the potential to be relapsing. Diagnostic evaluation for ADEM involves neuroimaging and laboratory studies to exclude potential infectious, inflammatory, neoplastic, and genetic mimics of ADEM. Acute treatment modalities include high-dose intravenous corticosteroids, therapeutic plasma exchange, and intravenous immunoglobulin. Long-term outcomes for ADEM are generally favorable, but some children have significant morbidity related to the severity of acute illness and/or manifest ongoing neurocognitive sequelae. Further research related to the optimal management of pediatric ADEM and its impact on prognosis is needed. This review summarizes the current knowledge of the pathogenesis, epidemiology, clinical features, diagnostic evaluation, treatment approaches, and outcomes in pediatric ADEM.

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.

A Case of Acute Disseminated Encephalomyelitis in a Middle-Aged Adult

Objectives. Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disorder that is often preceded by infection or recent vaccination. Encephalopathy and focal neurological deficits are usually manifest several weeks after a prodromal illness with rapidly progressive neurologic decline. ADEM is most commonly seen in children and young adults, in which prognosis is favorable, but very few cases have been reported of older adults with ADEM and thus their clinical course is unknown. Methods. Here we present a case of ADEM in a middle-aged adult that recovered well after treatment. Results. A 62-year-old man presented with encephalopathy and rapid neurological decline following a gastrointestinal illness. A brain MRI revealed extensive supratentorial white matter hyperintensities consistent with ADEM and thus he was started on high dose intravenous methylprednisolone. He underwent a brain biopsy showing widespread white matter inflammation secondary to demyelination. At discharge, his neurological exam had significantly improved with continued steroid treatment and four months later, he was able to perform his ADLs. Conclusions. This case of ADEM in a middle-aged adult represents an excellent response to high dose steroid treatment with a remarkable neurological recovery. Thus it behooves one to treat suspected cases of ADEM in an adult patient aggressively, as outcome can be favorable.

Pneumococcal-meningitis associated acute disseminated encephalomyelitis (ADEM) - case report of effective early immunotherapy

Introduction

Unvaccinated patients with history of splenectomy are prone to fulminant courses of Streptococcus pneumoniae-associated bacterial meningitis. Besides direct brain damage those patients may additionally suffer from parainfectious syndromes, notably vasculitis and acute disseminated encephalomyelitis (ADEM). Differentiation and treatment of these immunological reactions is challenging.

Methods

Case report.

Results

A 61 year-old woman with history of splenectomy without vaccination for S. pneumoniae presented with progressive headache and meningism. CSF-analysis revealed pleocytosis with microbiological evidence for pneumococcal meningitis. After unsuspicious initial cranial CT imaging and initiation of appropriate antibiotic therapy, MRI two days later showed widespread FLAIR- and T2-hyperintense white matter lesions that further progressed upon follow-up MRI and that fulfilled imaging criteria of ADEM. Meanwhile the patient deteriorated and required mechanical ventilation. Cranial angiography showed no signs of vasculitis or vasospasms. Screening for autoimmune diseases remained negative, however oligoclonal bands turned positive. Brain biopsy mainly revealed perivascular CD4+ T-cells and demyelinated areas. Despite ongoing acute meningitis, a 10-day corticosteroid-pulse was initiated followed by steroid-tapering. Within 4 weeks, clinical and MRI findings ameliorated. In an one-year follow-up visit, the patient significantly recovered, MRI lesions were markedly reduced and no further relapses occurred.

Conclusion

Acute pneumococcal meningitis in unvaccinated splenectomized patients may be complicated by a monophasic course of parainfectious ADEM that can be controlled with high-dose corticosteroids. Parainfectious vasculitis or cerebritis are important differential diagnoses and exact differentiation of these entities is important to initiate early appropriate immunotherapy.

MRI mimics of multiple sclerosis

Diagnosis of multiple sclerosis (MS) is based on the demonstration of dissemination of lesions in space (DIS) and in time (DIT), as well as on the exclusion of an alternative neurologic disorder. As a paraclinical tool brain and/or spinal cord magnetic resonance imaging (MRI), showing typical lesion morphology, characteristic distribution of lesions, or involvement or specific anatomic structures, can support the diagnosis of MS. But from an imaging perspective a considerable amount of inherited and acquired disorders may manifest with radiologic evidence of DIT, DIS, or both. Hypoxic-ischemic vasculopathy, specially small-vessel disease, inflammatory disorders, vasculitis, and non-MS idiopathic inflammatory disorders, as well as some toxic, metabolic, and infectious disorders, may present mimicking MS on MR examinations and should be included in the differential diagnosis of MS-like lesions. Careful evaluation of associated findings on MRI, the so-called MRI red flags, such as the presence of infarcts, microbleeds, meningeal enhancement, and calcifications among others, are very helpful in suggesting a diagnosis other than MS. Complement MRI findings to patient's history, demographics, and serologic findings are crucial to achieve the correct diagnosis. We will review the most frequent radiologic appearance and differential features from the most frequent MS mimickers.

A second case of Marburg’s variant of multiple sclerosis with vasculitis and extensive demyelination

Marburg’s variant of multiple sclerosis is a rapidly progressive and malignant form of multiple sclerosis (MS) that usually leads to severe disability or death within weeks to months without remission. Few cases have been described in the literature since the original description by Marburg. The classic pathological findings usually include highly destructive zones of extensive demyelination, necrosis with dense cellular infiltrate, and giant reactive astrocytes. We report a case of a 31-year-old woman with Marburg’s variant of MS who, over a period of eight months, became totally disabled, blind, and quadriplegic, with vocal cord paralysis, requiring a tracheostomy. The patient underwent diagnostic stereotactic brain biopsy. Clinical findings, magnetic resonance imaging (MRI), serologic and cerebrospinal fluid (CSF) findings, and neuropathology are discussed. MRI showed extensive white matter involvement in the brain and spinal cord that continuously progressed over time. A diagnostic stereotactic brain biopsy revealed extensive active demyelination with unexpected finding of active vasculitis and fibrinoid necrosis with a vascular inflammatory cell infiltrate, including polymorphonuclear neutrophils and rare eosinophils. Serologic work-up for vasculitis and neuromyelitis optica was unremarkable and the CSF showed only one oligoclonal band (OCB) not present in serum. This is the second case of Marburg’s variant of MS that demonstrated both demyelination and vasculitis. In our case these features were demonstrated simultaneously, even though the demyelination was the predominant pathological finding. Since vasculitis is not a feature of classic MS, these findings pose the question as to whether Marburg’s variant of MS is a true variant or different entity altogether.

Acute anterior uveitis and optic neuritis as ocular complications of influenza A infection in an 11-year-old boy

The authors describe an 11-year-old boy developing bilateral acute anterior uveitis, papillitis in one eye, and neuroretinitis in the other eye after an upper respiratory tract infection of influenza A virus, possibly H1N1. Steroid pulse therapy resolved these conditions. The authors recommend alertness for visual blurring and ocular inflammation after influenza A infection.

Diagnostic imaging in acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis is an idiopathic inflammatory demyelinating disease of the CNS that is particularly difficult to differentiate from the first episode of multiple sclerosis, so called clinically isolated syndrome. Currently, no diagnostic criteria exist that could reliably differentiate these two diseases. More importantly no single clinical, neuroimaging or cerebrospinal fluid feature defines a disorder with absolute certainty. This review will summarize clinical and paraclinical characteristics of acute disseminated encephalomyelitis in adults, with special emphasis on diagnostic imaging.

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.

The clinical spectrum and immunobiology of parainfectious neuromyelitis optica (Devic) syndromes

In a subgroup of patients with neuromyelitis optica (NMO), a severe inflammatory demyelinating disorder of autoimmune origin characterized by recurrent attacks of optic neuritis and longitudinally extensive transverse myelitis, a parainfectious pathogenesis may play a central role. We systematically evaluated such reports in the literature published between 1975 and 2009 in order to characterize parainfectious NMO syndromes. Identified were 25 cases, whereof 11 were in association with viral and 14 with bacterial pathogens. Sufficient clinical and paraclinical information was available in 16 patients (11 women). Median age was 8 years for children and 32 years for adults. Acute febrile illness preceding or in close relation with neurological symptoms was most common and the association with varicella-zoster virus and Mycobacterium pneumonia most frequent. In the majority, the course was monophasic (88%) and disability sustained (with complete recovery in only 25%). Seven patients fulfilled the revised NMO diagnosis criteria of 2006; none was seropositve for aquaporin-4 antibodies. Immune mechanisms potentially involved in parainfectious NMO syndromes include bystander activation, molecular mimicry, and the exacerbation of a pre-existing central nervous system (CNS) disorder by a systemic infection. However, current studies are not sufficient to define the place of parainfectious NMO syndromes within the spectrum of inflammatory disorders of the CNS.

[Acute disseminated encephalomyelitis]

Acute disseminated encephalomyelitis (ADEM) is an acute widespread autoimmune demyelinating condition, which principally affects the white matter of the brain and spinal cord. It usually follows an infection or vaccination. The typical presentation is that of multifocal neurologic disturbances accompanied by change in mental status. CSF analysis reveals lymphocytic pleocytosis and elevated protein content, but may also yield normal results. MRI is regarded as the diagnostic imaging modality of choice and typically demonstrates involvement of deep cerebral hemispheric and subcortical white matter as well as lesions in the basal ganglia, gray-white junction, diencephalon, brainstem, cerebellum and spinal cord. Unlike multiple sclerosis (MS), ADEM has a monophasic course and a favorable long-term prognosis.

A medical overview of encephalitis

Encephalitis is uncommon but is a neurological emergency which must be considered in a patient presenting with altered consciousness. Encephalitis is a diffuse inflammatory process of the brain parenchyma associated with evidence of brain dysfunction. The presentation of encephalitis can be acute or chronic. The aetiology of encephalitis can be broadly divided into two major subtypes. (1) Infection-related encephalitis which is a direct consequence of pathogenic viral, bacterial or parasitic agents. Herpes simplex virus (HSV) and varicella-zoster virus (VZV) are the most common cause of acute infectious encephalitis. (2) Autoimmune-mediated encephalitis which is mediated by an aberrant immune response. This can be triggered by a recent viral infection or vaccination. An example of this would be acute disseminated encephalitis (ADEM). This article will focus on the medical management of acute encephalitis. This will involve an extensive overview of the literature reviewing the diagnosis, investigation and treatment of acute viral encephalitis, ADEM and acute haemorrhagic leukoencephalopathy (AHLE). Encephalitis can also present chronically, and some of the different types of chronic encephalitis will be discussed.

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.

Idiopathic inflammatory-demyelinating diseases of the central nervous system

Idiopathic inflammatory-demyelinating diseases (IIDDs) include a broad spectrum of central nervous system disorders that can usually be differentiated on the basis of clinical, imaging, laboratory and pathological findings. However, there can be a considerable overlap between at least some of these disorders, leading to misdiagnoses or diagnostic uncertainty. The relapsing-remitting and secondary progressive forms of multiple sclerosis (MS) are the most common IIDDs. Other MS phenotypes include those with a progressive course from onset (primary progressive and progressive relapsing) or with a benign course continuing for years after onset (benign MS). Uncommon forms of IIDDs can be classified clinically into: (1) fulminant or acute IIDDs, such as the Marburg variant of MS, Baló's concentric sclerosis, Schilder's disease, and acute disseminated encephalomyelitis; (2) monosymptomatic IIDDs, such as those involving the spinal cord (transverse myelitis), optic nerve (optic neuritis) or brainstem and cerebellum; and (3) IIDDs with a restricted topographical distribution, including Devic's neuromyelitis optica, recurrent optic neuritis and relapsing transverse myelitis. Other forms of IIDD, which are classified clinically and radiologically as pseudotumoral, can have different forms of presentation and clinical courses. Although some of these uncommon IIDDs are variants of MS, others probably correspond to different entities. MR imaging of the brain and spine is the imaging technique of choice for diagnosing these disorders, and together with the clinical and laboratory findings can accurately classify them. Precise classification of these disorders may have relevant prognostic and treatment implications, and might be helpful in distinguishing them from tumoral or infectious lesions, avoiding unnecessary aggressive diagnostic or therapeutic procedures.

MRI and the diagnosis of multiple sclerosis: expanding the concept of "no better explanation"

Although the diagnosis of multiple sclerosis relies on the demonstration of disease dissemination in space and time, the exclusion of other neurological disorders is also essential. The limited specificity of abnormalities disclosed by MRI may increase the likelihood of diagnosis of multiple sclerosis in patients affected by other disorders. The available criteria for diagnosis of multiple sclerosis have not taken advantage of the potential of MRI to detect features "not suggestive" of multiple sclerosis. Recognition of such features in the work-up of patients suspected of having multiple sclerosis may reduce the likelihood of a false positive diagnosis of the disorder in some, while suggesting the correct alternative diagnosis in other patients. On the basis of this, a workshop of the European MAGNIMS (Magnetic Resonance Network in Multiple Sclerosis) was held to define a series of MRI red flags in the setting of clinically suspected multiple sclerosis that is derived from evidence-based findings and educated guesses. The presence of such red flags should alert clinicians to reconsider the differential diagnosis more extensively. In this review we will report on the conclusions of this international consensus, which should represent a first step beyond the concept of "no better explanation", and inform future diagnostic criteria for multiple sclerosis.

Acute disseminated encephalomyelitis or multiple sclerosis: can the initial presentation help in establishing a correct diagnosis?

The differential diagnosis of CNS white matter disease is broad, and can be divided into vascular, metabolic, infective, or inflammatory aetiologies. Isolated inflammatory disorders of the CNS are often associated with demyelination, and the two terms (inflammatory and demyelinating) are often used in conjunction. When the disease is monophasic, the term acute disseminated encephalomyelitis (ADEM) is used. ADEM typically occurs as a post-infectious phenomenon, and by definition, must be an isolated (monophasic) episode. If a relapse occurs shortly after the ADEM presentation in association with a further infection or steroid withdrawal, the term MDEM (multiphasic disseminated encephalomyelitis) is used. When there are relapses or progressive disease, the term multiple sclerosis (MS) is used (for full recommended diagnostic criteria for multiple sclerosis refer to McDonald and colleagues).

Viral diseases of the central nervous system

Viral diseases of the central nervous system encompass a wide range of different processes, mainly inflammation affecting the brain (encephalitis), the meninges (meningitis), or a combined meningoencephalitis. The spinal cord can be affected as well (myelitis). Another group of viral-related disorders, sometimes without a clear pathophysiological mechanism disclosed, include post-viral illnesses. All of these groups of diseases are discussed in this article, with an emphasis on their imaging presentation, using magnetic resonance imaging.

Fulminant acute disseminated encephalomyelitis mimicking acute bacterial menigoencephalitis

Most patients with acute disseminated encephalomyelitis (ADEM) recover quickly under corticosteroid treatment and have a favourable long-term prognosis. We report on a young woman with acute onset of an extensive and solitary white-matter lesion in the left hemisphere. Fever, high pleocytosis and elevated protein in cerebrospinal fluid initially suggested bacterial meningoencephalitis. The patient died from brain herniation despite maximal conservative therapy. Histological changes in necropsy were consistent with the diagnosis ADEM. Treatment options of fulminant ADEM are discussed.

Sclérose en plaques rémittente ou encéphalomyélite multiphasique disséminée ?

INTRODUCTION

The imaging presentation of some forms of multiple sclerosis may be misleading. In patients with a history of recent infection or vaccination, especially for adolescents or young adults, the differential diagnosis with acute disseminated encephalomyelitis can be difficult.

CASE REPORT

We report an unusual clinical and radiological presentation of multiple sclerosis, mimicking acute disseminated encephalomyelitis. We discuss clinical and radiological differential diagnosis, and the outcome after immunosuppressive treatment.

CONCLUSION

Distinguishing between acute disseminated encephalomyelitis and the first relapse of multiple sclerosis can be difficult. Brain imaging is a precious tool for differentiating between the two diseases.

Mycoplasma pneumoniae and its role as a human pathogen

Mycoplasma pneumoniae is a unique bacterium that does not always receive the attention it merits considering the number of illnesses it causes and the degree of morbidity associated with it in both children and adults. Serious infections requiring hospitalization, while rare, occur in both adults and children and may involve multiple organ systems. The severity of disease appears to be related to the degree to which the host immune response reacts to the infection. Extrapulmonary complications involving all of the major organ systems can occur in association with M. pneumoniae infection as a result of direct invasion and/or autoimmune response. The extrapulmonary manifestations are sometimes of greater severity and clinical importance than the primary respiratory infection. Evidence for this organism's contributory role in chronic lung conditions such as asthma is accumulating. Effective management of M. pneumoniae infections can usually be achieved with macrolides, tetracyclines, or fluoroquinolones. As more is learned about the pathogenesis and immune response elicited by M. pneumoniae, improvement in methods for diagnosis and prevention of disease due to this organism may occur.

Postinfectious encephalomyelitis

Postinfectious forms of encephalomyelitis, also termed acute disseminated encephalomyelitis (ADEM), form one of several categories of inflammatory demyelinating disorders of the central nervous system (CNS). Recent large, retrospective case series have refined our understanding of the clinical, laboratory, and neuroimaging characteristics of ADEM. The differences between childhood and adult ADEM, risks of development of multiple sclerosis, and the contributions of recent studies to refining the nosology of CNS demyelinating syndromes are discussed.

Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is a monophasic inflammatory disorder of the central nervous system (CNS). Unlike viral encephalitis, microorganisms do not invade the CNS. Instead, ADEM is a postinfectious disease mediated by auto-reactive cells or molecules. Clinical characteristics of ADEM are consistent with disseminated involvement of the CNS, including encephalopathy and pyramidal, cerebellar, and brainstem signs. Bilateral optic neuritis and transverse myelitis are particularly suggestive of demyelinating diseases such as ADEM. Unlike viral encephalitis, seizures rarely are a prominent symptom. The most useful diagnostic investigation is magnetic resonance neuroimaging that commonly shows multifocal lesions throughout the brain and spinal cord. As ADEM is an immune-mediated disorder, treatment includes immunomodulatory therapies (particularly steroids), although no clinical trials have been performed to define the most efficacious agent. In view of the treatment differences between ADEM and viral encephalitis, being familiar with ADEM is essential for pediatricians managing acute neurological disorders.

A diffusion tensor MRI study of basal ganglia from patients with ADEM

Using diffusion tensor (DT) MRI and histogram analysis, we measured mean diffusivity ((-)D) of basal ganglia grey matter (GM) from eight patients with acute disseminated encephalomyelitis (ADEM), 10 patients with multiple sclerosis (MS), and 10 healthy controls. Patients with ADEM had higher average (-)D (p=0.02) and lower (-)D histogram peak height (p=0.008) of the basal ganglia GM than patients with MS. Microscopic tissue damage occurs in the basal ganglia of ADEM patients, but not in MS patients with a similar burden of MRI-visible brain lesions.

Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an acute demyelinating disorder of the central nervous system, and is characterised by multifocal white matter involvement. Diffuse neurological signs along with multifocal lesions in brain and spinal cord characterise the disease. Possibly, a T cell mediated autoimmune response to myelin basic protein, triggered by an infection or vaccination, underlies its pathogenesis. ADEM is a monophasic illness with favourable long term prognosis. The differentiation of ADEM from a first attack of multiple sclerosis has prognostic and therapeutic implications; this distinction is often difficult. Most patients with ADEM improve with methylprednisolone. If that fails immunoglobulins, plasmapheresis, or cytotoxic drugs can be given. Recent literature suggests that a significant proportion of patients with ADEM will later develop multiple sclerosis; however, follow up experience from developing countries does not support this view.

Sleep and EEG power spectrum in post encephalitis hypersomnia: a case report

The nocturnal recordings of breathing, and sleep and daytime multiple sleep latency tests over the 5 year follow-up of a patient with post encephalitis hypersomnia are presented. EEG power spectrum analysis was performed on the last polysomnographic recording, and the results were compared with those obtained for a matched control subject. The patient presented initially a hypoventilation syndrome controlled by nasal bilevel positive pressure at night. The syndrome progressively improved, but daytime sleepiness stayed unchanged with limited help from stimulants. Fast Fourier transformation analysis of the last nocturnal recording demonstrates a decrease in absolute power for all frequency bands in all sleep stages, but a cyclical presence of the NREM/REM.

Demyelinating disorder of the central nervous system occurring in black South Africans

OBJECTIVES

To investigate the nature and cause in eight black South African patients of a recurrent (multiphasic), remitting, and relapsing demyelinating disease of the CNS.

METHODS

The clinical and laboratory investigations and radiological manifestations of these patients were documented.

RESULTS

Each patient had two or more acute attacks of demyelinating disease affecting the CNS. The clinical presentations of the patients were predominantly those of multiphasic neuromyelitis optica (NMO). Brain MRI in these patients showed features consistent with those described for acute disseminated encephalomyelitis (ADEM), as well as lesions that are described in multiple sclerosis. There was involvement of the corpus callosum in addition to typical ADEM lesions. Laboratory investigations excluded all other known causes of multiphasic CNS demyelination. Oligoclonal antibodies were not detected in these patients at any time. The patients were all from a population with a low risk for MS (black South Africans).

CONCLUSION

The patients described here represent a new phenotypic expression of a recurrent (multiphasic), steroid sensitive, inflammatory demyelinating disorder of the CNS occurring in black South Africans. The disorder is either a distinct inflammatory demyelinating disorder of the CNS of as yet unknown aetiology, or a varied form of MS (ADEM/NMO) occurring in a population with a low risk (where the genetic trait and environmental risk factors for MS do not exist) for MS.

Multiple sclerosis, acute disseminated encephalomyelitis, and related conditions

Multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM) are conditions whose closely related pathology suggests shared pathophysiological elements, but whose clinical courses are usually, but not always quite dissimilar. The former is largely a disease of adulthood, the latter of childhood. Optic neuritis, demyelinative transverse myelitis, and Devic's syndrome are neurological syndromes that may occur as manifestations of either MS or ADEM. Patients with Miller-Fisher syndrome and encephalomyelradiculoneuropathy usually have features suggesting ADEM in combination with acute demyelinative polyneuropathy. These various conditions and other forms of ADEM share an indistinct border with encephalitides, granulomatous, and vasculitic conditions. MS, ADEM, and the pertinent syndromic subtypes, their differential diagnosis, treatment, and prognosis are considered in this review. Acute cerebellar ataxia is a syndrome that is likely to be pathophysiologically distinct from ADEM, although its occurrence as a postinfectious illness suggests a distant kinship. It is also reviewed.