Diagnostic imaging in acute disseminated encephalomyelitis

Clinical-evolutive particularities and therapeutic-rehabilitative approach in the rare case of acute disseminated encephalomyelitis following an episode of viral meningitis of unknown etiology

Acute disseminated encephalomyelitis (ADEM) is a disease mainly affecting children, however, adult cases have been also reported. The disease represents a demyelinating disorder of the central nervous system, with a monophasic evolution and mostly full recovery. Mortality is documented at only 2%, but there are risks of complications in the acute phase, mostly due to the vast number of lesions and their distribution in the cerebrum. We present the case of a 40 year-old female patient who presented with visual impairment, coordination issues with walking difficulties, hypoesthesia of the entire body, back and upper limbs paresthesia, upper limbs and torso tremor as well as speech impairment. Symptoms appeared on the same day after discharge from the Infectious Disease Hospital where she was treated for viral meningitis. MRI findings on admission described multiple demyelinating lesions located bilaterally in the white matter and in the cervical spine. The patient was started on high dose parenteral methylprednisolone 1g/day for 5 days and afterwards was switched to oral corticoids with dose tapering over a period of 40 days. Rehabilitation treatment was started during hospitalization and continued after discharge. Evolution was favorable, with almost complete recovery, the patient presenting with only minor hypoesthesia of the torso at discharge. Key words: acute disseminated encephalomyelitis, ADEM, meningitis, rehabilitation,

Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function that results from immune-mediated inflammation, demyelination, and subsequent axonal damage.

Clinically, most MS patients experience recurrent episodes (relapses) of neurological impairment, but in most cases (60–80%) the course of the disease eventually becomes chronic and progressive, leading to cumulative motor, sensory, and visual disability, and cognitive deficits.

The course of the disease is largely unpredictable and its clinical presentation is variable, but its predilection for certain parts of the CNS, which includes the optic nerves, the brain stem, cerebellum, and cervical spinal cord, provides a characteristic constellation of signs and symptoms. Several variants of MS have been nowadays defined with variable immunopathogenesis, course and prognosis. Many new treatments targeting the immune system have shown efficacy in preventing the relapses of MS and have been introduced to its management during the last decade.

[An interpretation of consensus statements on diagnostic criteria for multiple sclerosis and demyelinating diseases of the central nervous system in children (2012 version)]

The International Pediatric Multiple Sclerosis Study Group (IPMSSG) put forward the 2007 version of the diagnostic criteria for multiple sclerosis and other immune-mediated demyelinating diseases of the central nervous system in children in 2007 ("2007 version" for short). In 2012, IPMSSG proposed the new diagnostic criteria with reference to the latest research achievements of 150 members ("2012 version" for short). The 2012 version of the consensus statements covers the diagnostic criteria for acute disseminated encephalomyelitis, clinically isolated syndrome, neuromyelitis optica, and multiple sclerosis in children. As the two IPMSSG members in China, the authors give an interpretation of the 2012 version of the consensus statements with reference to related literature and clinical and scientific experience. The authors focus on how the 2012 version comprehensively and thoroughly elaborates on the clinical features, diagnostic criteria, influencing factors, and new ideas of acute demyelinating diseases of the central nervous system in children. These become more operable in clinical diagnosis and treatment of multiple sclerosis and other immune-mediated demyelinating diseases of the central nervous system in children.

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.

The diagnosis of multiple sclerosis and the various related demyelinating syndromes: a critical review

Multiple sclerosis (MS), is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function, that results from immune-mediated inflammation, demyelination and subsequent axonal damage. MS is one of the most common causes of neurological disability in young adults. Several variants of MS (and CNS demyelinating syndromes in general) have been nowadays defined in an effort to increase the diagnostic accuracy, to identify the unique immunopathogenic profile and to tailor treatment in each individual patient. These include the initial events of demyelination defined as clinically or radiologically isolated syndromes (CIS and RIS respectively), acute disseminated encephalomyelitis (ADEM) and its variants (acute hemorrhagic leukoencephalitis-AHL, Marburg variant, and Balo's concentric sclerosis), Schilder's sclerosis, transverse myelitis, neuromyelitis optica (NMO and NMO spectrum of diseases), recurrent isolated optic neuritis and tumefactive demyelination. The differentiation between them is not only a terminological matter but has important implications on their management. For instance, certain patients with MS and prominent immunopathogenetic involvement of B cells and autoantibodies, or with the neuromyelitic variants of demyelination, may not only not respond well but even deteriorate under some of the first-line treatments for MS. The unique clinical and neuroradiological features, along with the immunological biomarkers help to distinguish these cases from classical MS. The use of such immunological and imaging biomarkers, will not only improve the accuracy of diagnosis but also contribute to the identification of the patients with CIS or RIS who, are at greater risk for disability progression (worse prognosis) or, on the contrary, will have a more benign course. This review summarizes in a critical way, the diagnostic criteria (historical and updated) and the definitions/characteristics of MS of the various variants/subtypes of CNS demyelinating syndromes.

Comparison of deep gray matter lesions on magnetic resonance imaging among adults with acute disseminated encephalomyelitis, multiple sclerosis, and neuromyelitis optica

BACKGROUND

Deep gray matter lesions have been reported in patients with acute disseminated encephalomyelitis (ADEM), multiple sclerosis (MS), and neuromyelitis optica (NMO).

OBJECTIVES

The purpose of this study was to compare the features of deep gray matter lesions on magnetic resonance imaging (MRI) among adult patients with ADEM, MS, and NMO.

METHODS

Ninety-five adult patients with ADEM (n=12), MS (n=60), and NMO (n=23) who had deep gray matter lesions on MRI were enrolled. Morphological features of deep gray matter lesions among these patients were assessed.

RESULTS

Putamen involvement was more common in patients with ADEM than in patients with MS and NMO. Differing from children, thalamus involvement might not be helpful in differentiating ADEM from MS in adults. Hypothalamus involvement was more common in patients with NMO than in patients with ADEM and MS. More importantly, bilateral hypothalamus involvement was more helpful in differentiating NMO from MS. The diameter of the thalamus lesions in patients with ADEM was larger than that in patients with NMO.

CONCLUSIONS

Morphological features of deep gray matter lesions vary among adult patients with ADEM, MS, and NMO, and may be helpful in distinguishing these diseases.

Isolated and persistent cognitive dysfunction in a patient with acute disseminated encephalomyelitis

We report a case of pathology-proven acute disseminated encephalomyelitis (ADEM) in which the patient's symptoms were solely cognitive. Although cognitive dysfunction is a well-recognized symptom in adults with multiple sclerosis, cognitive assessment of adults with ADEM has rarely been reported. A 35-year-old woman was referred to our center for evaluation of cognitive disturbance and demyelinating lesions seen on brain magnetic resonance imaging (MRI). We performed a neurologic examination, full neuropsychological assessment, brain MRI, blood and cerebrospinal fluid analyses, visual evoked potentials, and brain biopsy. The patient's Mini-Mental State Examination score was 26/30. Cognitive assessment revealed multiple severe dysfunctions, mainly in executive and attention tasks. She scored below the normal range on the Digit Span Forward and Backward Test and the Trail Making Test Part B. The Frontal Assessment Battery showed deficits in mental flexibility, motor programming, and inhibitory control. She also scored in the impaired range on tests of verbal fluency and memory. The brain MRI and biopsy confirmed a diagnosis of ADEM. This case report points to the limitations of relying on clinical presentation, neuroimaging, and current controversial diagnostic criteria in diagnosing ADEM in adults, and highlights the essential role of pathologic evaluation.

Diagnostic approach of patients with longitudinally extensive transverse myelitis

The aim of this study is to present a diagnostic and therapeutic approach in patients with LETM. In a period between June 2008 and June 2010, all patients who fulfilled criteria for LETM were included in the study. All patients underwent a standardized protocol of investigations presented in this paper. Ten patients were included (5 male, 5 female, with the age distribution from 24 to 70 years). Four patients were diagnosed with NMO/spatially limited NMO spectrum disorder, three patients were diagnosed with spinal cord ADEM, two multiple sclerosis (MS) and one patient with copper deficiency myelopathy. Laboratory support for the diagnosis of NMO was positive NMO-IgG antibody; for the diagnosis of ADEM signs of peripheral nervous system involvement on electromyoneurography; and for the diagnosis of MS brain MRI lesions typical for MS, as well as positive oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). All cases with inflammatory myelopathy were treated either with steroids or plasma exchange and copper replacement was started in the case of copper deficiency. The mean time from the first symptom until the final diagnosis was 16.3 months (range 1 month to 7 years). As each of idiopathic inflammatory demyelinating diseases that can present with LETM have specific therapy, the postponement in making the correct diagnosis can lead to a poor recovery. In patients with LETM, a standardized diagnostic approach can result in a correct diagnosis and appropriate treatment.

Comparative brain stem lesions on MRI of acute disseminated encephalomyelitis, neuromyelitis optica, and multiple sclerosis

Background

Brain stem lesions are common in patients with acute disseminated encephalomyelitis (ADEM), neuromyelitis optica (NMO), and multiple sclerosis (MS).

Objectives

To investigate comparative brain stem lesions on magnetic resonance imaging (MRI) among adult patients with ADEM, NMO, and MS.

Methods

Sixty-five adult patients with ADEM (n = 17), NMO (n = 23), and MS (n = 25) who had brain stem lesions on MRI were enrolled. Morphological features of brain stem lesions among these diseases were assessed.

Results

Patients with ADEM had a higher frequency of midbrain lesions than did patients with NMO (94.1% vs. 17.4%, P<0.001) and MS (94.1% vs. 40.0%, P<0.001); patients with NMO had a lower frequency of pons lesions than did patients with MS (34.8% vs. 84.0%, P<0.001) and ADEM (34.8% vs. 70.6%, P = 0.025); and patients with NMO had a higher frequency of medulla oblongata lesions than did patients with ADEM (91.3% vs. 35.3%, P<0.001) and MS (91.3% vs. 36.0%, P<0.001). On the axial section of the brain stem, the majority (82.4%) of patients with ADEM showed lesions on the ventral part; the brain stem lesions in patients with NMO were typically located in the dorsal part (91.3%); and lesions in patients with MS were found in both the ventral (44.0%) and dorsal (56.0%) parts. The lesions in patients with ADEM (100%) and NMO (91.3%) had poorly defined margins, while lesions of patients with MS (76.0%) had well defined margins. Brain stem lesions in patients with ADEM were usually bilateral and symmetrical (82.4%), while lesions in patients with NMO (87.0%) and MS (92.0%) were asymmetrical or unilateral.

Conclusions

Brain stem lesions showed various morphological features among adult patients with ADEM, NMO, and MS. The different lesion locations may be helpful in distinguishing these diseases.

Pathology of acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an acute, monophasic neurologic syndrome that occurs after vaccination against various viruses and after many viral infections and rarely occurs again in the same patient. Weston Hurst disease or acute hemorrhagic encephalomyelitis (AHE) is a hyperacute ADEM variant that shares many pathological similarities with ADEM. ADEM clinically and neuropathologically faithfully reflects the animal model of experimental allergic encephalomyelitis (EAE), and animal studies have provided us with new insights into pathogenesis of this disorder. Although there is much controversy whether ADEM is a separate disease or just one of possible manifestations of multiple sclerosis, there are clear histopathological characteristics that support ADEM as a separate disease This mini review will focus on pathological characteristics of ADEM emphasizing differences from other types of idiopathic demyelinating diseases.

Rare infections mimicking MS

The diagnosis of multiple sclerosis (MS), despite well defined clinical criteria is not always simple. On many occasions it is difficult to differentiate MS from various non-MS idiopathic demyelinating disorders, specific and infectious inflammatory diseases or non-inflammatory demyelinating diseases. Clinicians should be aware of various clinical and MRI "red flags" that may point to the other diagnosis and demand further diagnostic evaluation. It is generally accepted that atypical clinical symptoms or atypical neuroimaging signs determine necessity for broad differential diagnostic work up. Of the infectious diseases that are most commonly mistaken for MS the clinician should take into account Whipple's disease, Lyme disease, Syphilis, HIV/AIDS, Brucellosis, HHV-6 infection, Hepatitis C, Mycoplasma and Creutzfeld-Jacob disease, among others. Cat scratch disease caused by Bartonella hensellae, Mediterranean spotted fever caused by Riketssia connore and Leptospirosis caused by different Leptospira serovars rarely cause focal neurological deficit and demyelinating MRI changes similar to MS. When atypical clinical and neuroimaging presentations are present, serology on rare infectious diseases that may mimic MS may be warranted. This review will focus on the infectious diseases mimicking MS with presentation of rare illustrative cases.