New evidence and consensus has led to further revision of the McDonald Criteria for diagnosis of multiple sclerosis. The use of imaging for demonstration of dissemination of central nervous system lesions in space and time has been simplified, and in some circumstances dissemination in space and time can be established by a single scan. These revisions simplify the Criteria, preserve their diagnostic sensitivity and specificity, address their applicability across populations, and may allow earlier diagnosis and more uniform and widespread use.

/pdf/diagnostic-criteria-for-multiple-sclerosis-2010-revisions-to-24iph50480.pdf

Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(12)61729-2.pdf

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

New diagnostic criteria for multiple sclerosis integrating magnetic resonance image assessment with clinical and other paraclinical methods were introduced in 2001. The "McDonald Criteria" have been extensively assessed and used since 2001. New evidence and consensus now strengthen the role of these criteria in the multiple sclerosis diagnostic workup to demonstrate dissemination of lesions in time, to clarify the use of spinal cord lesions, and to simplify diagnosis of primary progressive disease. The 2005 Revisions to the McDonald Diagnostic Criteria for MS should simplify and speed diagnosis, whereas maintaining adequate sensitivity and specificity.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/ana.20703

Diagnostic criteria for multiple sclerosis: 2005 revisions to the "McDonald Criteria".

Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS. Astrocytes respond to all forms of CNS insults through a process referred to as reactive astrogliosis, which has become a pathological hallmark of CNS structural lesions. Substantial progress has been made recently in determining functions and mechanisms of reactive astrogliosis and in identifying roles of astrocytes in CNS disorders and pathologies. A vast molecular arsenal at the disposal of reactive astrocytes is being defined. Transgenic mouse models are dissecting specific aspects of reactive astrocytosis and glial scar formation in vivo. Astrocyte involvement in specific clinicopathological entities is being defined. It is now clear that reactive astrogliosis is not a simple all-or-none phenomenon but is a finely gradated continuum of changes that occur in context-dependent manners regulated by specific signaling events. These changes range from reversible alterations in gene expression and cell hypertrophy with preservation of cellular domains and tissue structure, to long-lasting scar formation with rearrangement of tissue structure. Increasing evidence points towards the potential of reactive astrogliosis to play either primary or contributing roles in CNS disorders via loss of normal astrocyte functions or gain of abnormal effects. This article reviews (1) astrocyte functions in healthy CNS, (2) mechanisms and functions of reactive astrogliosis and glial scar formation, and (3) ways in which reactive astrocytes may cause or contribute to specific CNS disorders and lesions.

/pdf/astrocytes-biology-and-pathology-2hq13zf0bo.pdf

Astrocytes: biology and pathology

The 2010 McDonald criteria for the diagnosis of multiple sclerosis are widely used in research and clinical practice. Scientific advances in the past 7 years suggest that they might no longer provide the most up-to-date guidance for clinicians and researchers. The International Panel on Diagnosis of Multiple Sclerosis reviewed the 2010 McDonald criteria and recommended revisions. The 2017 McDonald criteria continue to apply primarily to patients experiencing a typical clinically isolated syndrome, define what is needed to fulfil dissemination in time and space of lesions in the CNS, and stress the need for no better explanation for the presentation. The following changes were made: in patients with a typical clinically isolated syndrome and clinical or MRI demonstration of dissemination in space, the presence of CSF-specific oligoclonal bands allows a diagnosis of multiple sclerosis; symptomatic lesions can be used to demonstrate dissemination in space or time in patients with supratentorial, infratentorial, or spinal cord syndrome; and cortical lesions can be used to demonstrate dissemination in space. Research to further refine the criteria should focus on optic nerve involvement, validation in diverse populations, and incorporation of advanced imaging, neurophysiological, and body fluid markers.

/pdf/diagnosis-of-multiple-sclerosis-2017-revisions-of-the-55ct02l5o1.pdf

Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria

A serum autoantibody marker of neuromyelitis optica : distinction from multiple sclerosis

Background: The authors previously proposed diagnostic criteria for neuromyelitis optica (NMO) that facilitate its distinction from prototypic multiple sclerosis (MS) However, some patients with otherwise typical NMO have additional symptoms not attributable to optic nerve or spinal cord inflammation or have MS-like brain MRI lesions Furthermore, some patients are misclassified as NMO by the authors’ earlier proposed criteria despite having a subsequent course indistinguishable from prototypic MS A serum autoantibody marker, NMO-IgG, is highly specific for NMO The authors propose revised NMO diagnostic criteria that incorporate NMO-IgG status Methods: Using final clinical diagnosis (NMO or MS) as the reference standard, the authors calculated sensitivity and specificity for each criterion and various combinations using a sample of 96 patients with NMO and 33 with MS The authors used likelihood ratios and logistic regression analysis to develop the most practical and informative diagnostic model Results: Fourteen patients with NMO (146%) had extra-optic-spinal CNS symptoms NMO-IgG seropositivity was 76% sensitive and 94% specific for NMO The best diagnostic combination was 99% sensitive and 90% specific for NMO and consisted of at least two of three elements: longitudinally extensive cord lesion, onset brain MRI nondiagnostic for MS, or NMO-IgG seropositivity Conclusions: The authors propose revised diagnostic criteria for definite neuromyelitis optica (NMO) that require optic neuritis, myelitis, and at least two of three supportive criteria: MRI evidence of a contiguous spinal cord lesion 3 or more segments in length, onset brain MRI nondiagnostic for multiple sclerosis, or NMO-IgG seropositivity CNS involvement beyond the optic nerves and spinal cord is compatible with NMO

https://n.neurology.org/content/neurology/66/10/1485.full.pdf

Revised diagnostic criteria for neuromyelitis optica

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that selectively affects optic nerves and spinal cord. It is considered a severe variant of multiple sclerosis (MS), and frequently is misdiagnosed as MS, but prognosis and optimal treatments differ. A serum immunoglobulin G autoantibody (NMO-IgG) serves as a specific marker for NMO. Here we show that NMO-IgG binds selectively to the aquaporin-4 water channel, a component of the dystroglycan protein complex located in astrocytic foot processes at the blood-brain barrier. NMO may represent the first example of a novel class of autoimmune channelopathy.

/pdf/igg-marker-of-optic-spinal-multiple-sclerosis-binds-to-the-5cre8njxbr.pdf

IgG marker of optic-spinal multiple sclerosis binds to the aquaporin-4 water channel.

Summary Neuromyelitis optica (also known as Devic's disease) is an idiopathic, severe, demyelinating disease of the central nervous system that preferentially affects the optic nerve and spinal cord. Neuromyelitis optica has a worldwide distribution, poor prognosis, and has long been thought of as a variant of multiple sclerosis; however, clinical, laboratory, immunological, and pathological characteristics that distinguish it from multiple sclerosis are now recognised. The presence of a highly specific serum autoantibody marker (NMO-IgG) further differentiates neuromyelitis optica from multiple sclerosis and has helped to define a neuromyelitis optica spectrum of disorders. NMO-IgG reacts with the water channel aquaporin 4. Data suggest that autoantibodies to aquaporin 4 derived from peripheral B cells cause the activation of complement, inflammatory demyelination, and necrosis that is seen in neuromyelitis optica. The knowledge gained from further assessment of the exact role of NMO-IgG in the pathogenesis of neuromyelitis optica will provide a foundation for rational therapeutic trials for this rapidly disabling disease.

/pdf/the-spectrum-of-neuromyelitis-optica-1apj94f51h.pdf

The spectrum of neuromyelitis optica

Background Neuromyelitis optica (NMO) is a severe demyelinating disease defined principally by its tendency to selectively affect optic nerves and the spinal cord causing recurrent attacks of blindness and paralysis. Contemporary diagnostic criteria require absence of clinical disease outside the optic nerve or spinal cord. We have, however, frequently encountered patients with a well-established diagnosis of NMO in whom either asymptomatic or symptomatic brain lesions develop suggesting that the diagnostic criteria for NMO should be revised. Objective To describe the magnetic resonance image (MRI) brain findings in NMO. Design Observational, retrospective case series. Patients We ascertained patients through a clinical biospecimens database of individuals with definite or suspected NMO. We included patients who (1) satisfied the 1999 criteria of Wingerchuk et al for NMO except for the absolute criterion of lacking symptoms beyond the optic nerve and spinal cord and the supportive criterion of having a normal brain MRI at onset; (2) had MRI evidence of a spinal cord lesion extending 3 vertebral segments or more (the most specific nonserological feature to differentiate NMO from MS); and (3) were evaluated neurologically and by brain MRI at the Mayo Clinic. Main Outcome Measures Magnetic resonance images were classified as normal or as abnormal with either nonspecific, multiple sclerosis–like or atypical abnormalities. We evaluated whether brain lesions were symptomatic and analyzed the neuropathologic features of a single brain biopsy specimen. Results Sixty patients (53 women [88%]) fulfilled these inclusion criteria. The mean ± SD age at onset was 37.2 ± 18.4 years and the mean ± SD duration of follow-up was 6.0 ± 5.6 years. Neuromyelitis optica–IgG was detected in 41 patients (68%). Brain MRI lesions were detected in 36 patients (60%). Most were nonspecific, but 6 patients (10%) had multiple sclerosis–like lesions, usually asymptomatic. Another 5 patients (8%), mostly children, had diencephalic, brainstem or cerebral lesions, atypical for multiple sclerosis. When present, symptoms of brain involvement were subtle, except in 1 patient who was comatose and had large cerebral lesions. Conclusions Asymptomatic brain lesions are common in NMO, and symptomatic brain lesions do not exclude the diagnosis of NMO. These observations justify revision of diagnostic criteria for NMO to allow for brain involvement.

https://jamanetwork.com/journals/jamaneurology/articlepdf/790890/noc50329.pdf

Sean J. Pittock

Papers

A serum autoantibody marker of neuromyelitis optica : distinction from multiple sclerosis

Revised diagnostic criteria for neuromyelitis optica

IgG marker of optic-spinal multiple sclerosis binds to the aquaporin-4 water channel.

The spectrum of neuromyelitis optica

Brain abnormalities in neuromyelitis optica.