Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly ...recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation.
Background and objectives
Diagnosis of multiple sclerosis (MS) requires exclusion of diseases that could better explain the clinical and paraclinical findings. A systematic process for exclusion of ...alternative diagnoses has not been defined. An International Panel of MS experts developed consensus perspectives on MS differential diagnosis.
Methods
Using available literature and consensus, we developed guidelines for MS differential diagnosis, focusing on exclusion of potential MS mimics, diagnosis of common initial isolated clinical syndromes, and differentiating between MS and non-MS idiopathic inflammatory demyelinating diseases.
Results
We present recommendations for 1) clinical and paraclinical red flags suggesting alternative diagnoses to MS; 2) more precise definition of “clinically isolated syndromes” (CIS), often the first presentations of MS or its alternatives; 3) algorithms for diagnosis of three common CISs related to MS in the optic nerves, brainstem, and spinal cord; and 4) a classification scheme and diagnosis criteria for idiopathic inflammatory demyelinating disorders of the central nervous system.
Conclusions
Differential diagnosis leading to MS or alternatives is complex and a strong evidence base is lacking. Consensus-determined guidelines provide a practical path for diagnosis and will be useful for the non-MS specialist neurologist. Recommendations are made for future research to validate and support these guidelines. Guidance on the differential diagnosis process when MS is under consideration will enhance diagnostic accuracy and precision.
To evaluate the efficacy, tolerability, optimal dosing, and monitoring of azathioprine in patients with neuromyelitis optica (NMO).
This was a chart review and telephone follow-up study of 99 ...patients with NMO spectrum of disorders (NMOSD) treated with azathioprine (1994-2009). NMOSD were NMO (2006 diagnostic criteria) or partial NMO forms (NMO-immunoglobulin G seropositive). Wilcoxon signed rank test was used to compare pretreatment and postinitiation of azathioprine (posttreatment) annualized relapse rates (ARR), Expanded Disability Status Scale (EDSS) score, and visual acuity outcome. Linear regression was used to assess the effects of various factors on ARR change and disability.
The median duration of NMOSD symptoms prior to initiation of azathioprine was 2 years (range 1-27); 79 patients were women. Eighty-six patients had NMO and 13 limited NMO versions, including transverse myelitis in 8 and optic neuritis in 5. Median posttreatment follow-up was 22 months. Thirty-eight patients discontinued drug (side effects, 22; no efficacy, 13; lymphoma, 3). Among 70 patients with >12 months follow-up, 48 received ≥2.0 mg/kg/day (ARR: pretreatment, 2.20; posttreatment, 0.52); 22 received <2.0 mg/kg/day (ARR: pretreatment, 2.09; posttreatment, 0.82); 52 received concomitant prednisone (ARR: pretreatment, 2.20; posttreatment, 0.89) and 18 did not (ARR: pretreatment, 1.54; posttreatment, 0.23); p < 0.0001 for each comparison. EDSS was stable or improved despite ongoing attacks in 22 patients (31%). Twenty-six patients tolerated azathioprine and were relapse-free (37%, median follow-up 24 months; range 12-151). Mean corpuscular volume increase influenced ARR change (p = 0.049).
Azathioprine is generally effective and well-tolerated. Early initiation, adequate dosing, and hematologic parameter monitoring may optimize efficacy.
This study provides Class IV evidence that azathioprine is effective for reducing relapse rates and improving EDSS and visual acuity scores in patients with NMO spectrum of disorders.
To assess the evidence for diagnostic tests and therapies for transverse myelitis (TM) and make evidence-based recommendations.
A review of the published literature from 1966 to March 2009 was ...performed, with evidence-based classification of relevant articles.
Level B recommendations: neuromyelitis optica (NMO)-immunoglobulin G (IgG) antibodies should be considered useful to determine TM cause in patients presenting with clinical acute complete transverse myelitis (ACTM) features. The presence of NMO-IgG antibodies (aquaporin-4-specific antibodies) should be considered useful in determining increased TM recurrence risk. Level C recommendations: in suspected TM, distinction between ACTM or acute partial transverse myelitis may be considered useful to determine TM etiology and risk for relapse (more common with APTM). Age and gender may be considered useful to determine etiology in patients presenting with TM syndrome, with spinal infarcts seen more often in older patients and more female than male patients having TM due to multiple sclerosis (MS). Brain MRI characteristics consistent with those of MS may be considered useful to predict conversion to MS after a first partial TM episode. Longer spinal lesions extending over >3 vertebral segments may be considered useful in determining NMO vs MS. CSF examination for cells and oligoclonal bands may be considered useful to determine the cause of the TM syndrome. Plasma exchange may be considered in patients with TM who fail to improve after corticosteroid treatment. Rituximab may be considered in patients with TM due to NMO to decrease the number of relapses. Level U recommendations: there is insufficient evidence to support or refute the efficacy of other TM therapies or the usefulness of ethnicity to determine the cause of a subacute myelopathy.
To determine the prognostic value of neuromyelitis optica (NMO)-immunoglobulin G (IgG) in patients with recurrent optic neuritis (ON). The aquaporin-4-specific serum autoantibody, NMO-IgG, is a ...biomarker for NMO and relapsing transverse myelitis. Recurrent ON may herald multiple sclerosis (MS) or NMO, or it may occur as an isolated syndrome. The prognosis and response to therapy differs in each of these contexts.
We evaluated 34 patients who were tested for NMO-IgG between 2000 and 2007 and who had two or more episodes of ON without satisfying a diagnosis of MS or NMO prior to serologic testing. Clinical data were available for 25 Mayo Clinic patients (5 NMO-IgG positive and 20 NMO-IgG negative) and for an additional 9 seropositive patients whose serum was referred to the Mayo Clinic Neuroimmunology laboratory for testing.
Twenty percent of the patients with recurrent ON seen at Mayo Clinic were seropositive. All NMO-IgG-positive patients (vs 65% NMO-IgG-negative patients) had at least one attack with visual acuity in the affected eye worse than 20/200 (p = 0.05). In seropositive patients for whom long-term follow-up was possible (median 8.9 years after the initial ON), 6 of 12 (50%) experienced an episode of myelitis and fulfilled criteria for NMO. In contrast, 1 of 15 seronegative patients (6.7%) fulfilled McDonald criteria for MS (p = 0.03). Seropositive patients had a final visual score which was worse than that of seronegative patients (p = 0.02).
Neuromyelitis optica (NMO)-immunoglobulin G seropositivity predicts poor visual outcome and development of NMO. Seropositive recurrent optic neuritis is a limited form of NMO.
Background:
Optic neuritis (ON) is often associated with multiple sclerosis (MS). Early diagnosis is critical to optimal patient management.
Objective:
To estimate the incidence of acute ON and the ...rates of conversion to MS and antibody-mediated ON.
Method:
Population-based prospective study was performed in patients with ON from three ophthalmological departments and 44 practicing ophthalmologists from 2014 to 2016. Ophthalmological and neurological examination, magnetic resonance imaging (MRI), determination of aquaporin-4(AQP4)-IgG and myelin-oligodendrocyte glycoprotein (MOG)-IgG were investigated blindly.
Results:
In all, 63 patients were evaluated and 51 fulfilled the criteria for ON. All were Caucasian, with female:male ratio of 2.2:1 and a median age of 38 years (16–66); 44 (86%) had a single episode of ON (four bilateral), while 7/51 (14%) had recurrent ON. The overall age-specific incidence was 3.28 (2.44–4.31) per 100,000 person years, 2.02 for men and 4.57 for women. At follow-up, 20 patients met the diagnostic criteria for MS, MRI lesions disseminated in space and time in 17/20 patients. AQP4-IgG was detected in none, MOG-IgG was detected in two patients.
Conclusion:
The prospective incidence of ON was estimated. MRI enabled a diagnosis of MS in a subgroup of patients. Antibody-mediated ON with specificity for MOG was detected in 4% of cases.
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.
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.
Fourteen patients with NMO (14.6%) 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.
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.
To determine seroprevalence of neuromyelitis optica (NMO)-IgG in childhood CNS inflammatory demyelinating disorders.
We analyzed demographic, clinical, and radiologic data in a blinded fashion and ...assessed serum NMO-IgG status for 87 children: 41 with relapsing-remitting multiple sclerosis (RRMS), 17 with NMO, 13 with monophasic/recurrent optic neuritis (ON), 13 with transverse myelitis, of whom 10 were longitudinally extensive on MRI spine (LETM), and another 3 with LETM in the context of acute disseminated encephalomyelitis (ADEM).
Ten of the 87 children (11%) were seropositive. Eight of 17 with NMO (47%) were seropositive (7 of 9 with relapsing NMO 78%, 1 of 8 with monophasic NMO 12.5%). Two other children were seropositive: 1 of 5 with recurrent ON and one child with recurrent LETM. No seropositive case was identified among 41 with RRMS (14% of whom had LETM at some point in their clinical course), 8 with monophasic ON, 9 with monophasic LETM, or 3 with LETM in the context of ADEM.
The similar frequency of neuromyelitis optica (NMO)-IgG in both childhood and adult cases of NMO, and its rarity in relapsing-remitting multiple sclerosis, supports the concept that these diseases have a similar pathogenesis in childhood and adulthood. It is noteworthy that none of nine children with monophasic longitudinally extensive transverse myelitis (LETM) was NMO-IgG-seropositive. Furthermore, LETM does not appear to be as predictive of an NMO spectrum disorder in children as it is in adults. Longitudinal studies of larger pediatric LETM cohorts are required to ascertain whether the absence of NMO-IgG is a negative predictor for relapse in this childhood entity.
To report the clinical phenotype and outcome of isolated paraneoplastic myelopathy.
We systematically reviewed clinical, serologic, and MRI data for 31 patients (20 female) who presented with an ...isolated myelopathy and coexisting cancer: carcinoma (lung, 9; breast, 7; kidney, 2; thyroid, 2; ovary/endometrium, 2), melanoma (2), or other cancer (3), or a paraneoplastic autoantibody with strong cancer association (amphiphysin-immunoglobulin G IgG, 9; collapsin response-mediator protein 5-IgG, 9; Purkinje-cell cytoplasmic autoantibody type 1, 2; antineuronal nuclear autoantibody ANNA-1, 1; ANNA-3, 1).
Of 31 patients who presented with a progressive myelopathy, symptom onset was subacute in 16 (52%). The median age was 62 years. CSF abnormalities included elevated protein (>45 mg/dL), 22; pleocytosis, 15; excess oligoclonal bands (normal <4), 7. MRI cord abnormalities identified in 20 patients were longitudinally extensive (>3 vertebral segments), 14; symmetric tract or gray matter-specific signal abnormality, 15 (enhancing in 13). Myelopathy preceded cancer diagnosis in 18 patients (median interval 12 months; range 2-44). After myelopathy onset, 26 patients underwent oncologic treatment, immunosuppressive treatment (median delay to commencing immunotherapy 9.5 months range 1-54), or both; only 8 improved (31%). At last neurologic evaluation (median interval after onset 17 months; range 1-165 months), 16 patients (52%) were wheelchair-dependent (median time from onset to wheelchair 9 months range 1-21). Ten patients died after a median of 38 months from symptom onset (range 7-152).
Symmetric, longitudinally extensive tract or gray matter-specific changes on spinal MRI should raise suspicion for a paraneoplastic myelopathy. Resulting disability is often severe. Only a minority of patients improve with treatment.
The clinical course of immune mediated optic neuritis (ON) will depend on the specific underlying inflammatory disease. These disorders have traditionally been classified according to clinical and ...MRI findings. Aquaporin-4 (AQP4) autoantibodies (neuromyelitis optica-IgG (NMO-IgG)) may have diagnostic and prognostic value in patients who present with isolated ON. In this prospective study, NMO-IgG was evaluated in 114 patients with ON in the following contexts: neuromyelitis optica (NMO), multiple sclerosis (MSON), chronic relapsing inflammatory ON (CRION), relapsing isolated ON (RION) and single isolated ON (SION). The proportion seropositive was 56% for NMO (n = 9), 0% for MSON (n = 28) and 5% for the remaining diagnostic categories (CRION (n = 19), RION (n = 17) and SION (n = 41)). Testing for NMO-IgG in patients with recurrent or severe ON who lack convincing evidence of MS may identify patients who would benefit from immunosuppression rather than MS directed immunomodulatory therapies.
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