High diagnostic accuracy of T2FLAIR at 3 T in the detection of optic nerve head edema in acute optic neuritis.

OBJECTIVES: Optic nerve head edema (ONHE) detected by fundoscopy is observed in one-third of patients presenting optic neuritis (ON). While ONHE is an important semiological feature, the correlation between ONHE and optic nerve head MRI abnormalities (ONHMA), sometimes called "optic nerve head swelling," remains unknown. Our study aimed to assess the diagnostic accuracy of T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence in detecting ONHE in patients with acute ON. METHODS: In the present single-center study, data were extracted from two prospective cohort studies that consecutively included adults with a first episode of acute ON treated between 2015 and 2020. Two experienced readers blinded to study data independently analyzed imaging. A senior neuroradiologist resolved any discrepancies. The primary judgment criterion of ONHMA was assessed as optic nerve head high signal intensity on gadolinium-enhanced T2FLAIR MRI sequence. Its diagnostic accuracy was evaluated with both the gold standard of ONHE on fundus photography (FP) and peripapillary retinal nerve fiber layer thickening on optic coherence tomography (OCT). RESULTS: A total of 102 patients were included, providing 110 affected and 94 unaffected optic nerves. Agreement was high between the different modalities: 92% between MRI and FP (k = 0.77, 95% CI: 0.67-0.88) and 93% between MRI and OCT (k = 0.77, 95% CI: 0.67-0.87). MRI sensitivity was 0.84 (95% CI: 0.70-0.93) and specificity was 0.94 (95% CI: 0.89-0.97) when compared with the FP. CONCLUSION: Optic nerve head high T2FLAIR signal intensity corresponds indeed to the optic nerve head edema diagnosed by the ophthalmologists. MRI is a sensitive tool for detecting ONHE in patients presenting acute ON. CLINICAL RELEVANCE STATEMENT: In patients with optic neuritis the high T2FLAIR (fluid-attenuated inversion recovery) signal intensity of the optic nerve head corresponds indeed to optic nerve head edema, which is a useful feature in optic neuritis etiological evaluation and treatment. KEY POINTS: Optic nerve head edema is a prominent clinical feature of acute optic neuritis and is usually diagnosed during dilated or non-dilated eye fundus examination. Agreement was high between magnetic resonance imaging, fundus photography, and optical coherence tomography. Optic nerve head high T2 fluid attenuation inversion recovery signal intensity is a promising detection tool for optic nerve head edema in patients presenting acute optic neuritis.

Improving the decision to switch from first- to second-line therapy in multiple sclerosis: A dynamic scoring system.

BACKGROUND: In relapsing-remitting multiple sclerosis (RRMS), early identification of suboptimal responders can prevent disability progression. OBJECTIVE: We aimed to develop and validate a dynamic score to guide the early decision to switch from first- to second-line therapy. METHODS: Using time-dependent propensity scores (PS) from a French cohort of 12,823 patients with RRMS, we constructed one training and two validation PS-matched cohorts to compare the switched patients to second-line treatment and the maintained patients. We used a frailty Cox model for predicting individual hazard ratios (iHRs). RESULTS: From the validation PS-matched cohort of 348 independent patients with iHR ⩽ 0.69, we reported the 5-year relapse-free survival at 0.14 (95% confidence interval (CI) 0.09-0.22) for the waiting group and 0.40 (95% CI 0.32-0.51) for the switched group. From the validation PS-matched cohort of 518 independent patients with iHR > 0.69, these values were 0.37 (95% CI 0.30-0.46) and 0.44 (95% CI 0.37-0.52), respectively. CONCLUSIONS: By using the proposed dynamic score, we estimated that at least one-third of patients could benefit from an earlier switch to prevent relapse.

Prospective longitudinal study on prognostic factors of visual recovery and structural change after a first episode of optic neuritis.

BACKGROUND AND PURPOSE: This study was undertaken to determine the role of optical coherence tomography (OCT) in predicting the final visual and structural outcome, and to evaluate the correlation between functional eye outcome and retinal changes, in patients with a first episode of optic neuritis (ON). METHODS: In this prospective study, consecutive adult patients with acute ON underwent ophthalmological evaluation at baseline and at 1 and 12 months, including OCT measurements of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell and inner plexiform layer, and inner nuclear layer thicknesses; high- and low-contrast visual acuity; visual field assessment; and baseline brain magnetic resonance imaging. Univariate and multivariate linear regressions were used to assess predictive factors of outcome. Correlations between 12-month visual function and retinal structure were estimated by Spearman coefficients. Two groups of patients were analyzed, with or without multiple sclerosis (MS). RESULTS: Among 116 patients, 79 (68.1%) had MS, and 37 (31.9%) had ON not related to MS (including 19 idiopathic [i.e., isolated] ON, and 13 and five with myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies, respectively). We found no independent predictive factor of visual and retinal outcome. Analysis of the relationship between the visual field test (mean deviation) and pRNFL thickness demonstrated a threshold of 75.4 µm and 66.4 µm, below which the mean deviation was worse, for patients with MS (p = 0.007) and without MS (p < 0.001), respectively. CONCLUSIONS: We found that inner retinal layer measurements during the first month are not predictive of final outcome. The critical threshold of axonal integrity, below which visual function is damaged, is different between patients with and without MS.

Visual field loss and structure-function relationships in optic neuritis associated with myelin oligodendrocyte glycoprotein antibody.

BACKGROUND: A paradoxical discrepancy between severe peripapillary retinal nerve fiber layer (pRNFL) atrophy and good visual outcome had been reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated optic neuritis (ON). However, only visual acuity (VA) was assessed. OBJECTIVES: To study visual field (VF) outcomes of patients with MOG-IgG-associated ON and evaluate the correlation between functional eye outcome and retinal structural changes assessed by optical coherence tomography. METHODS: The records of 32 patients with MOG-IgG-associated ON who underwent ophthalmological examination at least 12 months after ON onset were reviewed. Degree of VF disability was determined by mean deviation (MD). RESULTS: At final assessment (median, 35 months), 4.2% of 48 affected eyes (AE) had VA ⩽ 0.1, 40% had abnormal MD, and among AE with final VA ⩾ 1.0, 31% had mild to moderate damage. Thinning of the inner retinal layers was significantly correlated with MD impairment. Analysis demonstrated a threshold of pRNFL thickness (50 µm), below which MD was significantly worse (mean, -2.27 dB vs -17.72 dB; p = 0.0003). ON relapse was significantly associated with poor visual outcome assessed by MD. CONCLUSION: Functional impairment measured with VF is not rare, and MD assessment better reflects actual structural damage.

Vascular origin in acute transient visual disturbance: A prospective study.

BACKGROUND AND PURPOSE: This study was undertaken to validate a clinical score of vascular origin in patients with acute transient visual disturbances (TVDs) without diplopia. METHODS: We conducted a prospective study in an ophthalmology emergency department and a transient ischemic attack (TIA) clinic. Patients underwent clinical evaluation including a tailored questionnaire, brain, vascular, and ophthalmologic investigations, and 3-month follow-up. TVDs were classified according to vascular or nonvascular origin by three independent experts based on all clinical, cerebrovascular, and ophthalmologic investigations, but blind to the questionnaire results. A clinical score was derived based on clinical variables independently associated with a vascular origin, and was externally validated in an independent cohort. RESULTS: An ischemic origin of TVD was found in 45% (67/149) of patients in the derivation cohort. Age and six questions were independently associated with an ischemic origin. A nine-point score (≥70 years old = 2; monocular visual loss = 2; black or white vision = 1; single episode = 1; lack of headache = 2; diffuse, constricted, altitudinal, or lateralized visual loss pattern on drawings = 1) showed good discriminative power in identifying ischemic origin (c-statistic = 0.82) and was replicated in the validation cohort (n = 130, 25% of ischemic origin, c-statistic = 0.75). With a score ≥ 4, sensitivity was 85% (95% confidence interval = 68-95) and specificity was 52% (95% confidence interval = 41-62). In both cohorts, ophthalmologic evaluation found a vascular cause in 4% and was noncontributive in 85%. After 3 months, no patients had a stroke, TIA, or retinal infarct. CONCLUSIONS: Our score may assist in predicting a vascular origin of TVD. Ophthalmologic evaluation, when not readily available, should not delay the neurovascular evaluation.

The long-term outcome of MOGAD: An observational national cohort study of 61 patients.

BACKGROUND AND OBJECTIVE: The prognosis in myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a matter of debate. Our aim was to assess the long-term outcomes of patients with MOGAD. METHODS: We retrospectively analysed the clinical and paraclinical data of patients from the French nationwide observatory study NOMADMUS who tested positive for MOG antibodies (MOG-IgG) and who had clinical follow-up of at least 8 years from their first episode. RESULTS: Sixty-one patients (median [range] age at onset 27 [3-69] years), with a median (mean; range) follow-up of 177 (212.8; 98-657) months, were included. Among 58 patients with a relapsing course, 26.3% relapsed in the first year after onset. Of the 61 patients, 90.2% experienced at least one episode of optic neuritis. At last visit, the median (mean; range) Expanded Disability Status Scale (EDSS) score was 1 (2.12; 0-7.5), 12.5% had an EDSS score ≥6 and 37.5% had an EDSS score ≥3. Of 51 patients with final visual acuity (VA) data available, 15.7% had VA ≤0.1 in at least one eye and 25.5% had VA ≤0.5 in at least one eye. Bilateral blindness (VA ≤0.1) was present in 5.9% of patients. Finally, 12.5% of patients presented bladder dysfunction requiring long-term urinary catheterization. No factor associated significantly with a final EDSS score ≥3 or with final VA ≤0.1 was found. CONCLUSION: Overall long-term favourable outcomes were achieved in a majority of our patients, but severe impairment, in particular visual damage, was not uncommon.

Untreated patients with multiple sclerosis: A study of French expert centers.

BACKGROUND AND PURPOSE: Disease-modifying therapies (DMTs) have an impact on relapses and disease progression. Nonetheless, many patients with multiple sclerosis (MS) remain untreated. The objectives of the present study were to determine the proportion of untreated patients with MS followed in expert centers in France and to determine the predictive factors of nontreatment. METHODS: We conducted a retrospective cohort study. Data were extracted from the 38 centers participating in the European Database for Multiple Sclerosis (EDMUS) on December 15, 2018, and patients with MS seen at least once during the study period (from June 15, 2016 to June 14, 2017) were included. RESULTS: Of the 21,189 patients with MS (age 47.1 ± 13.1 years; Expanded Disability Status Scale (EDSS) score 3.4 ± 2.4), 6,631 (31.3%; 95% confidence interval [CI] 30.7-31.9) were not receiving any DMT. Although patients with a relapsing-remitting course (n = 11,693) were the most likely to receive DMT, 14.8% (95% CI 14.2-15.4) were still untreated (6.8% never treated). After multivariate analysis among patients with relapsing-remitting MS, the main factors explaining never having been treated were: not having ≥9 lesions on brain magnetic resonance imaging (odds ratio [OR] 0.52 [95% CI 0.44-0.61]) and lower EDSS score (OR 0.78 [95% CI 0.74-0.82]). Most patients with progressive MS (50.4% for secondary and 64.2% for primary progressive MS) did not receive any DMT during the study period, while 11.6% of patients with secondary and 34.0% of patients with primary progressive MS had never received any DMT. CONCLUSION: A significant proportion of patients with MS did not receive any DMT, even though such treatments are reimbursed by the healthcare system for French patients. This result highlights the unmet need for current DMTs for a large subgroup of patients with MS.

Myelin oligodendrocyte glycoprotein antibody-associated diffuse orbital inflammation.

An 87-year-old man presented with a 2-day history of painful bilateral visual loss. On examination, exophthalmos, lid edema, chemosis, and optic disc edema, on the left side only, were found. Visual acuity was 4/10 OD and no light perception OS. Magnetic resonance imaging (MRI) revealed bilateral optic neuritis and a diffuse and severe infiltration of the intra- and extraconal fat on the left. Laboratory testing was negative except for serum myelin oligodendrocyte glycoprotein (MOG) antibodies. This presentation adds a new variant to the MOG-associated disease spectrum. Testing for MOG antibodies should be considered in patients presenting with diffuse orbital inflammation and optic neuritis.

Efficacy of rituximab in refractory RRMS.

OBJECTIVE: To investigate the efficacy of rituximab as rescue therapy in patients with relapsing-remitting multiple sclerosis (RRMS) and persistent disease activity confirmed by magnetic resonance imaging (MRI) despite immunosuppressive disease-modifying therapy (DMT). METHODS: In this observational nationwide retrospective multicenter study, we first identified 351 off-label rituximab-treated patients through a cohort of 15,984 RRMS patients. In this group, we identified patients with disease activity prior to rituximab confirmed by MRI (one or more new T2 lesion and/or gadolinium-enhancing lesion) despite immunosuppressive DMT (fingolimod, natalizumab, or mitoxantrone) with a follow-up after rituximab initiation longer than 6 months. Outcome data were collected from the French Observatory of Multiple Sclerosis (OFSEP) register and medical charts. RESULTS: A total of 50 patients were identified. Median rituximab treatment duration was 1.1 (0.5-6.4) year. Mean annualized relapse rate significantly decreased from 0.8 during last immunosuppressive DMT to 0.18 after rituximab ( p < 0.0001). While 72% of patients showed gadolinium-enhancing lesions on the last MRI performed during last immunosuppressive DMT, 8% of them showed gadolinium-enhancing lesions on the first MRI performed 6.1 (range 1.4-18.4) months after rituximab ( p < 0.0001). CONCLUSION: This study provides level IV evidence that rituximab reduces clinical and MRI disease activity in patients with active RRMS despite immunosuppressive DMT.

MRI features of demyelinating disease associated with anti-MOG antibodies in adults.

The spectrum of Myelin Oligodendrocytes Glycoprotein (MOG) antibody disease constitutes a recently described challenging entity, referring to a relatively new spectrum of autoimmune disorders with antibodies against MOG predominantly involving the optic nerve and spinal cord. The purpose of this article is to describe MRI features of MOG-AD involvement in the optic nerves, spinal cord and the brain of adults.

Rituximab for corticosteroid-resistant relapsing IgG4-related intracranial pachymeningitis: report of two cases.

IgG4-related disease is now recognised as an important cause of intracranial and spinal hypertrophic pachymeningitis. Treatment with corticosteroids generally leads to significant clinical improvement. We present two cases of IgG4 pachymeningitis unresponsive to corticosteroids who improved with rituximab.

Human T-Lymphotropic Virus Type 1-Induced Overexpression of Activated Leukocyte Cell Adhesion Molecule (ALCAM) Facilitates Trafficking of Infected Lymphocytes through the Blood-Brain Barrier.

UNLABELLED: Human T-lymphotropic virus type 1 (HTLV-1) is the etiological agent of a slowly progressive neurodegenerative disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). This disease develops upon infiltration of HTLV-1-infected lymphocytes into the central nervous system, mostly the thoracic spinal cord. The central nervous system is normally protected by a physiological structure called the blood-brain barrier (BBB), which consists primarily of a continuous endothelium with tight junctions. In this study, we investigated the role of activated leukocyte cell adhesion molecule (ALCAM/CD166), a member of the immunoglobulin superfamily, in the crossing of the BBB by HTLV-1-infected lymphocytes. We demonstrated that ALCAM is overexpressed on the surface of HTLV-1-infected lymphocytes, both in chronically infected cell lines and in primary infected CD4(+) T lymphocytes. ALCAM overexpression results from the activation of the canonical NF-κB pathway by the viral transactivator Tax. In contrast, staining of spinal cord sections of HAM/TSP patients showed that ALCAM expression is not altered on the BBB endothelium in the context of HTLV-1 infection. ALCAM blockade or downregulation of ALCAM levels significantly reduced the migration of HTLV-1-infected lymphocytes across a monolayer of human BBB endothelial cells. This study suggests a potential role for ALCAM in HAM/TSP pathogenesis. IMPORTANCE: Human T-lymphotropic virus type 1 (HTLV-1) is the etiological agent of a slowly progressive neurodegenerative disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). This disease is the consequence of the infiltration of HTLV-1-infected lymphocytes into the central nervous system (CNS), mostly the thoracic spinal cord. The CNS is normally protected by a physiological structure called the blood-brain barrier (BBB), which consists primarily of a continuous endothelium with tight junctions. The mechanism of migration of lymphocytes into the CNS is unclear. Here, we show that the viral transactivator Tax increases activated leukocyte cell adhesion molecule (ALCAM/CD166) expression. This molecule facilitates the migration of lymphocytes across the BBB endothelium. Targeting this molecule could be of interest in preventing or reducing the development of HAM/TSP.

MD1003 (high-dose biotin) for the treatment of progressive multiple sclerosis: A randomised, double-blind, placebo-controlled study.

BACKGROUND: Treatment with MD1003 (high-dose biotin) showed promising results in progressive multiple sclerosis (MS) in a pilot open-label study. OBJECTIVE: To confirm the efficacy and safety of MD1003 in progressive MS in a double-blind, placebo-controlled study. METHODS: Patients (n = 154) with a baseline Expanded Disability Status Scale (EDSS) score of 4.5-7 and evidence of disease worsening within the previous 2 years were randomised to 12-month MD1003 (100 mg biotin) or placebo thrice daily, followed by 12-month MD1003 for all patients. The primary endpoint was the proportion of patients with disability reversal at month 9, confirmed at month 12, defined as an EDSS decrease of ⩾1 point (⩾0.5 for EDSS 6-7) or a ⩾20% decrease in timed 25-foot walk time compared with the best baseline among screening or randomisation visits. RESULTS: A total of 13 (12.6%) MD1003-treated patients achieved the primary endpoint versus none of the placebo-treated patients (p = 0.005). MD1003 treatment also reduced EDSS progression and improved clinical impression of change compared with placebo. Efficacy was maintained over follow-up, and the safety profile of MD1003 was similar to that of placebo. CONCLUSION: MD1003 achieves sustained reversal of MS-related disability in a subset of patients with progressive MS and is well tolerated.

Northern African strains of human T-lymphotropic virus type 1 arose from a recombination event.

UNLABELLED: Although recombination is a major source of genetic variability in retroviruses, no recombinant strain had been observed for human T-lymphotropic virus type 1 (HTLV-1), the first isolated human-pathogenic retrovirus. Different genotypes exist for HTLV-1: Genotypes b and d to g are restricted to central Africa, while genotype c is only endemic in Australo-Melanesia. In contrast, the cosmopolitan genotype a is widely distributed. We applied a combination of phylogenetics and recombination analysis approaches to a set of new HTLV-1 sequences, which we collected from 19 countries throughout Africa, the continent where the virus has the largest endemic presence. This led us to demonstrate the presence of recombinants in HTLV-1. Indeed, the HTLV-1 strains currently present in North Africa have originated from a recombinant event between strains from Senegal and West Africa. This recombination is estimated to have occurred around 4,000 years ago. This recombination seems to have been generated during reverse transcription. In conclusion, we demonstrate that, albeit rare, recombination can occur in HTLV-1 and may play a role in the evolution of this retrovirus. IMPORTANCE: A number of HTLV-1 subtypes have been described in different populations, but none of the genetic differences between these subtypes have been ascribed to recombination events. Here we report an HTLV-1 recombinant virus among infected individuals in North Africa. This demonstrates that, contrary to what was thought, recombination can occur and could play a role in the evolution of HTLV-1.

Abnormal inflammatory activity returns after natalizumab cessation in multiple sclerosis.

OBJECTIVE: To characterise recurrence of multiple sclerosis (MS) inflammatory activity during the year following natalizumab (NTZ) cessation. METHODS: Thirty-two patients with MS were included in a monocentric cohort study. Data were collected prospectively during and after NTZ, with serial clinical and MRI evaluations. The first relapse occurring after interrupting NTZ was the primary outcome measure. The numbers of gadolinium-enhancing lesions before, during and after NTZ treatment, were compared. RESULTS: During the year following NTZ cessation, the cumulative probability of relapses was estimated at 52.9% and an unusually high MRI inflammation was noticed. It was defined by a number of gadolinium-enhancing lesions >5 and exceeding the gadolinium lesions existing before NTZ initiation. Rebound of MS activity after NTZ cessation was characterised by association of relapses and unusual MRI inflammation. Cumulative probability of rebound was estimated at 39% and mostly occurring between 3 months and 9months after interrupting NTZ. Risk of rebound appears related with a higher annualised relapse rate and a lower Expanded Disability Status Scale score before NTZ initiation. Rebound was associated with severe recurring relapses in 9% of the patients. CONCLUSIONS: This study identifies rebound after NTZ cessation as an association of relapses and high MRI activity.

An FMRI investigation of the cortical network underlying detection and categorization abilities in hemianopic patients.

The current study aims to investigate visual scene perception and its neuro-anatomical correlates for stimuli presented in the central visual field of patients with homonymous hemianopia, and thereby to assess the effect of a right or a left occipital lesion on brain reorganization. Fourteen healthy participants, three left brain damaged (LBD) patients with right homonymous hemianopia and five right brain damaged (RBD) patients with left homonymous hemianopia performed a visual detection task (i.e. "Is there an image on the screen?") and a categorization task (i.e. "Is it an image of a highway or a city?") during a block-designed functional magnetic resonance imaging recording session. Cerebral activity analyses of the posterior areas-the occipital lobe in particular-highlighted bi-hemispheric activation during the detection task but more lateralized, left occipital lobe activation during the categorization task in healthy participants. Conversely, in patients, the same network of activity was observed in both tasks. However, LBD patients showed a predominant activation in their right hemisphere (occipital lobe and posterior temporal areas) whereas RBD patients showed a more bilateral activation (in the occipital lobes). Overall, our preliminary findings suggest a specific pattern of cerebral activation depending on the task instruction in healthy participants and cerebral reorganization of the posterior areas following brain injury in hemianopic patients which could depend upon the side of the occipital lesion.

Natalizumab extended-interval dosing in a real-life setting.

BACKGROUND: Natalizumab is a high-efficacy therapy for recurrent multiple sclerosis (RMS) with a four-week administration interval. Controlled trials have shown that extending this interval to six weeks led to better safety without increasing the risk of relapse. We aimed to analyze the safety of extending the natalizumab interdose interval from 4 to 6 weeks in a real-life setting. METHODS: This monocentric retrospective self-controlled study included adult patients with RMS treated with natalizumab with a four-week interval between infusions for a minimum of six months, before switching to a six-week interval. The main outcomes were the incidence of MS relapse, new MRI lesions, and MRI activity signs during the two periods, with patients being their own controls. RESULTS: Fifty-seven patients were included in the analysis. The mean (95%CI) annualized relapse rate (AAR) before natalizumab introduction was 1.03 (0.52; 1.55). During the four-week interval dosing period, no patient presented with an MS relapse, and seven (13.5%) patients had new MRI lesions. During the six-week interval dosing period, no relapse was observed and two (3.6%) patients had new MRI lesions. CONCLUSION: We did not observe more relapses or signs of MRI activity when extending the interval between natalizumab infusions from four to six weeks.

HTLV-1 positive and negative T cells cloned from infected individuals display telomerase and telomere genes deregulation that predominate in activated but untransformed CD4+ T cells.

Untransformed HTLV-1 positive CD4(+) cells from infected individuals are selected for expressing tax and displaying morphological features consistent with telomere dysfunctions. We show that in resting HTLV-1 positive CD4(+) cells cloned from patients, hTERT expression parallels tax expression and cell cycling. Upon activation, these cells dramatically augment tax expression, whereas their increase in telomerase activity is about 20 times lower than that of their uninfected counterpart. Activated HTLV-1 positive CD4(+) but not uninfected CD4(+) or CD8(+) clones also repress the transcription of TRF1, TPP1, TANK1, POT1, DNA-PKc and Ku80. Both infected and uninfected lymphocytes from infected individuals shared common telomere gene deregulations toward a pattern consistent with premature senescence. ATLL cells displayed the highest telomerase activity (TA) whereas recovered a telomere gene transcriptome close to that of normal CD4(+) cells. In conclusion HTLV-1-dependent telomere modulations seem involved in clonal expansion, immunosuppression, tumor initiation and progression.

Generalization of ocular myasthenia gravis 10 years after onset.

BACKGROUND: Generalization of ocular myasthenia gravis (OMG) represents a pejorative evolution, and no validated generalization-prevention strategy exists. The study aimed to determine the percentage of patients with OMG generalization and identify factors predictive of it to establish a prediction score. METHODS: This retrospective, observational study included 151 patients diagnosed with OMG after an initial work-up in our institution. The outcome measure was time to MG generalization. The explanatory variables were age at onset (> 55 years), sex, first-year anti-acetylcholine-receptor antibody-positivity, repetitive nerve stimulation showing electromyogram decrement and corticosteroid use. Kaplan-Meier estimations of the probability of risk of generalization, and descriptive and multivariate Cox model analyses were computed. A nomogram combining explanatory variables was used to establish a score to predict the probability of OMG generalization. RESULTS: Among 183 patients' charts identified, 151 had confirmed OMG. Their median follow-up was 5.7 years. Estimations (95% CI) of OMG-generalization risk at 1, 3 and 10 years post-symptom onset, respectively, were: 13.0% (7.3-18.2), 25.1% (17.5-32.0) and 37.8% (27.2-45.2). The p-value-based multivariate analysis associated generalization with female sex, electromyogram decrement and first-year anti-acetylcholine-receptor antibody positivity, and Akaike information criterion-based analysis retained those three parameters and corticosteroid use. A nomogram was built and validated with an optimism-corrected C-statistic of 0.68, and calibration plots showed good fit. CONCLUSIONS: Our population's percentage of OMG generalization is in line with recent publications. Using the identified prognostic factors, the nomogram provided a score to predict the probable risk of generalization in our cohort.