Diagnostic MRI Score to Differentiate Susac Syndrome from Primary Angiitis of the Central Nervous System and Multiple Sclerosis.

OBJECTIVE: Susac syndrome (SuS), multiple sclerosis (MS), and primary angiitis of the central nervous system (PACNS) present diagnostic challenges due to overlapping clinical features. We aimed to enhance diagnostic precision by developing the SPAMS (SuS, PACNS, MS) score, a practical radiological tool. METHODS: This multicenter study included 99 patients (43 SuS, 37 MS, 19 PACNS) from South American countries. Relevant MRI features were identified through an elastic-net model determined key variables. RESULTS: The SPAMS score assigned 2 points for snowball lesions, 1 point for spokes-like lesions, or if there are more than 4 lesions in the corpus callosum, corpus callosum involvement, or cerebellar involvement. It subtracted 1 point if gadolinium-enhancing lesions or 4 points if Dawson's fingers are present. Bootstrapping validated the optimal cutoff at 2 points, exhibiting a diagnostic performance of area under the curve = 0.931, sensitivity = 88%, specificity = 89%, positive predictive value = 88%, negative predictive value = 89%, and accuracy = 88%. INTERPRETATION: When specific MRI findings coexisted, the SPAMS score differentiated SuS from MS and PACNS. Access to MRI and standard protocol sequences makes it a valuable tool for timely diagnosis and treatment, potentially preventing disability progression and severe clinical outcomes. ANN NEUROL 2024;96:846-854.

Performance of McDonald 2017 multiple sclerosis diagnostic criteria and evaluation of genetic ancestry in patients with a first demyelinating event in Argentina.

BACKGROUND: Information on performance of multiple sclerosis (MS) diagnostic criteria is scarce for populations from Latin America, Asia, or the Caribbean. OBJECTIVE: To assess performance of revised 2017 McDonald criteria as well as evaluate genetic ancestry in a group of MS patients from Argentina experiencing a debut demyelinating event. METHODS: Demographic and clinical characteristics, cerebrospinal fluid (CSF), and magnetic resonance imaging (MRI) findings and new T2 lesions were recorded at baseline and during relapses. Diagnostic accuracy in predicting conversion to clinically defined MS (CDMS) based on initial imaging applying revised 2017 criteria was evaluated and genetic ancestry-informative markers analyzed. RESULTS: Of 201 patients experiencing their first demyelinating event (median follow-up 60 months), CDMS was confirmed in 67. We found 2017 diagnostic criteria were more sensitive (84% vs 67%) and less specific (14% vs 33%) than 2010 criteria, especially in a group of patients revised separately, presenting positive oligoclonal bands (88% vs 8%). Genetic testing performed in 128 cases showed 72% of patients were of European ancestry and 27% presented genetic admixture. CONCLUSION: 2017 McDonald criteria showed higher sensitivity and lower specificity compared with 2010 criteria, shortening both time-to-diagnosis and time-to-treatment implementation.

Clinically relevant increases in serum neurofilament light chain and glial fibrillary acidic protein in patients with Susac syndrome.

BACKGROUND AND PURPOSE: Serum levels of neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) are promising neuro-axonal damage and astrocytic activation biomarkers. Susac syndrome (SS) is an increasingly recognized neurological condition and biomarkers that can help assess and monitor disease evolution are highly needed for the adequate management of these patients. sNfL and sGFAP levels were evaluated in patients with SS and their clinical relevance in the relapse and remission phase of the disease was assessed. METHODS: As part of a multicentre study that enrolled patients diagnosed with SS from six international centres, sNfL and sGFAP levels were assessed in 22 SS patients (nine during a relapse and 13 in remission) and 59 age- and sex-matched healthy controls using SimoaTM assay Neurology 2-Plex B Kit. RESULTS: Serum NfL levels were higher than those of healthy controls (p < 0.001) in SS patients and in both subgroups of patients in relapse and in remission (p < 0.001 for both), with significantly higher levels in relapse than in remission (p = 0.008). sNfL levels showed a negative correlation with time from the last relapse (r = -0.663; p = 0.001). sGFAP levels were slightly higher in the whole group of patients than in healthy controls (p = 0.046) and were more pronounced in relapse than in remission (p = 0.013). CONCLUSION: In SS patients, both sNFL and sGFAP levels increased compared with healthy controls. Both biomarkers had higher levels during clinical relapse and much lower levels in remission. sNFL was shown to be time sensitive to clinical changes and can be useful to monitor neuro-axonal damage in SS.

Susac syndrome: challenges in the diagnosis and treatment.

Susac syndrome is a disorder thought to be mediated by an autoimmune response towards endothelial cells, leading to a characteristic clinical triad of encephalopathy, visual disturbances due to branch arterial occlusions and sensorineural hearing impairment. Although it is a rare disease, three reasons make it important. First, given its variable presentation, Susac syndrome is underdiagnosed. Second, it is considered an important differential diagnosis in different neurological, psychiatric, ophthalmological and hearing disorders, and consequently is frequently misdiagnosed. Third, in many cases, Susac syndrome is diagnosed and treated late, with significant irreversible sequelae including dementia, blindness and hearing loss. Neuropathology findings derived from both Susac syndrome patient tissue and novel transgenic mouse models indicate cytotoxic CD8+ T cells adhere to microvessels, inducing endothelial cell swelling, vascular narrowing and occlusion, causing microinfarcts. Anti-endothelial cell antibodies are present in serum in 25% of Susac syndrome patients, but it is unclear whether they are aetiologically related to the disease, or an epiphenomenon. The clinical triad comprising encephalopathy, branch arterial occlusions, and sensorineural hearing impairment is considered pathognomonic, although great variability is found in presentation and natural course of disease. At first evaluation, only 13-30% of patients exhibit the full clinical triad, making diagnosis difficult. Retinal fluorescein angiography, optic coherence tomography, MRI and tonal audiometry are helpful methods for diagnosing and monitoring disease activity during treatment. By contrast, there are no reliable objective immune markers to monitor disease activity. Immunosuppression is the current treatment, with high-dose corticosteroid therapy as the mainstay, but additional therapies such as intravenous immunoglobulins, cyclophosphamide, rituximab and mycophenolate mofetil are often necessary, because the disease can be devastating, causing irreversible organ damage. Unfortunately, low rates of disease, variability in presentation and paucity of objective biomarkers make prospective controlled clinical trials for Susac syndrome treatment difficult. Current immunosuppressive treatments are therefore based on empirical evidence, mainly from retrospective case series and expert opinion. In this review, we draw attention to the need to take consider Susac syndrome in the differential diagnosis of different neurological, psychiatric, ophthalmological and hearing disorders. Furthermore, we summarize our current knowledge of this syndrome, in reference to its pathophysiology, diagnosis and management, emphasizing the need for prospective and controlled studies that allow a better therapeutic approach.

The frequency and characteristics of multiple sclerosis misdiagnosis in Latin America: A referral center study in Buenos Aires, Argentina.

OBJECTIVE: Most contemporary data concerning the frequency and causes of multiple sclerosis (MS) misdiagnosis are from North America and Europe with different healthcare system structure and resources than countries in Latin America. We sought to determine the frequency, and potential contributors to MS misdiagnosis in patients evaluated at an MS referral center in Argentina. METHODS: The study was a retrospective medical record review. We included patients evaluated at the MS Clinic at Fleni between April 2013 and March 2021. Diagnoses prior to consultation, final diagnoses after consultation, demographic, clinical and paraclinical data, and treatment were extracted and classified. RESULTS: Seven hundred thirty-six patients were identified. Five hundred seventy-two presented with an established diagnosis of MS and after evaluation, misdiagnosis was identified in 89 (16%). Women were at 83% greater risk of misdiagnosis (p = 0.034). The most frequent alternative diagnoses were cerebrovascular disease, radiological isolated syndrome (RIS), and headache. Seventy-four (83%) of misdiagnosed patients presented with a syndrome atypical for demyelination, 62 (70%) had an atypical brain magnetic resonance imaging (MRI), and 54 (61%) were prescribed disease-modifying therapy. CONCLUSION: Sixteen percent of patients with established MS were subsequently found to have been misdiagnosed. Women were at higher risk for misdiagnosis. Expert application of the McDonald criteria may prevent misdiagnosis and its associated morbidity and healthcare system cost.

Progressive multiple sclerosis: from pathogenic mechanisms to treatment.

During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved in progressive multiple sclerosis, correlations between histopathology and magnetic resonance imaging studies, along with possible new therapeutic approaches.

Sodium intake is associated with increased disease activity in multiple sclerosis.

BACKGROUND: Recently, salt has been shown to modulate the differentiation of human and mouse Th17 cells and mice that were fed a high-sodium diet were described to develop more aggressive courses of experimental autoimmune encephalomyelitis. However, the role of sodium intake in multiple sclerosis (MS) has not been addressed. We aimed to investigate the relationship between salt consumption and clinical and radiological disease activity in MS. METHODS: We conducted an observational study in which sodium intake was estimated from sodium excretion in urine samples from a cohort of 70 relapsing-remitting patients with MS who were followed for 2 years. The effect of sodium intake in MS disease activity was estimated using regression analysis. We then replicated our findings in a separate group of 52 patients with MS. RESULTS: We found a positive correlation between exacerbation rates and sodium intake in a multivariate model adjusted for age, gender, disease duration, smoking status, vitamin D levels, body mass index and treatment. We found an exacerbation rate that was 2.75-fold (95% CI 1.3 to 5.8) or 3.95-fold (95% CI 1.4 to 11.2) higher in patients with medium or high sodium intakes compared with the low-intake group. Additionally, individuals with high-sodium intake had a 3.4-fold greater chance of developing a new lesion on the MRI and on average had eight more T2 lesions on MRI. A similar relationship was found in the independent replication group. CONCLUSIONS: Our results suggest that a higher sodium intake is associated with increased clinical and radiological disease activity in patients with MS.

Benign multiple sclerosis: does it exist?

Although the definition of benign multiple sclerosis (BMS) remains controversial, it is generally applied to a subgroup of MS patients showing little disease progression, with minimal disability decades after disease onset, and is based mainly on changes in motor function. Recent studies, however, reveal that deterioration of cognitive function, fatigue, pain, and depression also occur in BMS patients, causing negative impact on work and social activities, despite complete preservation of motor function. Using conventional MRI techniques, lesion load observed in BMS is similar to levels in other disease subtypes; however, newer quantitative MRI techniques show less tissue damage, as well as greater repair and compensatory efficiency following MS injury. Currently accepted criteria for BMS diagnosis may cause overestimation of true prevalence, underscoring the need for routine monitoring of nonmotor symptoms and imaging studies. Clearly, the definition of BMS currently applied in clinical practice requires reassessment.

Absence of latitudinal gradient in oligoclonal bands prevalence in Argentina.

BACKGROUND: Like MS prevalence, oligoclonal bands (OCB) frequency seems to follow a latitudinal gradient. Argentina is extensive, latitude-wise, and previous studies have not found an MS prevalence latitudinal gradient. Our aim is to describe OCB prevalence in MS, clinically isolated syndrome (CIS) and radiologically isolated syndrome (RIS) patients included in the Argentinean MS and NMOSD registry (RelevarEM) and to investigate if it follows a latitudinal gradient. METHODS: For each province, an average latitude was calculated, and OCB frequency was investigated. Multivariate logistical regression analysis and linear correlation were performed. Statistical analysis was repeated after excluding patients from centers using isoelectric focusing (IEF) in less than 95% of patients (CwIEF<95). RESULTS: We included 2866 patients. OCB where positive in 73.9% of patients. No association or correlation were found between OCB and latitude of residence, even after excluding patients from (CwIEF<95). CONCLUSION: OCB positivity does not follow a latitudinal gradient in Argentina. Also, OCB positivity is lower than described in other world regions.

Quality of Life Assessment in Multiple Sclerosis: Different Perception between Patients and Neurologists.

BACKGROUND: In recent years, neurologists are noticing that evaluation of multiple sclerosis (MS) patients based on combining relapses, disability progression, and magnetic resonance imaging activity may be insufficient to adequately assess suboptimal responses to available therapy. Inclusion of quality of life (QoL) parameters may contribute to breach this gap. OBJECTIVE: To evaluate agreement levels between doctor and patient perception of QoL in MS. METHODS: A total of 700 MS patients and 300 neurologists were invited to participate in a cross-sectional study by answering an e-mail questionnaire. The survey collected information on demographical data and included the Short Form questionnaire (SF-36). After completing the questionnaire, patients were given a standard written description of each of the subdomains assessed by SF-36 and asked to identify which three were the most important determinants of their overall health-related QoL. RESULTS: A total of 135 neurologists and 380 MS patients responded the survey. Study population mean age was 42.1 ± 10.5 years, with 61% presenting relapsing-remitting MS. SF-36 results were physical function 68.4 ± 30, physical role limitation 56.8 ± 41.7, vitality 47.6 ± 21.4, pain 71.2 ± 26.1, social function 72.6 ± 28.6, emotional role limitation 63.2 ± 39.8, mental health 60 ± 14.1, and general health 55.8 ± 22. Doctors considered physical function (75%) and physical role limitation (70%) as the most important QoL determinants in MS, followed by emotional role limitation (52%). Patients however, assigned significantly different levels of importance to physical function (58%), and physical role limitation (46%) and considered vitality (52%) more important than their physicians (p < 0.001). Important to note, the results of SF-36 questionnaire were highly correlated with the perception gap between patients and neurologists (r = 0.89; p = 0.0004). CONCLUSION: Concerns on QoL in MS are different for patients and physicians. It is essential to enhance communication in order to better understand actual patient needs.

White matter relapsing remitting disease: "Susac's syndrome"-An underdiagnosed entity.

Susac's syndrome is a treatable microangiopathy of unknown etiology affecting arterioles of the brain, retina, and cochlea. The typical clinical manifestation is the triad of encephalopathy, visual loss, and sensorineural hearing loss. One or more of these features may not be present at onset and therefore Susac's syndrome's diagnosis may be difficult. We describe the clinical presentation, diagnostic tests, and treatment of three cases diagnosed and treated at our institution.