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.

Autoimmune encephalitis and immune therapy: lessons from Argentina.

Autoimmune encephalitis (AE) is a common cause of noninfectious acute encephalitis. We aimed to provide the first review of immune therapy regimens used for patients with AE in Latin America, as well as the safety and efficacy associated with them, by reviewing the medical records of Argentine patients with AE treated between 2013 and 2018. Data included clinical symptoms, laboratory tests, electroencephalography, magnetic resonance imaging, cerebral spinal fluid, and neoplasm screenings. We examined ten AE patients who received first-line immunotherapy at a median of 2.5 months following symptom onset. Among these patients, five required second-line treatment: three received therapy at a median of 4 months (2-112) after symptom onset and were treated with rituximab, while two received therapy at a median of 4.5 (4-5) months after onset and received methylprednisolone for 6 months and initiated chronic treatment with azathioprine. By the last follow-up, their respective outcomes improved significantly. On the modified Rankin Scale, the median score decreased from 5 to 1 (p ≤ 0.05). Only two of the ten patients in our series experienced relapses; both had been treated with a combination of methylprednisolone and IVIG. The regimen after recurrence included rituximab and corticoids plus azathioprine. Neither patient had experienced another relapse by their last follow-up. Our findings demonstrate the importance of early and aggressive immunosuppressive therapy to achieve a good clinical outcome and a fast recovery without relapses.

C3, C5a and anti-acetylcholine receptor antibody as severity biomarkers in myasthenia gravis.

BACKGROUND: Although the pathogenesis of myasthenia gravis (MG) is well known, prognostic markers are not yet available. We assessed the utility of anti-acetylcholine receptor (AChR) antibody (AChR-ab) titer and concentration of C3, C4, and C5a as potential severity biomarkers in MG. METHODS: Levels of C3, C4, C5a, and AChR-ab were measured in 60 AChR-ab-positive patients with MG. Their relationship with clinical severity was analyzed using the activities of daily living (ADL) and MG composite (MGC) scales. RESULTS: AChR-ab titer correlated with severity of MG according to ADL (p = 0.002) and MGC scales (p = 0.001). When patients were classified according to disease duration, a statistically significant correlation between AChR-ab titer and clinical severity was only found in the subgroup of patients with fewer than 5 years from symptoms onset. C5a levels showed a positive correlation with MG severity according to the ADL scale (p = 0.041; τb = 0.18), although C5a levels were not different from the control group. DISCUSSION: AChR-ab titers and C5a levels could potentially be considered markers of severity in patients with MG.