Predictors of Mechanical Ventilation in Guillain-Barré Syndrome with Axonal Subtypes.

BACKGROUND: The early clinical predictors of respiratory failure in Latin Americans with Guillain-Barré syndrome (GBS) have scarcely been studied. This is of particular importance since Latin America has a high frequency of axonal GBS variants that may imply a worse prognosis. METHODS: We studied 86 Mexican patients with GBS admitted to the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, a referral center of Mexico City, to describe predictors of invasive mechanical ventilation (IMV). RESULTS: The median age was 40 years (interquartile range: 26-53.5), with 60.5% men (male-to-female ratio: 1.53). Most patients (65%) had an infectious antecedent (40.6% gastrointestinal). At admission, 38% of patients had a Medical Research Council (MRC) sum score <30. Axonal subtypes predominated (60.5%), with acute motor axonal neuropathy being the most prevalent (34.9%), followed by acute inflammatory demyelinating polyneuropathy (32.6%), acute motor sensory axonal neuropathy (AMSAN) (25.6%), and Fisher syndrome (7%). Notably, 15.1% had onset in upper limbs, 75.6% dysautonomia, and 73.3% pain. In all, 86% received either IVIg (9.3%) or plasma exchange (74.4%). IMV was required in 39.5% patients (72.7% in AMSAN). A multivariate model without including published prognostic scores yielded the time since onset to admission <15 days, axonal variants, MRC sum score <30, and bulbar weakness as independent predictors of IMV. The model including grading scales yielded lower limbs onset, Erasmus GBS respiratory insufficiency score (EGRIS) >4, and dysautonomia as predictors. CONCLUSION: These results suggest that EGRIS is a good prognosticator of IMV in GBS patients with a predominance of axonal electrophysiological subtypes, but other early clinical data should also be considered.

Clinical and neurophysiological description of patients with POEMS syndrome.

INTRODUCTION: POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) is a monoclonal gammopathy with polyneuropathy as a mandatory criterion. OBJECTIVE: To describe potential associations between clinical expression and electrodiagnostic patterns in POEMS syndrome. METHOD: Observational, retrospective, cross-sectional study of cases cared for in a referral center, diagnosed with POEMS syndrome from 2009 to 2019. RESULTS: Eleven patients (8 men) were analyzed. Median age at diagnosis was 40 years (range: 31-51; mean: 37.19 ± 15.67 years). Mean latency at diagnosis was 9.7 ± 8.37 months. In all subjects, initial clinical manifestation was polyneuropathy. Most patients had an axonal pattern (n = 5), followed by demyelinating (n = 4) and mixed patterns (n = 2). Monoclonal gammopathy was observed in all (6 l and 5 k cases; immunoglobulin [Ig] G: 72 %; IgA: 18 %; IgM: 9 %). Medical Research Council sum score was lower in the axonal pattern (median: 37.00 vs. 45.5; p = 0.024). There were no differences in systemic involvement between electrophysiological patterns. CONCLUSION: Electrophysiological patterns are unlikely to have a clear extra-neurological clinical correspondence; however, this will have to be definitively proven with a larger sample size.

INTRODUCCIÓN: El síndrome POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) es una gammapatía monoclonal con polineuropatía como criterio obligatorio. OBJETIVO: Describir las potenciales asociaciones entre la expresión clínica y los patrones de electrodiagnóstico en el síndrome POEMS. MÉTODO: Estudio observacional, retrospectivo y transversal de los casos atendidos en un centro de referencia con diagnóstico de síndrome de POEMS de 2009 a 2019. RESULTADOS: Se analizó a 11 pacientes (8 hombres). La mediana de la edad al diagnóstico fue de 40 años (rango: 31-51, media: 37.19 ± 15.67 años). La latencia media al diagnóstico fue de 9.7 ± 8.37 meses. En todos la manifestación clínica inicial fue la polineuropatía. La mayoría de los pacientes presentaron un patrón axonal (n = 5), seguido del desmielinizante (n = 4) y mixto (n = 2). La gammapatía monoclonal se observó en todos (6 casos l y 5 k, inmunoglobulina [Ig] G: 72%, IgA: 18%, IgM: 9%). El Medical Research Council sum score fue menor en el patrón axonal (medianas: 37.00 vs. 45.5, p = 0.024). No se presentaron diferencias en la afección sistémica entre patrones electrofisiológicos. CONCLUSIÓN: Es poco probable que los patrones electrofisiológicos tengan una correspondencia clínica extraneurológica clara, sin embargo, esto deberá probarse de forma definitiva con un mayor tamaño de muestra.

Association of MGAT4C with major neurocognitive disorder in the Mexican population.

BACKGROUND: Neurocognitive disorders (NCDs) are characterized by cognitive decline. Most genetic studies of NCDs have been focused on single-nucleotide polymorphism; other genetic variations, such as copy number variants (CNV), have been less explored. The aim of the present study was to explore CNVs associated with NCDs in a small sample of Mexican individuals and search for the frequency in a larger replication sample of individuals at high-risk for or diagnosed with NCDs. METHOD: The exploratory analysis analyzed whole-genome CNVs associated with NCDs in 1335 individuals, of whom 35 were diagnosed with NCDs and 1300 were population-based controls. Whole-genome CNVs were derived from PsychArray and the PennCNV algorithm. The frequency of associated CNVs in a sample of 277 individuals diagnosed with NCDs and 70 high-risk individuals was then determined using RT-PCR. RESULTS: The exploratory analysis identified one deletion associated with NCDs (p = 0.007) affecting the gene MGAT4C (Mannosyl (Alpha-1,3-)-Glycoprotein Beta-1,4-N-Acetylglucosaminyltransferase, Isozyme C). In the replication sample, a frequency of 3.97% was found in individuals diagnosed with NCDs and 1.43% in high-risk individuals. CONCLUSIONS: An association between a rare CNV on MGAT4C and cognitive impairment was found in this sample of the Mexican population. Nevertheless, studies with larger sample sizes are needed in order to further explore the association.