Application of the international criteria for optic neuritis in the Acute Optic Neuritis Network.

OBJECTIVE: The first international consensus criteria for optic neuritis (ICON) were published in 2022. We applied these criteria to a prospective, global observational study of acute optic neuritis (ON). METHODS: We included 160 patients with a first-ever acute ON suggestive of a demyelinating CNS disease from the Acute Optic Neuritis Network (ACON). We applied the 2022 ICON to all participants and subsequently adjusted the ICON by replacing a missing relative afferent pupillary defect (RAPD) or dyschromatopsia if magnetic resonance imaging pathology of the optical nerve plus optical coherence tomography abnormalities or certain biomarkers are present. RESULTS: According to the 2022 ICON, 80 (50%) patients were classified as definite ON, 12 (7%) patients were classified as possible ON, and 68 (43%) as not ON (NON). The main reasons for classification as NON were absent RAPD (52 patients, 76%) or dyschromatopsia (49 patients, 72%). Distribution of underlying ON etiologies was as follows: 78 (49%) patients had a single isolated ON, 41 (26%) patients were diagnosed with multiple sclerosis, 25 (16%) patients with myelin oligodendrocyte glycoprotein antibody-associated disease, and 15 (9%) with neuromyelitis optica spectrum disorder. The application of the adjusted ON criteria yielded a higher proportion of patients classified as ON (126 patients, 79%). INTERPRETATION: According to the 2022 ICON, almost half of the included patients in ACON did not fulfill the requirements for classification of definite or possible ON, particularly due to missing RAPD and dyschromatopsia. Thorough RAPD examination and formal color vision testing are critical to the application of the 2022 ICON.

Guillain-Barré Syndrome and COVID-19 Vaccine: A Multicenter Retrospective Study of 46 Cases.

ABSTRACT: In the context of the global vaccination campaign against COVID-19, several cases of postvaccinal Guillain-Barré syndrome (GBS) were reported. Whether a causal relationship exists between these events has yet to be established. We investigated the clinical and electromyographic characteristics of patients who developed GBS after COVID-19 vaccination and compare these with findings in patients with GBS, without a history of recent vaccination. We included 91 cases between March 2020 and March 2022, treated at 10 referral hospitals of Buenos Aires, Argentina. Of these, 46 had received vaccination against COVID-19 within the previous month. Although Medical Research Council sum-scores were similar in both groups (median 52 vs. 50; P = 0.4), cranial nerve involvement was significantly more frequent in the postvaccination group (59% vs. 38%; P = 0.02), as was bilateral facial paralysis (57% vs. 24%; P = 0.002). No differences were found in clinical or neurophysiological phenotypes, although 17 subjects presented the variant of bilateral facial palsy with paresthesias (11 vs. 6; P = 0.1); nor were significant differences observed in length of hospital stay or mortality rates. Future vaccine safety monitoring and epidemiology studies are essential to demonstrate any potential causal relationship between these events.

SARS-CoV-2 RNA detection in cerebrospinal fluid: Presentation of two cases and review of literature.

Neurological manifestations of SARS-CoV-2 infection are multiple and heterogeneous. However, confirmation of nervous system impairment by viral RNA detection in cerebrospinal fluid (CSF) is uncommon. We report two cases of central nervous system (CNS) involvement with positive real-time reverse-transcriptase polymerase chain reaction (RT-PCR) test in CSF.

Marchiafava-Bignami Disease Associated with Spinal Involvement.

Marchiafava-Bignami disease (MBD) is a rare disorder of unknown etiology, strongly associated with alcoholism and malnutrition. MBD causes primary involvement of the corpus callosum, leading to confusion, dysarthria, seizures, and frequent death. We report the case of a 54-year-old male without a history of alcoholism or known malabsorption disease, who presented with altered consciousness and neurologic impairment. Complex B deficiency was addressed. Magnetic resonance imaging (MRI) showed typical corpus callosum lesions. The clinical features and radiologic images suggested spinal cord involvement. Brain histopathologic findings were consistent with MBD. Despite vitamin replacement therapy, he had a poor outcome.