Pittock, Sean J.

Background: Optic neuritis (ON) is often the presenting symptom in inflammatory central nervous system demyelinating disorders. Objective: To compare the frequency and pattern of optic chiasm involvement in patients with aquaporin-4-immunoglobulin G (AQP4-IgG)-associated ON to patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated ON. Methods: Retrospective review of all patients evaluated at Mayo Clinic, Stanford University and Ramathibodi Hospital who were found to have: (1) ON, (2) either MOG-IgG or AQP4-IgG by cell-based assay, and (3) magnetic resonance imaging (MRI) at the time of ON. MRI was reviewed for contrast enhancement of the optic chiasm and the pattern of involvement. Results: One hundred and fifty-four patients (74 AQP4-IgG and 80 MOG-IgG) were included. Among patients with AQP4-IgG-ON, 20% had chiasmal involvement, compared with 16% of patients with MOG-IgG-ON ( p = 0.66). In patients with chiasmal involvement, longitudinally extensive optic nerve enhancement (from orbit extending to chiasm) was identified in 54% of MOG-IgG-ON patients, compared with 7% of AQP4-IgG-ON patients ( p = 0.01). Conclusion: Chiasmal involvement of MOG-IgG-ON and AQP4-IgG-ON occur at more similar frequencies than previously reported. Furthermore, MOG-IgG-ON chiasmal involvement is more likely to be part of a longitudinally extensive optic nerve lesion.

AbstractThe objective of this study was to describe serological association of musicogenic epilepsy and to evaluate clinical features and outcomes of seropositive cases. Through retrospective chart review, musicogenic epilepsy patients were identified. Among 16 musicogenic epilepsy patients, nine underwent autoantibody evaluations and all had high‐titer glutamic acid decarboxylase 65–immunoglobulin G (GAD65‐IgG; >20 nmol·L–1, serum, normal ≤ .02 nmol·L–1, eight women). Median GAD65‐IgG serum titer was 294 nmol·L–1 (20.3–3005 nmol·L–1), and median cerebrospinal fluid titer (n = 4) was 14.7 nmol·L–1. All patients had temporal lobe epilepsy, and bitemporal epileptiform abnormalities were common. Right temporal lobe seizures were most frequently captured when seizures were induced by music on electroencephalogram (3/4; 75%). Intravenous (IV) methylprednisolone and/or IV Ig (IVIG) was utilized in four patients, with one having greater than 50% reduction. Rituximab (n = 2) and mycophenolate (n = 1) were ineffective. Two patients underwent right temporal lobe resections but continued to have seizures. Vagus nerve stimulation was effective at reducing seizures in one patient by 50%, and an additional patient was seizure‐free by avoiding provoking music. Right temporal lobe epilepsy was more common among patients with musicogenic epilepsy when compared to nonmusicogenic GAD65 epilepsies (n = 71, 89% vs. 47%, p = .03). GAD65‐IgG should be tested in patients with musicogenic epilepsy, given implications for management and screening for comorbid autoimmune conditions.

AbstractParaneoplastic neurological syndrome (PNS) comprises a group of neurological disorders that result from a misguided immune response to the nervous system triggered by a distant tumor. These disorders frequently manifest before the diagnosis of the underlying neoplasm. Since the first reported case in 1888 by Oppenheim, the knowledge in this area has evolved rapidly. Several classic PNS have been described, such as limbic encephalitis, paraneoplastic cerebellar degeneration, encephalomyelitis, opsoclonus-myoclonus, sensory neuronopathy, Lambert-Eaton Myasthenic syndrome, and chronic gastrointestinal dysmotility. It is now recognized that PNS can have varied nonclassical manifestations that extend beyond the traditional syndromic descriptions. Multiple onconeural antibodies with high specificity for certain tumor types and neurological phenotypes have been discovered over the past 3 decades. Increasing use of immune checkpoint inhibitors (ICIs) has led to increased recognition of neurologic ICI-related adverse events. Some of these resemble PNS. In this article, we review the clinical, oncologic, and immunopathogenic associations of PNS.