ビッカースタッフ脳幹脳炎

Anti-GQ1b antibody syndromes span a clinical continuum from peripheral Guillain-Barré syndrome (GBS) to central Bickerstaff brainstem encephalitis (BBE), but reliable biomarkers of central nervous system (CNS) involvement that could guide treatment intensity are lacking. We report a 37-year-old woman with a relapsing GBS-Miller Fisher syndrome (MFS)-BBE overlap phenotype. In the first episode (March 2024), plasma exchange, intravenous methylprednisolone and IVIG were administered after anti-GD1a IgG was detected. After self-discontinuation of immunotherapy, she was readmitted in May 2024 with a two-month course of progressive weakness acutely worsened over four days, ophthalmoplegia, dysarthria, intermittent choking and bilateral extensor plantar responses. CSF showed albuminocytologic dissociation (protein 2.21 g/L; total cell count 40×106/L with a normal nucleated cell count) together with evidence of intrathecal IgG synthesis (IgG index 1.13; synthesis rate 147.10 mg/24h; oligoclonal bands type III with homologous serum bands). Electrophysiology revealed an acute motor axonal neuropathy pattern. IVIG and methylprednisolone were administered, with substantial improvement but persistent mild dysarthria and ataxia at three-month follow-up. The diagnosis was based mainly on the clinical course and electrophysiological findings, supported by serology and CSF analysis. This case shows that intrathecal IgG synthesis may complement albuminocytologic dissociation as a marker of CNS involvement in anti-GQ1b syndromes and supports the hypothesis-requiring prospective testing-that CSF immunological profiling could inform treatment intensity.

Autoimmune encephalitis (AE) comprises clinically and immunopathologically heterogeneous central nervous system disorders whose early recognition should be syndrome-based and should not depend on antibody results alone. Cerebellar and brainstem manifestations occur in selected AE and related central nervous system neuroimmune disorders, but their frequency, anatomical specificity, and mechanisms remain incompletely defined. In this narrative Review, we use the cerebellum-brainstem network as an anatomical and clinical organizing framework rather than proposing a discrete anatomical axis or a new disease entity. In selected neuronal-surface-antibody disorders, antibodies can directly alter receptor trafficking, receptor availability, protein interactions, or synaptic transmission, whereas intracellular-antigen-associated and paraneoplastic syndromes are more often linked to cytotoxic T-cell-dominant neuronal injury. To stabilize disease scope, central AE and directly relevant central nervous system autoimmune syndromes form the core evidence base; immune-mediated cerebellar ataxias, paraneoplastic syndromes, acute disseminated encephalomyelitis, and myelin oligodendrocyte glycoprotein antibody-associated disease are included only when they provide direct infratentorial evidence; and Miller Fisher syndrome and Guillain-Barré syndrome are retained solely as peripheral anatomical comparators, whereas Bickerstaff brainstem encephalitis represents a central brainstem syndrome. We present a hypothesis-generating circuit framework linking immune target engagement to cerebellar output and connected brainstem manifestations, while explicitly marking extrapolations from non-AE models as hypotheses [H]. We also distinguish a predominantly functional pattern from an established structural-injury pattern as non-sequential research constructs rather than stages, biomarker-defined transitions, treatment windows, or clinical algorithms. Current imaging studies demonstrate that infratentorial metabolic and structural abnormalities can occur, but no reproducible cerebellum-brainstem diagnostic, prognostic, or treatment-selection signature has been prospectively validated.

The neurologic manifestations of anti-GQ1b antibody syndrome continue to expand and include a spectrum of immune-mediated neuropathies such as Miller Fisher syndrome, Bickerstaff brainstem encephalitis, and optic neuropathy. Asialo-GM1 antibodies are associated with motor or sensorimotor neuropathies, particularly multifocal motor neuropathy. Reports describing concurrent seropositivity for anti-GQ1b and asialo-GM1 antibodies presenting with unilateral facial weakness and limb symptoms remain scarce. A 55-year-old woman with chronic back pain initially presented to an outside facility with new-onset left lower motor neuron facial palsy accompanied by paresthesia and extremity weakness. Neuro-axis MRI demonstrated moderate-to-severe multilevel spinal and neuroforaminal stenosis. She was discharged with prednisone and acyclovir for presumed idiopathic Bell's palsy. Shortly thereafter, she presented to our institution with worsening symptoms. Examination revealed diminished strength, hypoesthesia, and decreased reflexes with a persistent left lower motor neuron cranial nerve VII palsy. The remainder of the cranial nerve examination was normal, and there was no ophthalmoplegia or ataxia. Lumbar puncture demonstrated albuminocytologic dissociation. A ganglioside antibody panel was positive for anti-GQ1b and asialo-GM1 antibodies. This case highlights an unusual presentation of concurrent anti-GQ1b and asialo-GM1 antibody positivity manifesting as unilateral facial palsy and limb weakness initially attributed to Bell's Palsy. Recognition of ganglioside antibody syndromes as potential mimickers of Bell's palsy is essential to ensure prompt diagnosis and treatment, thereby reducing the risk of neurological morbidity.

Bickerstaff brainstem encephalitis (BBE) is rare in children, and neurophysiologic abnormalities may be detected and resolve at different times. A 12-year-old boy developed ophthalmoplegia, ataxia, somnolence, hyporeflexia, and weakness after a respiratory illness. On illness day 3, cerebrospinal fluid protein and magnetic resonance imaging were normal. On day 4, distal limb studies and needle electromyography were unrevealing, but tibial F-wave persistence was reduced, bilateral R1 and R2 blink responses were absent despite preserved facial compound muscle action potentials, and electroencephalography showed slowing. By days 15-16, albuminocytologic dissociation was present and the blink reflex had normalized, whereas F-wave persistence had declined; sensory nerve conduction, lower-limb sympathetic skin responses, and brainstem auditory evoked responses were abnormal. By day 84, limb electrophysiology and electroencephalography were normal, while the auditory waveform abnormality persisted. This case demonstrates temporally dissociated detection and recovery across pathways and supports serial multimodal reassessment when early routine studies are nondiagnostic.