Autoimmune encephalitis (AE) represents a severe neuropsychiatric disorder that requires early diagnosis. This study describes the frequency, clinical characteristics, and paraclinical findings in patients with possible autoimmune encephalitis treated in a neurological emergency department, as well as factors associated with poor functional prognosis at discharge.

This was an observational ambispective cohort study including patients diagnosed with AE who were treated in a neurological emergency department in 2022. Demographic, clinical, and paraclinical characteristics were evaluated, along with functional outcomes using the modified Rankin scale (mRS); ≤2 points, was considered as good prognosis. In the statistical analysis we used the chi-squared test, Fisher's exact test, Student's T-test, and Mann-Whitney U test.

Out of 9046 patients, 31 (0.3%) met the criteria for probable autoimmune encephalitis (PAE). The average age was 28.4 ± 12.1 years and 51.6% were female. Cognitive alterations (90.3%), psychosis (74.2%), abnormal movements (71%), catatonia (67.7%), seizures/status epilepticus (64.5%, 19.4%), and dysautonomia (58.1%) were observed; 58.1% had a good functional prognosis. Factors associated with poor prognosis included older age (24.8 ± 5.0 vs. 33.4 ± 16.8, p = 0.049), status epilepticus (0% vs. 46.2%, p = 0.002), and lower frequency of headache (61.1% vs. 15.4%, p = 0.025).

AE represents a rare diagnosis even in a neurological emergency center; older age, status epilepticus and absence of headache were associated with poor functional prognosis at discharge.

We present a rare case of acute immune-mediated polyradiculoneuritis, a Guillain-Barré Syndrome (GBS) variant, manifesting as ophthalmoparesis-ataxia, facial diplegia, and acute bulbar palsy, accompanied by a unique autoimmune profile.

A 75-year-old female developed rapidly progressive symptoms, including bilateral non-reactive mydriasis, ptosis, complete ophthalmoplegia, bilateral facial weakness, tongue immobility, palatal paralysis, limb dysmetria, ataxia, and brisk generalized tendon reflexes, all while maintaining a preserved mental state. Symptoms emerged 10 days after a probable gastrointestinal infection. Severe bulbar dysfunction necessitated orotracheal intubation and a tracheotomy. Extensive cranial nerve involvement initially suggested a brainstem lesion, with oculomotor and acute bulbar palsy as prominent signs. However, brainstem and spinal magnetic resonance imaging along with cerebrospinal fluid analysis yielded negative results. Electromyography reveled a sensorimotor demyelinating polyradiculoneuropathy, and serum testing identified IgG antibodies targeting multiple gangliosides, including the disialosyl group and terminal NeuNAc(α2-3)Gal. Treatment with intravenous immunoglobulin (IVIG) led to gradual clinical improvement.

This case highlights a rare and severe GBS phenotype characterized by reactivity to multiple gangliosides. It highlights the role of shared ganglioside epitopes in antibody-mediated neurological damage and expands the clinical spectrum of GBS variants.