Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study

Background

The frequency of antibodies in autoimmune encephalitis (AIE) may vary in different populations, however, data from developing countries are lacking. To describe the clinical profile of AIE in Brazil, and to evaluate seasonality and predictors of AIE in adult and pediatric patients.

Methods

We evaluated patients with possible AIE from 17 centers of the Brazilian Autoimmune Encephalitis Network (BrAIN) between 2018 and 2022. CSF and serum were tested with TBAs and CBAs. Data on clinical presentation, complementary investigation, and treatment were compiled. Seasonality and predictors of AIE in adult and pediatric populations were analyzed.

Results

Of the 564 patients, 145 (25.7%) were confirmed as seropositive, 69 (12.23%) were seronegative according to Graus, and 58% received immunotherapy. The median delay to diagnosis confirmation was 5.97 ± 10.3 months. No seasonality variation was observed after 55 months of enrolment. The following antibodies were found: anti-NMDAR (n=79, 54%), anti-MOG (n=14, 9%), anti-LGI1(n=12, 8%), anti-GAD (n=11, 7%), anti-GlyR (n=7, 4%), anti-Caspr2 (n=6, 4%), anti-AMPAR (n=4, 2%), anti-GABA-BR (n=4, 2%), anti-GABA-AR (n=2, 1%), anti-IgLON5 (n=1, 1%), and others (n=5, 3%). Predictors of seropositive AIE in the pediatric population (n=42) were decreased level of consciousness (p=0.04), and chorea (p=0.002). Among adults (n=103), predictors of seropositive AIE were movement disorders (p=0.0001), seizures (p=0.0001), autonomic instability (p=0.026), and memory impairment (p=0.001).

Conclusion

Most common antibodies in Brazilian patients are anti-NMDAR, followed by anti-MOG and anti-LGI1. Only 26% of the possible AIE patients harbor antibodies, and 12% were seronegative AIE. Patients had a 6-month delay in diagnosis and no seasonality was found. Findings highlight the barriers to treating AIE in developing countries and indicate an opportunity for cost-effect analysis. In this scenario, some clinical manifestations help predict seropositive AIE such as decreased level of consciousness, chorea, and dystonia among children, and movement disorders and memory impairment among adults.

Stiff-person syndrome with paraneoplastic neurological syndrome: a case report and literature review

BACKGROUND

Stiff-person syndrome (SPS) manifests by progressive rigidity along with muscle spasms that affect the axial and limb muscles. First discovered in 1956, significant progress has been made in its clinical characterization, comprehension of pathogenesis, as well as effective treatment therapy.

CASE PRESENTATION

A 67-year old female patient presented with a 2-year history of progressive stiffness along with painful spasms in both legs, with her condition worsening over the previous year making it considerably difficult for her to stand and walk. Here, we report a Stiff-person syndrome patient (SPS) with lung adenocarcinoma who was positive for anti-glutamate decarboxylase (anti-GAD) antibodies. Treatment with hormones and gamma-globulin improved her symptoms. In addition, we present a literature review of SPS patients with tumors.

CONCLUSIONS

The diagnosis of autoimmune SPS was on the basis of clinical, electrophysiological, as well as immunological findings. Early SPS detection is critical to preventing long-term disability.

Progressive Encephalomyelitis With Rigidity and Myoclonus With Thymoma: A Case Report and Literature Review

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is part of the variant type of the Stiff Person Syndrome (SPS) and is a rare neurological disease. We report here a patient with PERM who had thymoma and was positive for anti-glutamic acid decarboxylase (anti-GAD) antibodies. Her symptoms improved after treatment with hormones and gamma globulin. We also summarized the literature review of patients with PERM accompanied by tumors reported.

[A case of stiff-limb syndrome with anti-glycine receptor antibody]

A 48-year-old woman with a 3-month history of spontaneously resolving stiff leg symptom at the age of 43 years presented with progressive onset of leg rigidity, walking difficulty, and myoclonic jerks. On admission she had marked stiffness in her foot joints with symmetric sustained dorsiflexion of the ankles and toes, with spontaneous and reflex myoclonic jerks easily provoked by knee tendon tap. She appeared to have a spastic gait due to stiffness in her legs. Needle electromyogram (EMG) examination revealed continuous motor unit activity in the tibialis anterior muscle at rest even when voluntary contraction of the gastrocnemius muscle was instructed, but no myokimic discharge or acute denervation sign was seen. The laboratory tests were unremarkable, including glutamic acid decarboxylase antibody. Cerebrospinal fluid (CSF) examination was also normal, without oligoclonal bands or elevated IgG index. She was diagnosed with stiff-limb syndrome based on neurologic examination and needle EMG findings, and she was treated with intravenous high-dose methylprednisolone (500 mg/day, 3 days), resulting in marked improvement in her symptoms. Anti-glycine receptor antibodies were subsequently identified in her archived serum and CSF obtained before immunotherapy. She was then started on oral prednisolone (30 mg/day) and had been free of symptoms.

Progressive Encephalomyelitis with Rigidity and Myoclonus Resolving after Thymectomy with Subsequent Anasarca: An Autopsy Case

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is an autoimmune disorder involving the brainstem and spinal cord and is sometimes associated with thymoma. We encountered a 75-year-old woman with typical PERM features, glycine receptor antibody, and thymoma. Her neurologic symptoms improved after thymectomy, but she unexpectedly developed anasarca with massive pleural effusions and hypoalbuminemia and finally succumbed to death. The autopsy showed edema and mononuclear infiltration in the pleura but no neuropathological findings typical of PERM. Effective treatment of PERM can reverse the neuropathological signs of encephalomyelitis. The autoimmune nature of anasarca is possible but not proven.