Relapse and Functional Outcomes in Anti-LGI1 Encephalitis

• Study Background:

Anti-LGI1 encephalitis is an autoimmune disorder where the body produces antibodies that attack the brain, leading to symptoms like memory loss, psychiatric issues, and seizures. Initial treatments with immunotherapy (like steroids) are effective for most patients. However, a significant number of patients are left with lasting neurological problems, and some experience a return of the disease (relapse) after a period of improvement. The rates of relapse and poor long-term outcomes reported in previous studies vary widely, and it is not clear which patients are most vulnerable. Furthermore, the best strategy for long-term treatment after the initial phase to prevent relapses is not well-established.

• Study Objectives

This study aims to:

• Describe how often patients with anti-LGI1 encephalitis experience a relapse of the disease.
• Assess their long-term functional recovery.
• Identify patient characteristics, symptoms, or treatment factors that may increase the risk of relapse or poor recovery.
• Data Collection

Data was gathered from electronic medical records and, when necessary, follow-up phone interviews. The information collected includes:

• Patient Demographics: Age, sex.
• Initial Illness: Symptoms at diagnosis, severity of the disease.
• Test Results: Findings from brain scans (MRI), brain wave tests (EEG), antibody levels and other relevant information.
• Treatments: Primarily types and durations of immunotherapy received (e.g., steroids, intravenous immunoglobulin, and maintenance immunosuppressants).
• Outcome Definitions

• Relapse: The return of new or worsening symptoms after the patient had been stable or improving for at least 3 months.
• Functional Outcome: The patient was largely independent in their daily activities at the last follow-up.

Inclusion criteria

• Characteristic presentations of anti-LGI1 encephalitis;
• LGI1-immunoglobulin G (IgG) positivity in serum and/or cerebrospinal fluid (CSF) by fixed cell-based assay (Euroimmun, Lübeck, Germany)
• follow-up ≥ 18 months after initial immunotherapies
• exclusion of alternative diagnoses

Exclusion criteria

• presence of coexisting neural autoantibodies
• history of central nervous system (CNS) infections, severe neurological or primary psychiatric disorders
• no prior use or lack of first-line immunotherapy
• insufficient follow-up data