(026) Neuropsychiatric approach of autoimmune encephalitis: a case series with treatment courses and outcomes

Abstract: Background/Significance:
Autoimmune encephalitis (AE) is a serious neuropsychiatric disorder that can be misperceived as a primary psychiatric illness. We present 3 cases that highlight the heterogeneity in which AE presents with catatonia and unique treatment courses.
Case Presentations:
• Case 1: 55-year-old male without significant medical history presented with 2-month onset of dysphagia, dysarthria, diplopia, and altered mental status. Workup significant for MRI hyperintensities suggesting inflammation of the left cerebral peduncle, thalamocapsular region, basal ganglia, and cranial nerves three and six. Three unremarkable serum and cerebrospinal fluid (CSF) autoimmune panels suggested seronegative AE. By week 1 of hospitalization, the patient developed hyperactive catatonia treated with lorazepam and zolpidem titration then transitioned to electroconvulsive therapy (ECT). The inflammatory component was managed with intravenous immunoglobulin (IVIG), stress-dose steroids, and rituximab. The catatonia improved and CNS hyperintensities on MRI resolved, however, baseline mentation remained significantly below baseline.
• Case 2: 22-year-old male with a remote history of herpes simplex encephalitis and febrile seizure presented with seizures, behavioral changes, and cognitive dysfunction. Electroencephalogram and MRI brain were unremarkable. CSF showed a lymphocytic-predominant pleocytosis and positive for anti-N-methyl-D-aspartate (NMDA) receptor antibodies. He was treated with methylprednisolone and IVIG without improvement. Three weeks after admission, the patient developed mood lability, disorganized behavior, and psychosis. Catatonia emerged during the fifth week and responded well to lorazepam and plasmapheresis, recovering to baseline functioning within 6 weeks.
• Case 3: 59-year-old female with a history significant for breast cancer (in remission) and gastric bypass surgery who was admitted for acute alteration in mental status. Her serum AE panel was mildly elevated for anti-glutamic acid decarboxylase antibody (anti-GAD), but negative on the CSF panel. She was treated with stress-dose steroids and IVIG without clinical improvement. A lorazepam challenge was equivocal, and patient received ECT for atypical catatonia with mild improvement in her ability to track and follow commands. However, she remained mute without significant improvement in mentation.

Discussion:
These cases represent the complex intersection within psychoneuroimmunology. Age of onset ranged from 22-60 years old and the literature also reports pediatric age range (Eyre, 2020). AE etiologies varied with case 2 reflecting the most common auto-antibody (anti-NMDA), case 1 being seronegative, and case 3 possibly being seronegative, as low anti-GAD65 titers are less associated with AE (Muñoz-Lopetegi, 2020). Each case derived benefit from a combination of immunosuppressive and psychiatric treatment modalities. The outcomes of our cases align with a cohort study demonstrating better outcomes in earlier age onset and antibody-positive AE (Lee, 2022).

References:
Eyre M, Kaushik A, Barrett E, et al. Catatonic features in children and adolescents with N-methyl-d-aspartate receptor antibody encephalitis. BJPsych open. 2020;6(4):e71. doi:10.1192/bjo.2020.55
Muñoz-Lopetegi A, de Bruijn MAAM, Boukhrissi S, et al. Neurologic syndromes related to anti-GAD65: Clinical and serologic response to treatment. Neurol Neuroimmunol neuroinflammation. 2020;7(3). doi:10.1212/NXI.0000000000000696
Lee WJ, Lee HS, Kim DY, Lee HS, Moon J, Park KI, Lee SK, Chu K, Lee ST. Seronegative autoimmune encephalitis: clinical characteristics and factors associated with outcomes. Brain. 2022 Oct 21;145(10):3509-3521. doi: 10.1093/brain/awac166.

Presentation Eligibility: Not previously published or presented

Diversity, Equity, and Inclusion: Catatonia and autoimmune encephalitis (AE) can present very differently, influenced by the biopsychosocial model. Sociocultural aspects of care are crucial to be recognized by understanding patient's backgrounds and addressing inequities they face. A deeper understanding of AE can help clinicians better find ways to address patient inequities and improve cultural competence in this unique area.