Cost-Effectiveness of Routine Screening for Autoimmune Encephalitis in Patients With First-Episode Psychosis in the United States

Neural Antibodies in First-episode Psychosis Patients with Warning Signs for Autoimmune Encephalitis

Objective

: Autoimmune encephalitis (AE) remains an essential differential diagnosis in patients with first-episode psychosis (FEP). In this study, we aimed to assess to prevalence of AE in a cohort of FEP patients.

Methods

: We used a phenotype-driven algorithm to detect AE in patients with FEP. Initially, we screened patients for warning signs with a low or high pre-test probability for AE, defined as "yellow" and "red flags", respectively. In the next step, patients with red flags underwent cerebrospinal fluid analysis (including neural antibodies), while patients with yellow flags underwent tests for serum neural antibodies, electroencephalography, and brain magnetic resonance imaging.

Results

: We screened 78 patients with FEP and found that eight (10.3%) had at least one warning sign for AE: four (5.13%) patients had at least one red flag, while four (5.13%) had only yellow flags. Among these, two patients (2.56%) had anti-N-methyl-D-aspartate receptor encephalitis, while the remaining six (7.69%) received a primary psychiatric disorder diagnosis.

Conclusion

: Our study highlights the importance of considering AE in the differential diagnosis of FEP.

The relevance of anti-N-methyl-D-aspartate receptor encephalitis for psychiatrists

Psychiatrists are often the first to be consulted in patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. While this disease is rare, psychiatrists need to be aware of its relevant fundamental, clinical and therapeutic aspects. We begin by reviewing the connection between anti-NMDAR encephalitis and the glutamate hypothesis of schizophrenia. Next, we focus on the profile of the patient typically afflicted with this disease. Then, we tackle the limited utility of current diagnostic criteria during the early stage of the disease. After reviewing the psychiatric features, we debate the quest for finding specific psychiatric phenotypes that could facilitate early-stage diagnosis. We conclude by discussing the treatment of psychiatric symptoms and disease outcomes. As follows, this paper presents the relevance of anti-NMDAR encephalitis for psychiatrists.

Anti-glutamic acid decarboxylase antibody screening in first-episode psychosis

OBJECTIVE

The Royal Australian and New Zealand College of Psychiatrists recommends screening for a range of antibodies in first-episode psychosis, including anti-glutamic acid decarboxylase antibodies. Glutamic acid decarboxylase antibody-associated encephalitis occurs with high antibody titres and may cause cognitive dysfunction, seizures and psychiatric symptoms. However, glutamic acid decarboxylase antibodies are more frequently found in lower titre in association with other autoimmune disorders (such as diabetes mellitus type 1) and in healthy individuals. The utility of testing unselected populations of consumers with psychosis is unclear. The psychiatric manifestations of this disorder are also poorly described.

METHODS

First, systematic review of cohort and case-control studies that tested for IgG glutamic acid decarboxylase antibodies in psychiatric populations was conducted. Random-effects meta-analysis of odds ratio for antibody positivity in cases with psychosis and controls assessed prevalence. Second, literature review of all published cases and case series of glutamic acid decarboxylase antibody-associated limbic encephalitis was assessed for frequency and description of psychotic symptoms.

RESULTS

There were 17 studies, in which 2754 individuals with psychotic disorders were tested for glutamic acid decarboxylase IgG antibodies. Thirty-one consumers with psychosis (0.7%) had positive glutamic acid decarboxylase antibodies compared to 24 controls (1.0%), all at low titre and not fulfilling diagnostic criteria for autoimmune encephalitis. Meta-analysis found no significant difference in rates of glutamic acid decarboxylase antibody positivity (odds ratio = 1.8, 95% confidence interval: [0.90, 3.63]). Literature review found 321 cases of glutamic acid decarboxylase antibody-associated limbic encephalitis, with psychosis in 15 (4.3%) cases. Clinical screening would have identified all cases that presented to psychiatric services.

CONCLUSION

Glutamic acid decarboxylase antibodies were uncommon in consumers with psychosis, with no significant difference in prevalence from controls and no cases of encephalitis identified. In cases with established glutamic acid decarboxylase antibody-associated limbic encephalitis, psychotic symptoms were uncommon and identifiable by clinical assessment. Targeted antibody testing guidelines should be further considered.

Anti-N-Methyl-d-Aspartate Receptor Antibody Testing in First-Episode Psychosis: Universal or Targeted Testing

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an immune-mediated disorder that typically presents with rapid development of neuropsychiatric symptoms. As a potentially reversible cause of psychosis, there have been calls internationally for routine serological screening for anti-NMDAR antibodies in patients presenting with first-episode psychosis (FEP). Increased serological testing has, however, exposed several limitations of universal screening and rekindled debate as to which patients should be tested. Screening criteria have been proposed for high-risk clinical features in FEP in which antineuronal antibody testing is indicated. The authors present a clinical vignette and a service audit as well as discuss the limitations of universal screening advocating instead for targeted testing for antineuronal antibodies in patients diagnosed as having FEP.

First-line immunotherapy of neuronal surface antibody-mediated autoimmune encephalitis: Assessment of therapeutic effectiveness and cost-efficiency

OBJECTIVE

To evaluate the therapeutic effectiveness and cost-efficiency of first-line immunotherapies on neuronal surface antibody-mediated autoimmune encephalitis (AE) based on a real-world observational study in China.

METHODS

Our study retrospectively collected the clinical and paraclinical data of patients with definite neuronal surface antibody-mediated AE between July 2014 and July 2020. Regular follow-up was performed after administering standard regimens of first-line immunotherapies, including intravenous methylprednisolone (IVMP) and / or intravenous immunoglobulin (IVIG). Therapeutic effectiveness was reflected by modified Rankin Scale scores. The health resource utilization and direct medical costs were extracted to analyze the cost-efficiency.

RESULTS

Among the 78 eligible patients, 48 (61.5%) were males with a median age of 40 years. More than half (56, 71.8%) were treated with combination therapy, with the rest receiving IVMP and IVIG monotherapy (both of 11, 14.1%). Related objective variables, i.e., sex, onset age, disease course, onset symptoms, antibody types, abnormal paraclinical results, disease severity, and the health insurance, showed insignificant differences on the selection of therapy. Each therapy showed similar short-term (4-week) and long-term (1-year) therapeutic effects. Yet the single or combination of IVIG had a slightly better effectiveness but higher cost than the monotherapy of IVMP.

CONCLUSION

The combination of IVMP and IVIG was used more frequently than either alone, which may be associated with neurologist's personal experience and patient's wishes. Though with similar therapeutic effectiveness, the use of IVMP alone might be a better choice with a better cost-efficiency.

Autoimmune antibodies in first-episode psychosis with red flags: A hospital-based case-control study protocol

BACKGROUND

Research is increasingly identifying an overlap between psychosis and immunological dysregulation. Certain autoantibodies are being identified in a small but probably relevant subgroup of patients with psychosis. The term "autoimmune psychosis" (AIP) and its corresponding red-flag signs present the opportunity for a new field in psychiatry to promote diagnostic workup and immunomodulating therapy in individual cases.

OBJECTIVES

The present protocol aims to determine the seroprevalence of autoantibodies in first-episode psychosis (FEPs) using AIP red flag signs, and to explore the frequency of autoantibody subtypes and potential mediating confounders.

METHODS/DESIGN

This is a hospital-based case-control study. All participants will be consecutively selected from the main tertiary psychiatric hospital in Shenzhen City, China. Individuals admitted to the psychiatric ward and diagnosed with FEPs will be enrolled. Based on recent consensus, participants with red flags of AIPs will be defined as cases, while the remainder will be matched as controls. Seropositive antibodies will be detected and verified in cerebrospinal fluid (CSF) samples based on the fixed cell-based assay (CBA) method. The propensity score-adjusted odds ratios will be determined to investigate the key mediating confounders regarding autoantibody subtypes and red flag subsets.

DISCUSSION

The results of this study will facilitate the early identification of AIPs in FEP patients using the red flag sign and help identify key mediators that improve the accuracy of diagnostic algorithms. It will have clinical significance to focus on serum antibodies that have been verified in CSF samples, due to its consistency with clinical practices in current psychiatry.