Anti-thyroid antibodies and thyroid function in anti-N-methyl-d-aspartate receptor encephalitis

Low triiodothyronine (T3) levels predict worse outcomes in autoimmune encephalitis-A meta-analysis of current literature

INTRODUCTION

An unusual association between thyroid dysfunction and autoimmune encephalitis (AE) was noticed when patients presented with low free triiodothyronine (fT3) levels and antithyroid antibodies. We conducted a meta-analysis to investigate whether thyroid dysfunction, that is, lower fT3 levels are associated with worsening clinical manifestations and prognosis in patients with AE.

METHODS

Literature search of five electronic databases was performed till April 5, 2023. Inclusion criteria were as follows: Observational studies reporting patients with all subtypes of AE and assessing thyroid dysfunction categorized as low fT3 and non-low fT3. Primary endpoints included modified Rankin scale (mRS) at admission, abnormal magnetic resonance imaging, length of stay, seizures, and consciousness declination.

RESULTS

Comprehensive literature search resulted in 5127 studies. After duplicate removal and full-text screening, six observational studies were included in this analysis. Patients with low fT3 were 2.95 times more likely to experience consciousness declination (p = .0003), had higher mRS at admission (p < .00001), had 3.14 times increased chances of having a tumor (p = .003), were 3.88 times more likely to experience central hypoventilation, and were 2.36 times more likely to have positivity for antithyroid antibodies (p = .009) as compared to patients with non-low fT3.

CONCLUSION

The findings of our study suggest that low fT3 levels might be related to a more severe disease state, implying the significance of thyroid hormones in AE pathogenesis. This finding is crucial in not only improving the early diagnosis of severe AE but also in the efficient management of the disease.

Analysis of the relation between cerebrospinal fluid antibody titers and clinical characteristics in pediatric patients with anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVE

This retrospective study aimed to investigate the relationship between cerebrospinal fluid (CSF) antibody titers of N-methyl-d-aspartate receptor (NMDAR), and clinical characteristics in pediatric patients with anti-NMDAR encephalitis.

METHODS

The clinical and laboratory characteristics of hospitalized patients with anti-NMDAR encephalitis, stratified by antibody titers in CSF and disease severity, were retrospectively studied. The demographics, clinical characteristics, main accessory examinations, immunotherapy, and prognosis of patients were recorded, and each observed indicator was statistically analyzed.

RESULTS

A total of 103 pediatric anti-NMDAR encephalitis patients were enrolled in the study, including 41 males (39.8%) and 62 females (60.2%) with a mean age of 8.0 ± 4.0 years. The proportion of patients with cognitive dysfunction and the positive pathogen was higher in the high-titer group than in the low-titer group (p = 0.023, p = 0.042). Consciousness disturbance that occurred as an initial symptom or during the course in the severe group was higher than in the non-severe group (p = 0.002, p < 0.001). More patients in the high-titer group received plasma exchange (PE) than in the low-titer group (p = 0.022). The cure rate of patients was higher with PE (65.2%) than with Corticosteroids and (or) intravenous immunoglobulin (58.1%).

CONCLUSIONS

Patients with symptoms of disturbance of consciousness may be severer. The severity in pediatric anti-NMDAR encephalitis patients was not correlated with anti-NMDAR antibody titers. Patients with high CSF antibody titers had a better prognosis after early PE therapy.

Role of N-methyl-d-aspartate receptors in anxiety disorder with thyroid lesions

OBJECTIVE

Patients with anxiety disorder (AD) often have structural and functional abnormalities of the thyroid gland, but their specific causes remain unclear. N-methyl- d-aspartate receptors (NMDARs) play an important role in many psychosomatic diseases and tumorigenesis, but there are few reports on the role of NMDARs in AD with thyroid lesions, especially thyroid nodules (TNs).

METHODS

A cross-sectional study was conducted on patients admitted to the hospital with AD (n = 71) as the main diagnosis from April to October 2021. Meanwhile, patients with TNs with no AD (NAD-TN group, n = 20) and healthy subjects (HS group, n = 37) with matched age, sex, and education were randomly collected as controls. Patients with AD were sub-grouped into the AD with TNs (AD-TN group, n = 41) and the AD with no TNs (AD-NTN group, n = 30). The thyroid ultrasound reports, Hamilton Anxiety Scale (HAMA) scores, and the expression of NMDARs and their subunits (NR1, NR2A, and NR2B) and hypothalamic-pituitary-thyroid (HPT) axis-related hormones were analyzed in all subjects. Some patients with TNs underwent surgery and postoperative pathological examination.

RESULTS

Patients with AD showed a lower level of free triiodothyronine (FT3) and higher levels of thyrotropin-releasing hormone (TRH) and NMDARs and their subunits compared to the healthy controls. The expression of the NR2A subunit was higher in the AD-TN group than that in other three groups (AD-NTN, NAD-TN, and HS groups, F = 13.650, p &lt; 0.001). Regression analysis showed that the level of NMDARs was positively correlated with the HAMA scores (B = 1.622, p = 0.029) and the maximum diameter of TNs (B = 3.836, p = 0.005). Immunohistochemical results showed that the NR2A subunit was widely expressed in multinodular goiter (MNG) and papillary thyroid carcinoma (PTC) tissues, while the expression of the NR2B subunit was lower in PTC adjacent and MNG tissues and almost absent in PTC tissues.

CONCLUSION

In a sample of mostly women hospitalized with generalized anxiety disorder (GAD) or panic disorder, abnormal expression of NMDARs is closely related to AD with thyroid lesions, NMDAR subunits may have various activities and exert diverse effects in TNs, and the NR2A subunit may be an important regulator in AD with TNs.

The detection of up-regulated anti-thyroid antibodies and autoimmune thyroid diseases in patients with autoimmune encephalitis: a retrospective study of 221 patients

OBJECTIVE

To investigate the potential detection rate of anti-thyroid antibodies' (ATAbs) positivity, thyroid dysfunctions, and autoimmune thyroid diseases (AITDs) in autoimmune encephalitis (AE) and to analyze whether thyroid autoimmunity/dysfunction can affect the clinical course of AE.

METHODS

Two hundred twenty-one AE patients and 229 age- and sex-matched controls were included in this study. We measured the levels of ATAbs (anti-thyroglobulin antibodies [TgAb], anti-thyroid peroxidase anti-bodies [TPOAb]) and thyroid hormones in all the individuals. In addition, the association of thyroid autoimmunity/dysfunctions with functional outcomes of AE was identified by using logistic regression and Kaplan-Meier analyses.

RESULTS

The prevalence of TPOAb-positive and TgAb-positive was significantly higher in AE patients (16.3% and 16.7%, respectively) as compared with controls (9.6% and 7.4%, respectively; P = 0.034 and P = 0.002, respectively). In addition, the free triiodothyronine (fT3) level was significantly lower in AE patients as compared to the controls (P < 0.001). However, the frequency of AITDs (Hashimoto's thyroiditis and Graves' disease) did not significantly differ between AE patients and control subjects. Importantly, low fT3 was found to be associated with poor functional outcomes at the 3-month follow-up in AE. Adjustment of potential confounders did not change the association. However, the presence of ATAbs did not significantly alert the disease course of AE.

CONCLUSIONS

ATAbs-positive and/or AITD patients with symptomatic encephalopathy should undergo proper surveillance for AE. Moreover, low fT3 could serve as a possible predictor of poor short-term outcome in AE, thereby suggesting that monitoring of thyroid function in AE may be necessary.

Thyroid Function and Low Free Triiodothyronine in Chinese Patients With Autoimmune Encephalitis

Background and Objectives

Low free triiodothyronine (FT3) is usually associated with worse functional outcome in critical illness; however, the information on thyroid dysfunction and autoimmune encephalitis (AE) is limited. This study aims to evaluate the clinical prognostic value of thyroid function and low-T3 syndrome in patients with multiple subtypes of AE.

Methods

In this retrospective study, we identified the hospital records of 319 candidate patients with AE admitted between January 2016 and December 2020. We then extracted the clinical features and outcomes. Modified Rankin scale (mRS) scores were used to evaluate the patients’ neurological function. The serum levels of FT3, free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured upon admission. Normal thyroid stimulating hormone level with FT3 below the lower limit of the reference interval (2.63 nmol/L) was defined as low-T3 syndrome.

Results

A total of 237 AE cases remained after screening. Among these, 57.81% (137/237) were men and the average age at onset was 41 y (interquartile range, 12–61 y). We found that 83.54% (198/237) of the patients had a good prognosis, and 16.46% (39/237) had a poor prognosis. Abnormal thyroid function was observed in 30.80% of these patients, with a relatively greater prevalence in the group with a poor prognosis (p < 0.001). The serum FT3 levels in the poor-prognosis group were significantly lower than those in the good-prognosis group (p < 0.001). Low-T3 syndrome occurred in 15.19% of AE cases and was more frequent in patients with poor prognosis (p < 0.001).

Conclusions

Abnormal thyroid function in AE is frequent, and serum FT3 levels in patients with poor prognosis are significantly lower than in those with good prognosis. Low-T3 syndrome could be a potential candidate for predicting the prognosis of AE following future research.

Thyroid Function and Anti-thyroid Antibodies in Pediatric Anti-NMDAR Encephalitis

Objective: Recent studies found that changes of thyroid antibodies (ATAbs), thyroid hormone, and non-thyroidal illness syndrome (NTIS) characterized by thyroid hormone inactivation with low triiodothyronine and high reverse triiodothyronine followed by suppressed thyroid-stimulating hormone (TSH) in adult anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis were associated with disease severity. This study aimed to explore thyroid function and ATAbs in pediatric anti-NMDAR encephalitis and their clinical association. Methods: We retrospectively analyzed the clinical data of 51 pediatric cases with anti-NMDAR encephalitis hospitalized in Guangzhou Women and Children's Medical Center from August 2016 to 2019. Results: A percentage of 52.9% of patients belonged to the ATAb (+) group, with 26 cases both positive for anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TGAb), and one patient only positive for TPOAb. A percentage of 62.7% of patients had at least one abnormality in terms of FT₃, free thyroxin (FT₄), or TSH levels. Meanwhile, 45.1% of patients were diagnosed with NTIS. Among 25 cases retested for thyroid function 2 months after the initial test, the respectively decreased FT₃ and FT₄ in 13 and 11 cases on admission returned to normal or closer normal than before; TPOAb in eight cases and TGAb in 12 cases were changed from positivity to negativity. Compared with onset, the level of TPOAb and TGAb at relapse remained stable or significantly decreased, respectively. Compared with the ATAb (-) group, the ATAb (+) group had an older onset age, a higher ratio of movement disorders, elevated rate of sleep disorders, increased anti-nuclear antibody positivity rate, and higher ratio of more than one course of intravenous immunoglobulin treatment. There were no significant differences between the NTIS and non-NTIS groups in clinical characteristics. Conclusion: Anti-thyroid antibody positivity, abnormality of FT₃, FT₄, or TSH levels and NTIS are frequent in pediatric anti-NMDAR encephalitis. Thyroid antibody and thyroid hormone abnormalities could be improved through the course of treatment of anti-NMDAR encephalitis. Cases with ATAbs (+) are at older onset ages and more likely to be treated by intravenous immunoglobulin therapy more than once. Unlike adult anti-NMDAR encephalitis, NTIS might not be associated with the clinical characteristics of anti-NMDAR encephalitis in pediatric patients.

Presence of Anti-Thyroid Antibodies Correlate to Worse Outcome of Anti-NMDAR Encephalitis

Objective

To investigate the characteristics and prognosis of anti-NMDAR encephalitis with the prevalence of anti-thyroid antibodies (ATAbs).

Methods

The clinical data of anti-NMDAR encephalitis patients admitted to Xuanwu Hospital from January 2012 to August 2018 was prospectively analyzed, and the patients were followed up for 24 months.

Results

A total of 120 patients were enrolled, of which 34.2% (41/120) were positive for ATAbs. The antibodies were more frequent in patients with severe disease compared to the non-severe group (51.4% vs. 25.6%, P=0.008). In addition, prevalence of ATAbs correlated with a higher incidence of disturbed consciousness, autonomic dysfunction, central hypoventilation and mechanical ventilation. The ATAbs-positive patients were also more likely to receive intravenous gamma immunoglobulin and immunosuppressor compared to the ATAbs-negative cases (P=0.006; P=0.035). Although the presence of ATAbs was associated with longer hospital stays and worse prognosis at 6 months (P=0.006; P=0.038), it had no impact on long-term patient prognosis. Positive status of anti-thyroglobulin antibody was an independent risk factor for worse prognosis at 6 months [odds ratio (OR)= 3.907, 95% CI: 1.178-12.958, P=0.026].

Conclusion

ATAbs are prevalent in patients with anti-NMDAR encephalitis, especially in severe cases, and correlate with poor prognosis and impaired short-term neurological recovery.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis Associated with Ovarian Teratoma in South China-Clinical Features, Treatment, Immunopathology, and Surgical Outcomes of 21 Cases

Objective

To study the clinical characteristics and surgical outcomes of anti-NMDAR encephalitis and the immunopathology of associated teratomas.

Methods

Twenty-one patients were enrolled in this retrospective study, who were diagnosed with anti-NMDAR encephalitis with ovarian teratoma and admitted to two tertiary hospitals in South China from July 2014 to December 2019. The clinical data of patients were reviewed. Comparisons were made between the patients with different outcomes after surgery. Immunohistochemical analyses of associated ovarian teratomas were performed.

Results

The mean age of the patients was 24.33 ± 5.12 years. The peak seasons of disease onset were autumn and winter (30.61% and 32.65%). The symptoms could be divided into 8 categories, including psychiatric abnormalities, seizures, movement dysfunction, consciousness disorders, autonomic dysregulation, speech disturbance, central hypoventilation, and memory deficits. All patients developed four or more categories of symptoms within the first four weeks. Twelve patients (57.1%) had a maximum mRS of 5, and 11 patients (52.4%) were admitted to ICU. Twenty patients received surgery, and only 3 patients were diagnosed pathologically with immature ovarian teratomas, while the other 17 patients had mature ovarian teratomas. After surgery, 17 patients (85.0%) got clinical improvement. The central hypoventilation symptom and mature ovarian teratomas were associated with surgical outcome. Immunohistochemical analysis revealed that there were NMDAR-positive neural tissues in all 8 teratomas and in which 3 cases also contained large numbers of NMDAR-positive sebaceous glands and squamous epithelial tissues.

Conclusion

The disease is of high prevalence in autumn and winter. The central hypoventilation symptom and mature ovarian teratomas were associated with surgical outcome. NMDAR-positive neural tissue is not the only etiological factor of encephalitis. We speculate that encephalitis development in some patients may result from NMDAR expression in sebaceous glands and squamous epithelial tissues.

Emerging role of free triiodothyronine in patients with anti-N-methyl-D-aspartate receptor encephalitis

We aimed to investigate the role of free triiodothyronine (FT3) in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. 137 consecutive inpatients (2016–2019) were registered prospectively and followed up for 12 months. 96 eligible patients were included in the study. The modified Rankin scale (mRS) score was collected, and the score of 3–6 was defined as a poor outcome. The patients were equally classified into 3 subgroups based on their FT3 levels obtained within 24 h of admission, and the subgroup differences were analyzed by parametric or nonparametric tests as appropriate. Logistic regression analysis was performed. We found that there was no difference in the mRS scores upon admission among 3 subgroups, however, patients in the low-FT3 subgroup tended to have higher disease severity during hospitalization and worse outcome in follow-up visits, represented by higher chances of intense care unit (ICU) admission (P < 0.001), longer hospital stay (P < 0.001), greater maximum mRS scores during hospitalization (P = 0.011), lower rates of getting clinical improvement within 4 weeks of starting treatment (P = 0.006), and higher percentages of poor 1-year outcome (P = 0.002). The level of FT3 was an independent factor correlated with ICU admission (P = 0.002) and might be a potential predictor for 1-year outcome. Our preliminary results suggest that the FT3 may be a risk factor involved in the evolution and progression of anti-NMDAR encephalitis, whereas the underline mechanisms remain to be explored. Attention should be paid to these patients with relatively low FT3 upon admission, which might possibly aid clinical prediction and guide clinical decision-making.

Serum Systemic Autoantibodies in Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Objective: The aim of this retrospective study was to investigate the relationship between serum systemic autoantibodies and anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.

Methods: Thirty-nine patients with anti-NMDAR encephalitis were examined for serum systemic autoantibodies (antinuclear antibodies, extractable nuclear antigen autoantibodies, rheumatoid factors, and anti-neutrophil cytoplasmic antibodies), in comparison with 39 neuromyelitis optica spectrum disorder (NMOSD) and 78 healthy controls. Clinical features, cerebrospinal fluid characteristics, and outcomes were compared between the two subgroups of anti-NMDAR patients with positive and negative systemic autoantibodies, respectively.

Results: Anti-NMDAR encephalitis patients had higher frequency of positive serum systemic autoantibodies than healthy controls (23.1 vs. 2.6%, p = 0.001) and lower frequency than NMOSD (23.1 vs. 48.7%, p = 0.018). No patients were diagnosed comorbidities with non-organ-specific autoimmune diseases. Consciousness disturbance was more frequent in autoantibodies positive group than in the negative group (88.9 vs. 40.0%, p = 0.02). Autoantibody positive group had a poorer outcome than autoantibody negative group (55.6 vs. 86.7%, p = 0.043). There was a negative correlation between serum autoantibodies and outcomes in anti-NMDAR encephalitis patients (r = −0.325, p = 0.044).

Conclusion: Our data demonstrated serum systemic autoantibodies were more frequent in anti-NMDAR encephalitis patients than in healthy controls and less frequent than NMOSD, which were associated with higher severity of disease.

Epilepsy and autoimmune diseases: Comorbidity in a national patient cohort

PURPOSE

To examine if autoimmune disorders occur with an increased frequency in patients with epilepsy. An autoimmune etiology of epilepsies has been suggested. By using data from The Norwegian Prescription Database (NorPD) we have surveyed a national cohort of patients with active epilepsy treated with antiepileptic drugs.

METHODS

NorPD contains all prescriptions of drugs dispensed at pharmacies in Norway since 2004. We received data of all drugs prescribed January 2004 - June 2014 for patients receiving an antiepileptic drug.79 751 patients receiving at least two prescriptions of antiepileptic drugs with the reimbursement code for epilepsy were included. To examine autoimmune comorbidity, medications specific for autoimmune diseases were retrieved. Standardized Incidence Ratios (SIR) with 95 % confidence interval (CI) were used to determine whether the occurrence of the prescribed autoimmune drugs in the epilepsy group deviated from the general population. Subgroups stratified for sex and age were examined.

RESULTS

The epilepsy patients were more often treated with insulin and insulin analogs, SIR 1.8 (95 % CI 1.7-1.9); thyroid substitution, SIR 1.7 (95 % CI 1.7-1.8); pyridostigmine, SIR 1.5 (95 % CI 1.1-2.1); multiple sclerosis (MS) medications, SIR 4.9 (95 % CI 4.6-5.3); and immunosuppressive drugs SIR 1.2 (95 % CI 1.1-1.2). All epilepsy subgroups were more often than expected treated with thyroid substitution.

CONCLUSIONS

Based on a large, unselected patient cohort we find that epilepsy patients more often are prescribed medications used to treat type 1 diabetes mellitus, hypothyroidism, myasthenia gravis and MS. This was true for both men and women, and in most age-groups.