Association between acute disseminated encephalomyelitis and thyroid autoimmunity in children

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.

Seizures in myelin oligodendrocyte glycoprotein antibody-associated disorders and related immune factors

PURPOSE

Epileptic seizures in myelin oligodendrocyte glycoprotein (MOG) antibody-associated disorders (MOGAD) have been increasingly reported in the past two decades. However, the characteristics and possible mechanism largely remain unknown. This study aimed to investigate the clinical characteristics and immune mechanism of epileptic seizures in children with MOGAD.

METHODS

We conducted a retrospective single-center case-control study from February 2019 to February 2021. Clinical characteristics and immune parameters of enrolled patients with seizures (n = 12) in MOGAD (n = 32), as compared with the antibody-negative (n = 13) and control (n = 23) groups were then analyzed.

RESULTS

Seizures occurred in 24.5% (12/49, including cases that were not enrolled) of MOGAD. In this group, magnetic resonance imaging (MRI) abnormalities, especially unilateral cortical lesion and leptomeningeal enhancement, were more frequent in patients with seizures than in individuals without seizures (p < 0.05). Levels of thyroid peroxidase antibodies (TPOAb) in the seizure+/MOG+ group were significantly (p < 0.05) higher than those in the seizure-/MOG+ and control groups, whereas no significant differences as compared with the seizure+/MOG- group were observed. TPOAb level and brain MRI performance may be associated with disease course, since two cases with increased TPOAb and abnormal brain MRI were reported, after a second seizure attack occurred.

CONCLUSION

Unilateral cerebral cortical encephalitis and isolated seizures, especially in clusters and focal seizures, may be special phenotypes of seizures in MOG-AD. TPOAb may be associated with seizures in immune-related neurological diseases, but not a specific marker of MOGAD. Therefore, TPOAb may be considered but not strongly recommended to be monitored in MOGAD.