Hashimoto's encephalopathy and anti-MOG antibody encephalitis: 50 years after Lord Brain's description

Autoimmune diseases and cancers overlapping with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD): A systematic review

Background

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has various similarities with AQP4-IgG-seropositive Neuromyelitis Optica Spectrum Disorder (AQP4-IgG + NMOSD) in terms of clinical presentations, magnetic resonance imaging (MRI) findings, and response to treatment. But unlike AQP4-IgG + NMOSD, which is known to coexist with various autoimmune diseases and cancers, an association of MOGAD with these conditions is less clear.

Methods

We conducted a systematic search in PubMed, Scopus, Web of Science, and Embase based on the preferred reporting items for systematic reviews and meta-analysis (PRISMA). Duplicates were removed using Mendeley 1.19.8 (USA production) and the citations were uploaded into Covidence systematic review platform for screening.

Results

The most common autoimmune disease overlapping with MOGAD was anti-N-Methyl-D-Aspartate receptor encephalitis (anti-NMDAR-EN), followed by autoimmune thyroid disorders, and the most common autoantibody was antinuclear antibody (ANA), followed by AQP4-IgG (double-positive MOG-IgG and AQP4-IgG). A few sporadic cases of cancers and MOG-IgG-associated paraneoplastic encephalomyelitis were found.

Conclusion

Unlike AQP4-IgG + NMOSD, MOGAD lacks clustering of autoimmune diseases and autoantibodies associated with systemic and organ-specific autoimmunity. Other than anti-NMDAR-EN and perhaps AQP4-IgG + NMOSD, the evidence thus far does not support the need for routine screening of overlapping autoimmunity and neoplasms in patients with MOGAD.

Clinical Features and Imaging Findings of Myelin Oligodendrocyte Glycoprotein-IgG-Associated Disorder (MOGAD)

Myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD) is a nervous system (NS) demyelination disease and a newly recognized distinct disease complicated with various diseases or symptoms; however, MOGAD was once considered a subset of neuromyelitis optica spectrum disorder (NMOSD). The detection of MOG-IgG has been greatly improved by the cell-based assay test method. In one study, 31% of NMOSD patients with negative aquaporin-4 (AQP-4) antibody were MOG-IgG positive. MOGAD occurs in approximately the fourth decade of a person’s life without a markedly female predominance. Usually, optic neuritis (ON), myelitis or acute disseminated encephalomyelitis (ADEM) encephalitis are the typical symptoms of MOGAD. MOG-IgG have been found in patients with peripheral neuropathy, teratoma, COVID-19 pneumonia, etc. Some studies have revealed the presence of brainstem lesions, encephalopathy or cortical encephalitis. Attention should be given to screening patients with atypical symptoms. Compared to NMOSD, MOGAD generally responds well to immunotherapy and has a good functional prognosis. Approximately 44-83% of patients undergo relapsing episodes within 8 months, which mostly involve the optic nerve, and persistently observed MOG-IgG and severe clinical performance may indicate a polyphasic course of illness. Currently, there is a lack of clinical randomized controlled trials on the treatment and prognosis of MOGAD. The purpose of this review is to discuss the clinical manifestations, imaging features, outcomes and prognosis of MOGAD.

Myelin Oligodendrocyte Glycoprotein-antibody-associated Disorder Presenting with Corticomeningeal Encephalitis Prior to the Onset of Optic Neuritis

We herein report a case of myelin oligodendrocyte glycoprotein-antibody-associated disorder (MOG-AD) presenting with corticomeningeal encephalitis. The patient exhibited oral ulceration, a mild impairment of consciousness, fever, nausea, nuchal rigidity, positivity for human leukocyte antigen type B51, and neutrophil-dominant pleocytosis and interleukin-6 level in cerebrospinal fluid (CSF). Magnetic resonance imaging (MRI) revealed a right temporal lesion with leptomeningeal gadolinium enhancement. The initial diagnosis was neuro-Behçet's disease presenting with meningoencephalitis; however, a cell-based assay detected anti-MOG antibody in the serum and CSF and the patient also experienced bilateral optic neuritis. After administering steroid therapy, his neurologic symptoms and CSF abnormalities improved along with the disappearance of gadolinium enhancement and the lesion on MRI. This case suggests that MOG-AD may present with corticomeningeal encephalitis prior to the onset of optic neuritis.

Clinical characteristics of paediatric Hashimoto's encephalopathy

BACKGROUND

Hashimoto's encephalopathy, also known as steroid responsive encephalopathy, is associated with thyroid antibodies (SREAT) and is a rare but serious form of encephalopathy. In this paper, we describe the signs, symptoms, outcome, and treatments as noted in the case reports reviewed.

METHODS

We searched PubMed, Embase, and the Cochrane library for articles in which cases of Hashimoto's encephalopathy were described. The case description had to include the diagnosis, age, sex, presenting symptoms, and diagnostic tests.

RESULTS

We retrieved 360 articles and 65 fulfilled the inclusion criteria. These articles gave reports of 100 cases, with a mean age of 10.9 (range 2.8-19), 78 of whom were female. Epilepsy (79) - including epileptic state [24] - behavioural problems [36], hallucinations [21], headache [21], and decline in school performance [19] were most often reported. Antithyroid peroxidase (aTPO) was reported elevated in all patients. Most children [70] recovered fully, however 16 had late sequelae, mostly epilepsy. Therapies used include steroids, intravenous gammaglobulines, and cytostatics.

CONCLUSIONS

Epilepsy, behavioural problems, decline in school performance, and hallucinations are frequent symptoms of Hashimoto's encephalopathy. Steroids are the basis of treatment, although other immunomodulatory drugs seem to be successful. About one in ten children will experience late sequelae. In any child with unexplained neurological, psychiatric, or psychological dysfunction, serum anti-thyroidperoxidase (aTPO) should be determined.

Association between acute disseminated encephalomyelitis and thyroid autoimmunity in children

BACKGROUND

Abnormal thyroid peroxidase antibody (TPOAb) levels are observed in various autoimmune diseases. However, the relationship between TPOAb and pediatric acute disseminated encephalomyelitis (PADEM) remains unclear. This study aimed to investigate the positive rate of TPOAb and thyroid dysfunction in children with acute disseminated encephalomyelitis (ADEM) and assess the relationship between TPOAb and clinical features of PADEM.

METHODS

This retrospective single-center case-control study was conducted from April 2017 to April 2019. We enrolled 23 children with ADEM and 23 age- and sex-matched healthy controls. Based on whether they were positive for TPOAb, the children with ADEM were allocated either to the TPOAb+ or TPOAb- group. The median follow-up time was 12 months (6-30 months). Observers were blinded to the patient groupings. We compared the clinical and imaging characteristics of the two groups.

RESULTS

Among the 23 patients with PADEM, 47.8% presented with abnormal TPOAb levels, while there were no TPOAb+ cases in the control group. Among the children with ADEM, there were significantly increased TPOAb positive rates and significantly decreased fT3 levels. TPOAb+ and TPOAb- subgroup analysis revealed significant differences in gait, fever, and total IgG. In the TPOAb+ group, there was a significant decrease in TPOAb levels at 2 weeks after ADEM onset. The follow-up of patients who were TPOAb+ at 3 months after onset showed a gradual decrease in their TPOAb levels back to normal. One patient who presented new nervous system symptoms after over 1 month also showed a simultaneous increase in TPOAb levels. There was a significant negative correlation between Glasgow Coma Scale (GCS) scores and TPOAb levels (p = 0.042, r = -0.892).

CONCLUSION

There was a negative correlation of TPOAb levels with GCS scores. Therefore, TPOAb levels could be used for the prognosis of patients with PADEM. We recommend determining thyroid function when assessing patients with PADEM during follow-up.

Unidentified Neuronal Surface IgG Autoantibodies in a Case of Hashimoto's Encephalopathy

Hashimoto's encephalopathy is an encephalitis of presumed autoimmune origin characterized by the presence of autoantibodies against thyroid proteins. We present a case of a young patient with pre-existing Hashimoto's thyroiditis and progressive cognitive complaints, absence-like episodes, and sporadic bilateral epileptiform frontal and frontotemporal activity. No abnormalities were observed during the neurological examination and on MRI. Antibodies to thyroid peroxidase (TPO) were elevated and remained positive while the symptoms were present. Levothyroxine and methylprednisolone did not ameliorate the complaints. Subsequent treatment with high-dose intravenous immunoglobulins (IVIG) led to improved cognitive functions and to the disappearance of the absence-like-episodes. Patient's serum, but not CSF, gave a characteristic IgG-specific hippocampal pattern in rat brain immunohistochemistry; this immunoreactivity was maintained after specific and complete depletion of TPO antibodies. Serum IgG bound to primary neurons in cell culture, likely targeting a yet unidentified neuronal surface antigen. The clinical response to IVIG suggests but does not prove, that the circulating novel autoantibodies may induce the encephalopathy. It would be of interest to investigate more patients with Hashimoto's encephalopathy for the presence of neuronal surface autoantibodies, to define their role in the disease and their target antigen(s).

Thyroid gland and brain: Enigma of Hashimoto's encephalopathy

The versatile clinical manifestations of the Hashimoto's chronic autoimmune thyroiditis often include psycho-neurological disorders. Although hypothyroidism disturbs significantly the ontogenesis and functions of central nervous system, causing in severe cases of myxedema profound impairment of cognitive abilities and even psychosis, the behavioral, motor and other psychoneurological disorders accompany euthyroid and slightly hypothyroid cases and periods of Hashimoto's disease as well, thus constituting the picture of so called "Hashimoto's encephalopathy". The entity, although discussed and explored for more than 50 years since its initial descriptions, remains an enigma of thyroidology and psychiatry, because its etiology and pathogenesis are obscure. The paper describes the development of current views on the role of thyroid in ontogeny and functions of brain, as well as classical and newest ideas on the etiology and pathogenesis of Hashimot's encephalopathy. The synopsis of the world case reports and research literature on this disorder is added with authors' own results obtained by study of 17 cases of Hashimoto's thyroiditis with schizophrenia-like clinical manifestations. The relation of the disease to adjuvant-like etiological factors is discussed. Three major mechanistic concepts of Hashimoto's encephalopathy are detailed, namely cerebral vasculitis theory, hormone dysregulation theory and concept, explaining the disease via direct action of the autoantibodies against various thyroid (thyroperoxidase, thyroglobulin, and TSH-receptor) and several extrathyroid antigens (alpha-enolase and other enzymes, gangliosides and MOG-protein, onconeuronal antigens) - all of them expressed in the brain. The article demonstrates that all above mentioned concepts intermingle and prone to unification, suggesting the unified scheme of pathogenesis for the Hashimoto's encephalopathy. The clinical manifestations, criteria, forms, course, treatment and prognosis of Hashimoto's encephalopathy and its comorbidity to other diseases - are also discussed in brief. The relation between Hashimoto's encephalopathy and non-vasculitis autoimmune encephalomyelitides of paraneoplastic and non-paraneoplastic origin is emphasized [1 figure, bibliography - 200 references].

Optic Neuritis in the Older Chinese Population: A 5-Year Follow-Up Study

Objective

This study aims to describe the clinical manifestations and outcomes in a cohort of older Chinese patients.

Method

A retrospective study of patients aged ≥ 45 years who had a first episode of optic neuritis (ON) between May 2008 and November 2012. Clinical features at onset and last follow-up were analyzed within subgroups (age 45–65 years and age ≥ 65 years).

Results

76 patients (99 eyes) were included, of which 58% were females. The mean age at presentation was 55.53 ± 8.29 years (range: 45–83 years). Vision loss was severe at presentation, with initial best corrected vision activity (BCVA) < 20/200 in 93% and final BCVA < 20/200 in 53% of patients at 5-year follow-up. Final BCVA significantly correlated with the initial BCVA and peripapillary retinal nerve fiber layer. At last follow-up, 14.5% were diagnosed with neuromyelitis optica spectrum disorder (NMOSD), 1.3% were diagnosed with multiple sclerosis (MS), 5.2% with chronic relapsing inflammatory optic neuropathy, 1.3% with infectious ON, and 19.7% with autoimmune ON. None of the elderly group (≥65 years) developed NMOSD or MS.

Conclusion

Chinese patients in the age group ≥ 65 years with ON are less likely to develop NMOSD or MS. Notwithstanding, they had more severe visual loss at onset and poor recovery.