Hashimoto's encephalopathy

Clinical and diagnostic characteristics of Hashimoto's encephalopathy: a single-center, retrospective study

BACKGROUND AND PURPOSE

Diagnosing Hashimoto's encephalopathy (HE) is challenging. In contrast to other types of autoimmune encephalitis, HE shows an excellent response to steroid treatment. We aimed to investigate the rates of antithyroid antibodies (ATAs) and probable HE in patients with unexplained mental dysfunction and compare the clinical characteristics between the good- and poor-outcome groups.

METHODS

We retrospectively reviewed the medical records and electroencephalography (EEG) and neuroimaging findings of patients admitted to the Department of Neurology of our hospital from March 1, 2006, to February 28, 2023. Using our proposed diagnostic criteria for probable HE, we compared the clinical characteristics between the good- and poor-outcome groups. We also investigated the rates of ATA positivity and probable HE.

RESULTS

In total, 198 patients exhibited altered mentation, rapidly progressive cognitive decline, or myoclonus. ATA tests were performed on 86 patients, and the detection rates of ATAs and probable HE were 29.1% and 25.6%, respectively. Of the 22 patients enrolled, the good- and poor-outcome groups comprised 19 and 3 patients, respectively. Clinical seizures occurred in seven patients. Nonconvulsive status epilepticus on EEG was observed in six patients, all of whom were intractable to antiepileptic drugs. Nineteen of 21 patients (90.5%) treated with immunosuppressants showed good outcomes.

CONCLUSIONS

HE is a rare clinical disorder, but not as rare as previously thought. When HE is suspected, steroids should be considered the first-line treatment. Early diagnosis and adequate treatment are critical to achieve good outcomes in HE.

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.

Characterization of neurological morbidity associated with thyroid antibodies: Hashimoto's encephalopathy and beyond

BACKGROUND

Hashimoto's Encephalopathy (HE) manifests with various neurologic symptoms associated with elevated thyroglobulin (TG) and/or thyroperoxidase (TPO) antibodies. Some patients with thyroid antibodies exhibit neurological presentations not consistent with HE. This study aims to characterize the spectrum of neurological morbidity in patients with thyroid antibodies.

METHODS

We reviewed all patients tested for TG or TPO antibodies from 2010 to 2019. Patients tested for thyroid antibodies as part of a neurological workup for new symptoms were classified into the following categories: patients meeting full criteria for HE, patients with other neuroimmunological disorders, patients with unexplained neurological symptoms not fully meeting HE criteria, and patients with incidental non neuroimmunological disorders.

RESULTS

There were 2717 patients with positive thyroid antibodies in the dataset including 227 patients (78% female, age 54 ± 19 years) who met inclusion criteria. Twelve patients (5%) met HE criteria, 30 (13%) had other neuroimmunological disorders, 32 (14%) had unexplained neurological symptoms, and 153 (67.4%) had incidental disorders. In addition to cognitive dysfunction, seizures, movement disorders, motor weakness, and psychosis, HE patients were also more likely to have cerebellar dysfunction, language impairment, and sensory deficits. They were more likely to carry a Hashimoto's thyroiditis diagnosis and had higher titers of thyroid antibodies. They all had a robust response to steroids.

CONCLUSION

The neurological spectrum of HE may be wider than previously reported, including frequent cerebellar, sensory, and language dysfunction. A subgroup of thyroid antibody positive patients with unexplained neurological symptoms may represent further expansion of thyroid antibody-related neurological disorders.

Clinical presentations and treatment outcomes of Hashimoto encephalopathy at Siriraj Hospital - Thailand's largest national tertiary referral center

BACKGROUND

Hashimoto encephalopathy has multiple clinical presentations, and other than the presence of thyroid antibody, laboratory and imaging investigations are all non-specific. Data specific to the clinical presentations and treatment outcomes of patients with Hashimoto encephalopathy in Thailand remain scarce.

OBJECTIVES

To retrospectively investigate the clinical presentations and treatment outcomes of patients with Hashimoto encephalopathy at Siriraj Hospital.

METHODS

Patients who presented with acute encephalopathy at our center during July 2012-March 2017 were evaluated for eligibility. The inclusion criteria were positive anti-thyroperoxidase (anti-TPO) or anti-thyroglobulin (anti-Tg) in serum with negative neuronal antibody in serum or cerebral spinal fluid (CSF). Clinical presentations, symptom duration, laboratory results of thyroid status and thyroid autoantibody, CSF study, and clinical outcomes were collected.

RESULTS

Of the 204 patients who presented with encephalopathy, 31 (15.2%) were positive for the anti-TPO or anti-Tg antibody. Of those, 13 patients met the diagnostic criteria for Hashimoto encephalopathy. Clinical presentations included cognitive impairment (76.9%), clouding of consciousness (46.2%), and behavior change (30.8%). The neuropsychiatric presentations were visual hallucination (30.8%), auditory hallucination (15.4%), delusion (7.7%), and mood disturbance (23.1%). Other clinical presentations included seizure (38.5%), abnormal movement (23.1%), sleep disturbance (38.5%), ataxia (46.2%), stroke-like episode (15.4%), and fever (15.4%). Most patients (76.9%) had onset within < 3 months. Regarding outcomes, 1 patient who did not receive corticosteroid died from status epilepticus and septic shock. Among the 12 patients who received corticosteroid, 9 (75%) had marked improvement, 1 (8.3%) had slight improvement, and 2 (16.6%) had no clinical improvement. Seven patients (53.9%) had normal thyroid function, 4 patients (30.8%) had subclinical hypothyroidism, and 2 patients (15.4%) had subclinical hyperthyroidism.

CONCLUSIONS

The results of this study revealed cognitive impairment, neuropsychiatric symptoms, seizure, ataxia, and sleep disturbance to be common manifestations of Hashimoto encephalopathy. This condition should always be considered in individuals with subacute onset of unexplained cognitive impairment or cerebellar ataxia. Laboratory and neuroimaging investigations were all found to be nonspecific in Hashimoto encephalopathy. Most patients responded well to treatment, so clinical suspicion and early diagnosis and treatment will lead to improved patient outcomes.

Early warning signs of thyroid autoantibodies seroconversion: A retrospective cohort study

BACKGROUND

Serum anti-thyroid peroxidase antibody (anti-TPO) and anti-thyroglobulin antibody (anti-Tg) levels are key indicators for the diagnosis of autoimmune diseases, especially autoimmune thyroiditis. Before the thyroid autoantibodies turn from negative to positive, it is unknown whether any clinical indicators in the body play a warning role.

PURPOSE

To establish an early prediction model of seroconversion to positive thyroid autoantibodies.

METHODS

This retrospective cohort study collected information based on clinical laboratory data. A logistic regression model was used to analyse the risk factors associated with a change in thyroid autoantibodies to an abnormal status. A machine-learning approach was employed to establish an early warning model, and a nomogram was used for model performance assessment and visualisation. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analyses were used for internal and external validation.

RESULTS

Logistic regression analysis revealed that albumin to globulin ratio, triglyceride levels, and Glutamic acid levels among liver function and some metabolism-related indicators, high density lipoprotein C among metabolism-related indicators, and cystatin C among renal function indicators were all risk factors for thyroid antibody conversion (P<0.05). In addition, several indicators in the blood count correlated with thyroid conversion (P<0.05). Changes in the ratio of free thyroxine to free triiodothyronine were a risk factor for positive thyroid antibody conversion (OR_fT4/fT3=1.763; 95% confidence interval 1.554-2.000). The area under the curve (AUC) of the early warning model based on the positive impact of clinical laboratory indicators, age, and sex was 0.85, which was validated by both internal (AUC 0.8515) and external (AUC 0.8378) validation.

CONCLUSIONS

The early warning model of anti-TPO and anti-Tg conversion combined with some clinical laboratory indicators in routine physical examination has a stable warning efficiency.

Epilepsy, Immunity and Neuropsychiatric Disorders

Several studies have focused on the emerging role of immunity and inflammation in a wide range of neurological disorders. Autoimmune diseases involving central nervous system share well defined clinical features including epileptic seizures and additional neuropsychiatric symptoms, like cognitive and psychiatric disturbances. The growing evidence about the role of immunity in the pathophysiologic mechanisms underlying these conditions lead to the concept of autoimmune epilepsy. This relatively-new term has been introduced to highlight the etiological and prognostic implications of immunity in epileptogenesis. In this review, we aim to discuss the role of autoimmunity in epileptogenesis and its clinical, neurophysiological, neuroimaging and therapeutic implications. Moreover, we wish to address the close relationship between immunity and additional symptoms, particularly cognitive and psychiatric features, which deeply impact clinical outcomes in these patients. To assess these aspects, we first analyzed Rasmussen's encephalitis. Subsequently, we have covered autoimmune encephalitis, particularly those associated with autoantibodies against surface neuronal antigens, as these autoantibodies express a direct immune-mediated mechanism, different from those against intracellular antigens. Then, we discussed the connection between systemic immune disorders and neurological manifestations. This review aims to highlight the need to expand knowledge about the role of inflammation and autoimmunity in the pathophysiology of neurological disorders and the importance to early recognize these clinical entities. Indeed, early identification may result in faster recovery and a better prognosis.

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.

Hashimoto's encephalopathy with gait disturbance caused by sensory ganglionopathy: A case report and review of the literature

Hashimoto's encephalopathy (HE) is a steroid-responsive encephalopathy characterized by several neurological symptoms. HE mainly involves the central nervous system; the peripheral nervous system is rarely involved. We treated a previously healthy elderly man showing mild cognitive decline and subacute progressive gait disturbance due to severe sensory deficits, including sensation of touch and deep sensation with elevated anti-NH2 terminal of α-enolase and anti-thyroid antibodies. His sensory disturbance symptoms improved after steroid therapy, suggesting that the neuropathy was related to HE. His disease was characteristic of HE in that his sensory deficits responded well and rapidly to steroid therapy. A nerve conduction study showed reduced sensory nerve action potentials in all limbs, indicating that his neuropathy was not “axonopathy”, but “sensory ganglionopathy”, which can occur concurrently with autoimmune disorders. Dysautonomia may be the responsible pathomechanism because of the vulnerability of the blood–nerve barrier at the ganglia. Although the pathophysiology of HE has not been clearly elucidated, autoimmune inflammation has been reported in a number of autopsy cases, indicating that sensory ganglionopathy can develop with HE. Therefore, HE should be recognized as one type of “treatable neuropathy”.

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.

A Rare Cause of Autistic Regression in a Boy with Down Syndrome: Hashimoto Encephalopathy

Background:

Hashimoto encephalopathy (HE) is a rare condition associated with autoimmune thyroid disease. We aimed to report the youngest patient with Down syndrome and HE with an unusual presentation.

Case Report:

Six years and six months old boy with Down syndrome admitted due to loss of speech. His physical development was appropriate for his age and had no goiter. Neurological examination revealed the absence of eye contact and stereotypic movements. Autism spectrum disorder was considered based on his result on Gilliam autism evaluation scale. He had subclinical hypothyroidism with markedly elevated anti-thyroid peroxidase antibody level, rare spikes in the frontocentral area were found in electroencephalography, and cranial magnetic resonance imaging was normal. Neurologic improvement was observed to a treatment with glucocorticoid and thyroid hormone.

Conclusion:

HE might be considered in patients with Down syndrome along with progressive cognitive decline and autistic regression.

MRI Findings of Two Patients With Hashimoto Encephalopathy

Hashimoto encephalopathy (HE), also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is a rare type of autoimmune encephalitis that typically presents with cognitive and neuropsychiatric symptoms that resolve with steroids. Positive neuroimaging findings of HE are rarely reported in the literature. We present two cases of HE with abnormal MRI findings, including signal abnormalities in the claustrum, cerebral white matter, and mesial temporal lobes. HE and other forms of autoimmune encephalopathies can often be misdiagnosed as viral encephalopathies. As such detection of subtle neuroimaging findings in the context of suspicious clinical history should prompt further investigations to ensure accurate and timely diagnosis.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis with Serum Anti-Thyroid Antibodies: A Case Report and Literature Review

BACKGROUND Anti-N methyl D-aspartate receptor encephalitis (anti-NMDArE) is a disorder in which triggers such as infectious agents or neoplastic disease can lead to an autoimmune response against the nervous system, although this disorder is usually idiopathic. Some patients with anti-NMDArE have evidence of other autoimmune alterations. Here, we present a case of non-paraneoplastic anti-NMDArE with elevation of serum anti-thyroid antibodies and a literature review of this association. CASE REPORT A 16-year-old girl was admitted in the University Hospital of Bari for a new onset of tonic-clonic seizures. Progressively, the patient manifested also psychomotor agitation, language difficulties, memory impairment, psychotic symptoms, autonomic dysfunction, and psychomotor retardation. Blood evaluation revealed the presence of anti-thyroglobulin, anti-thyroperoxidase, and anti-NMDAr antibodies. Cerebrospinal fluid analysis confirmed the diagnosis of anti-NMDArE. No tumors were found. Treatment with intravenous immunoglobulin, steroids, and plasma exchange relieved symptoms and decreased levels of serum anti-NMDAr antibodies. After 12 months, the patient had full recovery of communicative capacity, with the persistence of slight difficulty of memory and mild tendency to irritability. Blood exams shown persistence of anti-NMDAr positivity and absence of anti-thyroid antibodies. CONCLUSIONS We report a rare case in which an autoimmune involvement of thyroid gland was concurrent with an anti-NMDArE. It would be useful for clinical practice to clarify whether the presence of anti-thyroid antibody an characterize the clinical course, prognosis, and response to treatment of the idiopathic type of anti-NMDArE.

Brain dysfunction and thyroid antibodies: autoimmune diagnosis and misdiagnosis

Hashimoto encephalopathy, also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis, has been defined by sub-acute onset encephalopathy, with elevated thyroid antibodies, and immunotherapy responsiveness, in the absence of specific neural autoantibodies. We aimed to retrospectively review 144 cases referred with suspected Hashimoto encephalopathy over a 13-year period, and to determine the clinical utility of thyroid antibodies in the course of evaluation of those patients. One hundred and forty-four patients (all thyroid antibody positive) were included; 72% were women. Median age of symptom onset was 44.5 years (range, 10-87). After evaluation of Mayo Clinic, 39 patients (27%) were diagnosed with an autoimmune CNS disorder [autoimmune encephalopathy (36), dementia (2) or epilepsy (1)]. Three of those 39 patients had neural-IgGs detected (high glutamic acid decarboxylase-65, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-receptor and neural-restricted unclassified antibody), and 36 were seronegative. Diagnoses among the remaining 105 patients (73%) were functional neurological disorder (n = 20), neurodegenerative disorder (n = 18), subjective cognitive complaints (n = 14), chronic pain syndrome (n = 12), primary psychiatric (n = 11), sleep disorder (n = 10), genetic/developmental (n = 8), non-autoimmune seizure disorders (n = 2) and other (n = 10). More patients with autoimmune CNS disorders presented with sub-acute symptom onset (P < 0.001), seizures (P = 0.008), stroke-like episodes (P = 0.007), aphasia (P = 0.04) and ataxia (P = 0.02), and had a prior autoimmune history (P = 0.04). Abnormal brain MRI (P = 0.003), abnormal EEG (P = 0.007) and CSF inflammatory findings (P = 0.002) were also more frequent in the autoimmune CNS patients. Patients with an alternative diagnosis had more depressive symptoms (P = 0.008), anxiety (P = 0.003) and chronic pain (P = 0.002). Thyoperoxidase antibody titre was not different between the groups (median, 312.7 versus 259.4 IU/ml; P = 0.44; normal range, <9 IU/ml). None of the non-autoimmune group and all but three of the CNS autoimmune group (two with insidious dementia presentation, one with seizures only) fulfilled the autoimmune encephalopathy criteria proposed by Graus et al. (A clinical approach to diagnosis of autoimmune encephalitis. Lancet Neurol 2016; 15: 391-404.) (sensitivity, 92%; specificity, 100%). Among patients who received an immunotherapy trial at our institution and had objective post-treatment evaluations, the 16 responders with autoimmune CNS disorders more frequently had inflammatory CSF, compared to 12 non-responders, all eventually given an alternative diagnosis (P = 0.02). In total, 73% of the patients referred with suspected Hashimoto encephalopathy had an alternative non-immune-mediated diagnosis, and more than half had no evidence of a primary neurological disorder. Thyroid antibody prevalence is high in the general population, and does not support a diagnosis of autoimmune encephalopathy in the absence of objective neurological and CNS-specific immunological abnormalities. Thyroid antibody testing is of little value in the contemporary evaluation and diagnosis of autoimmune encephalopathies.

Hashimoto Encephalopathy With Status Epilepticus

Hashimoto encephalopathy (HE) is a heterogenous neurological syndrome that can manifest with encephalopathy, seizures, headaches, and variable neuropsychiatric disturbances. The underlying mechanism remains unclear; however, autoimmune pathogenesis is suspected due to its association with autoimmune thyroid disease, high titers of anti-thyroid antibodies, and quick response to steroid therapy. We report a 59-year-old female patient with a remote history of hypothyroidism who presented with status epilepticus and complaints of chronic headaches and cognitive impairment. The presence of sharp frontal waves was identified on her EEG. The patient was initially started on anti-epileptics only; however, her headaches and memory loss escalated, further diagnostic workup was pursued, which revealed high anti-thyroid peroxidase antibodies with normal thyroid function tests. The only cerebrospinal fluid (CSF) abnormality noticed was an elevated protein concentration. MRI showed non-specific right frontal lobe pial enhancement. Remaining infectious, rheumatologic, and neurologic testing was unremarkable. The patient was started on a steroid regimen with successful resolution of symptoms and return of cognitive baseline. Hashimoto’s encephalopathy is a diagnosis of exclusion; however, it should be considered in patients with high titers of anti-thyroid antibodies and neurological symptoms that cannot be explained by thorough infectious, metabolic, and autoimmune testing. It is essential to recognize this neurological entity as fast clinical improvement may be achieved with steroids and other immunotherapies. 

Hashimoto's thyroiditis: An update on pathogenic mechanisms, diagnostic protocols, therapeutic strategies, and potential malignant transformation

Hashimoto's thyroiditis, characterized by thyroid-specific autoantibodies, is one of the commonest autoimmune disorders. Although the exact etiology has not been fully elucidated, Hashimoto's thyroiditis is related to an interaction among genetic elements, environmental factors and epigenetic influences. Cellular and humoral immunity play a key role in the development of the disease; thus, a T and B cells inflammatory infiltration is frequently found. Histopathologic features of the disease include lymphoplasmacytic infiltration, lymphoid follicle formation with germinal centers, and parenchymal atrophy. Moreover, the occurrence of large follicular cells and oxyphilic or Askanazy cells is frequently associated to Hashimoto's thyroiditis. Clinically, Hashimoto's thyroiditis is characterized mainly by systemic manifestations due to the damage of the thyroid gland, developing a primary hypothyroidism. Diagnosis of Hashimoto's thyroiditis is clinical and based on clinical characteristics, positivity to serum antibodies against thyroid antigens (thyroid peroxidase and thyroglobulin), and lymphocytic infiltration on cytological examination. The mainstream of treatment is based on the management of the hypothyroidism with a substitution therapy. A relationship between Hashimoto's thyroiditis and a possible malignant transformation has been proposed in several studies and involves immunological/hormonal pathogenic links although specific correlation is still debated and needs to be further investigated with prospective studies.

Hashimoto's Encephalopathy with Unusual MRI Findings Mimicking Meningoencephalitis: A Case Report and Literature Review

Hashimoto's encephalopathy (HE) is a rare autoimmune disease characterized by a high serum concentration of antithyroid antibodies without evidence of cerebral disease. Magnetic resonance imaging (MRI) findings in HE patients are nonspecific, although diffuse or focal white matter changes have been reported in several cases. We present a rare case involving a 79-year-old woman with elevated antithyroid antibody levels and abnormal imaging findings similar to meningoencephalitis. Serial MRI initially showed multiple T2 hyperintense lesions with diffuse leptomeningeal enhancement that disappeared after steroid therapy.

Hashimoto encephalopathy in the 21st century

Objective

To report the presenting syndromes and to determine whether pretreatment criteria of Hashimoto encephalopathy (HE) predict response to steroids.

Methods

We assessed symptoms and steroid responsiveness in 24 patients with pretreatment criteria of HE, including (1) subacute onset of cognitive impairment, psychiatric symptoms, or seizures; (2) euthyroid status or mild hypothyroidism; (3) serum thyroid peroxidase antibodies (TPOAb) >200 IU/mL; (4) absent neuronal antibodies in serum/CSF; and (5) no other etiologies. Additional studies included determination of TPOAb (>200 IU/mL) in 74 patients with criteria of possible autoimmune encephalitis (AE) without neuronal antibodies and 205 patients with different neuroimmunologic diseases, psychosis, or new-onset refractory status epilepticus (NORSE). Serum antibodies to the amino (ΝΗ2)-terminal of α-enolase (NH2-α-enolaseAb) were examined in the indicated 24 patients and 13 controls.

Results

The 24 patients (14 women) with suspected HE had a median age of 48 years (range 8–79 years). Four syndromes were identified: psychiatric (7, 29%), encephalopathy (7, 29%), NORSE-like (6, 25%), and limbic encephalitis (4, 17%). Only 6 of 19 (31.6%) patients completely responded to steroids. The frequency of TPOAb in the 74 patients with possible AE (6 of 74, 8.1%) was similar to that of the 205 controls (17 of 205, 8.2%; p = 0.84). NH2-α-enolaseAb were identified in 1 of 24 suspected HE cases and 1 of 13 controls.

Conclusion

Current pretreatment criteria of HE do not predict steroid responsiveness. The detection of TPOAb across all control groups reveals their poor disease-specificity. NH2-α-enolaseAb did not help in the diagnosis of HE. These findings imply a redefinition of HE that requires a systematic exclusion of antibody-mediated encephalitis.

Psychiatric Presentations Heralding Hashimoto's Encephalopathy: A Systematic Review and Analysis of Cases Reported in Literature

Hashimoto's encephalopathy (HE) may often present initially with psychiatric symptoms. These presentations are often variable in clinical aspects, and there has been no systematic analysis of the numerous psychiatric presentations heralding an eventual diagnosis of HE which will guide clinicians to make a correct diagnosis of HE. This systematic review was done to analyze the demographic characteristics, symptom typology, and clinical and treatment variables associated with such forerunner presentations. Electronic databases such as PubMed, ScienceDirect, and Google Scholar databases were searched to identify potential case reports that described initial psychiatric presentations of HE in English language peer-reviewed journals. The generated articles were evaluated and relevant data were extracted using a structured tool. We identified a total of forty articles that described 46 cases. More than half of the total samples (54.4%) were above the age of 50 years at presentation. The most common psychiatric diagnosis heralding HE was acute psychosis (26.1%) followed by depressive disorders (23.9%). Dementia (10.9%) and schizophrenia (2.2%) were uncommon presentations. Antithyroid peroxidase antibodies were elevated in all patients but not antithyroglobulin antibodies. Preexisting hypothyroidism was absent in majority of cases (60.9%). Steroid doses initiated were 500-1000 mg of intravenous methylprednisolone for majority (52.1%) of patients while oral steroid maintenance was required for a significant minority (39.1%). Psychiatric manifestations of HE may be heterogeneous and require a high index of clinical suspicion, especially in older adults. A range of clinical and treatment variables may assist clinicians in making a faster diagnosis and instituting prompt and effective management.

Steroid-responsive Encephalopathy Associated with Autoimmune Thyroiditis (SREAT) Presenting with Pure Cerebellar Ataxia

Background

Myoclonus and tremor are common movement disorder phenomenologies in steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT). Pure ataxia without encephalopathy has rarely been reported.

Case report

We report 21- and 40-year-old females who presented with subacute pure ataxia without encephalopathy. After immunotherapies, both exhibited initial improvement of ataxia, and subsequently remained in plateau phase.

Discussion

This treatable disorder should be added to the differential diagnoses of progressive cerebellar ataxia, and anti-thyroid peroxidase and anti-thyroglobulin should be considered as part of the workup. It is crucial not to misdiagnose SREAT presenting with pure cerebellar ataxia as degenerative or spinocerebellar ataxia.

Hashimoto encephalopathy: literature review

Hashimoto encephalopathy (HE) presents as an encephalopathy without central nervous system infection or tumor. HE is associated with autoimmune thyroiditis and is thus considered to be an autoimmune disorder. The prevalence of HE is low, but death and status epilepticus have been reported. HE manifests with a wide range of symptoms that include behavioral changes and confusion. Elevated thyroid antibodies are present in the majority of cases and are required for the diagnosis of HE. Normal brain MRI findings are found in the majority of patients diagnosed with HE. The most consistent CSF abnormality noted in HE patients is the presence of elevated protein. Most HE patients respond well to steroid therapy. Clinical improvements are also observed with IV immunoglobulin and plasmapheresis. In conclusion, it is now generally accepted that the diagnosis of HE must include encephalopathy characterized by cognitive impairment associated with psychiatric features, such as hallucinations, delusions, and paranoia. Autoimmune encephalitis and prion disease should be considered in the differential diagnosis due to the similarity of the clinical features of these conditions to those of HE.

Risks and Benefits of Rituximab in the Treatment of Hashimoto Encephalopathy in Children: Two Case Reports and a Mini Review

Hashimoto encephalopathy is a rare condition, characterized by the association of encephalopathy with a variety of neurological symptoms and autoantibodies to the thyroid gland. Its etiology is unknown, and symptoms are usually treated with immune suppressive therapy, e.g., high doses of corticosteroids.

METHODS AND RESULTS

Here, we report the long-term outcome in two steroid-refractory adolescents with Hashimoto encephalopathy who were treated with rituximab, a monoclonal antibody directed against CD20. In addition, we reviewed the literature regarding treatment strategies in Hashimoto encephalopathy.

CONCLUSIONS

Anti-B-cell therapy can be of value in the treatment of Hashimoto encephalopathy, especially in steroid refractory cases, but side effects due to low levels of immunoglobulins warrant careful monitoring.

A clinical approach to diagnosis of autoimmune encephalitis

Encephalitis is a severe inflammatory disorder of the brain with many possible causes and a complex differential diagnosis. Advances in autoimmune encephalitis research in the past 10 years have led to the identification of new syndromes and biomarkers that have transformed the diagnostic approach to these disorders. However, existing criteria for autoimmune encephalitis are too reliant on antibody testing and response to immunotherapy, which might delay the diagnosis. We reviewed the literature and gathered the experience of a team of experts with the aims of developing a practical, syndrome-based diagnostic approach to autoimmune encephalitis and providing guidelines to navigate through the differential diagnosis. Because autoantibody test results and response to therapy are not available at disease onset, we based the initial diagnostic approach on neurological assessment and conventional tests that are accessible to most clinicians. Through logical differential diagnosis, levels of evidence for autoimmune encephalitis (possible, probable, or definite) are achieved, which can lead to prompt immunotherapy.

Bipolar disorder and antithyroid antibodies: review and case series

Mood disorders and circulating thyroid antibodies are very prevalent in the population and their concomitant occurrence may be due to chance. However, thyroid antibodies have been repeatedly hypothesized to play a role in specific forms of mood disorders. Potentially related forms include treatment-refractory cases, severe or atypical depression, and depression at specific phases of a woman’s life (early gestation, postpartum depression, perimenopausal). With regard to bipolar disorder, studies of specific subgroups (rapid cycling, mixed, or depressive bipolar) have reported associations with thyroid antibodies. Offspring of bipolar subjects were found more vulnerable to develop thyroid antibodies independently from the vulnerability to develop psychiatric disorders. A twin study suggested thyroid antibodies among possible endophenotypes for bipolar disorder. Severe encephalopathies have been reported in association with Hashimoto’s thyroiditis. Cases with pure psychiatric presentation are being reported, the antithyroid antibodies being probably markers of some other autoimmune disorders affecting the brain. Vasculitis resulting in abnormalities in cortical perfusion is one of the possible mechanisms.

Hashimoto's encephalopathy: A rare proteiform disorder

Hashimoto's encephalopathy (HE) is a rare not well understood, progressive and relapsing multiform disease, characterized by seizures, movement disorders, subacute cognitive dysfunction, psychiatric symptoms and responsiveness to steroid therapy. The disorder is generally associated with thyroid diseases and the most common feature is the presence of anti-thyroperoxidase antibodies (TPOAb). Patients are usually euthyroid or mildly hypothyroid at presentation. All age groups can be affected. The pathophysiology is still unclear, especially the link between elevated serum TPOAb and the encephalopathy. Most reported cases occurred in women and girls. Unspecific symptoms, non-pathognomonic laboratory neurophysiology and neuroimaging features make its diagnosis a real challenge for clinicians. The case of a 16 year old boy, with a clinical picture of HE associated with hypothyroidism, demonstrating an excellent response to high dose steroids is presented together with a systematic review of the literature.

Autoimmune neurologic disorders in children

Autoimmune neurologic diseases are of major clinical importance in children. Antibody-mediated diseases of the central nervous system are now increasingly recognized in childhood, where the antibodies bind to cell surface epitopes on neuronal or glial proteins, and the patients demonstrate either focal or more generalized clinical signs depending on the extent of brain regions targeted by the antibodies. The antibodies are directed towards ion channels, receptors, and membrane proteins; and the diseases include limbic encephalitis and N-methyl-d-aspartate receptor-antibody encephalitis, among many others. Additionally there are conditions where the wider immune system is implicated. Neurologic features like seizures, movement disorders, autonomic dysfunction, and sleep disorders, with neuroimaging and electrophysiologic features, may indicate a specific antibody-mediated or immune disorder. Often, phenotypic overlap is observed between these conditions, and phenotypic variation seen in children with the same condition. Nevertheless, many patients benefit from immunotherapy with substantial improvement, although huge efforts are still required to optimize the outcome for many patients. In many patients no antibodies have yet been identified, even though they respond to immunotherapies. Here we describe the known antibodies and associated diseases, discuss conditions that are thought to be immune-mediated but have no known immunologic biomarker, and provide guidelines for the investigation and classification of these disorders.

Cognitive Impairments Preceding and Outlasting Autoimmune Limbic Encephalitis

Mild cognitive impairment (MCI) can be the initial manifestation of autoimmune limbic encephalitis (ALE), a disorder that at times presents a diagnostic challenge. In addition to memory impairment, clinical features that might suggest this disorder include personality changes, agitation, insomnia, alterations of consciousness, and seizures. Once recognized, ALE typically responds to treatment with immune therapies, but long-term cognitive deficits may remain. We report two cases of patients with MCI who were ultimately diagnosed with ALE with antibodies against the voltage gated potassium channel complex. Months after apparent resolution of their encephalitides, both underwent neuropsychological testing, which demonstrated persistent cognitive deficits, primarily in the domains of memory and executive function, for cases 1 and 2, respectively. A brief review of the literature is included.

Thyroid Autoantibodies in the Cerebrospinal Fluid of Subjects with and without Thyroid Disease: Implications for Hashimoto's Encephalopathy

Introduction. Plasma antithyroid peroxidase (anti-TPO) and anti-thyroglobulin antibodies (anti-Tg) are widely used in the diagnosis of autoimmune thyroiditis. No research has compared anti-TPO and anti-Tg both in plasma and cerebrospinal fluid (CSF) of healthy individuals vis-à-vis patients with thyroid disease. Methods. We measured anti-TPO and anti-Tg antibodies in plasma and CSF in nine subjects (mean age ± SD: 73 ± 6 years) with hypothyroidism and nine subjects (mean age ± SD: 73 ± 8 years) without thyroid disease. Results. The concentration of anti-TPO autoantibodies in CSF was very low compared to plasma in both subjects with thyroid and without thyroid disease (P = 0.007). CSF anti-Tg autoantibodies titers were very low compared to the plasma in subjects with thyroid disease (P = 0.004), whereas, in subjects without thyroid disease, this difference did not reach statistical significance (P = 0.063). Conclusions. Thyroid autoantibodies levels were low in plasma and CSF; we did not observe any transfer of thyroid autoantibodies from the peripheral blood to the CSF. Therefore, regarding Hashimoto's encephalopathy, where elevated antithyroid autoantibodies are often measured in blood, it is more likely that thyroiditis and encephalopathy represent nonspecific, but distinct, events of an aggressive immune system.

Antibodies as Mediators of Brain Pathology

The brain is normally sequestered from antibody exposure by the blood brain barrier. However, antibodies can access the brain during fetal development before the barrier achieves full integrity, and in disease states when barrier integrity is compromised. Recent studies suggest that antibodies contribute to brain pathology associated with autoimmune diseases such as systemic lupus erythematosus and neuromyelitis optica, and can lead to transient or permanent behavioral or cognitive abnormalities. We review these findings here and examine the circumstances associated with antibody entry into the brain, the routes of access and the mechanisms that then effect pathology. Understanding these processes and the nature and specificity of neuronal autoantibodies may reveal therapeutic strategies toward alleviating or preventing the neurological pathologies and behavioral abnormalities associated with autoimmune disease.

Non-tumor-Associated Anti-N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis in Chinese Girls With Positive Anti-thyroid Antibodies

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a new category of autoimmune encephalitis associated with anti-NMDA receptor antibodies. The disease was first described in 2007, and it predominantly affects young women with or without ovarian teratomas. Most patients typically present with seizures, a decreased consciousness level, dyskinesia, autonomic dysfunction, and psychiatric symptoms. The presence of anti-thyroid antibodies in non-tumor-associated anti-NMDA receptor encephalitis was first described in 2010. Additionally, anti-thyroid antibodies were found in teratoma-associated anti-NMDA receptor encephalitis. We report the cases of 3 Chinese girls with non-tumor-associated anti-NMDA receptor encephalitis with positive anti-thyroid antibodies. We followed up the details of their titers and suggest that anti-thyroid antibodies were an indicator of autoimmune predisposition in the development of non-tumor-associated anti-NMDA receptor encephalitis.

Steroid responsive encephalopathy associated with autoimmune thyroiditis following ipilimumab therapy: a case report

Background

Ipilimumab is a cytotoxic T-lymphocyte-associated protein 4 receptor antibody used for immunotherapy in cancer. Several immune-related adverse events are known. Steroid responsive encephalopathy associated with autoimmune thyroiditis is an autoimmune encephalopathy associated with Hashimoto’s Disease and elevated serum levels of the related antibodies (anti-thyroid-peroxidase antibody or anti-thyroglobulin antibody). Our case implies that steroid responsive encephalopathy associated with autoimmune thyroiditis may be another previously unreported side effect of ipilimumab therapy.

Case presentation

We report the case of a 64 years old caucasian patient with prostatic cancer who received ipilimumab therapy in a clinical trial. He presented with aphasia, tremor and ataxia, myocloni, hallucinations, anxiety and agitation in turns with somnolence. Cranial nerves, deep tendon reflexes, motor and sensory functions were normal. Electroencephalography showed background slowing but no epileptic discharges. Brain magnetic resonance imaging was normal and showed no signs of hypophysitis. Cerebrospinal fluid findings ruled out infection and neoplastic meningitis. Anti-thyroid antibodies (anti-thyroid-peroxidase antibody and anti-thyroglobulin antibody) were heavily increased. Assuming steroid responsive encephalopathy associated with autoimmune thyroiditis the patient was treated with 1,000 mg methylprednisolone i.v. for 3 days and continued with 1 mg/kg orally. On the 3rd day of treatment the patient’s condition started to improve. Within the next few days he gradually returned to his previous state, and electroencephalography eventually showed only slight slowing. Seven months later the patient’s condition was stable, and anti-thyroid antibodies were no more detectable.

Conclusion

Steroid responsive encephalopathy associated with autoimmune thyroiditis may be a hitherto unrecognized complication of ipililumab treatment and should be taken into consideration in patients developing central nervous symptoms undergoing this treatment.

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT): case report of reversible coma and status epilepticus in an adolescent patient and review of the literature

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), also termed Hashimoto's encephalopathy (HE), is a rare immune-mediated disorder and is also affecting children and adolescents. It is characterized by altered mental status, seizures, and cognitive dysfunction. Therapeutic options include steroid treatment and prognosis range from complete recovery, a relapsing course to long-term cognitive sequelae. We describe a previously healthy 13-year-old girl presenting to the emergency room with coma and refractory status epilepticus. Generalized tonic-clonic seizures persisted after pre-hospital infusion of antiepileptic medication. She was found to have highly elevated levels of thyroid-stimulating hormone and anti-thyroid peroxidase antibodies not only in blood but also in cerebrospinal fluid while showing negative results for traumatic, infectious, metabolic, toxic, neoplastic, or other known specific autoimmune diseases. Cranial neuroimaging revealed no abnormality. A diagnosis of SREAT was established, and the patient improved rapidly on corticosteroids and levothyroxine therapy. However, 3 months after the discontinuation of steroid treatment, the girl relapsed. The current literature regarding SREAT is reviewed and summarized.

CONCLUSION

In children with SREAT, early diagnosis and treatment with corticosteroids is crucial and can lead to rapid clinical improvement. Clinicians should be aware of this uncommon but treatable condition, especially in female adolescents with unexplained seizures or an encephalopathic state.

Symptomatic aggravation after corticosteroid pulse therapy in definite sporadic Creutzfeldt-Jakob disease with the feature of Hashimoto's encephalopathy

Background

Creutzfeldt-Jakob disease and Hashimoto’s encephalopathy often show similar clinical presentation. Among Creutzfeldt-Jakob disease mimics, Hashimoto’s encephalopathy is particularly important as it is treatable with corticosteroids. Thus, in cases of middle-aged woman diagnosed with probable Creutzfeldt-Jakob disease and who exhibit high titers of antithyroid antibodies, corticosteroid pulse therapy is typically performed with expectations of near complete recovery from Hashimoto’s encephalopathy. Herein, we provide the first case report that exhibited a negative effect of corticosteroid pulse therapy for a patient with Creutzfeldt-Jakob disease with features of Hashimoto’s encephalopathy.

Case presentation

We report a case of 59-year-old Asian woman with blurred vision, dysarthria, myoclonus, and rapidly progressive dementia. Cerebrospinal fluid showed 14-3-3 protein positive. Electroencephalogram showed periodic sharp waves (1.5 Hz) at the bilateral frontal or occipital areas. Magnetic resonance imaging showed high signal intensities at the bilateral cerebral cortex, caudate nucleus, and putamen. The patient was diagnosed with probable Creutzfeldt-Jakob disease. However, serum analysis showed a high titer of antithyroid antibodies. We started corticosteroid pulse therapy with subsequent aggravation of seizure activity including generalized myoclonus, epilepsia parialis continua, and ballistic dyskinesia, which was effectively treated with clonazepam.

Conclusion

We provide evidence of a case of Creutzfeldt-Jakob disease that exhibited clinical deterioration after corticosteroid therapy. Although histopathological confirmation with brain biopsy is not easily available in Creutzfeldt-Jakob disease patients, selective initiation of corticosteroid pulse therapy should be considered in cases of uncertain diagnosis for differentiation with Hashimoto’s encephalopathy.

Hashimoto's encephalopathy: South Korean experiences

Hashimoto's encephalopathy (HE) is a rare neurological disorder. Early diagnosis and treatment are critical to prevent irreversible brain damage. In the present study, we aimed to describe and classify HE on the basis of clinical, neuroimaging, and EEG findings. We retrospectively reviewed the clinical, radiological, and electrophysiological findings in patients who showed both neurological symptoms and high titers of anti-thyroid antibodies, and who were admitted between 2006 and 2012. Our patients were classified into two groups: those presenting seizures (group 1) and those with diffuse encephalopathies (group 2). Group 1 contained two patients. Patient 1, who showed verbal memory disturbance, focal MRI lesions, and partial seizure activity on EEG, recovered with antiepileptic and steroid treatments. Five of six patients assigned to group 2 were treated with steroids and showed significant improvement. One patient treated with azathioprine showed moderate improvement. Four of these patients had accompanying metabolic disturbances. HE is a treatable neurologic disorder with different subtypes, each with its own clinical manifestations and treatment options. HE can be difficult to identify and requires careful and attentive clinical observation for diagnosis.

Genetic disorders of thyroid metabolism and brain development

Normal thyroid metabolism is essential for human development, including the formation and functioning of the central and peripheral nervous system. Disorders of thyroid metabolism are increasingly recognized within the spectrum of paediatric neurological disorders. Both hypothyroid and hyperthyroid disease states (resulting from genetic and acquired aetiologies) can lead to characteristic neurological syndromes, with cognitive delay, extrapyramidal movement disorders, neuropsychiatric symptoms, and neuromuscular manifestations. In this review, the neurological manifestations of genetic disorders of thyroid metabolism are outlined, with particular focus on Allan-Herndon-Dudley syndrome and benign hereditary chorea. We report in detail the clinical features, major neurological and neuropsychiatric manifestations, molecular genetic findings, disease mechanisms, and therapeutic strategies for these emerging genetic 'brain-thyroid' disorders.

Clinical manifestations and treatment response of steroid in pediatric Hashimoto encephalopathy

Hashimoto encephalopathy is a steroid-responsive encephalopathy associated with elevated titers of antithyroid antibodies. Clinical symptoms are characterized by behavioral and cognitive changes, speech disturbance, seizures, myoclonus, psychosis, hallucination, involuntary movements, cerebellar signs, and coma. The standard treatment is the use of corticosteroids along with the treatment of any concurrent dysthyroidism. Other options are immunoglobulins and plasmapheresis. We described symptoms and outcomes on 3 teenage girls with Hashimoto encephalopathy. Presenting symptoms were seizure or altered mental status. One patient took levothyroxine due to hypothyroidism before presentation of Hashimoto encephalopathy. After confirmation of elevated antithyroid antibodies, all patients were treated with steroids. One patient needed plasmapheresis because of the lack of response to steroids and immunoglobulins. Hashimoto encephalopathy should be considered in any patient presenting with acute or subacute unexplained encephalopathy and seizures. Even though the use of steroids is the first line of treatment, plasmapheresis can rescue steroid-resistant patients.

Limbic encephalitis associated with elevated antithyroid antibodies

Immune-mediated limbic encephalitis affects both adults and children. Patients typically present with seizures, memory problems, and imaging changes in the medial temporal lobes. Both paraneoplastic and nonparaneoplastic forms have been described in which the antibody to the voltage-gated potassium channel-complex associated protein, leucine-rich glioma-inactivated 1, is most commonly reported. Elevated antithyroid antibodies have also been reported in a range of neurological syndromes with encephalopathy, such as limbic encephalitis, often collectively termed Hashimoto encephalopathy, a condition whereby corticosteroids responsiveness with a complete recovery is commonly observed. Here we describe 3 children presenting with limbic encephalitis with elevated thyroid antibodies that did not respond to corticosteroids alone and required more aggressive immunotherapy, mirroring the slower treatment response that is more frequently seen in other immune-mediated forms of limbic encephalitis.

Ethical issues in the management of thyroid disease

The focus of this article is on clinical ethics issues in the thyroid disease context. Clinical ethics is a subspecialty of bioethics that deals with bedside ethical dilemmas that specifically involve the provider-patient relationship. Such issues include consent and capacity; weighing therapeutic benefits against risks and side-effects; innovative therapies; end of life care; unintended versus intentional harms to patients or patient populations; and healthcare access. This article will review core ethical principles for practice, as well as the moral and legal requirements of informed consent. It will then discuss the range of unique and universal ethical issues and considerations that present in the management of autoimmune thyroid disease and thyroid cancer.

Thyroid antibodies, autoimmunity and cognitive decline: is there a population-based link?

BACKGROUND

Autoimmunity is considered an uncommon but under-recognised cause of cognitive decline.

METHODS

Serum samples from 3,253 randomly selected subjects enrolled in the Hunter Community Study, aged 55-85 years, were assayed for thyrotropin stimulatory hormone, anti-thyroid peroxidase antibodies (TPO-Ab), anti-nuclear antibodies (ANA) and extractable nuclear antigens (ENA). Cognitive function was assessed using the Audio Recorded Cognitive Screen (ARCS) tool.

RESULTS

TPO-Ab were found in 8.4% and ANA in 27.9% of the study population, of whom 3% had positive ENA findings. No relationship was found between the ARCS score and either TPO-Ab (coefficient = 0.133; 95% CI -0.20, 0.82, p = 0.616), ANA at a low (coefficient = 1.01; 95% CI -2.58, 0.55, p = 0.203) or a high titre (coefficient = -0.65; 95% CI -2.59, 1.28, p = 0.508), or ENA antibodies (coefficient = 5.12; 95% CI -0.53, 10.77; p = 0.076).

CONCLUSIONS

Autoantibody findings are common in an aging population and are not associated with cognitive decline.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

Anti-NMDAR encephalitis misdiagnosed as Hashimoto's encephalopathy

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a well-defined autoimmune disorder. Hashimoto's encephalopathy (HE) is a still controversial entity, lacking definite diagnostic criteria. We described a 14-year-old-girl presenting with a clinical picture consistent with the diagnosis of anti-NMDAR encephalitis, confirmed by NMDAR antibody testing. Four years earlier, she had presented a similar episode of acute encephalopathy diagnosed as HE. Anti-NMDAR encephalitis and HE share similar clinical features so that the differential diagnosis can be difficult if specific antibodies are not tested. The correct diagnosis of anti-NMDAR encephalitis is crucial to plan the appropriate management and follow-up, namely in term of oncological screening, since it can be paraneoplastic in origin. We suggest to re-evaluate the clinical history of all subjects with previous HE diagnosis in order to evaluate the possible diagnosis of anti-NMDAR encephalitis and plan the appropriate management of these patients.

Brain-reactive antibodies and disease

Autoimmune diseases currently affect 5-7% of the world's population; in most diseases there are circulating autoantibodies. Brain-reactive antibodies are present in approximately 2-3% of the general population but do not usually contribute to brain pathology. These antibodies penetrate brain tissue only early in development or under pathologic conditions. This restriction on their pathogenicity and the lack of correlation between serum titers and brain pathology have, no doubt, contributed to a delayed appreciation of the contribution of autoantibodies in diseases of the central nervous system. Nonetheless, it is increasingly clear that antibodies can cause damage in the brain and likely initiate or aggravate multiple neurologic conditions; brain-reactive antibodies contribute to symptomatology in autoimmune disease, infectious disease, and malignancy.

Epilepsy associated with systemic autoimmune disorders

Systemic autoimmune disorders affect multiple organ systems. Brain involvement commonly causes seizures, which may be the presenting symptom. Systemic lupus erythematosus, Sjorgren's syndrome, Wegener's granulomatosis, sarcoidsosis, celiac disease, Crohn's disease, Behcet's, and Hashimoto's encephalopathy are reviewed. Mechanisms underlying CNS pathology in systemic autoimmune disorders-and specifically factors predisposing these patients-are discussed, including vascular disease (e.g., prothrombotic state, anticardiolipin antibody, emboli, vasculitis), antineuronal antibodies, immune complexes, cytokines, metabolic disorders, infection, and therapy. Diagnostic and therapeutic strategies must be individualized for both the disorder and the patient. Systemic autoimmune disorders affect multiple organ systems and frequently involve the central and peripheral nervous systems. Seizures are among the most common neurological manifestation and occasionally can be the presenting symptom. There are many causes of seizures in systemic autoimmune disorders (Table 1), and the first clinical challenge is to determine not only the cause but also the significance of seizures. In some cases, they are clues to metabolic or infectious disorders or medication toxicity; in other cases, seizures herald a life-threatening progression of the underlying illness.