Hashimoto's encephalitis as a differential diagnosis of Creutzfeldt-Jakob disease

IgLON5 autoimmunity in a patient with Creutzfeldt-Jakob disease: case report and review of literature

Objective

We present the case of a patient with clinical and imaging features of sporadic Creutzfeldt-Jakob disease (sCJD) and positive IgLON5 antibodies (Abs) in the serum and CSF.

Case report

A 66-year-old Chinese man presented to the hospital with a stroke-like episode, followed by rapidly progressive cognitive decline, mutism, and parkinsonism. The MRI results showed a cortical ribboning sign in diffusion-weighted MRI, periodic triphasic waves with a slow background in EEG, and positive protein 14-3-3 in CSF. There were matching IgLON5 Abs in the serum and CSF. A literature review showed positive autoimmune encephalitis Abs or autoimmune inflammatory disease between 0.5 and 8.6% among patients with clinical suspicion of CJD, most commonly anti-voltage-gated potassium channel (VGKC) complex and anti-N-methyl-D-aspartate receptor (NMDAR) Abs; however, IgLON5 autoimmunity in CJD has been rarely reported. This is an intriguing association as both conditions have been associated with brain deposits of phosphorylated tau protein.

Conclusion

IgLON5 Abs may be observed in patients with a diagnosis of CJD; it is unknown whether a synergistic effect of IgLON5 Abs with CJD exists, increasing neurodegenerative changes.

Hashimoto’s Encephalopathy Presenting as Recurrent Brief Psychotic Episodes in a 13-Year-Old Girl: A Case Report

Background: :

Hashimoto’s encephalopathy (HE) is a debilitating manifestation of an autoimmune reaction against the thyroid that rarely can present with prominent psychiatric symptoms. It is often under-diagnosed primarily due to its variety of symptoms as well as a lack of definitive diagnostic criteria.

Method: :

We report the case of a 13-year-old girl who has been diagnosed with HE after presenting with recurrent and severe psychosis with fever and a thyroidopathy. The patient had prominent visual hallucinations and paranoid delusions. Between episodes, the patient did not show evidence of psychiatric symptoms. This patient struggled with several incorrect diagnoses and treatments for two years before the correct diagnosis of HE was made and displayed extreme improvement upon corticosteroid administration.

Discussion: :

This case illustrates the importance of increasing awareness of HE as well as including HE in a differential diagnosis when paediatric patients present with psychosis and concurrent thyroidopathy.

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].

Hashimoto's encephalopathy in children: different manifestations of five cases

Hashimoto's encephalopathy (HE) is a rare, poorly understood, progressive and relapsing, steroid-responsive multiform disease. HE presents with subacute cognitive dysfunction, psychiatric symptoms, seizures, and movement disorders. The disorder is usually related to thyroid disease and the most frequent feature is the presence of anti-thyroperoxidase antibodies. Patients are generally euthyroid or mildly hypothyroid. The clinical features of two patients at presentation included refractory seizures and confusion, another patient had behavioral problems and altered cognitive status, one patient presented with right-sided weakness and numbness especially in his leg and tongue, dysphagia, speech disorder, aggressiveness, nightmares and nocturnal enuresis and last patient had focal seizures with altered mental status. All patients manifested increased anti-thyroid antibodies. Four patients improved with steroid treatment, and one of the patients responded to plasmapheresis instead of corticosteroid treatment. Physicians' awareness of this complication is of great importance because HE is a highly treatable condition among children and adolescents.

Learning from history: Lord Brain and Hashimoto's encephalopathy

We present two historic cases of severe encephalopathy associated with antithyroid antibodies. The first was published by Lord Brain of Eynsham, and the second was from our department's archives. Although both cases are from archival sources, they continue to inform current clinical care. We briefly review the poorly defined entity, Hashimoto's encephalopathy, and discuss diagnostic advances for autoimmune encephalopathy and for Creutzfeldt-Jakob disease. We advocate for giving a trial of corticosteroids to patients with 'encephalopathy, not otherwise specified' while awaiting antibody results or more definitive testing. Our case, initially diagnosed as having Creutzfeldt-Jakob disease, responded remarkably (with video evidence) to a trial of corticosteroids.

Endocrine disorders and the cerebellum: from neurodevelopmental injury to late-onset ataxia

Hormonal disorders are a source of cerebellar ataxia in both children and adults. Normal development of the cerebellum is critically dependent on thyroid hormone, which crosses both the blood-brain barrier and the blood-cerebrospinal fluid barrier thanks to specific transporters, including monocarboxylate transporter 8 and the organic anion-transporting polypeptide 1C1. In particular, growth and dendritic arborization of Purkinje neurons, synaptogenesis, and myelination are dependent on thyroid hormone. Disturbances of thyroid hormone may also impact on cerebellar ataxias of other origin, decompensating or aggravating the pre-existing ataxia manifesting with motor ataxia, oculomotor ataxia, and/or Schmahmann syndrome. Parathyroid disorders are associated with a genuine cerebellar syndrome, but symptoms may be subtle. The main conditions combining diabetes and cerebellar ataxia are Friedreich ataxia, ataxia associated with anti-GAD antibodies, autoimmune polyglandular syndromes, aceruloplasminemia, and cerebellar ataxia associated with hypogonadism (especially Holmes ataxia/Boucher-Neuhäuser syndrome). The general workup of cerebellar disorders should include the evaluation of hormonal status, including thyroid-stimulating hormone and free thyroxine levels, and hormonal replacement should be considered depending on the laboratory results. Cerebellar deficits may be reversible in some cases.

Plasmapheresis Responsive Rapid Onset Dementia with Predominantly Frontal Dysfunction in the Context of Hashimoto's Encephalopathy

BACKGROUND

Hashimoto's encephalopathy (HE) is a rare immunological neuropsychiatric disorder characterized by increased antithyroid antibodies and mixed neurological and psychiatric symptoms. HE has been previously discussed as a differential diagnosis for rapid progressive dementia. However, most of these patients suffered from additional neurological symptoms, like ataxia or seizures.

CASE PRESENTATION

Here, we present the case of a 59-year-old female patient suffering rapid onset dementia with salient frontal executive dysfunction. She developed rapid onset symptoms, including apathy, verbal depletion up to a stuporous state, severe working memory deficits, evidence of primitive reflexes, disturbed Luria's three-step test, and micturition disorder. Analysis of her cerebrospinal fluid was normal. The serum analyses showed increased antithyroid (antithyroid peroxidase and antithyroglobulin) antibodies. In the cerebral magnetic resonance imaging, supratentorial deep and peripheral white matter lesions were found; the electroencephalography showed intermittent slowing, and the [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET) depicted medial and superior dorsolateral frontal hypometabolism. Several different psychopharmacological therapeutic approaches with various neuroleptics, antidepressants, and high doses of lorazepam were unsuccessful. Due to the organic alterations, including increased antithyroid antibodies, HE was suspected. Against expectations, treatment with high-dose corticosteroids proved to be ineffective and was associated with worsening symptoms. However, escalated treatment with plasmapheresis over 5 days led to significant improvement in all reported symptoms and in psychometric testing. The neuropsychological improvement was stable over a 6-month follow-up period, and the FDG-PET normalized.

CONCLUSION

This case report reveals that (1) HE can mimic rapid onset dementia with predominantly frontal dysfunction; (2) this syndrome can be successfully treated in the context of HE; and (3) plasmapheresis can be effective in such a disease constellation. The detection of the immunological causes of rapid onset dementia and other psychiatric syndromes is important because it opens opportunities for new, innovative immunosuppressive treatment options.

Hashimoto Encephalopathy Presenting With Stroke-Like Episodes in an Adolescent Female: A Case Report and Literature Review

BACKGROUND

Hashimoto encephalopathy is a rare form of encephalopathy thought to be of autoimmune etiology. Cognitive changes and seizures are the most commonly reported presenting manifestation. Stroke-like episodes have also been documented in these individuals. We describe a rare adolescent with Hashimoto encephalopathy who presented with stroke-like symptoms.

PATIENT DESCRIPTION

A previously well 15-year-old girl experienced sudden-onset language disturbance and right hemiparesis. Her symptoms resolved, but weeks later, she began experiencing refractory seizures, episodes of status epilepticus, and cognitive decline. An extensive evaluation was unremarkable, but thyroid peroxidase antibodies were elevated, and a diagnosis of Hashimoto encephalitis was made. Steroid therapy was initiated, and her symptoms resolved with return to baseline cognitive function.

CONCLUSION

Hashimoto encephalopathy is a highly treatable condition that may be considered in the differential diagnosis of children and adolescents presenting with stroke-like symptoms.

Whole Blood Gene Expression Profiling in Preclinical and Clinical Cattle Infected with Atypical Bovine Spongiform Encephalopathy

Prion diseases, such as bovine spongiform encephalopathies (BSE), are transmissible neurodegenerative disorders affecting humans and a wide variety of mammals. Variant Creutzfeldt-Jakob disease (vCJD), a prion disease in humans, has been linked to exposure to BSE prions. This classical BSE (cBSE) is now rapidly disappearing as a result of appropriate measures to control animal feeding. Besides cBSE, two atypical forms (named H- and L-type BSE) have recently been described in Europe, Japan, and North America. Here we describe the first wide-spectrum microarray analysis in whole blood of atypical BSE-infected cattle. Transcriptome changes in infected animals were analyzed prior to and after the onset of clinical signs. The microarray analysis revealed gene expression changes in blood prior to the appearance of the clinical signs and during the progression of the disease. A set of 32 differentially expressed genes was found to be in common between clinical and preclinical stages and showed a very similar expression pattern in the two phases. A 22-gene signature showed an oscillating pattern of expression, being differentially expressed in the preclinical stage and then going back to control levels in the symptomatic phase. One gene, SEL1L3, was downregulated during the progression of the disease. Most of the studies performed up to date utilized various tissues, which are not suitable for a rapid analysis of infected animals and patients. Our findings suggest the intriguing possibility to take advantage of whole blood RNA transcriptional profiling for the preclinical identification of prion infection. Further, this study highlighted several pathways, such as immune response and metabolism that may play an important role in peripheral prion pathogenesis. Finally, the gene expression changes identified in the present study may be further investigated as a fingerprint for monitoring the progression of disease and for developing targeted therapeutic interventions.

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.

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.

Hashimoto encephalopathy: A study of the clinical profile, radiological and electrophysiological correlation in a Tertiary Care Center in South India

Background:

Hashimoto encephalopathy (HE) is a poorly understood and often misdiagnosed entity with variable clinical spectrum. There are many uncertainties that still remain about this condition and the pathological significance of thyroid peroxidase (TPO) antibody.

Objective:

To characterize the clinical, laboratory and radiologic findings in patients with HE.

Design:

Retrospective analysis of clinical features and diagnostic test data.

Main Outcome Measures:

Clinical features, laboratory, radiologic, electroencephalography (EEG) findings associated with HE and therapeutic outcome.

Results:

Thirteen consecutive patients were identified as having HE. The median age at onset was 48.5 years (range, 19–62 years). There was a female preponderance (76.9%). Clinical manifestations were cognitive impairment and behavioral changes in 10 (76.9%), sleep disturbance in 9 (69.2%), seizures in 6 (46.1%), headache in 4 (30.8%), psychosis or paranoia in 5 (38.5%), transient symptoms in 6 (46.1%), myoclonus in 4 (30.8%), ataxia or gait disorder in 4 (30.8%). The most frequent laboratory abnormalities were increased TPO (n = 13) in all cases, increased thyroid stimulating hormone levels (n = 6), and increased erythrocyte sedimentation rate (n = 5). The cerebrospinal fluid protein level was elevated in 8 of 9 patients (88.8%). Magnetic resonance imaging abnormalities were present in 2 patients (15.4%). EEG changes were seen in 7 patients (53.8%). All but two patients showed significant therapeutic benefit with steroids.

Conclusions:

HE has a wide range of clinical, laboratory, and radiologic findings. All patients with an unexplained encephalopathy should be screened for this condition as treatment response is excellent. To the best of our knowledge, this is the largest single center clinical series of HE from the Indian subcontinent.

When dementia progresses quickly: a practical approach to the diagnosis and management of rapidly progressive dementia

Making a diagnosis of rapidly progressive dementia requires practical adaptation of the skills used to assess patients with chronic causes of cognitive impairment. An expedited assessment, commensurate with the accelerated pace of the disease, is required to identify the cause of symptoms amidst a myriad of possibilities. Features upon history, physical examination and cognitive assessment that support specific diagnoses are reviewed, and a stratified approach to testing is presented. The use of readily-accessible investigations is prioritized, acknowledging the implications and applications of novel diagnostic tests. The coordinated use of clinical and laboratory measures are promoted as a means of facilitating rapid evaluation, with the ultimate goal of identifying patients with potentially reversible causes of rapidly progressive dementia.

Ethics in prion disease

This paper is intended to discuss some of the scientific and ethical issues that are created by increased research efforts towards earlier diagnosis, as well as to treatment of, human prion diseases (and related dementias), including the resulting consequences for individuals, their families, and society. Most patients with prion disease currently are diagnosed when they are about 2/3 of the way through their disease course (Geschwind et al., 2010a; Paterson et al., 2012b), when the disease has progressed so far that even treatments that stop the disease process would probably have little benefit. Although there are currently no treatments available for prion diseases, we and others have realized that we must diagnose patients earlier and with greater accuracy so that future treatments have hope of success. As approximately 15% of prion diseases have a autosomal dominant genetic etiology, this further adds to the complexity of ethical issues, particularly regarding when to conduct genetic testing, release of genetic results, and when or if to implement experimental therapies. Human prion diseases are both infectious and transmissible; great care is required to balance the needs of the family and individual with both public health needs and strained hospital budgets. It is essential to proactively examine and address the ethical issues involved, as well as to define and in turn provide best standards of care.

Steroid-responsive encephalopathy in autoimmune thyroiditis: Clinical spectrum and MRI observations in three cases

Hashimoto's encephalopathy (H.E.) is probably of autoimmune etiology, and manifests with seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms, myoclonus. It is presumed to be autoimmune in origin with high serum titers of antithyroid peroxidase antibodies (anti-TPA). Thyroid function might often be normal. The diagnosis is arrived at by excluding other toxic, metabolic and infectious causes of encephalopathies, supportive clinical profile, elevated thyroid antibodies and optimum steroid response. We present the characteristic phenotypic manifestations, magnetic resonance imaging and electroechography observations and response to immunomodulation with follow-up in three cases of H.E. All the three cases manifested with subacute to chronic progressive encephalopathy, cerebellar dysfunction, seizures, behavioral abnormalities and oculomotor disturbances and had evidence of hypothyroidism, elevated titers of anti-TPA and positive thyroid anti-microsomal antibodies. Atypical and uncommon presentations are known. This report emphasizes that a high index of suspicion is often required in cases with “investigation negative encephalopathy” for early diagnosis of H.E.

Clinical manifestations, diagnostic criteria and therapy of Hashimoto's encephalopathy: report of two cases

Hashimoto's encephalopathy (HE) is a rare, still not well understood, autoimmune disease with neurological and psychiatric manifestations. and elevated titers of antithyroid antibodies in serum and cerebrospinal fluid (CSF) as a hallmark of the disease. Patients are mostly women. Current diagnostic criteria include corticosteroide responsiveness, but it is the case in only 50% of patients with HE. In steroid non-responders other immunomodulatory therapies or plasmapheresis could be applied. Disease course can be acute, subacute, chronic or relapsing-remitting. Two distinct forms emerged from the reported cases: a vasculitic type characterized by multiple relapsing-remitting stroke-like episodes and mild cognitive impairment and a diffuse progressive type characterized by dementia and psychiatric symptoms. Both forms may be accompanied by depressed level of consciousness (stupor or coma), tremor, seizures, or myoclonus. We present two patients with two distinct forms of HE who had different clinical manifestations and response to therapy.

Updated clinical diagnostic criteria for sporadic Creutzfeldt-Jakob disease

Several molecular subtypes of sporadic Creutzfeldt–Jakob disease have been identified and electroencephalogram and cerebrospinal fluid biomarkers have been reported to support clinical diagnosis but with variable utility according to subtype. In recent years, a series of publications have demonstrated a potentially important role for magnetic resonance imaging in the pre-mortem diagnosis of sporadic Creutzfeldt–Jakob disease. Magnetic resonance imaging signal alterations correlate with distinct sporadic Creutzfeldt–Jakob disease molecular subtypes and thus might contribute to the earlier identification of the whole spectrum of sporadic Creutzfeldt–Jakob disease cases. This multi-centre international study aimed to provide a rationale for the amendment of the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease. Patients with sporadic Creutzfeldt–Jakob disease and fluid attenuated inversion recovery or diffusion-weight imaging were recruited from 12 countries. Patients referred as ‘suspected sporadic Creutzfeldt–Jakob disease’ but with an alternative diagnosis after thorough follow up, were analysed as controls. All magnetic resonance imaging scans were assessed for signal changes according to a standard protocol encompassing seven cortical regions, basal ganglia, thalamus and cerebellum. Magnetic resonance imaging scans were evaluated in 436 sporadic Creutzfeldt–Jakob disease patients and 141 controls. The pattern of high signal intensity with the best sensitivity and specificity in the differential diagnosis of sporadic Creutzfeldt–Jakob disease was identified. The optimum diagnostic accuracy in the differential diagnosis of rapid progressive dementia was obtained when either at least two cortical regions (temporal, parietal or occipital) or both caudate nucleus and putamen displayed a high signal in fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging. Based on our analyses, magnetic resonance imaging was positive in 83% of cases. In all definite cases, the amended criteria would cover the vast majority of suspected cases, being positive in 98%. Cerebral cortical signal increase and high signal in caudate nucleus and putamen on fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging are useful in the diagnosis of sporadic Creutzfeldt–Jakob disease. We propose an amendment to the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease to include findings from magnetic resonance imaging scans.

Acute confusional state caused by Hashimoto's encephalopathy in a patient with hypothyroidism: a case report

Introduction

Hashimoto's Encephalopathy is an unusual condition associated with Hashimoto's Thyroiditis. This immune-mediated, steroid-dependent entity was first described thirty years ago. In this case report, we discuss the importance of considering this diagnosis in the evaluation of confusion.

Case presentation

The patient is a 55-year-old African-American woman residing in United States, who was admitted to the hospital with a four-day history of mental status changes. Her past medical history was significant for type II Diabetes Mellitus, Hypertension, and Hypothyroidism. There was no reported seizure activity. The patient's vital signs were stable on admission. On examination, the patient was awake, alert, oriented to place and time. Her neurological examination revealed agraphia and dyslexia. Her speech showed lack of fluency and hesitation. Her complete blood count and electrolytes were within normal limits. The patient's brain CT scan did not reveal any significant findings. Her Magnetic Resonance Imaging only revealed mild chronic microangiopathy, which caused by “small vessel disease.” Her Electroencephalogram did not reveal any finding consistent with seizure activity. Cerebral spinal fluid analysis was likewise did not reveal a cause for this patient's acute onset of confusion. In contrast to the above negative finding, this patient's Thyroid stimulating hormone was discovered to be 15 UIU/ml. She was subsequently given 1000 mg of intravenous Methylprednisolone daily for 3 days. This three-day course of high-dose, intravenous steroids resulted complete resolution of the patient's symptoms. She was then discharged on an eleven-day course of oral prednisone 60 mg.

Conclusion

Hashimoto's Encephalopathy should be considered in the differential diagnosis of an acute confusional state since it is responsive to steroid therapy and represents a readily reversible cause acute mental status changes. Clues to this diagnosis include elevated antithyroid antibodies, abnormal Thyroid stimulating hormone values, and exclusion of other causes of acute mental status changes.

Hashimoto's encephalopathy: an under diagnosed entity

We describe a 60-year-old woman with Hashimoto's thyroiditis who presented with neuropsychiatric manifestations even on optimal and stable doses of levothyroxine replacement therapy. She had high anti-thyroid peroxidase antibody and responded to glucocorticoid treatment.

Hashimoto encephalopathy: Neurological and psychiatric perspective

Hashimoto encephalopathy (HE) is an autoimmune disease with neurological and neuropsychiatric manifestations and elevated titers of antithyroid antibodies in serum and cerebrospinal fluid. Patients are mostly women. Age varies from 8 to 86 years. Prevalence of HE is estimated to be 2.1/100,000. Neurological and/or psychiatric symptoms and signs constitute the clinical picture. The disease responds well to corticosteroid therapy, but sometimes other immunomodulatory therapies must be applied. Autoimmune mechanisms with antibodies against antigens in the brain cortex are suspected. The course of the disease can be acute, subacute, chronic, or relapsing/remitting. Some patients improve spontaneously, but a few died in spite of adequate therapy.

Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE) is a controversial neurological disorder that comprises a heterogenous group of neurological symptoms that manifest in patients with high titers of antithyroid antibodies. Clinical manifestations of HE may include encephalopathic features such as seizures, behavioral and psychiatric manifestations, movement disorders, and coma. Although it has been linked to cases of Hashimoto's thyroiditis or thyroid dysfunction, the most common immunological feature of HE is the presence of high titers of antithyroglobulin or anti-TPO (antimicrosomal) antibodies. At present, it is unclear whether antithyroid antibodies represent an immune epiphenomenon in a subset of patients with encephalopathic processes or they are really associated with pathogenic mechanisms of the disorder. The significance of classifying encephalopathies under the term HE will be determined in the future once the relevance of the role of antithyroid antibodies is demonstrated or dismissed by more detailed experimental and immunopathological studies. The responsiveness of HE to steroids or other therapies such as plasmapheresis supports the hypothesis that this is a disorder that involves immune pathogenic mechanisms. Further controlled studies of the use of steroids, plasmapheresis, or immunosuppressant medications are needed in the future to prove the concept of the pathogenic role of antithyroid antibodies in HE.

A 50-year-old woman with recurrent generalised seizures

Ronald Ma and colleagues discuss the differential diagnosis, investigation, and management of this patient.

Rapidly progressive dementia

In contrast with more common dementing conditions that typically develop over years, rapidly progressive dementias can develop subacutely over months, weeks, or even days and be quickly fatal. Because many rapidly progressive dementias are treatable, it is paramount to evaluate and diagnose these patients quickly. This review summarizes recent advances in the understanding of the major categories of RPD and outlines efficient approaches to the diagnosis of the various neurodegenerative, toxic-metabolic, infectious, autoimmune, neoplastic, and other conditions that may progress rapidly.

Hashimoto's encephalopathy : epidemiology, pathogenesis and management

Hashimoto's encephalopathy is a term used to describe an encephalopathy of presumed autoimmune origin characterised by high titres of antithyroid peroxidase antibodies. In a similar fashion to autoimmune thyroid disease, Hashimoto's encephalopathy is more common in women than in men. It has been reported in paediatric, adult and elderly populations throughout the world. The clinical presentation may involve a relapsing and remitting course and include seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms and myoclonus. Thyroid function is usually clinically and biochemically normal.Hashimoto's encephalopathy appears to be a rare disorder, but, as it is responsive to treatment with corticosteroids, it must be considered in cases of 'investigation negative encephalopathies'. Diagnosis is made in the first instance by excluding other toxic, metabolic and infectious causes of encephalopathy with neuroimaging and CSF examination. Neuroimaging findings are often not helpful in clarifying the diagnosis. Common differential diagnoses when these conditions are excluded are Creutzfeldt-Jakob disease, rapidly progressive dementias, and paraneoplastic and nonparaneoplastic limbic encephalitis. In the context of the typical clinical picture, high titres of antithyroid antibodies, in particular antithyroid peroxidase antibodies, are diagnostic. These antibodies, however, can be detected in elevated titres in the healthy general population. Treatment with corticosteroids is almost always successful, although relapse may occur if this treatment is ceased abruptly. Other forms of immunomodulation, such as intravenous immune-globulin and plasma exchange, may also be effective. Despite the link to autoimmune thyroid disease, the aetiology of Hashimoto's encephalopathy is unknown. It is likely that antithyroid antibodies are not pathogenic, but titres can be a marker of treatment response. Pathological findings can suggest an inflammatory process, but features of a severe vasculitis are often absent. The links between the clinical pictures, thyroid disease, auto-antibody pattern and brain pathology await further clarification through research. It may be that Hashimoto's encephalopathy will be subsumed into a group of nonvasculitic autoimmune inflammatory meningoencephalopathies. This group may include disorders such as limbic encephalitis associated with voltage-gated potassium channel antibodies. Some authors have suggested abandoning any link to Hashimoto and renaming the condition 'steroid responsive encephalopathy associated with autoimmune thyroiditis' to better reflect current, if limited, understanding of this condition.

Rapidly progressive dementia

Rapidly progressive dementias (RPDs) are neurologic conditions that develop subacutely over weeks to months or, rarely, acutely over days. In contrast to most dementing conditions that take years to progress to death, RPD quickly can be fatal. It is critical to evaluate patients who have RPD without delay, usually in a hospital setting, as they may have a treatable condition. This review discusses a differential diagnostic approach to RPD, emphasizing neurodegenerative, toxic and metabolic, infectious, autoimmune, neoplastic, and other conditions to consider.

Cortico-responsive encephalopathy associated with autoimmune thyroiditis (SREAT): about two case reports characterized by a gap between the diagnosis of autoimmune thyroiditis and neurological disorders

We report two cases of steroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT) often called "Hashimoto's encephalopathy" in which the neurological manifestations develop years before or after the Hashimoto's diagnosis. Because of this specific presentation, the etiological diagnosis of this type of encephalopathy can be a difficult task. In our patients there was a gap of 10 to 20 years between the proof of autoimmune thyroiditis and the neurological symptoms. Case reports of this type of presentation are rare in the literature. A dramatic responsiveness to steroids with total recovery, after several relapses, was confirmed 3 years after the end of treatment. We suggest that antithyroid antibodies should be checked in all patients with unexplained acute or subacute encephalopathy even in elderly subjects in whom the most important differential diagnosis with Creutzfeldt-Jacob disease remains rapidly progressive Alzheimer's disease. A brief review of the literature is proposed.

[Steroid responsive encephalopathy associated with auto-immune thyroiditis]

Since the first description of encephalopathy associated with Hashimoto's thyroiditis in 1966, more than 100 cases of this entity called Hashimoto's encephalopathy or SREAT [steroid-responsive encephalopathy associated with auto-immune thyroiditis] have been reported. The two cases reported here illustrate different diagnostic criteria and offer the opportunity to discuss the many pathophysiological hypotheses based on particularly pertinent biological data, especially the activity of anti-TPO and anti-TG antibodies present in serum and cerebrospinal fluid and the recent discovery of anti-alpha-enolase antibody. Different treatment options are also discussed, in particular corticosteroid therapy.

Painful legs and moving toes syndrome associated with Hashimoto's disease

A patient with Hashimoto' s disease presented with painful legs and moving toes (PLMT). The neurological and electrophysiological findings suggest that, in this case, PLMT syndrome is a variety of dystonic movement and is associated with Hashimoto's disease.

Psychiatric presentation of Hashimoto's encephalopathy

INTRODUCTION

Hashimoto's encephalopathy is an unusual condition that is associated with Hashimoto's thyroiditis. Myoclonus, epileptic seizures, dementia, and disturbances of consciousness are the most common features.

CASE REPORT

We present an atypical case of Hashimoto's encephalopathy in a 33-year-old woman who presented with several brief and acute psychotic episodes. After treatment with steroids, there was an improvement in the patient's psychiatric symptoms and electroencephalogram, and antithyroglobulin antibody titers returned to normal levels.

CONCLUSIONS

It is our opinion that Hashimoto's encephalopathy should be considered in the differential diagnosis of atypical psychosis, especially because this is a treatable syndrome. This is particularly important in patients with a previous history of thyroid disease, despite current normal thyroid function.

An 85-year-old case with Hashimoto's encephalopathy, showing spontaneous complete remission

We report an 85-year-old man with Hashimoto's encephalopathy (HE) who showed spontaneous complete remission. The autoantibody against the amino (NH2) terminal region of alpha-enolase was positive in our patient. Neuropsychological manifestations, such as personality change and progressive cognitive impairment, gradually improved over approximately 6 weeks after onset of disease without corticosteroid treatment in parallel with a decrease in the anti-thyroglobulin antibody in the cerebrospinal fluid. HE should be considered as a possible diagnosis even in elderly patients with neuropsychiatric symptoms, particularly when a previous history of thyroid disease is present.

[Lithium-induced encephalopathy mimicking Creutzfeldt-Jakob disease]

INTRODUCTION

Creutzfeldt-Jakob disease (CJD) has a poor prognosis. Certain clinical presentations can be suggestive yet mimic a curable disease.

OBSERVATION

In the present study, we report the case of a 67-year-old man with a one-month history of progressive dementia, with myoclonic jerks and cerebellar syndrome suggesting a diagnosis of Creutzfeldt-Jakob encephalopathy. He had been treated for 9 years with lithium for a bipolar disorder. The results of the different investigations and the favorable course after discontinuation of lithium were in favor of the diagnosis of drug-induced Creutzfeldt-Jakob syndrome.

CONCLUSION

This case illustrates the importance for researching a curable etiology in presence of clinical features suggesting a CJD.

The neurological disorder associated with thyroid autoimmunity

The neurological disorder associated with thyroid autoimmunity is an elusive disease that neurologists have learned to recognize in the last few years. The diagnosis is made, after excluding more common diseases, when neuropsychiatric symptoms develop in a patient with high serum concentrations of anti-thyroid antibodies. The clinical presentations of the disease and the many controversial issues surrounding the diagnosis, the pathogenesis, the role of thyroid autoantibodies, and the choice of therapy are reviewed and discussed in the light of the medical literature in English.

Depression bei Hashimoto-Enzephalopathie

Characteristic clinical findings of Hashimoto's encephalopathy (HE) are stroke-like episodes, epileptic seizures, myoclonus, psychosis, and progressive cognitive impairment. Diagnosis of HE is supported by elevated antithyroid antibodies, an abnormal EEG, and by good response to steroids. We report on a 74-year-old female patient with a severe depressive episode who showed no treatment response to citalopram 40 mg/day and venlafaxine 150 mg/day. Diagnostic examination revealed an abnormal EEG, elevated thyroid peroxidase antibodies (TPO-Ab), and older postinflammatory changes in thyroidal sonography. We diagnosed a depression in HE and began treatment with prednisolone 70 mg/day with stepwise dose reduction, continuing treatment with venlafaxine 150 mg/day. Within 4 weeks of treatment, the severe depressive episode disappeared as well as abnormal EEG. In addition, serum values of TPO-Ab decreased. In HE, depressive symptoms can possibly be seen in a subgroup of patients or in the early course of the disease. Diagnosis of HE should be included in diagnostic procedures in cases of therapy-refractory depression because of a good response of HE to steroids.

Hashimoto's encephalopathy: myth or reality? An endocrinologist's perspective

Since the first description of a case of episodic encephalopathy associated with Hashimoto's thyroiditis in 1966, many cases of corticosteroid-responsive encephalopathy associated with positive antithyroid antibodies, clinical Hashimoto's thyroiditis, or spontaneous autoimmune thyroid failure have been reported. These patients have neurologic manifestations of encephalopathy unrelated to other known causes. The condition has thus been termed 'Hashimoto's encephalopathy'. The literature shows no proven association between thyroid disease and the neurologic process. Although the association of a common endocrinologic condition and a rare neurologic disease may occur by chance, this type of encephalopathy probably has an autoimmune nature and thus is more likely to occur in the background of another autoimmune condition such as autoimmune thyroid disease. Until the pathogenesis of these coincident conditions is better defined, the term 'corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis' is more accurate and descriptive than Hashimoto's encephalopathy. Advances in the field may clarify this seemingly inconsistent terminology.