Hashimoto's myoclonic encephalopathy: an underdiagnosed treatable condition?

Hashimoto's encephalopathy with cerebellar ataxia as the main symptom: A case report and literature review

Hashimoto's encephalopathy (HE), also known as steroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT), has a variety of clinical manifestations, with various neuropsychiatric characteristics, including tremors, transient aphasia, seizures, altered consciousness, myoclonus, cognitive impairment, and psychiatric manifestations. The hallmark presenting feature is a non-specific encephalopathy characterized by alteration of mental status and consciousness ranging from confusion to coma and impaired cognitive function, while those with cerebellar ataxia as the main manifestation is rare. We reported a case of Hashimoto's encephalopathy with cerebellar ataxia as the main manifestation, elevated anti-thyroid antibodies (anti-TPO/TG), and normal thyroid function. The symptoms of cerebellar ataxia improved after steroid treatment. Meanwhile, we reviewed the clinical features of 20 representative cases of HE with cerebellar ataxia as the core symptoms. In conclusion, based on our case findings and literature review, the diagnosis of HE should be suspected in cases of encephalopathy without an obvious cause, to quickly start an effective treatment.

Hashimoto Encephalopathy of a Middle-Aged Man With Progressive Symptoms of Dementia

Autoimmune encephalitis is caused by immunological reactions showing unconsciousness, agitation, and other neurological symptoms. Autoimmune diseases can be related to autoantibodies, causing encephalitis. These autoantibody-related encephalitides could appear in various clinical courses. As laboratory tests for detecting these antibodies are limited, diagnosis is difficult. Hashimoto’s encephalopathy is autoimmune encephalitis caused by antibodies against the thyroid gland. This time, we experienced a case of a 69-year-old man with a chief complaint of subacute progression of amnesia and suspected autoimmune encephalitis, who was finally diagnosed with Hashimoto’s encephalopathy in a rural community hospital. In this case, clinicians should consider Hashimoto's encephalopathy as a differential diagnosis and measure antithyroid antibodies when acute or subacute onset cognitive impairment is observed in middle-aged patients. As a super-aging society significantly affects community hospitals, general physicians need to start treatments for encephalopathy and encephalitis when clinicians suspect the disease and rule out other critical diseases.

Use of therapeutic plasma exchange for pediatric neurological diseases

Therapeutic plasma exchange is used to treat neurological diseases in the pediatric population. Since its first use in pediatric patients with hepatic coma in the form of manual whole blood exchange, therapeutic plasma exchange has been increasingly used to treat these disorders of the nervous system. This expansion is a result of improved techniques and apheresis instruments suitable for small children, as well as the recognition of its applicability to many diseases in the pediatric population. This review provides a historical overview of the use of therapeutic apheresis in children and highlights the most common applications for therapeutic plasma exchange to treat neurological disorders in children.

Hashimoto's Encephalopathy Presenting with Smoldering Limbic Encephalitis

Hashimoto's encephalopathy (HE) is a steroid-responsive autoimmune encephalopathy associated with Hashimoto thyroiditis. We herein report a case of HE manifesting "smoldering" limbic encephalitis with persisting symptoms and abnormalities on examinations. Although our patient experienced partial clinical remission after treatment, hippocampal hypermetabolism on [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) and subclinical seizures on video electroencephalography persisted. Hypermetabolism on FDG-PET was improved by additional prednisolone therapy. Thus, as with other autoimmune limbic encephalitis cases, HE can take a course of "smoldering" encephalitis. FDG-PET and electroencephalogram findings can reflect the disease activity degree in such patients, although with certain neurophysiological and biochemical distinctions.

Limbic encephalitis associated with anti-NH2-terminal of α-enolase antibodies: A clinical subtype of Hashimoto encephalopathy

Several types of autoantibodies have been reported in autoimmune limbic encephalitis (LE), such as antibodies against the voltage-gated potassium channel (VGKC) complex including leucine-rich glioma inactivated 1 (LGI1). We recently reported a patient with autoimmune LE and serum anti-NH2-terminal of α-enolase (NAE) antibodies, a specific diagnostic marker for Hashimoto encephalopathy (HE), who was diagnosed with HE based on the presence of antithyroid antibodies and responsiveness to immunotherapy. This case suggests that LE patients with antibodies to both the thyroid and NAE could be diagnosed with HE and respond to immunotherapy. The aim of this study was to clarify the clinicoimmunological features and efficacy of immunotherapy in LE associated with anti-NAE antibodies to determine whether the LE is a clinical subtype of HE.We examined serum anti-NAE antibodies in 78 LE patients with limbic abnormality on magnetic resonance imaging and suspected HE based on positivity for antithyroid antibodies. Nineteen of the 78 patients had anti-NAE antibodies; however, 5 were excluded because they were double positive for antibodies to the VGKC complex including LGI1. No antibodies against the N-methyl-D-aspartate receptor (NMDAR), contactin-associated protein 2 (Caspr2), γ-aminobutyric acid-B receptor (GABABR), or α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) were detected in the 19 patients. Among the remaining 14 who were positive only for anti-NAE antibodies, the median age was 62.5 (20-83) years, 9 (64%) were women, and 8 (57%) showed acute onset, with less than 2 weeks between onset and admission. Consciousness disturbance (71%) and memory disturbance (64%) were frequently observed, followed by psychiatric symptoms (50%) and seizures (43%). The frequency of these symptoms significantly differed between the acute- and subacute-onset groups. Abnormalities in cerebrospinal fluid and electroencephalogram were commonly observed (92% for both). Tumors were not identified in any cases. All patients responded to immunotherapy or spontaneously remitted, thereby fulfilling the criteria of HE.This study demonstrated that LE associated with anti-NAE antibodies is a nonparaneoplastic LE and various limbic symptoms that depend on the onset type. Favorable therapeutic efficacy suggests that this LE can be considered a clinical subtype of HE and that anti-NAE antibodies may be a promising indicator of the need for immunotherapy.

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.

Spectroscopic correlation and role of Azathioprine in long-term remission in patients of Hashimoto encephalopathy

Hashimoto encephalopathy remains a Rubik's cube for the present generation of clinical research. Myriad presentations have been noted, and observations recorded in few subgroups of patients have gone on only to be trashed by a second group of patients with a completely different clinical profile. Steroids have been traditionally held to be the treatment for this condition, but long-term side effects associated with it limits its use. Although multiple drugs have been tried, yet there exists no data for their long-term efficacy in maintaining remission. No radiological findings have been consistently associated with this condition. We report the use of azathioprine in maintaining long-term remission in one such patient with Hashimoto encephalopathy and the presence of lactate peak in magnetic resonance spectroscopy of the patient, which showed dramatic regression with institution of immunosuppression.

Steroid-responsive thalamic lesions accompanying microbleeds in a case of Hashimoto's encephalopathy with autoantibodies against α-enolase

A 67-year-old man receiving antithrombotic therapy developed rapidly progressive amnesia. T2-weighted images of brain MRI revealed hyperintense lesions in the bilateral thalami accompanied by microbleeds. Antithyroglobulin antibodies and autoantibodies against the N-terminal of α-enolase (NAE) were identified in the patient's serum; therefore, Hashimoto's encephalopathy (HE) was suspected. Although the patient's radiological findings improved following steroid therapy, his symptoms did not improve, possibly due to increased thalamic microbleeds. Because anti-NAE antibodies are possibly associated with vasculitis, HE accompanied by anti-NAE antibodies may be exacerbated by microbleeds in patients receiving antithrombotic therapy.

A series report of autoimmune hypothyroidism associated with Hashimoto's encephalopathy: an under diagnosed clinical entity with good prognosis

Thyroid dysfunctions may be accompanied by numerous neurological and psychiatric disorders. The most well-known is cognitive impairment and depression in hypothyroid patients, as well as an increased risk of cerebrovascular accidents. A separate, although a rare entity, is Hashimoto's encephalopathy. Unlike encephalopathy associated with other conditions, management in Hashimoto's encephalopathy highly responds to steroid treatment and may be associated with normal thyroid profile at presentation. Hashimoto's encephalopathy, while rare, may have been under-recognised since its clinical presentation overlaps several more common disorders, such as depression, seizures or anxiety. We present two cases of hypothyroidism with peculiar presentation. The first case has rapidly progressive neurological dysfunction, normal thyroid function at presentation, normal MRI finding and responds to steroid treatment. The second case has a subacute progressive neurological deterioration with elevated thyroid-stimulating hormone titre at presentation. Both these cases are known hypothyroidism on regular thyroxin replacement therapy with elevated anti-thyroid peroxidase antibodies. We conclude that Hashimoto's encephalopathy can present with a wide spectrum of neurological illnesses in the setting of hypothyroidism. Thyroid status may vary from hypothyroid, normothyroid to even hyperthyroid. This condition usually has an abnormal electroencephalography (EEG) background and usually responds to high dose steroids.

Immunotherapy responsive autoimmune subacute encephalitis: a report of two cases

Objective. To describe the clinical characteristics and radiological findings in two patients with subacute encephalitis associated with elevated serum voltage-gated potassium channel antibody (VGKCAb) and antithyroperoxidase (TPO) antibody. Case Reports. Case 1: 63-year-old woman was admitted for altered mental status and possible seizure activity. MRI brain showed hyperintensity in the bilateral hippocampal areas. She was positive for VGKCAb and anti-TPO antibodies. She was treated with steroids, IVIG, plasma exchange and azathioprine. After 8 months, she had marked improvement in her memory and seizures. Case 2: 61-year-old woman was admitted for video EEG monitoring of unclassified seizure and cognitive function decline. MRI of the brain showed mild hyperintensity in bilateral hippocampal areas and significant atrophy in the frontotemporal lesion. Anti-TPO antibody and VGKCAb were positive. She was treated with steroids, plasma exchange and azathioprine. After 9 months, she had marked improvement in her memory and seizures. Conclusion. Autoimmune subacute encephalitis appears to be an underdiagnosed entity. It is important to screen patients with subacute encephalitis for anti-TPO antibody and VGKCAb, particularly in the presence of seizures. Immunosuppressive therapy appears to be effective in treating this entity.

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.

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.

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.

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.

Clinical and diagnostic aspects of encephalopathy associated with autoimmune thyroid disease (or Hashimoto's encephalopathy)

Encephalopathy associated with autoimmune thyroid disease, currently known as Hashimoto's encephalopathy, but also defined as corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis, is a relatively rare condition observed in a small percentage of patients presenting with autoimmune thyroid disease. It consists of a subacute, relapsing-remitting, steroid-responsive encephalopathy characterised by protean neurologic and neuropsychiatric symptoms, diffuse electroencephalographic abnormalities and increased titres of antithyroid antibodies in serum and/or in cerebrospinal fluid. Most of the cases presenting this neurologic complication are affected by Hashimoto's thyroiditis or, less frequently, by other autoimmune thyroid diseases, chiefly Graves' disease. The pathogenesis of this encephalopathy is still unknown and largely debated, because of extremely varied clinical presentation, possibly referable to different aetiologic and pathophysiologic mechanisms, as confirmed by the two clinical cases we report in this paper. Autoimmune aetiology is, however, very likely in view of the well established favourable response to corticosteroid administration. Both vasculitis and autoimmunity directed against common brain-thyroid antigens represent the most probable aetiologic pathways. Clinical manifestations include consciousness changes, neurologic diffuse or focal signs, headache, and altered cognitive function. Although unspecific, cerebral oedema has also been described. Cerebrospinal fluid examination often discloses an inflammatory process, with a mild increase in protein content and occasionally in lymphocyte count. In this review, clinical criteria for the diagnosis of defined, probable, or possible encephalopathy associated with autoimmune thyroid disease are suggested. Corticosteroid therapy currently allows us to obtain rapid remission of disease symptoms, but adverse outcomes as well as spontaneous remissions have also been reported.

Hashimoto Encephalopathy with Pegylated Interferon Alfa-2b and Ribavirin

OBJECTIVE:

To report an instance of Hashimoto encephalopathy probably resulting from pegylated interferon alfa-2b and ribavirin.

CASE SUMMARY:

A 36-year-old woman with a 10-year history of autoimmune thyroiditis presented with symptoms and signs consistent with Hashimoto encephalopathy during therapy with pegylated interferon alfa-2b and ribavirin for chronic hepatitis C.

DISCUSSION:

Hashimoto encephalopathy is a rare autoimmune condition that occurs in patients with Hashimoto thyroiditis and high titers of antithyroid antibodies. It is characterized by a variety of nonspecific neuropsychiatric symptoms, increased cerebrospinal fluid protein level, and abnormal brain imaging and electroencephalogram. Prompt response to corticosteroids is observed in most cases. As of August 29, 2005, this is the first report of such an association. An objective causality assessment revealed that the Hashimoto encephalopathy was probably caused by the patient's medications.

CONCLUSIONS:

Hashimoto encephalopathy may rarely be triggered by interferon alfa therapy in susceptible patients.

Multiple Sclerosis and Hashimoto Thyroiditis

Multiple sclerosis (MS) occurs with immune-mediated mechanisms, but its pathogenesis is not accurately known. The coexistence of MS with other autoimmune diseases has been reported. The hypothesis that MS coexists with other autoimmune diseases has been supported by the reported association of MS with type I diabetes mellitus and inflammatory disorders. Even though there have been only rare reports of associations between Hashimoto thyroiditis and MS, this association is important for its clinical and therapeutic aspects. Proximal muscle weakness, myalgia, and fatigue are symptoms that are common in both MS and hypothyroidism. When MS patients demonstrate these symptoms, thyroid function tests should be performed. The thyroid hormone levels of MS patients being treated with interferon-beta and Campath-1H also should be monitored. The authors report the clinical data of 2 definite MS patients who also fulfilled criteria for Hashimoto thyroiditis.

Autoantibodies against the amino terminal of alpha-enolase are a useful diagnostic marker of Hashimoto's encephalopathy

We investigated autoantibodies and their epitope(s) in Hashimoto's encephalopathy associated with Hashimoto's thyroiditis. In a proteomic analysis, they proved to recognize alpha-enolase. We further searched the epitope region in alpha-enolase using different regions of recombinant proteins expressed in cultured human cells. The amino terminal region was recognized by autobodies from a much higher proportion of patients with Hashimoto's encephalopathy (83.3%; 5/6) than from patients with Hashimoto's thyroiditis (11.8%; 2/17), and not at all by sera from controls (25 healthy individuals and 25 controls with other neurological disorders) (0%; 0/50). Neither the carboxyl terminal nor the mid-region of alpha-enolase showed specificity for Hashimoto's encephalopathy. Autoantibodies against the amino terminal of alpha-enolase are a useful diagnostic marker for Hashimoto's encephalopathy.

Reversible electroencephalographic and single photon emission computed tomography abnormalities in Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE) is a well-established disease that occurs most commonly in patients with euthyroidism. We report 3 patients diagnosed with HE. Cases 1 and 2 were young females who had experienced intractable seizures and presented with cognitive impairment. Reversible slow waves on the electroencephalogram (EEG), and nearly complete recovery of cognition, were noted after steroid treatment. Case 3 was an elderly male who presented with a sudden onset of vertigo, diplopia, and recurrent gait ataxia. Reversible hypoperfusion in the upper portion of the left cerebellum, on (99m)Tc hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT), was noted after steroid treatment. We also review 25 cases from the literature of patients diagnosed with HE. All patients had antithyroid antibodies. A reversible inflammatory process is supported by brain magnetic resonance imaging, SPECT, EEG and cerebrospinal fluid studies. Vasculitis is the most probable pathogenesis according to laboratory findings. Steroids are the treatment of choice, and result in a favorable outcome when administered early in the disease course.

Systemic diseases that cause movement disorders

The present review is aimed at providing practical assistance to the clinical neurologist in reaching a diagnosis, understanding the pathogenic mechanisms of movement disorders associated with systemic diseases, and determining appropriate therapy. Infectious disease by direct effect or as an acquired autoimmune neurological disease, stroke, hypoxia-ischemia, paraneoplastic syndromes, collagen disorders, endocrine, liver and kidney diseases that may cause hypokinetic or hyperkinetic abnormal movement are considered separately. The type and evolution of abnormal movement caused by systemic disease vary with age and underlying pathology. Therapy for abnormal movements should include a primary treatment for the systemic disease.

Anti-neuronal autoantibody in Hashimoto's encephalopathy: neuropathological, immunohistochemical, and biochemical analysis of two patients

Hashimoto's encephalopathy (HE) is thought to be caused by disorders of immune mechanisms. Although immunologically mediated central nervous system vasculitis or unidentified anti-neuronal autoantibodies have been suspected of causing HE, its pathogenesis is still unclear. For the study presented here, two patients with typical clinical and laboratory/electrophysiological findings of HE were analyzed to clarify the role of anti-neuronal autoantibodies in the pathogenesis of HE. The autopsied brain of one of the patients was histopathologically examined. For Western blotting analysis and immunohistochemistry, serum and purified immunoglobulin G obtained from the other patient were used. Autopsy revealed no evidence of central nervous system vasculitis or other abnormal findings in the brain. The patient's serum contained an anti-neuronal autoantibody that immunohistochemically labeled neurons of mouse and human cerebral cortices and reacted with the 36-kDa antigenic protein present in a soluble fraction obtained from human cerebral cortex. Our results indicate that anti-neuronal autoantibodies may be associated with the pathogenesis of HE.

Encephalopathy associated with Hashimoto's thyroiditis: an additional case

A 35-year-old female with a history of Hashimoto's thyroiditis (HT) presented with episodic dysphasia and a burst of axial jerks with abdominal muscle contraction and asymmetric blepharospasm as manifestations of encephalopathy associated with HT. Brain magnetic resonance imaging (MRI) showed scattered supratentorial white matter hyperintense T2 foci. Brain single photon emission computerized tomography (SPECT) demonstrated a cortical hypoperfusion in the upper frontal and parietal areas. Corticosteroid therapy induced a rapid improvement of the clinical picture.

Hashimoto's encephalopathy in the elderly: relationship to cognitive impairment

Hashimoto's encephalopathy (HE) is a steroid-responsive encephalopathy associated with high titers of antithyroid antibodies. To date, 57 pediatric-, adult-, and elderly-onset cases have been described in the literature. The clinical picture is pleomorphic, and cognitive impairment is a frequently reported symptom. We report the case of a patient with slowly progressive cognitive impairment possibly caused by HE. The issue of the differential diagnosis with primary dementia is discussed. A review of cases of HE showing cognitive deterioration is also presented, and factors possibly related to characteristics of cognitive impairment and outcome after therapy are considered.

Subacute cerebellar syndrome and Hashimoto's thyroiditis. Association or simple coincidence?

Numerous neurological symptoms have been observed in thyroid autoimmune disorders. The case of a 47-year-old euthyroid woman who develops a cerebellar syndrome associated with thyroiditis is discussed. Reference is made to the favorable outcome of combined per os thyroxine, corticosteroid and intravenous human normal immunoglobulin (Sandoglobulin) treatment.

Choreic syndrome due to Hashimoto's encephalopathy

We report on the instructive case of an elderly woman who became encephalopathic and concurrently developed chorea. Thyroid antibody studies were abnormal. She responded extremely well to oral corticosteroids.

Rarity of encephalopathy associated with autoimmune thyroiditis: a case series from Mayo Clinic from 1950 to 1996

Corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (also called Hashimoto's encephalopathy) is a rare, life-threatening, treatable, and possibly autoimmune condition. We identified nine patients (with the diagnosis made after 1979) who had relapsing encephalopathy compatible with previous reports of Hashimoto's encephalopathy and no other identifiable cause of encephalopathy at Mayo Clinic Rochester. Of these nine patients, three were clinically hypothyroid, four were subclinically hypothyroid, and two were euthyroid. Thyroid antibodies were positive in eight of eight patients in whom these measurements were made. Electroencephalographic abnormalities were identified in eight of the nine patients (89%). Magnetic resonance imaging (MRI) abnormalities considered etiologically related to encephalopathy were present in three patients (33%). An increased protein concentration was noted on cerebrospinal fluid examination in seven patients (78%). Of the six patients who received high-dose glucocorticoid therapy, 5 (83%) had improvement of neurologic symptoms. In conclusion, encephalopathy associated with autoimmune thyroiditis is rare but important to recognize because it may be responsive to high-dose glucocorticoid therapy. We believe that this condition is not caused by thyroid dysfunction or antithyroid antibodies but represents an association of an uncommon autoimmune encephalopathy with a common autoimmune thyroid disease. The term Hashimoto's encephalopathy is a misnomer and should not be used.

Hashimoto's encephalopathy: documentation of mesial temporal seizure origin by ictal EEG

Hashimoto's encephalopathy is a chronic relapsing and remitting encephalopathy associated with antithyroid antibodies. Seizures are a frequent manifestation, but are not well characterized in the literature with respect to their onset. We describe a 48-year-old patient with recurrent encephalopathy and seizures, and elevated antithyroid antibodies. One seizure was documented with video-EEG monitoring using scalp and sphenoidal electrodes. The ictal discharge originated in the left mesial-basal temporal region. MRI showed an increased T2 signal in the white matter of the centrum semiovale, but no temporal pathology. Symptoms resolved after treatment with prednisone and azathioprine. Hashimoto's encephalopathy should be considered in patients with unexplained encephalopathy and seizures, including those originating in the temporal lobe.

Encephalopathy associated to autoimmune thyroid disease: a more appropriate term for an underestimated condition?

Hashimoto's encephalopathy is a severe and rather infrequent clinical condition initially described in patients suffering from chronic lymphocytic thyroiditis. Its origin is still controversial but it can be agreed to have an autoimmune etiology. In fact, its most characteristic finding is the high titre of antithyroid antibodies, especially antimicrosomal. We describe three cases of Hashimoto's encephalopathy and establish a relationship between the clinical status, the antithyroid antibody levels and its response to corticosteroid treatment. There was an excellent response to corticosteroid treatment in all three cases. Interestingly, one case was associated with Graves' disease. Given this, and after the review of the literature, we believe that the term 'encephalopathy associated to autoimmune thyroid disease' could be more appropriate to define this entity. Finally, we suggest that autoimmune thyroid encephalopathy must be suspected in the face of unaccounted acute or subacute encephalopathy with high levels of antithyroid antibodies.

How to improve the clinical diagnosis of Creutzfeldt-Jakob disease

This paper describes a prospective follow-up of 364 patients initially notified as suspected Creutzfeldt-Jakob disease to a Surveillance Unit in Göttingen, Germany. Six patients were diagnosed as having genetic prion disease by blood analysis and were excluded from the study. After examination and review of the remaining 358, 193 were classified as probable Creutzfeldt-Jakob disease. However, autopsy revealed that five of the 193 did not have Creutzfeldt-Jakob disease (four cases, Alzheimer's disease; one case, cerebral lymphoma). Of the 54 patients classified as possible Creutzfeldt-Jakob disease, 10 had another diagnosis made at autopsy. Two of the 111 cases originally classified as having other diseases were found to have Creutzfeldt-Jakob disease on autopsy. Autopsy evidence, together with follow-up of the patients still living and those who died without autopsy, revealed a broad range of other diagnoses. In the younger age groups, the commonest were chronic inflammatory diseases including Hashimoto encephalitis, whilst rapidly progressive Alzheimer's disease was most common in the older age groups. The presence of 14-3-3 protein in the CSF discriminated better between Creutzfeldt-Jakob disease and other rapidly progressive dementias than did the EEG pattern or the MRI. The inclusion of this CSF protein in the criteria of Masters and colleagues (Ann Neurol 1979; 5: 177-88) improves the accuracy and confidence in the clinical diagnosis of Creutzfeldt-Jakob disease.

Pediatric manifestations of Hashimoto's encephalopathy

Hashimoto's encephalopathy is a steroid-responsive encephalopathy associated with elevated blood concentrations of antithyroid antibodies. The patients are usually euthyroid or mildly hypothyroid. The authors report two pediatric patients with Hashimoto's encephalopathy and review the literature. The clinical picture in adolescents, as with adults, is pleomorphic but frequently associated with seizures, confusion, and hallucinations. Alternatively, progressive cognitive decline manifested by a drop in school performance can be observed. The diagnosis of Hashimoto's thyroiditis is often overlooked at presentation and a high degree of suspicion is necessary for proper diagnosis.

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

OBJECTIVES

During an epidemiological study of Creutzfeldt-Jakob disease in Germany, Hashimoto's encephalitis was encountered as a differential diagnosis, which has not yet been described in this context.

METHODS

The symptoms and findings of seven patients who fulfilled the criteria for "possible" Creutzfeldt-Jakob disease are presented.

RESULTS

A Hashimoto's thyroiditis with antibodies against thyroglobulin or thyroid peroxidase, or both and a hypoechoic thyroid ultrasonogram were found in all cases. Analysis of CSF disclosed an increased leucocyte count in three patients, and a raised CSF:serum concentration ratio of albumin (QA1b) in four patients. The 14-3-3 protein, typical of Creutzfeldt-Jakob disease, could not be detected in any of our patients. No periodic sharp wave complexes, which are typical of Creutzfeldt-Jakob disease, were detected on EEG in any of the cases. By contrast with Creutzfeldt-Jakob disease, which leads to death within a few months, the patients with Hashimoto's encephalitis often recover quickly when treated adequately. All the patients improved after administration of corticosteroids.

CONCLUSION

The clinical symptomatology of both diseases may be very similar: dementia, myoclonus, ataxia, and personality change or psychotic phenomena are characteristic symptoms.