Hashimoto's encephalopathy as a treatable adult-onset cerebellar ataxia mimicking spinocerebellar degeneration

Myelitis preceding anti-N-terminal of α-enolase antibody-positive Hashimoto's encephalopathy

Hashimoto's encephalopathy is an autoimmune disease characterized by diverse clinical and imaging manifestations, often presenting considerable challenges in its diagnosis, especially when myelitis occurs before the onset of encephalopathy. Anti-N-terminal of α-enolase antibodies targeting the N-terminal of α-enolase are specific serum markers of Hashimoto's encephalopathy; however, studies analyzing their association with myelitis are lacking. Herein, we describe the case of a patient with myelitis who later developed encephalopathy. Owing to positivity for anti-N-terminal of α-enolase antibodies in the serum, a diagnosis of Hashimoto's encephalopathy was made. Detecting anti-NAE antibodies can be useful in diagnosing myelitis of unknown etiology.

Immune-mediated ataxias: Guide to clinicians

Immune-mediated cerebellar ataxias were initially described as a clinical entity in the 1980s, and since then, an expanding body of evidence has contributed to our understanding of this topic. These ataxias encompass various etiologies, including postinfectious cerebellar ataxia, gluten ataxia, paraneoplastic cerebellar degeneration, opsoclonus-myoclonus-ataxia syndrome and primary autoimmune cerebellar ataxia. The increased permeability of the brain-blood barrier could potentially explain the vulnerability of the cerebellum to autoimmune processes. In this manuscript, our objective is to provide a comprehensive review of the most prevalent diseases within this group, emphasizing clinical indicators, pathogenesis, and current treatment approaches.

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.

Rare Etiologies in Immune-Mediated Cerebellar Ataxias: Diagnostic Challenges

The cerebellum is particularly enriched in antigens and represents a vulnerable target to immune attacks. Immune-mediated cerebellar ataxias (IMCAs) have diverse etiologies, such as gluten ataxia (GA), post-infectious cerebellitis (PIC), Miller Fisher syndrome (MFS), paraneoplastic cerebellar degeneration (PCD), opsoclonus myoclonus syndrome (OMS), and anti-GAD ataxia. Apart from these well-established entities, cerebellar ataxia (CA) occurs also in association with autoimmunity against ion channels and related proteins, synaptic adhesion/organizing proteins, transmitter receptors, glial cells, as well as the brainstem antigens. Most of these conditions manifest diverse neurological clinical features, with CAs being one of the main clinical phenotypes. The term primary autoimmune cerebellar ataxia (PACA) refers to ataxic conditions suspected to be autoimmune even in the absence of specific well-characterized pathogenic antibody markers. We review advances in the field of IMCAs and propose a clinical approach for the understanding and diagnosis of IMCAs, focusing on rare etiologies which are likely underdiagnosed. The frontiers of PACA are discussed. The identification of rare immune ataxias is of importance since they are potentially treatable and may lead to a severe clinical syndrome in absence of early therapy.

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.

Immune-Mediated Cerebellar Ataxia Associated With Neuronal Surface Antibodies

BACKGROUND

Immune-mediated cerebellar ataxias (IMCAs) are common in paraneoplastic cerebellar degeneration (PCD) but rarely occur in patients with neuronal surface antibodies (NSAbs). Although cerebellar ataxias (CAs) associated with anti-NMDAR and anti-CASPR2 have been reported in a few cases, they have never been studied systematically. This study aimed to analyze the characteristics of anti-NSAbs-associated CAs.

METHODS

A retrospective investigation was conducted to identify patients using the keywords IMCAs and NSAbs. We collected the clinical data of 14 patients diagnosed with anti-NSAbs-associated CAs.

RESULTS

The median age was 33 years (16-66), and the male-to-female ratio was 4:3. Nine were positive for NMDAR-Ab, two for LGI1-Ab, two for CASPR2-Ab, and one for AMPA2R-Ab. CAs were initial symptoms in three patients and presented during the first two months of the disease course (10 days on average) among the rest of the patients. After the immunotherapy, two cases were free from symptoms, and eight cases recovered satisfactorily (10/14, 71.4%). Compared with other causes of IMCAs, anti-NSAbs were more frequently associated with additional extra-cerebellar symptoms (85.7%), mostly seizures (78.6%) and mental abnormalities (64.3%). In the CSF analysis, pleocytosis was detected in ten patients (71.4%) and oligoclonal bands (OB) were observed in nine patients (64.3%). Moreover, compared with PCD and anti-GAD65-Ab-associated CAs, anti-NSAbs-associated CAs showed a better response to immunotherapy.

CONCLUSION

IMCAs are rare and atypical in autoimmune encephalitis with neuronal surface antibodies. Compared with other forms of IMCAs, more symptoms of encephalopathy, a higher rate of pleocytosis and positive OB in CSF, and positive therapeutic effect were the key features of anti-NSAbs-associated CAs.

Spinocerebellar Ataxia Type 31 Exacerbated by Anti-amino Terminal of Alpha-enolase Autoantibodies

We herein report a 61-year-old woman who was genetically diagnosed with spinocerebellar ataxia type 31 whose symptoms were modified by anti-amino terminal of alpha-enolase (NAE) antibodies, known as a biomarker of Hashimoto's encephalopathy (HE), and ultimately responded to immunotherapy. The relative titers of anti-NAE antibodies increased when her cerebellar ataxia showed acute deterioration and decreased after immunotherapy. This is the first report of cerebellar ataxia associated with genetic spinocerebellar ataxia with concomitant cerebellar type HE. Physicians should be mindful of measuring anti-NAE antibodies to prevent overlooking patients with genetic spinocerebellar ataxia with treatable simultaneous ataxic diseases.

High prevalence of serum anti-NH2-terminal of α-enolase antibodies in patients with multiple system atrophy and corticobasal syndrome

BACKGROUND

Hashimoto's encephalopathy with serum anti-NH₂-terminal of α-enolase (NAE) antibodies occasionally displays clinical symptoms such as cerebellar ataxia and parkinsonism. We studied the frequency of anti-NAE antibodies in patients with Parkinson-plus syndrome.

METHODS

We examined the positive rates of anti-NAE antibodies in 47 patients with multiple system atrophy (MSA), 29 patients with Parkinson's disease (PD), eight patients with corticobasal syndrome (CBS), and 18 patients with progressive supranuclear palsy (PSP) using conventional immunoblot analysis.

RESULTS

Positive anti-NAE antibody rates of 31.9%, 10.3%, 50.0%, and 11.1% were reported in the MSA, PD, CBS, and PSP patients, respectively. The duration from onset to a wheelchair-bound state in seropositive MSA patients tended to be shorter than that in seronegative MSA patients.

CONCLUSIONS

Anti-NAE antibodies are detected in some patients clinically diagnosed with MSA and CBS. Although its pathophysiological significance remains uncertain, serum anti-NAE antibodies might represent a prognostic marker in the clinical course of MSA.

Nonparaneoplastic autoimmune cerebellar ataxias

PURPOSE OF REVIEW

The current review develops the clinical presentations of nonparaneoplastic autoimmune cerebellar ataxia (ACA) and analyzes the association with autoantibodies.

RECENT FINDINGS

Emerging evidence suggests that autoimmunity is involved in a significant proportion of sporadic ataxia cases. Moreover, numerous autoantibodies have recently been described in association with sporadic cerebellar ataxia, improving diagnosis and patient categorization.

SUMMARY

Nonparaneoplastic ACA encompasses postinfectious acute cerebellar ataxia, opsoclonus-myoclonus-ataxia syndrome, and pure cerebellar ataxia with or without autoantibodies. There is still confusion about how to diagnose and classify the patients, and retrospective data suggest that these very rare entities are in fact largely underrecognized. Numerous autoantibodies have been found associated with sporadic ataxia, improving diagnosis accuracy, and patient categorization. However, although anti-glutamate decarboxylase isotype 65 (GAD65), anti-contactin-associated protein 2 (CASPR2), and anti metabotropic glutamate receptor (mGluR1) antibodies are well recognized biomarkers, many other autoantibodies have been described in very small numbers of patients and their specificity is unknown. Efficient biomarkers for ACA are still lacking and in many cases the diagnosis has to rely on a body of converging evidence.

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.

The Comprehensive Management of Cerebellar Ataxia in Adults

PURPOSE OF REVIEW

In this review, we present the multidisciplinary approach to the management of the many neurological, medical, social, and emotional issues facing patients with cerebellar ataxia.

RECENT FINDINGS

Our holistic approach to treatment, developed over the past 25 years in the Massachusetts General Hospital Ataxia Unit, is centered on the compassionate care of the patient and their family, empowering them through engagement, and including the families as partners in the healing process. We present the management of ataxia in adults, beginning with establishing an accurate diagnosis, followed by treatment of the multiple symptoms seen in cerebellar disorders, with a view to maximizing quality of life and effectively living with the consequences of ataxia. We discuss the importance of a multidisciplinary approach to the management of ataxia, including medical and non-medical management and the evidence base that supports these interventions. We address the pharmacological treatment of ataxia, tremor, and other associated movement disorders; ophthalmological symptoms; bowel, bladder, and sexual symptoms; orthostatic hypotension; psychiatric and cognitive symptoms; neuromodulation, including deep brain stimulation; rehabilitation including physical therapy, occupational therapy and speech and language pathology and, as necessary, involving urology, psychiatry, and pain medicine. We discuss the role of palliative care in late-stage disease. The management of adults with ataxia is complex and a team-based approach is essential.

Immune-mediated Cerebellar Ataxias: Practical Guidelines and Therapeutic Challenges

Immune-mediated cerebellar ataxias (IMCAs), a clinical entity reported for the first time in the 1980s, include gluten ataxia (GA), paraneoplastic cerebellar degenerations (PCDs), antiglutamate decarboxylase 65 (GAD) antibody-associated cerebellar ataxia, post-infectious cerebellitis, and opsoclonus myoclonus syndrome (OMS). These IMCAs share common features with regard to therapeutic approaches. When certain factors trigger immune processes, elimination of the antigen( s) becomes a priority: e.g., gluten-free diet in GA and surgical excision of the primary tumor in PCDs. Furthermore, various immunotherapeutic modalities (e.g., steroids, immunoglobulins, plasmapheresis, immunosuppressants, rituximab) should be considered alone or in combination to prevent the progression of the IMCAs. There is no evidence of significant differences in terms of response and prognosis among the various types of immunotherapies. Treatment introduced at an early stage, when CAs or cerebellar atrophy is mild, is associated with better prognosis. Preservation of the "cerebellar reserve" is necessary for the improvement of CAs and resilience of the cerebellar networks. In this regard, we emphasize the therapeutic principle of "Time is Cerebellum" in IMCAs.

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.

Immune-mediated ataxias

Immune-mediated cerebellar ataxia (CA) comprises a group of rare diseases that are still incompletely described, and are probably underdiagnosed. Both acute and progressive progressions are possible. Different syndromes have been identified, including CA associated with anti-GAD antibodies, the cerebellar type of Hashimoto encephalopathy, primary autoimmune CA, gluten ataxia, opsoclonus-myoclonus syndrome, and paraneoplastic cerebellar degenerations. Most of these syndromes are associated with autoantibodies targeting neuronal antigens. Additionally, autoimmune CA can be triggered by infections, especially in children, and in rare cases occur in the context of an autoimmune multisystem disease, such as systemic lupus erythematosus, sarcoidosis, or Behçet disease. A careful workup is needed to distinguish autoimmune CA from other causes. In adults, a paraneoplastic origin must be ruled out, especially in cases with subacute onset. Neurologic outcome in adults is frequently poor, and optimal therapeutic strategies remain ill defined. The outcome in children is in general good, but children with a poor recovery are on record. The precise pathophysiologic mechanisms even in the presence of detectable autoantibodies are still largely unknown. Further research is needed on both the clinical and mechanistic aspects of immune-mediated CA, and to determine optimal therapeutic strategies.

Treatment of Cerebellar Ataxia in the Context of Systemic Diseases

Purpose of review The purpose of this review is to assess the evidence behind treatment regimens for cerebellar ataxias occurring in the context of systemic disease. We will address systemic conditions which are associated with specific involvement of the cerebellum (rather than widespread nervous system involvement) and those conditions for which some degree of evidence of treatment response exists.

Recent findings We have divided systemic disorders affecting the cerebellum into systemic immunological disorders, endocrine and metabolic disorders and paraneoplastic. Recent studies have increased understanding of the range of cerebellar disorders associated with a systemic immunological condition. The identification of newer pathogenic antibodies has improved diagnosis in conditions which would have previously been labelled as idiopathic. However, their rarity and phenotypic variability makes defining optimal immunomodulatory treatment regimens challenging. There is some evidence for beneficial effects of immunomodulation, particularly in anti-GAD ataxia and Hashimoto’s encephalopathy, although, at this time, specific treatment regimens cannot be defined. Immune-mediated paraneoplastic cerebellar disorders show response to therapy dependent, to some extent, on the underlying pathogenic antibody. Much is still to be understood concerning treatment regimens for the ataxic manifestations of metabolic disorders, notably alcohol-induced cerebellar injury, which are common and which are associated with significant disability.

Summary Despite their rarity, cerebellar ataxias occurring in the context of systemic disease cause significant morbidity and better therapies are required to improve outcomes associated with these conditions.

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.

Autoimmune epilepsy

Seizures are a common manifestation of autoimmune limbic encephalitis and multifocal paraneoplastic disorders. Accumulating evidence supports an autoimmune basis for seizures in the absence of syndromic manifestations of encephalitis. The autoimmune epilepsies are immunologically mediated disorders in which recurrent seizures are a primary and persistent clinical feature. When other etiologies have been excluded, an autoimmune etiology is suggested in a patient with epilepsy upon detection of neural autoantibodies and/or the presence of inflammatory changes on cerebrospinal fluid (CSF) or magnetic resonance imaging. In such patients, immunotherapy may be highly effective, depending on the particular autoimmune epilepsy syndrome present. In this chapter, several autoimmune epilepsy syndromes are discussed. First, epilepsies secondary to other primary autoimmune disorders will be discussed, and then those associated with antibodies that are likely to be pathogenic, such as voltage-gated potassium channel-complex and N-methyl-d-aspartate receptor, gamma-aminobutyric acid A and B receptor antibodies. For each syndrome, the typical clinical, imaging, electroencephaloram, CSF, and serologic features, and pathophysiology and treatment are described. Finally, suggested guidelines for the recognition, evaluation, and treatment of autoimmune epilepsy syndromes are provided.

Acute Cerebellar Ataxia Induced by Nivolumab

A 54-year-old woman with adenocarcinoma of the lung and lymph node metastasis experienced nystagmus and cerebellar ataxia 2 weeks after initiating nivolumab therapy. An evaluation for several autoimmune-related antibodies and paraneoplastic syndrome yielded negative results. We eventually diagnosed the patient with nivolumab-induced acute cerebellar ataxia, after excluding other potential conditions. Her ataxic gait and nystagmus resolved shortly after intravenous steroid pulse therapy followed by the administration of decreasing doses of oral steroids. Nivolumab, an immune checkpoint inhibitor, is known to induce various neurological adverse events. However, this is the first report of acute cerebellar ataxia associated with nivolumab treatment.

Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias

In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto's encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.

A case of human immunodeficiency virus infection with cerebellar ataxia that suggested by an association with autoimmunity

We report a case of human immunodeficiency virus (HIV) infection that showed subacute progressive cerebellar ataxia without HIV encephalopathy or other encephalopathies, including progressive multifocal leukoencephalopathy or encephalitis of other human herpes virus (HHV) infections. A 43-year-old man exhibited unsteady gait. Neurological examination disclosed ataxia of the trunk and lower extremities. Personality change and dementia were absent. Magnetic resonance imaging did not reveal any abnormal finding, including of the cerebellum. The serum HIV-1-RNA was 1.2 × 10(5) copies/ml, and the absolute CD4 lymphocyte count was 141 cells/ml. Remarkably, the serum anti-Yo antibody, as an anti-cerebellar antibody of paraneoplastic syndrome, and anti-gliadin antibody, associated with celiac disease or gluten ataxia, were positive. The cerebrospinal fluid (CSF) immunoglobulin G index was 1.2 (< 0.8), and oligoclonal bands were present. PCR of the CSF was negative for HIV, JC virus, other HHVs, and mycosis. Previous reports presented HIV-infected patients with concurrent autoimmune diseases such as systemic lupus erythematosus, anti-phospholipid syndrome, autoimmune thrombocytopenia, vasculitis, polymyositis and dermatomyositis, sarcoidosis, Graves' disease, and hepatic diseases. These might have been present in patients with a CD4 T lymphocyte count of more than 200 cells/ml. On the other hand, paraneoplastic syndrome, gluten ataxia, cerebellar ataxia associated with anti-glutamic acid decarboxylase antibody, and Hashimoto's encephalopathy might manifest as autoimmune cerebellar ataxia. As regards the association of HIV infection and autoimmune cerebellar ataxia, a previous report suggested that anti-gliadin antibody was detected in about 30% of HIV-infected children, though there is no reference to an association with cerebellar ataxia. Moreover, to our knowledge, detection of anti-Yo antibody in an HIV-infected patient with cerebellar ataxia has not been reported. These findings suggest that, although it is extremely rare, clinicians need to consider HIV infection in a patient exhibiting autoimmune cerebellar ataxia.

Guidelines for treatment of immune-mediated cerebellar ataxias

Immune-mediated cerebellar ataxias include gluten ataxia, paraneoplastic cerebellar degeneration, GAD antibody associated cerebellar ataxia, and Hashimoto’s encephalopathy. Despite the identification of an increasing number of immune-mediated cerebellar ataxias, there is no proposed standardized therapy. We evaluated the efficacies of immunotherapies in reported cases using a common scale of daily activity. The analysis highlighted the importance of removal of autoimmune triggering factors (e.g., gluten or cancer) and the need for immunotherapy evaluation (e.g., corticosteroids, intravenous immunoglobulin, immunosuppressants) and adaptation according to each subtype.

Treatable causes of cerebellar ataxia

The cerebellar ataxia syndromes are a heterogeneous group of disorders clinically characterized by the presence of cerebellar dysfunction. Initial assessment of patients with progressive cerebellar ataxia is complex because of an extensive list of potential diagnoses. A detailed history and comprehensive examination are required for an accurate diagnosis and hierarchical diagnostic investigations. Although no cure exists for most of these conditions, a small group of metabolic, hereditary, inflammatory, and immune-mediated etiologies of cerebellar ataxia are amenable to disease-modifying, targeted therapies. Over the past years, disease-specific treatments have emerged. Thus, clinicians must become familiar with these disorders because maximal therapeutic benefit is only possible when done early. In this article, we review disorders in which cerebellar ataxia is a prominent clinical feature requiring targeted treatments along with specific management recommendations.

Hashimoto's encephalopathy: a brief review

Hashimoto's encephalopathy (HE) is a syndrome of altered mental status, hallucinations, delusional thinking, and often, epileptic seizures. It is diagnosed by the clinical syndrome, the presence of elevated titers of antithyroid antibodies, the lack of another diagnosis based on clinical evaluation, and the response to corticosteroid and other immunosuppressant treatment. This review discusses the symptoms, pathophysiology, and treatment of HE. The disorder is important to recognize because aggressive treatment may bring about a favorable clinical outcome. The disorder has a relatively benign prognosis, compared with many of the entities for which it can be mistaken.

Multiple system atrophy of the cerebellar type: clinical state of the art

Multiple system atrophy (MSA) is a late-onset, sporadic neurodegenerative disorder clinically characterized by autonomic failure and either poorly levodopa-responsive parkinsonism or cerebellar ataxia. It is neuropathologically defined by widespread and abundant central nervous system α-synuclein-positive glial cytoplasmic inclusions and striatonigral and/or olivopontocerebellar neurodegeneration. There are two clinical subtypes of MSA distinguished by the predominant motor features: the parkinsonian variant (MSA-P) and the cerebellar variant (MSA-C). Despite recent progress in understanding the pathobiology of MSA, investigations into the symptomatology and natural history of the cerebellar variant of the disease have been limited. MSA-C presents a unique challenge to both clinicians and researchers alike. A key question is how to distinguish early in the disease course between MSA-C and other causes of adult-onset cerebellar ataxia. This is a particularly difficult question, because the clinical framework for conceptualizing and studying sporadic adult-onset ataxias continues to undergo flux. To date, several investigations have attempted to identify clinical features, imaging, and other biomarkers that may be predictive of MSA-C. This review presents a clinically oriented overview of our current understanding of MSA-C with a focus on evidence for distinguishing MSA-C from other sporadic, adult-onset ataxias.

Hashimoto thyroiditis: clinical and diagnostic criteria

Hashimoto thyroiditis (HT), now considered the most common autoimmune disease, was described over a century ago as a pronounced lymphoid goiter affecting predominantly women. In addition to this classic form, several other clinico-pathologic entities are now included under the term HT: fibrous variant, IgG4-related variant, juvenile form, Hashitoxicosis, and painless thyroiditis (sporadic or post-partum). All forms are characterized pathologically by the infiltration of hematopoietic mononuclear cells, mainly lymphocytes, in the interstitium among the thyroid follicles, although specific features can be recognized in each variant. Thyroid cells undergo atrophy or transform into a bolder type of follicular cell rich in mitochondria called Hürthle cell. Most HT forms ultimately evolve into hypothyroidism, although at presentation patients can be euthyroid or even hyperthyroid. The diagnosis of HT relies on the demonstration of circulating antibodies to thyroid antigens (mainly thyroperoxidase and thyroglobulin) and reduced echogenicity on thyroid sonogram in a patient with proper clinical features. The treatment remains symptomatic and based on the administration of synthetic thyroid hormones to correct the hypothyroidism as needed. Surgery is performed when the goiter is large enough to cause significant compression of the surrounding cervical structures, or when some areas of the thyroid gland mimic the features of a nodule whose cytology cannot be ascertained as benign. HT remains a complex and ever expanding disease of unknown pathogenesis that awaits prevention or novel forms of treatment.

Diagnostic and therapeutic aspects of Hashimoto's encephalopathy

OBJECTIVE

To share our experience on clinical presentation and management of patients diagnosed with Hashimoto's Encephalopathy (HE) at Vanderbilt Medical Center between 1999 and 2012.

BACKGROUND

HE is a rare disorder characterized by encephalopathy and central nervous system (CNS) dysfunction, elevated antithyroid antibodies, the absence of infection or structural abnormalities in the CNS, and a response to treatment with steroids. The relationship between thyroid antibodies and encephalopathy has remained unresolved.

DESIGN/METHODS

Retrospective chart review.

RESULTS

We identified 13 patients who met the criteria for the diagnosis of HE. The median age was 49 years (range, 2-66) and all except one were women. Encephalopathy in the form of altered mental status, stroke-like symptoms or seizures, with prompt resolution of symptoms upon receiving steroids, was the commonest presentation, seen in 7 patients. The second commonest presentation was subacute progressive decrease in cognitive function, which reversed within days to weeks after steroid therapy, seen in 4 patients. Electroencephalogram (EEG) was available in 12 patients and was abnormal in 8, showing nonspecific cerebral dysfunction in all 8 and epileptiform activity in 3. Treatment consisted of steroids in the acute phase for 12 of 13 patients with rapid improvement in symptoms. Maintenance therapy was rituximab in 7 patients, intravenous immunoglobulin (IVIg) in 7, azathioprine in 4, mycophenolate mofetil in 3, and methotrexate in 1 (some patients received sequential therapy with different agents). There was complete or near complete resolution of symptoms in 12 of the 13 patients.

CONCLUSIONS

We present a cohort of patients in whom CNS dysfunction was associated with elevated antithyroid antibodies and reversal of disease followed immunomodulatory therapies.