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

Hashimoto encephalopathy: literature review.

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

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

Autoimmune thyroid disease may occasionally associate with unspecific neurological symptoms, which are more commonly insidious, include cognitive or behavioural symptoms, and may associate with tremor, myoclonus, or ataxia. We report a 61-year-old female patient who presented with chronic headache, insidious mood, and cognitive disturbance which evolved in a few months to dementia associated with exuberant limb myoclonus. Diagnostic workup revealed high anti-thyroid peroxidase antibody titers and an inflammatory CSF profile, and it was negative for other possible etiologies. Treatment with steroids induced significant improvement. The diagnosis of encephalopathy associated with autoimmune thyroid disease is still controversial given the fact that the clinical presentation and diagnostic workup are unspecific, the pathophysiology is still undetermined, and the diagnosis is mostly of exclusion. No direct correlation is found between anti-thyroid antibody titers and clinical presentation, and it is currently speculated that other still unrecognized antibodies may be responsible for this clinical entity. It is extremely important to recognize this entity because it is potentially treatable with immunotherapies. It is also increasingly recognized that clinical improvement with first-line treatment with steroids may be absent or incomplete, and other immunotherapies as immunosuppressants, intravenous immunoglobulin, or plasma exchange must be attempted in the clinical suspicion of EEAT.

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Encephalopathy Associated with Autoimmune Thyroid Disease: A Potentially Reversible Condition.

Hashimoto’s encephalopathy (HE) is a rare autoimmune disorder with neurological and neuropsychiatric manifestations and elevated titres of anti-thyroid antibodies Here we are reporting a case of HE in a 19-year-old girl who presented with seizure-like episodes, confusion, and behavioural disturbances with catatonic symptoms such as posturing, echopraxia, echolalia, and ambivalence Patient did not respond to antipsychotics and anticonvulsants On further investigation, patient was found to have high serum anti-TPO antibodies of about 1261 U/mL with euthyroid status, which supported a suspicion of HE Our consultant neurologist confirmed the diagnosis and she was started on injection of methylprednisolone 750 mg OD Since patient started showing clinical improvement, her antipsychotic medications were tapered off On follow-up, patient has recovered and is functioning well Since HE is a diagnosis of exclusion, very high anti-TPO antibodies and good response to steroids supported the diagnosis of HE in this patient after excluding other etiological possibilities This case has been reported because the clinical presentation was predominantly neurobehavioural manifestations which is uncommon with HE

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Hashimoto's Encephalopathy Presenting with Unusual Behavioural Disturbances in an Adolescent Girl.

Background The present study was aimed to evaluate parameters of visual and brainstem auditory evoked potentials (VEP, BAEP) in euthyreotic Hashimoto's thyroiditis (HT) patients without central nervous system involvement. Methods 100 HT patients (92 women, 8 men), mean age 46.9 years, and 50 healthy controls. They underwent a neurological examination, thyroid hormone levels, thyroid autoantibody titers, and brain imaging. Latencies and amplitudes of the N75, P100, and N145 component of VEP and the I-V components of BAEP were analyzed. Results The neurological examination revealed in 31 patients signs of increased neurovegetative excitability. Brain resonance imaging showed no abnormalities in HT patients. The mean P100, relative P100, and N145 VEP latencies were significantly longer, and P100 amplitude significantly higher in HT patients than the controls. HT patients also had a longer mean wave BAEP V latency and mean wave III-V and I-V interpeak latencies, and significantly lower mean wave I and V amplitudes. Abnormal VEP and BAEP were recorded in 34% of the patients. There were no statistically significant correlations between the mean VEP parameters and thyroid profile and the applied dose of L-thyroxine. There was a relationship between the level of TSH and the wave BAEP III-V interpeak latency. Conclusions There were changes in the brain's bioelectrical activity in one-third of the patients with HT without nervous system involvement. The increased amplitude of the VEP may indicate increased cerebral cortex activity. Disorders of the brain's bioelectrical activity in the course of HT may be associated with an autoimmune process.

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Assessment of Visual and Brainstem Auditory Evoked Potentials in Patients with Hashimoto's Thyroiditis

Recently, several patients have been reported with various signs of encephalopathy and high thyroid antibody levels together with good responsiveness to glucocorticoid therapy. Despite the various clinical presentations, these cases have been termed "Hashimoto encephalopathy" (HE). Although all of the pathogenic components have not yet been clearly elucidated, it is believed that brain vasculitis and autoimmunity directed against common brain-thyroid antigens represent the most likely etiologic pathway. The most common clinical signs include unexplained or epilepsy-like seizures resistant to anti-convulsive treatment, confusion, headaches, hallucinations, stroke-like episodes, coma, impairment of cognitive function, behavioral and mood disturbance, focal neurological deficits, disturbance of consciousness, ataxia, and presenile dementia, together with the presence of high thyroid antibody levels, especially against thyroperoxidase (TPOab). In most cases, the thyroid function is normal or decreased; the thyroid function is rarely increased. The examination of the cerebrospinal fluid, EEG, MRI, SPECT, and neuropsychological examinations are primarily used as diagnostic tools. Most cases showed neural symptoms for months before the acute onset; in some cases, a dramatic acute onset was described. Once the diagnosis is made, corticosteroid treatment usually provides a dramatic recovery. The authors also present a short review of literary cases reported in last decade.

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Tomas Petrovic

Papers

Hashimoto Encephalopathy: A Rare Intricate Syndrome