Hashimoto’s Encephalopathy as a Treatable Adult-Onset Cerebellar Ataxia Mimicking Spinocerebellar Degeneration

Abstract

Background: Hashimoto’s encephalopathy (HE) presents with a variety of neurologic and neuropsychiatric features. In this study, we investigated the clinical and immunological profiles of the cerebellar ataxic form of HE. Methods: The clinical features, treatments, laboratory features, brain imaging, and serum anti-NH₂-terminal of α-enolase autoantibodies (anti-NAE Abs), a useful diagnostic marker for HE, were investigated in 13 patients who presented with sporadic adult-onset cerebellar ataxia and fulfilled the HE diagnostic criteria (antithyroid Abs and responsiveness to immunotherapy). Results: All of the patients presented with truncal ataxia, but nystagmus was uncommon (17%). Eight patients had an insidious onset that mimicked spinocerebellar degeneration (SCD), but brain imaging showed little or no cerebellar atrophy in all of the patients. Those patients with serum anti-NAE Abs (n = 8) did not have nystagmus and tended to respond better to immunotherapy than the anti-NAE Ab-negative patients. Conclusion: The present study suggests that insidious adult-onset and truncal ataxia are common in the cerebellar ataxic form of HE, which mimics SCD, but that nystagmus and severe cerebellar atrophy are uncommon. Antithyroid and anti-NAE Abs may be useful for diagnosing cerebellar ataxic HE.

Pathophysiological Decrease in the Regional Cerebral Blood Flow in Hashimoto's Encephalopathy: A Multiple-Case SPECT Study

“…However, rCBF was not decreased in the left prefrontal areas or anterior cingulate in either patient. We previously reported that 50% of patients with cerebellar ataxia tended to show decreased rCBF on brain SPECT imaging [7]. Our results were consisted with this report.…”

“…All patients were treated with corticosteroid therapy following SPECT acquisition and were improved as a result of therapy. The evaluated patients included 3 of our own cases that we have previously reported (cases 2, 6 and 7) [6,7,21]. The clinical features and laboratory findings of the patients are summarized in table 1.…”

“…Many HE patients present with acute neuropsychiatric symptoms, such as consciousness disturbance, psychosis, seizure and dementia [2,3,4,5], but some patients mainly present with cerebellar ataxia without consciousness disturbance or psychosis [6,7]. HE is distinct from myxoedema encephalopathy caused by hypothyroidism and can be effectively treated, not with thyroid hormone replacement but with immunotherapy [2].…”

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

“…Patients may be misdiagnosed with degenerative ataxia, especially spinocerebellar ataxia, given an all negative extensive workup, as has occurred in some reported cases with clinical features mimicking spinocerebellar ataxia 16,17. Since this is a treatable entity, we propose the inclusion of investigations for SREAT as a first or second tier in patients presenting with subacute or even chronic progressive cerebellar ataxia, so that an opportunity for treatment and improvement is not missed.…”

Limbic encephalitis associated with anti-NH2-terminal of α-enolase antibodies

“…[12–16] Various symptoms are used to define clinical subtypes of HE, such as the Creutzfeldt–Jakob disease-like form and the cerebellar ataxic form. [22–24] However, the diversity of symptoms and the high prevalence of antithyroid antibodies in healthy populations may make the diagnosis of HE difficult. We discovered anti-NAE antibodies, autoantibodies that specifically recognize only the NH 2 -terminal of α-enolase, in the serum of patients with HE by proteomic analyses and demonstrated a high prevalence and specificity of these antibodies in patients with HE.…”