Cerebellar Ataxia in the Setting of Hashimoto's Thyroiditis: A Case Report

Hashimoto's encephalopathy (HE) is a rare diagnosis with a heterogenous presentation. It may not be directly related to thyroid dysfunction as most patients are euthyroid when the symptoms start. There has been a lack of consensus building on the pathophysiology of HE, but most of the evidence points towards autoimmune vasculitis as the underlying process. HE can present as seizures, cognitive dysfunction, tremors, or stroke-like symptoms with focal neurological deficits. Cerebellar ataxia (motor incoordination due to dysfunction of the cerebellum) is seen in HE but is a rare occurrence. The objective of the article was to present a case of cerebellar ataxia in a patient with Hashimoto's thyroiditis. A 30-year-old previously healthy female presented with quickly progressive cerebellar ataxia, bilateral (B/L) limb weakness, and excessive tearing. She was found to have high titers of anti-TPO (anti-thyroid peroxidase) antibodies; a biopsy confirmed Hashimoto's thyroiditis and a battery of negative tests excluding other causes of encephalopathy. Hence, confirming a diagnosis of HE. The patient was given glucocorticoids which relieved her symptoms. After being symptom-free for a few months, she relapsed and was unsuccessfully treated by the steroids. Upon this, she was given IV immunoglobulins, which helped achieve complete resolution. HE can be treated with immunotherapy, and most patients have a good prognosis, but some can have persistent neurological defects if left untreated or treatment is delayed. Relapses are common and may require a more extended treatment regimen.