Cerebellar Ataxia in the Setting of Hashimoto's Thyroiditis: A Case Report Update and Review.

Hashimoto's encephalopathy (HE) is a rare diagnosis. Establishing the diagnosis itself is quite challenging, as symptoms vary among cases and there is still no standard confirmatory test. The clinical presentation is heterogeneous; however, patients with HE most commonly experience focal neurological deficits, frequently accompanied by cognitive dysfunction, aphasia, or paresis. The most widely recommended initial treatment for cases of HE is a course of corticosteroids. Nonetheless, their response varies from patient to patient, and some may become resistant to them. There are many proposed second-line treatments; however, there is little data and no consensus on the best alternative treatment when steroid therapy fails. This article provides an update on a case of cerebellar ataxia in a 30-year-old female patient with Hashimoto's thyroiditis. She initially presented with rapid-onset progressive symptoms of cerebellar ataxia (movement incoordination, dysmetria, and balance problems) and had elevated serum anti-thyroid peroxidase antibodies. She was diagnosed with HE and was initially treated with methylprednisolone. However, her symptoms recurred after tapering steroid therapy, and eventually, they ceased to manage her symptoms, plus she developed steroid-induced osteoporosis. She began treatment with intravenous immunoglobulin (IVIG) as an alternative in April 2022. Since then, she has had four infusions of IVIG that have allowed her to remain symptom-free.