Adult-onset temporal lobe epilepsy, cognitive decline, multi-antiepileptic drug hypersensitivity, and Hashimoto's encephalopathy: Two case studies

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.

A Case of Euthyroid Steroid-Responsive Encephalopathy With Subacute Dementia

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), frequently termed as Hashimoto's encephalopathy (HE), is characterized by reversible encephalopathy with the presence of elevated antithyroid antibodies. The condition was initially described due to its association with Hashimoto's thyroiditis. We report a case of euthyroid HE presenting as subacute dementia. A 50-year-old woman presented with progressive memory decline for six weeks. Thyroid function tests, thyroid ultrasound, and cerebrospinal fluid analysis were unremarkable. Electroencephalogram showed generalized slowing with triphasic waves. On magnetic resonance imaging, T1 weighted images revealed hyperintensity in bilateral basal ganglia. Antithyroglobulin and antithyroid peroxidase were markedly elevated. She improved remarkably on tablet prednisolone 60 mg once daily, confirming the suspicion of steroid-responsive encephalopathy. Thus, we conclude that patients with subacute cognitive decline could be screened for antithyroid antibodies in the dementia workup despite their euthyroid status.

Hashimoto encephalopathy: literature review

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.