Hashimoto encephalopathy: A brainstem vasculitis?

Since the first description of a characteristic clinical neuropsychiatric picture in a patient with Hashimoto thyroiditis by Brain et al.1 in 1966, several patients with similar or identical symptoms have been reported and Hashimoto’s encephalopathy (HE) has been generally accepted as a separate type of encephalopathy.2 Major characteristics include generalized or focal seizures, stroke-like events, temporary neurologic deficits, and a variety of psychiatric disturbances from dementia to visual hallucinations and frank psychosis.2,3 Usually, this encephalopathic affection goes along with significantly elevated antithyroid antibody titers, mainly anti-thyroid peroxidase (TPO) antibodies.3 However, encephalopathy seems to be quite independent of hormonal thyroid function, setting this cerebral complication of thyroid disease apart from other, more frequent, neurologic conditions accompanying thyroid dysfunction, such as thyrotoxicosis and myxedema.

The pathogenesis of HE is still unclear, mainly because exact neuropathologic data are lacking. Because steroids usually result in improvement of consciousness and neurologic status,2,4 fatal cases of HE are rare. We report here the autopsy findings of a patient with HE who died of a nonrelated condition.