Encephalopathy associated with Hashimoto thyroiditis: Diagnosis and treatment

Abstract

Six patients with Hashimoto thyroiditis (HT) and associated encephalopathy (HE) are described and compared with 14 well-documented cases retrieved from the literature. HE typically affects patients when they are euthyroid and, in an appropriate clinical situation, antithyroid autoantibodies are the main indicators of HE. Since clinical features of HE are unspecific, other aetiologies such as infectious, metabolic, toxic, vascular, neoplastic, and paraneoplastic causes have to be excluded. Our own six cases and those from the literature show that two types of initial clinical presentation can be differentiated: a vasculitic type with stroke-like episodes and mild cognitive impairment in nine patients, and a diffuse progressive type with dementia, seizures, psychotic episodes or altered consciousness in 11 patients. These types may overlap, particularly in the long-term course without treatment. Response to steroids was usually excellent with complete remission in 80%. Eighteen of the 20 patients were women. Characteristic, though unspecific, findings were abnormal EEG (90%) and CSF (80%). Together with quantitative neuropsychological testing, these proved sensitive for monitoring the efficacy of therapy. Conversely, antithyroid autoantibody titres did not correlate with the severity or type of clinical presentation. The link between HE and HT is not clear. A pathogenetic role for antithyroid autoantibodies in the central nervous system seems unlikely.

Bismuth Toxicity: A Rare Cause of Neurologic Dysfunction

“…Our patient's lumbar puncture and EEG were inconsistent with CJD. Hashimoto's encephalopathy, like CJD and bismuth toxicity, is rare but often presents with clues such as a degree of thyroid dysfunction (although euthyroid presentation is possible) and antithyroid autoantibodies [7,8]. Progressive myoclonic ataxia, which can be caused by celiac disease, has myoclonus and ataxia as its primary features, but usually does not present with cognitive decline [9,10].…”

Hormone Responsive Hashimoto Encephalopathy: A Case of Hashimoto Encephalopathy Treated with only Oral Thyroid Medication and Symptomatic Therapy for Seizures and Psychosis, but without Steroids

“…The clinical manifestations can range from cognitive impairment, alteration of consciousness, myoclonus, seizures, chorea, myelopathy, stroke like symptoms and agitation, psychosis, hallucinations etc. Two different forms have been suggested although there is considerable overlap between the clinical features in these patient [6,7]. Autoimmune vasculitic encephalopathy characterized by recurrent, acute to subacute episodes of focal neurologic deficits with a variable degree of cognitive dysfunction and alteration of consciousness.…”

Spontaneous Resolution of Postpartum Hashimoto Encephalopathy with Levothyroxine Therapy Alone

“…HE presents with a variety of neuropsychiatric symptoms, as most common manifestations include seizures, myoclonus, hyperreflexia, and psychosis (11). Rarely, HE manifests as a cerebellopathy with or without encephalopathy (8)(9)(10).…”